IR j- Human Sciences at Auburn homi li contt mi c a t t Xiiliii iiiI t'ti xlixit. an1iii academi iti tt keepiiug pace't \v it! t e 1 li ',i tI ill Ic tit uix it a ngt~tingit xxii . Ai, X it iteitt l Kar tIt Itd ill i i ( hI "iil l 'tiixti t int io l f r l intent S iltai. Iiattin s i u l c it,tt t ho FIil itt I ,txi iiiiiI ltitl.ll' w it-it atC it ix ,t at an wetii ~ll-bin oftt Iti li DR.t t U N HEN~ii T ONtliiIx Ill it it tit ~ ~~ itt'Etil ilobl e m s Itn .i't l ttt it reIn p u l c t ' liz t h tit ) .''Ii t i Iit i t xxro icl e piaii t it x t ii liti g t t ti-l lstxiitttt itijtt'atix tof xxt'unnce t',tt iul guidlti& s nrx xitil li'xt thu l thou nttitt 111xii r-ittc r litc Itti cox of l ai sn i11 t*tilt cild 11i1 it.k tiu -us minti ng nt ii i ti t rh c kI111S' ttl ttt iIich tur ba ~ t ith de in xs tti l lt s storg t it 't it i ti- tlts n c~tlt o lithing i texuit tilt resciiic l i ch xti t abttIl(ishe stiing~ttl t itii ix fot lit tlt 'icia1) it tdaly ll w ii lite iltit tintt fix l i t isst s Till i ttix I ',() ix g ptt 1 ii ttbt- pcu iptfiiamilisI.dcnuesi eoigmr n tr ope.Tw(c nu~graphic, technological, ,otitit'aIdItt tii ch ne tha w)t-,ttl cn front recltti ~ ~ ~ ~ ~ i'lii ihe ex ets oI hut igtl trie s 'tist ding l e g MAY WE INTRODUCE Ixi'i'\ ii a li1 xi of . iii icn t itc kce1c1 iiiitit liti t ot f I.S t'iai i n or-xan C liim iot t I i ii tl i ,itv . t l tilii'' ( t i A i. ii!lil i t I' D 'g e it fo icuitu and I llII tt- \it' att lii ru li iii sc ,creeit l it iiii,,i iit ii atu- ai'x te rc littii ait nt .i'4i i i ii~ ti x' ON THE COVER. A small electric aerator in operation in an Alabama catfish pond, see re- lated story on page 5. I :I.I. 19717 Y)L. 3-4. 1'O. 3 IOX 11I, 1' FBI itSI I l)iic' hil I )i t titi Ed itria lii I't iti e xxiii l i T \ .i i t/ 111/ o11mtit : E.L keith 'xi xsxii ic 1' xi- f I/itto lit ili t' I nd Poodst A. 1.ii atha'mi ftioi /t il Pa ttl ssuro / Pl'tix I I it I ii i1. iii and It i/i xxii/ i t/ls tqA Sic d n iiii t I)I /ultitgi/11(m ittIiI'S it xois 'it xiiil I 1) Ii S 'xOTV I \Ii'ittiii oft tiodl i,ii' lii ii ititi \' ittx t'llt'ra F S t it'l l Stlx i o ofit l liiic itteipo teitdi tit" lot xxinttit tc ii i Il- NADEQUATE soil moisture result- ing from too little rainfall is an im- portant factor limiting growth and yield of most crops in the Southeast. The absence of definitive information about the effects of drought stress on plant growth led to a 4-year Alabama Agricul- tural Experiment Station-USDA, ARS study in an underground root observa- tion laboratory (the Auburn Rhizotron) using soybeans. Responses of plants to different envi- ronmental conditions, such as drought stress or irrigation, were measured in the Rhizotron studies. Yields predictably increased 50-100% when plants were ir- rigated continuously, compared with rain-fed plants. A surprising observa- tion, however, was that the root system of drought-stressed plants was larger than that of the irrigated plants. Data from this research were then used to develop mathematical equations from which a computer model was designed to help ex- plain how plants respond to varying en- vironmental conditions. Important plant processes, such as food production through photosynthesis, shoot respiration, leaf and stem growth, and loss of water from plants via tran- spiration, were described in several sets of equations. A different set of equations summarized processes occurring in the FIG. 1 (title drawing). Soil profile. FIG. 2 (below). Shoot and root growth of irri- gated and nonirrigated plants. root system, such as water uptake, root growth, and respiration. These equa- tions were then combined into a com- puter model that simulates plant growth and development in relation to environ- mental variables. Special attention was given to the relationship between the shoot and root system, and the interac- tions that occur as a result of stress con- ditions imposed upon plants due to in- adequate soil moisture, figure 1. During the early part of the growing season, most of the root growth and water uptake occurs in the upper part of the soil profile. As the plants grow taller, however, the roots penetrate deeper into the soil and absorb soil moisture at these greater depths. Such interactions be- tween the above-ground and below- ground environment must be considered by the computer program for predicted growth to be accurate. To simulate plant growth, the environ- mental conditions under which the plant grows must be defined. Weather infor- mation, including minimum and maxi- mum daily temperatures, total radiation or light exposure, and rainfall, and soil information, such as water holding ca- pacity, drainage rate, and soil type, are required. With all the environmental inputs in place, plant growth simulation begins. The model calculates dry matter produc- tion, shoot and root growth, transpira- tion, water uptake, and soil water flow at 1-hour time intervals. De- pending on the type of computer system used, a 100-day season can be simulated in less than an hour. If model predictions prove accu- rate, the model can then be used to study such things as effect of drought stress on root-shoot parti- tioning. The model can predict at what depth most of the root growth occurs and where most of the water is extracted. The model also can predict root and shoot growth for irrigated vs. nonirrigated crops for a specific part of the growing season, figure 2. During the 3 days illustrated, shoot growth of irrigated plants exceeded that of rain-fed plants, except for a short period on July 3 when no growth was predicted. Also shown is that root growth was faster for the rain-fed plants than for the irrigated plants during this same period-a time of diminished rainfall. Computers help explain environmental effects on plant growth G. HOOGENBOOM, C.M. PETERSON, and M.G. HUCK The model demonstrates that the fast- est shoot and root growth occurs during the middle of the day when plants inter- cept most of the light and are quite ac- tive photosynthetically. On the last day of this 3-day simulation period, a severe drought began which caused a sharp re- duction in both shoot and root growth of the rain-fed plants. The irrigated plants were not affected. According to the model, rain-fed plants direct a larger portion of their car- bohydrates into the root system during drought periods than do well watered plants. As a result, the rain-fed plants have deeper roots; this allows them to absorb water from the deeper, wetter parts of the soil profile. This could be one of the plant's survival mechanisms for drought. As a consequence, however, the plant distributes more energy from photosynthesis into root dry matter pro- duction rather than into its shoot system (stems, leaves, pods), which can lead to decreased yield. Hoogenboom is former Graduate Research As- sistant of Agronomy and Soils, Peterson is Professor of Botany and Microbiology, and Huck is former Adjunct Associate Professor of Agronomy and Soils. Alabama Agricultural Experiment Station 3 DAYLENGTH is ont of the' most itmnpoirtant fact ors iniflui ent-ing tht dunration iof shoot growth andi affectinig thte otiset iif thu taric' in woo i pihIlatits. Gen'rerall'., the ratte andI duriiationi of shoiiit growXXth are inctrteasedl titnier long (lax conditions, wXlie short grow.th and hasten the iitset of, dor- iimanli.'. Do rtmancy. eat he dc' laedX btyh ex- posinig planits to supplemnttal light, but the e'ffectts ma. noit he tclear-itt due to pho1 topel(riod(1- tt'uptratm- Iinr'jt (ractiin oi 5ir tiX ity amlotig sptecit's. Daylieungth-stensitive species e'xpiosed to long Ipliiti) 1 eriods p~roduie e'ithe(r (1) cotintuioiis growth if temiperatures are faxvoralble, (2) extenidedl groXw.th with dior- tianct- evXenutuually ioctcurrinug, ior (3) an alteration of' growth flisshes Xwiti a sho~rt- tened( pleriod iof dlormratncy betxvc((i sot- cetssiXve flushes. By prov.idhing lotig day tcond~litiiins, doirmncyt- may lbt detlayed and~ thet growXXing tseason e'xtended(' ito thet fall, possibly shortening the overall p~roiducttionit' cic. Howevet, wintter itnjury mtay. he intcteased if platnts ate expose 1 to w~intter condtitionis betforte thiiy blet-otme ful (dirmlant. Based on trestearch at the Alabania Agticultur-al Expetitnt Sta- tin, if phiotop 1 eriodlic miuilationis are to be( uised( to increase' growth of phoiuto- petrioic itentisitive wioidy olrniamntal tcriops in zoitne 9a (southern Alabaima), suf- fitient Xwitter pro~ttettuion tust i)( pro- vide ito plrevetnt colt 1 ijuiry tio actively grow.ing andl nondormiant tissues.- Tiirt(etn sptecies of tt'mplerati' orna- meinttal tretes and~ slittils Xver' ev.aluiatedi for their grow'.th respotnses to ex\tended(' pe'riods ini zotne 9a. Tcst speces inc(luded-i ahclia, lboxw.ood, redbli~ud, ('uo'. tins, Japlaneis( holl'. dw.at-f, Buirfor-d holly, diwarf v aupon, trapltii'. tli, Sioiuhrn mnagnomlia, nanin~ a, Flortida azalea, a - sh- iion azal-a, ad l it'.r'a. Cointaitii- gtown' p lanits of eaech spe- citcs wXerI pliaced( o~udoors iii full still adtl min~tattied folloio''. g standard tiiis- gant. An e'xtentded'( phoitiopeiriold (EP) w.as prov~ided'l fronm 3 a.mn. utitil 2 houiris after sunrtise' and lroti 2 huiis biefoiie suntse't ittitil 9 p. Inl. iusiiig 100-watt itntantdescett hiulhs splafedh 48 in. apart antd~ 48 in.- aboviXe thu' platnt. A nuight iteuti pted phoiutoper'iiod (NI) w~as p~rhoXided hi'tx'.ceni on Juin' 21 toi 10 hou-s :37 in teis tin No- vemberi'i 1.5, at whi-h titte tnatuiiial phloto- periodils wetrieS iesume fnt al lilantts. -In the sprintg grox'.thi flush, gr-oX'tih inia- suitiii'its Xvere' taken.i (n Dt letetmber 10, al speieis, ex\cet't tnaninia, rece(iv ing FIP and NI w'.ire at- tively gr-owinig. Abel ia was flowerintg, while treci'itly emiierged leaves iif erapt' (liitg a light fi-ee iii No'.etiber. Oily groin tg iundetr the NP lify Alabama Agriculturatl Ex.perimnent S tationr Electric lightbulb arrangement used to ma- nipulate photoperiod of nursery plants. P'lait gr(owXth~ thriogh Deeear vard- ti (atnlttts. Slioot growth of F'lorida adl Faishioni aziea, (I lpeiirile, vautpon, (I I t ta lly ', Sou therni tmagnia, a.di redbudl( Xwer( gr-eate- for platnts g.rowXXn un der FTP atid N I c-ompjared to NPI. rOXw.th of other sp~ecies Xwas simtilar tin- dler the thri e photoperiodic trtmnts.t Root giroXwth of' spetcies whomst' top) gr oXwth w..as ittafleetet Ii'. plioto period dbl iia, dw~arf, Bitrford hollyi, and cit l(xra) wXas igheiir uitnder NP compiIaredl to FVP and NI. In conittrast, with species w..hose top) groth OXt as icreasedi w..ithi I'. andt NI (Japan icse hoilly i, x autponi, Flor ida an d Fa~shionit azaleas, r edbudl crapcnretli.Ite. adtl Southlertn mlagnolia), toot gr~o'.thii Xwas titaflectel lby photopleriodl. Neither shoiot nori roiot grothiX~ of b o\xwoodI, cu- Olnvntis, and( iittdita Xwas aflectel b)X pho~topieriodi manipuilatiotn. Duirinig the w..inter; sitfif e/zing tutu- perat itres wXere experietnced 2-1t times, blegitinlg D~ecetmbler 3 and eitntg M arch 22. Tlie to tal nitimIber of h(outrs 1be- low fIrezitg wvas 206 atid tile tniitiit tetmpleratutre Xwas :3?F Platnts of ahelia, Florida atd F( asio n azle(as, clevera, and redbludi exposiied to ElP and NI dutrting the previouis fall exhiblitedl extenisiv.e tXwig dijehack ini eatl Ixunie. Shoots of crape- tmy.rtle XXe(re either killed to the gtoitnd Xwith tne'.' gtroXwth etmergitng from tihe b ase or thle ettire plan t killed (57% tmo~r tal it'. tundlr F l, 29?l under N I). Fintrteen per- cent of c. era andl redbludl rieeivinig EP and 14% iii tie'.era utndet NI were al so killed. Ni) injulr iiccurredl to platits iif the retmaitintg species. Growth, as tiia- sitred itt June, wXas either greater iutdet NIP compilared tii EP arnd NI iir simiilar. Grow.thi of seX eral splecies of Xvioi)( or- tnamientals ini zone 9a was enhiated dutr- ing the fallI with EP' and NI comli paried to NPI; however, tli'he eefits of1 long (lay cind~itionls were niot prtesenit fllowi'.ing the' sp)rilng fhissh of growth, eithet 1becauise o~f greater groiXXvthi tinder NP or Xwilnter in- Jury undti~er F P atnd NI. If phoitopetrioici groiXXth of phiotopetriodtic setnsitiXe woodyi)( ortnamenttal tcriops in zonei( 9a, stiffiiet K'.vrisAsocite~ Profess,'or of' llotiulturc- o1aiietal I ortiicultuir S'ubistation. G.J. KEEVER and G.S. COBB C.E. BOYD AERATORIS have b~ecome iipor- tant tools in replacing depleted dissolved oxx gen supptlies in man- agenient of commnercial eatfish pond~s. 1Util recentl, inost fish fariners in Ala- baima relied on paddle wheel aerators pow~'ered by PTOs of tractors to prov ide cemergency aeration when dlissolved oxy- gen concentrations in p)ondIs dropped to loxx lexvels. However, it is more econoni- ical to use electrically p)oweredl paddle wheel aerators, and research on this type aerator was initiated at the Alabama Ag- ricu Iltiral Experiment Station to deter- moint' the most efficient designs. An electric p~acltle wxheel aerator eon- sists of 'a motor, a speed reduction inech- anisni, and paddle wheels mounted oin a trailer or oni a flotation dev icc'. Floating electric p~atdcle wheel arcators arce much tijrec coimmon than t railcer-mountdi onces. Thce oxygten-transfer e'fficency of a p~adle whec'l ac'rator tdependts upon die- sign andI opcerating c'haractceristics of the paddlle wheel. Thus, paddle' whcecl fb- rication spccifications are rigid, while design of the flotation sy stcem is flcexilec. In te'sts at Aubunrn, thce highcest oxygcen transfer ceffic'iencyx was achieve cw xith a patddlie xwheel :36 in. in diameter with tri- angular paddles (120 to 13,50 intcerior an- glce) spirallcet on the huh. Te most cffi- cien t of' thce electric p~addle itwxheetl at'rators testedc hadl padlecs exteintetd 3.5 to 4.0 in. into thte wvatcer antd thte padle wxhetels rotatcet at 7.5 to 80 r. p. in. Thte op- timiumi horsepox cr reqo ireinit was ab~out I hp per' lincar foot of' paddtle wvhcecl. If e'ithter paddlte submencrgec'ie or patlec whcecl spetet is inceascet, powe'r rtequii rtmint will inc'rease' antl oxygten transfcer efliciency xviil decline. Thel spi- ral arrangiemnt of patldles on thec hub, figure 1, allowcet a fairlv constant area of Paddle' siirfacec to moxe t'ontinlionsly throuigh thce wateri, rtetucinmg xvihration anti wtear. Patddlte whtetl shafts are fitted xwithi hearings anti moiunttet on a mnctal [r-amt which is floated wxithi steecl boxces, stxvro- fo~am b~loc'ks, or plastic or mectal tanks. Somc' mceans of raising anti lowecrinmg both entds of' the p~adlc xvhetel aire provxitdc't so) that minor atljustiments in tdtpth may' bet mnadec once the aerator is instalietd in a pontd. Takte-up bcearings providce ont' con- venient way of' atdjusting paddtlet xx icl elevation antd patdtle detpth. Aterators usuallx are anchorced in p~ondts byx aid of' txvo me'tal stablizer lbars at tac'hcd to e'ac'h entd of' thte floating frame and to mc'tal ibars tirixven inito thet p~ondt b~ank. A gt'ar redtucecr is the simnplt'st xwax to iretducet motor ouitpuit shaft spteed to 75 or 80 r: p.mi. A geairmotor has thte gceai it' tducetr buiilt onto the' inotor. Thei ouitpuit shaft of' a gt'armotor cai ie conn( iiiectetd to thte input shaft of' thte patdtle' xxhee(l xvith a fltexiblie coupiig. Alterniatixely, a gt'ai b)ox may het coninectedt oin one sidt' to thte output shaft of' the motor wxitih sicex cs anti cog ibelts antl coimplted oni the other sidet to thte input shaft of' thei aerato. A 10-hip teltectrical patlet xsheel ac'ra- tor is showxn ini figure' 2. Ae'rators of this typte haxvc standtairt oxygtei tm'ansfetr ti- c'icncimes of' about 4.5 lb. of' oxygtn peri horsc'poxw tr pe'r hn-i. Otht'r txvpes of sir-- f ace ac'rators usted in catfish farming ihavte oxy gcn tiransfetr e'fficiencies of 2 :3 liv. of' oxygen pter ioiscepoxxer peri loiui. A 10- hp elcctric patddle whcetl ac'iator oif this dtesign will trainsfetr abouit 80% as mulch oxygden pcer hour as a PTO) padlec wxhceel ac'rator dlrixven by a 65-hp tiracto. Af'ter the' acerator is instaltld in at pondl, thte teltctrical cuirieint usedt by the imotor call bet metasuretd wvith an ammiiete'r. Ifthe cuirrien t is hi giher than thce iratcet ciurrieint f'oi f'uii load of' thce imotoi, thte paddle xxhceel shoultd he raisedt. If' c'urrtent usis1 loxx, t he patdtle xxhleel shoultd bc' loxx t're'd. For betst serivicet l ift', thc' motor shoulti not bet loadett bey'ondt 90 to 95% of' ratec'turrcent. Te tcost of opceratinig at singi(e-phaIse teltectric patle xwheel aerator miay lbt ap- piroxiimatedt lby multiplyxing xoltagte times cumrre'nt (amnperets) to obitain xwatts. (Con- vcert xxatts to kiloxvatts lyividiting lbx 1,000 antI multiply kiloxxatts by thce cost of' lcicctricitx per kiioxxatt houi'. For cex- ample, a 5-lhp singole-phase' lcicctric um tor xxili usce abo(ut 28 ainpt'rtes of' c'urr'cnt at 2:30 xvolts; 28 amps x 230 xvolts 6,440) xxatts or 6. 44 kiloxwatts. At 7 5rt pter kilo xxatt-hourm, telec'tric'ai cost xxill be' 4 8 c' per' houir (6.44 kiloxxatts x 0. 075?/ kiioxvatt hour). In piracticec, thce opteiatiing cost xxili bec slighltlx itss, btcaus' mnotoirs xxill haxvc at power factor iless than I. t. For a tinrcec- phaste elecctrie inoto, to oibtain xvatts, imniltiply volts x amps x 1.732. BoyI is Pi of'ssor of Fisher'iesu and Alied \qia- ctures.ii FIG. 1. Spiral arrangement of paddles on the hub of an electric pond aerator. FIG. 2. A 10-horsepower electric pond aerator in operation. Alabama A-rict'nral Experimnnt Station .'-=y 1 -~- I~ - '0' -- GLUCOSE INJECTION IMPROVES POULT STATUS FOR SHIPMENT E.T. MORAN ADMINISTERING glucose to tur- key poults prior to farm shipment improves the likelihood of sur- vival by allowing young birds to better utilize yolk sac nutrients. Research at the Alabama Agricultural Experiment Station also indicates subcutaneous (SC) injection is more effective than oral dos- ing in providing the glucose. Poults, like chicks, have yolk sac nu- trients to provide for continued growth during their perinatal transition to feed. Although reserves are capable of sus- taining poults for 5 days prior to feeding, fat is the primary energy form and ad- verse changes in metabolism occur with- out early access to small amounts of die- tary carbohydrate. Carbohydrate reserve at hatch is low because muscles used in emergence re- quire and expend large amounts of glu- cose. In nature, immediate access to seed starch would satisfy the small needs to optimize yolk sac assimilation. This access is denied commercially, and the low remaining carbohydrate reserve is progressively depleted to create a ketotic condition. Ketosis itself is not lethal, however, the ensuing listlessness reduces the ini- tiation of feed intake after placement. "Starveouts" typically appear during the first week. Poults most likely to suffer from this condition come from small eggs in which the dynamics of heating and cooling during incubation encourages early emergence from the shell. Sugar solutions given orally at hatch have been shown to improve overall early performance; however, this method of administration is not commer- cially feasible. Subcutaneous injection (SC) of antibiotic-vitamin preparations in the nape of the neck is routine be- cause machinery exists for the rapid treatment of large numbers of birds. Having glucose dissolved in the aqueous carrier seemed to be a reasonable alter- native in supplying glucose to the poult; thus, its efficacy was examined in com- mercially simulated conditions. A 0.5-ml dose of 50% glucose in saline was used, and the SC method was com- pared to oral dosing. Based on the over- all status of poults 2 hours after treat- ment, SC glucose was far more effective than oral dosing. Body carbohydrates, as judged by liver glycogen and plasma glu- cose, were improved at a time when the stresses of transportation would have been imposed. Live weight at the time of slaughter was heavier after poults had been given SC glucose than when left untreated; however, oral glucose unexpectedly led to a weight loss, table 1. An examination of body composition indicated that both methods of glucose administration had improved the assimilation of protein and fat coming from the yolk sac, but oral dosing led to a decrease in moisture, ta- ble 2. At this stage of development, the poult's intestinal tract is in the midst of maturing, and its condition at this time could explain the loss of body water and reduced efficacy when glucose was orally administered. Microbes which could use a portion of the glucose for them- selves are just establishing a substantial population. While overall digestion- absorption of nutrients is functional at this time, full capacity in this respect is lacking because the gut wall still has a high proportion of cells retained from embryonic development. Strong glucose solutions have been shown to "pull" water through this comparatively weak wall to cause a transient diarrhea. In summary, administering glucose to poults prior to shipment improves their utilization of yolk sac nutrients. The SC method is preferred to oral dosing be- cause it is more effective, avoids prob- lems in water balance, and can be read- ily implemented. SC glucose is expected to be particularly advantageous to poults derived from young breeder flocks where small eggs dominate and whenever long distance shipping would further delay access to feed. Moran is Professor of Poultry Science. Alabama Agricultural Experiment Station6 BLACK BELT AREA farmers are leading Alabama in rate of sign-up for the Conser- vation Reserve Program (CRP) of the 1985 Food Security Act. Four counties-Greene, Marengo, Perry, and Wilcox-have already reached the 25% sign-up ceiling for cropland in any one county. The sign-up rate is much lower outside the Black Belt, as indicated by the map. Indications are that a 40% sign- up rate would be advantageous for the Black Belt, should the Secre- 3 tary of Agriculture waive the sign- up ceiling. The ceiling can be raised in counties where exceeding the 25% ceiling will not adversely affect the local economy. CRP pay- ments to participating land own- ers, expenditures to establish tree and grass cover on CRP land, pe- riodic expenditures for mainte- nance of grass cover, and value of tree growth would be expected to provide more net economic benefit than currently low crop production levels on the affected acres. Heavy CRP sign-up in the Black Belt reflects drastic changes in the agricultural economy. The decade of the 1970's saw dramatic growth in soybean acreage, with 10 Black Belt counties reaching a total of 470,000 acres (2.2 million acres statewide). Because of op- portunities for double-cropping, wheat production followed a similar pattern. Favorable soybean prices ($6-$8 per bushel) during the production build-up time had a lot to do with increasing acreages. By the end of 1986, however, prices had dropped to less than $5 per bushel. Other crop prices also were well below those 3 to 5 years earlier. With limited crop alternatives for large acreages of land, soybeans in the Black Belt led a trend towards drastically de- clining crop acreage. In fact, soybean production in the Black Belt dropped by 66% from the 1980 peak. This drop in crop acreage not only cre- ated idle land, but also resulted in fewer agricultural input purchases and re- duced crop sales-an overall drop in the Black Belt economy. Thus, CRP partici- pation can make a viable economic con- tribution to agricultural-based local economies from land that otherwise would probably remain idle. An Alabama Agricultural Experiment High Sign-up Rate in CRP is Desirable for Alabama's Black Belt N.R. MARTIN, JR., W.B. HUGHES, J.H. YEAC and G.C. JO Station study evaluated potential eco- nomic impacts of CRP participation at levels above the 25% ceiling for the Black Belt. This evaluation accounted for the enrollment of both idle and productive acreages. Benefits from CRP participation con- sidered in the anlaysis included annual payments to land owners, expenditures to establish tree and grass cover on CRP land, periodic expenditures for mainte- nance of grass cover, and value of tree growth. Conversely, economic costs to an area resulting from CRP participation consist of lost crop production expendi- tures because of reduced plantings. The economic analysis for the 10 Ala- bama Black Belt counties strongly sup- ports a level of CRP participation up to 40% of the cropland area, instead of the present ceiling of 25%. Beyond 40%, costs increased substantially and the ra- tio of benefits to costs declined. Net eco- nomic benefits would accrue not only to farmers, but to agribusiness and related firms from up to 40% participation. The increased business activity from CRP payments and expenditures would mostly benefit the 10-county area, but there would be some spill-over into other Numbers represent percent CRP par- ticipation in each county of Alabama ( = less than 5%). Shaded area is Black Belt. areas. A multiplier effect would generate additional income and employment. With 40% participa- tion, for example, an estimated $300 million of economic activity would be generated and about 6,600 additional jobs would be cre- ated from the expenditures be- tween 1985 and 1997. These esti- mates are based on multipliers reported in a previous study of the agricultural economy of Alabama. Certain long-term resource ben- efits not evaluated in the economic analysis would result from a higher than 25% level of CRP participa- tion. Soil erosion would be re- duced substantially on land placed in the CRP, thereby reducing sed- iment and agricultural chemicals entering the area's streams and im- proving water quality. The carry- ing capacity of the water and land for fish and wildlife would be in- creased. With a substantial por- tion of the CRP program land going into grass, soil organic mat- would be enhanced, producing a re- ve fertility potential for the future. is, benefits would accrue not only to ividual land owners but also to soci- in general. Vhile the study was specific for the ck Belt, similar results could be ex- ted for other areas with similar land- patterns that are experiencing signif- It crop acreage reductions. [artin is Professor of Agricultural Economics Rural Sociology; Hughes is Agricultural Econ- st, Soil Conservation Service; Yeager is Head of cultural Economics and Rural Sociology; and s is Agricultural Economist, Soil Conservation vice. MULTIPLIED INCOME AND EMPLOYMENT EFFECTS OF ALTERNATIVE CRP PARTICIPATION RATES IN THE BLACK BELT, ALABAMA, 1985 TO 1997 CRP Gross income Employment, participation Direct Total add. jobs rate benefits generated created' in region' Mil. Mil. No. 25% ....... $ 82 $199 4,400 33% ....... 105 255 5,600 40% ....... .124 301 6,600 50% ....... .148 360 7,900 'Based on multipliers from: The Structure of the Alabama Economy, Curtis, et al., 1972; An Input- Output Model of Alabama's Economy, Flick, et al., 1982; and USDA-SCS analyses. Alabama Agricultural Experiment Station 7 4 '4 '-, ~- t~ 'A d " .- A LABAMA IS BLESSEID with nu- mterous rivers, streams, and other waterways. There are approxi- miately 3,2(0) miles of rivers, plus alhott 11,000 miles of other major streams. Miost of the State's large-flow water- ways have heen impounded for naviga- tion, electric power generation, or 1both. This impouiidment resulted in a loss of natural river flows in those areas, hut createdl lakes that have blecome popular recreational resources. However, the re- maining segments of free-flowing rivers ad~ streams scatteredl throughout the State are popular for alternativ e forms of river recreation, such as hoating, white- water canoeing, and recreational floating or fishing. Strong appreciation for the State's rce- maining free-flowing streams showed up in an Alahama Agricultural Experiment Station survey that was done in the fall of 1986 to determine the extent and type of recreational use of such rivers. Results of the survey indicated that over half 'a mil- As iii 5(1 PRi 51 (5 5iON VIe IFS FORl SF.LF I IFl I' R1I?- F 11055 NI. Ils F i ioRioD ii I lot 51 1101 0 Al ilssAMA 1986-87 As erage rivetr prteservationi Tvpt' of va.lue. River Non- .All recn' recce-. respond- .ition ist' ation ist' cts' value'..........$ 7.51 $ 8.45 $ 7.98 Option valuei... 11.86 7.36 9.61 Existerict value 28.64 15.90 22.27 Bcqucslt't valuet' 22.75 11.65 17.20 ITotal oif all valuets .......... 70.17 4:3.12 56.64 Riv er recreation ists art' thost' who hd visitedl a free-flow ing river since 198.3. Non recreation 1sts we (re re'sp~ondIents wsho had not v isited a free-flow- ing river tduring the sami me'. labamians F Preservng State Free-Flowsn. J. MALONE and H.A. CLONTS lion Alabamians utilize free-flossiing riv- ers as a resolurce hase for recem .ation. Amonig river recrieationists, tlh' most popuilar rivers are Locust F'ork (of Black Warrior River, the Cahaba River, West Fork of the Sipsey River, the Little Ca- haba River, and Little Risver. Popular rec- reationual activities while svisitiiig these rivers incluide fishing, hiking, picnick- ing, photographing and/or viesving na- ture, swii mming, camping, canoeing, andI driviing fo~r plceastii'c. Attitudes towardl protection (If free- flowing rivers alsto were investigated in the telcephone survey (of 733 households throughout the State. River presers atiton valties were used as an imidicato~r (If the attitudes of Alabamians toward main- taining scelected free-flowing risers in a natural state. River p)reservationi v alties are cdef'ined as the. e'xpre'sse'd "wsilling- ness to pay" toI prevent co(nstruiction of water development p~rojects on f'ree-flow- ing rivers. P~reservation values were separated into fotir categories: (1) recreational tise value-the amount of moinesy each re- sp~ondleint would be willing to pay to visit a free-floiwing river for recreation, (2) ex- isteiice value-the willingness to pay to insure the rivers co(ntinue to exist as nat- tiral habitats for flora and fauna, (3) op- tion v alues the willingness to pay to insure possilble recreational use of the' riv ers in the future, and (4) hequiest v aloe-the willingness to pay to insure the riv ers remain free-flowing ftor future generatitons to enjoy. Thce averagce total willingness to pay to maintain the stmdv rivers in their natural cotndition was $56.64 per year per house- hold. Asstiming that all Alahamians have valtues similar to those interviewedl, the statewide aggregate preservation v alue thus amounted to ahouit $76 million iper year, excltuding any mtiltiplier effects. Existence value andl bequest value were the two highest average values among the four categories. This indicates that although some Alahamians einjtoy free-flowing river recreation, imost feel river p~reservationi is more important for p~rotec'tion o~f nattiral habitats along waterctourses and for enjoyment by fum- tuire generations. As the tahle indicates, hoth river recreationists and thtose wvho did not visit at free-flowing river ex- p~ressed a willingness to pay' f'or river preservation. Thus, there appears tto be ample supfport for maintaining these nat- tural streams. River resources in Alahama are adle- qutate to satisfy a wide variety of' river uses. Howev er, this situation can con- tiue to exist only if there are policies that will provide a b~alance between river dlevelop~ment and preservation. Alaham- ians incluided in the Experiment Station su rvey indicated suippor t for p~reserval- titon of some rivers in their natural, free- flowing state. Ma~lonie is a formeitr G raduate Research Assistant aiitlonIiits is Proifessor of Agi ico Itnrat Econioicis aind Ru rat Sociology. Alabama Agricultural Experiment S tatio~n H,: (GOPH ER TORTOISE has Tbeen a p~art of life for generations of' south Alabama farm families. Many people clalim that without the u- tritioni from meat of this gentle creature, at large part of the south Alabama rural p~opulationi might not have survived the G;reat Depression. Now ther'c is worry abiout survival of the gopher tortoise. Conservationist, hasve been conceerned for several vcar, that populations of the tortoise are de- elining. They cite loss and alteration of sand hill habitat, the most important ty pe fin the gopher tortoise, as a major factor ini this dIrop) in population. A gen- erally low reproductis e capacity of the tortoise, which is sloxw to attain sexual iuatiiritx, and the wide exploitation of the animal for humn food are cited as fae- tors involxed in declining populations. C:oncern oxver the decline of the gopher in Alabama resulted in a 1981 reguilationi by the State Department of Con ser a- tion and Natuiiral Resources that fully protects the gopher tortoise in the State. Another reason this protection is ineededl is that bulrrows dug by the gopher tor- tois(' prosvide shelter to niimieroiis inver- tebr ates and mor01e than :30 species of ver- tebrates. Some of' these are endangered or rare species. Thus, protection of the tortoise imay help) preserve someW scare sp)ecies. Sexveral states haxve documented de- cliiing gopher tor to ise populations, bu)tt Alabama had nol up-to-date data on its status and density until at recent Alabama Agricultural Experiment Station study wsas done. This prioject stud~iedl the gen- ciral dlistr ibutionm of' the gopher tortoise iin sourthern Alabama e'ast of' the Toimbigbee Hisr cin icludiing 24 c'ounities south of the fall line. (The three counjties wxest of' the Toimbigb~ee Riv er had been studied by Mlississippi researchers.) One obijective wxas to dleterin1ie the cuirrent status of' the tortoise in the 24-counts area, in- chiding an examination of habitats as thex relate to tortoise' de'nsitx. D~ata on (distrilbution were'( gatherecd( thirough q oest iriairies, peirson al in tei- xviewss, and f'ield stu'x cs. Data on status w cr(' gatherced bx de'termining tortoise d 1 ensi ty per' ac re th rough uise of' a biurross-viewsing desvice on 339 sample plots in eight habitat ty pes swi thin re'- gio ns 1haxvin g sandy 5(oil s gr'eateir than :3 ft. in depth. Thelun the ac'reage' of' each liab- itat ty pe on sands soils in the 24-comiity' airea wvas determined using Landsat sat- Alabama Agriculto ral Experiment Station ellite imnagemrx. arious xc cgc'tatioin param- eters were' measured in the sample p~lots toi c'omplare undcerstoiry, midlstory, aiid (iverstory charactristics. Ini co(unmties wvith small re'lict popula- tioins, direct cenlsusinig wvas used. Age class structure e'stimate's were oibtainedl by measu iig the width of (iccupi 1 ied bu- rowvs in the sample plots and by using a foiriula that esti mate s age from shc'll lecngt h which is als r(iel ated( to liiuirirow width. The estimated inumbiler (if toiitoises in the 24-couimnty arc'a wxas 482,848. All pop- oulatio ns sampIled( coni t ainied sexual ly ima- tuire adults and jiusen iles, the latteir ii- dic'atiiig icen'it irepioduction and hmencec a v iabile population. TIhe highest asverage densities (if tor- to ise s iccurii'ied in fi eldcs that hiad oince bieen farmed (termed "ildfield" habitat), 0.6(2 per acre. Next ini order xxere plante'd pine (0.29 pei' acre), horn-led pine scrul (iak (0.26 per~ ace), coimpos- ite' field-foirest ed(ge' (0).26 per acre), and p~asture (0.0t2 per acre) habiitat ty pes,re- spectis cl. Agricultural fields, unburned pinc'/scriub oiak, aiid inew clearcumts had tero( deinsitie's. TIhe edges of' all habitat ty pes other than oldlfields had higher densities than thc' iinteriors. Conis iderin g the two tvxege'tat ion vaia- bles that xvere sign ificantly related ti tor- tise deinsi ty (b asal airea and~ per'ceni t cam- oipy closuire) amid the'ir optimomin salnts (aproximnately 5 sq. ft. per' acre aiid 10%k), it seciis that gopher tortoises pmre- fer' haiiitat s wsi th an open( ov(5eirs toiry aind a variety (if unide~rstoiry plant species as fouind in oildfields hut no~t iin pasturmes or agr'iciultumral ficecds . IHowexver, hiumman ac- tiv ities freqjiuntly deter toirtoiises from iimaini taiin g burow i''in pastureis amnd( ag- ricultural fields. Edge habitats omr eecotonial (tnansi- D.W. SPEAKE and D.M. SPILLERS tional) areas appear i mportant to tor- toises. In each habitat type except (o1(1 fields, tortoises tended to cluster near the edges. Oldlfields in various stages (if success ion appr'oxi mate an ecotonal area. Inm genc-ral, the' more edge axvailab~le in at given habitat typce, the higher the gopher tortoise dlensit. Some tortoises were' found in the eadges of all habitat ty pes saimple'd, ev en the ones wsithi zeroi density ini the interio. Habitat that had been bulrned recentlx had much higher tortoise dlensity than iiuniuii'd habitat. Unbummrned wvoodls had a den se oxveirstory and midlstory and a ve'ry sparse' uiiderstorv. Bu rued habitat xsith a loss basal are'a and low c'anopy clo- sure' will usually hav e a lush heirbaceous growvth and still wxill iretain some (over- story cov er. Another factor that may be c'oirrelatedl with open oxverstorv and tor- toise density may he the ainount (if sun- light reaching the' ground. G~ophe'r tor- toises tend to lay their ceggs in areas that arc' e'xposed to sunlight. Ohsviouisl, the hiahitat just descibed has a high aimount oif sunlight reaching the ground. Since the gopher tortoisce is misw pro- teted in Alabama, habitat availability is the tprimnary conservation concern. 'Themre is adequate habitat axvailabile, but correct manage'ment is nee'ldd if highem tortoise' denisities are dlesiired. Ciontrollcd huirn- ing, thinning, and inc'reasing the aimiunt of' edge asvailaleh are' all beineficial mian- agement tch niq ues for tortoises as well as iny other xxildllife' species. Loss ov5erstorx den sity is pre'ferre'd, along wxith a lush and diverse uinderstor. Go- phe'r toirtoiises are adaptable, hosver i, and aire found in the edges (if pastures, agricuoltumral fields, and unburnied Voiodls. Spaeis Assoctetd Pt ofesso() of l.oologx and \5ildlifi % Scie' and Spiller is a 'lechical Asis- tant. Special Management Is Needed for Bass-Bluegill in Ponds with Gizzard Shad or Golden Shiners W.D. DAVIES GOLDEN SHINERS and gizzard shad are undesirable in ponds in which largemouth bass and blue- gill are being cultured for maximum pro- duction. The golden shiner competes di- rectly with adult bluegill for food and eats the eggs of both species. Gizzard shad compete directly with young-of- year of both species by removing many of the larger microorganisms from the water by filter-feeding. In both cases, the bluegill populations exhibit relatively slow growth, few young-of-year bass sur- vive to age 1, and ultimately fishing is poor. Experiments have been conducted since 1976 in 10 bass-bluegill stocked farm ponds in east-central Alabama where either golden shiners or gizzard shad were present. Results suggest the need for management strategies that shift the balance in favor of the principle species and improve fishing. The experimental ponds ranged in size from 0.6 to 9.7 acres. Six ponds were fer- tilized and limed at the recommended rates for high fish production, while the others had relatively soft water and little plankton production to reduce visibility. The ponds were seined during the sum- mer months with a standard 30-ft., 3/8- in.-mesh seine with a 6-ft. bag con- structed of 1/8 in. "ace"-type mesh. Seine results suggested that bass- bluegill stocked ponds with golden shin- ers receiving fertilization had more de- sirable fish populations than those not receiving fertilization. Of interest was the apparent competitive advantage ex- hibited by bluegill. On the average, bluegill reproduction throughout the summer was higher, with small bluegill available for food for young-of-year large- mouth bass. Young-of-year largemouth bass appeared to be more abundant. The situation was altered when giz- zard shad were present. Under highly fertile conditions, no reproduction of bluegill was evident throughout most of the summer, and the rela- tively few young-of-year largemouth bass were B small. Four pond fish popula- tions were recovered in Au- gust after renovating with a 2 p.p.m. concentration of a 5% rotenone formulation. Giz The contributions of each species to total standing stock are illustrated in the graph. There is some indi- cation that bluegill and bass populations are better able to compete (occupy a higher percentage of total standing stock) at higher levels of fertility when the golden shiner is the com- peting species, but not when gizzard shad are pres- ent. The reasons for this ap- pear to be a function of relative growth rates, time of spawning, and feeding strategies of the competitor as influenced by the productivity of the system. If the pond cannot be drained, or it is deemed undesirable to eliminate the fish populations and restock, two options are available to bring bass-bluegill popula- tions into better balance when one or the other competing species is present. If golden shiners are the competitor, feeding a commercially prepared feed to the pond's fish populations can be advan- tageous. Both bluegill and golden shiners will respond to feeding. Three-in, to 5- in. bluegill already in the population will reach a harvestable size of 6 in. by mid- summer if fed a total of 10 lb. per acre per day. The ideal feeding method is the use of an electronic feeder with a timer that al- lows food to be distributed three to five times each day. Feeding a floating pellet, commonly sold for feeding catfish finger- lings, during March-October has pro- duced harvestable crops of bluegills where few were present before. Most bass, especially larger individuals in ex- cellent condition (i.e., deep bodied), should not be harvested when caught, as bass production will still be less than when only bluegill and bass are present. A different approach is necessary if gizzard shad are present since its com- petition cannot be overcome by feeding a pelleted ration. In this case, a better so- lution is to remove a portion of the shad population every second or third year by applying a 0.1 p. p.m. concentration of a 5% rotenone formulation during fall or winter. Largemouth bass and bluegill are not usually affected by that concentra- tion. The following year all species will spawn abundantly, thus bringing the populations into better balance. As in ponds containing golden shiners, few, if any, of the larger bass should be har- vested if shad persist in the system. Davies is Professor of Fisheries and Allied Aqua- cultures. Alabama Agricultural Experiment Station 10 H :K'I1) S~I II I i' lit iilo iictle (apprJ ii l t (41%( 7lSx ro It RESPONSE OF DAIRY COWS TO ELEVATED ENVIRONMENTAL TEMPERATURES K.A. CUJMMINS ul til(11111ring lii t \ tat IIi to r('( c i(the li Iron nii I X(f struc tre aiiN ld ( tire'(s to pro lom ii rom11) thet N ii to pro ii fa i uLin, XX ati 'I iiit('I uN l sprI inklerX to iu\ aO 'dir in hoiititIi'iiht tilthe illce iN d il ie t f(d tii dair I \('iXX in hot XX tathlii XX ldc wi1(11(11(4 ftIier in th l it'(et. I Iii - Ii'tii i tal'.e N liii at i present it ui d X liniist a" 2o Xov m'cl rto('incI It utrent XXon-ii lied" to co N ('if t lilt t Ii Ie u e i' l tt'i it intk s i iit liii tio is iat'i'ifii N" fto hoIX uhliditk wl l A it(X(i X jt ii t 2 v u e c c It (IoiX t f ita Xon-' inci'i it t II (i bll I Il t _i l (X I II d I,:i - IX('X inl t it (iI u duriti the~ till cr lit I I hoiit witti I o'n fee (X i' takI I 'NI I t o de-i ttempeatu' at \\hi ln ic t hai n s It i n m 'ill produc('tion ;('tBillt intake o'txcitX ortd. itliil red ce i c i nlilitakii 1 t' t tilt' i n ter- XXaX hiat liii sonIin thu s matlt i to in - ftoss.l A c eall t iI I(n-I wcl abit t ht X t ilt t uppe crii tita 'inhp rtr o( i(~ f~t It ii Iiliti to I oo all nitg c thII cllt oI XhI liatI I Isi Ir''Iss.11 \111k lili -11 14(0( 11 h1111)1' II 1)) rcc 9) (1 1) 4) 1c51" I) Il Ir' Il N Itil N an I'mll I ilI'ttI tiii 1i tt1( il( kt i II I11 14111 pfIa I 1111 I li ti11 1 I II ('V )1I 11Ii ' l Ii I iii I I Il III'.- stressX occurretd, probalet(I aX a I sult oif 100t.1 T" tii th' peioitd hilt I -X-August 31. I1IX86. t~c' Nint ke fltlitill i crI(t asedtio Nfl Xi I olste'n andt22c it'. cse cw NiX till a I Inat 'ii con'it nt (X i ' t ' NiXca fitn (i il mi'nilk Hols l itein" i ap iae it o' Idt mor I mlit' ilXIiiu in it u of tiedi i n- ii til' ii lth (I I sgi('t i tti l t r theX )lir X f (,](. Act enlilt''alte lp "W, rk III F RECENT financial stress~ of' miaiiy farmers in the Unoitedl States has 1hron gh t abot thle needl fotr gr( ate u1iise of kin i girow~th mod()(els5 to ev aluate r esou ree allocat io n fri-oii a long- range perspective. Tlhe NMutiiPeriod Liiner- Programinig Iodel (NI ITP) is the iiost eoiitiioiil used,11 butt an alter- naIltiv5e app~roach to the to tl Ri eutrsiv e Strategie Linear Progr amning (RIL), xxas recently d1(5 (0oped at the Alabiamta AXgriciltutral Experiiment Station. Ott entmes hrom the two miiodiels wxere coinl pat ed ini tr acking the 8-y ear groswth of a tiorthi Alab~atma farmiiig op~eration. The MIPLP mtodel is free fron risk of baniikru tp tcy, numaageri al errors ini ju dge - iient, atnd prodiictioit shociks such as pests, xweathier, andc dliseases. Whilie tians_ adv anees hasve bleen nmade in thte MIP1P m)0odel to) allows its practical use ini farmt planintg, it still fails to take into ac-coutnit feedback resul t ing wh~en wxhat actual ly Itappetns ont the farmi dev-siates fromi whlat the model expects to htappent. Imh RSLP model incetldes Litrt pro- Net worth growth, dollars 70,000 - - --PP pro 8000 I I I I 1978 1979 1980 1981 1982 1983 1984 1985 E. F KOLAJO and N.k. MAR I IN', JR. finantcing dlecisionts ini ant anialsti-al fi-aitiessotk intvolv5intg tinte, tisk, antd utni c-ertatintx. Both thte NI 1L1 and( RS11 1 toel-s xwer-- applied (15er ani 8-s ear pe- tiodl tot a rowS c-i-p fat-tintg operitiont itt nth Alabiatia. lisitng three- d-bt-to-as- Se-t tatilos, thte grIxtht tof thte farmt xwas fol- lowed utsintg e-ac-h tmoidel. TIe to Ilject iv-e f ilnetint of 1)1 thi miodel-s wxas tol miax timize c-ittit atix - expected inet woirtht of the farmt at thte etnd of ani 8- year tplatintg peiodti subjlect tio price, y ild, andi ftimiic-iaI conistrainits. Gro~ss rt-c-rn-ts ft-out ptice-s and~ y ields iobtainied vet-e as sutme d to folo e xp ectat ion dt) - iised byx synitlu-sizing thte USDA) s inifor- mtattioni iof aggre'gat- prtoduic-tion andi lbx to cotmmtodity price foriec-asttiig. 'Ilii- thr-ee det-lto-a~ssc-t tatios exalutatcd xwere 25, 40, antd 70%, wltichl i-cptrese-it altet- natix e farmt firti responises to fintancial risk.- IThe gr-aphl illustrates samptle i-cstilts dlesciintg thte growxtht ofitet wxorth of'tl- Farm Models Aid in Decision Making \Xl ~-xi its (,ixt \xt on xiist tovi (3isnoiti Itt. D iaii/A sst:i- 4017,) 1)1 tin i (Cm Sn Fwi, 19t 78 x\ 1) 1985 Beginin of En o4978 Endt ofI 198.5 Ie1978 S1I'} PiP IS SI P1.1' RSLI' appro1 achi approalcih appIroa(hi approa)i Ih LIdii ii-., iln acu-- .. . .. . . ... 600 876 786j 968 876 Slit liiiiii asst \dIJt ini dllaiis .... 86.751 75,076 125.866 246,:356 194. 197 I otal liaol cahm in doliis ....... 316,200 161,652 .114 222 744,:392 680,565 Otstanding dlibt[ ini dllals ..... t16 180) 176,826 .374,887 289,251 lIihterst paid on det-h ill dollrs.... 15,50:3 17,561 47,277 :31,276 Nt wxotli n dloli . . . . . ... -402,951 -4:31,706 :3019,44(4 777,116 721,155 Alabamia Ag-ri-nlto ral Experimnt Stationi faiot fr-om 1978 to 1985 underl~ the as- tion, si ch as a (11]bt-to-asset i-at io of 4( 0(4n. Tlttoughoiut thce stuidy pertiod, the gi-th t r tate- desc-ribied bx the It P1LP mod~iel wxas faster thati thte RSIT mod~tel. Beginintg from ita total asset valite of' $402,9-51 itn 1978, results of. the- RSI A miodfel ini the abov~se situtationis ind~icaItedl ni e-inig niet wxortht of $721,155, whlile lic \I PIT motde-l indicated( 8777,1 16. I-.s almiat ittIg gr-owth ini tertis of' plixsical mii asuties, su1 c-i as aci-cs,- the fitrm grew-x ftrot i600 ac-r(-s in 19 78 to 8 76 ac-res itinder lie RSL P mtodel anti 968 acres itt 1955 undt(er thte NI PIlA miodlel. IThe oper ationtal routtitic of the NiP1 modl (loles nolt r- flect it its tr-stilts howx the mtain solitu-cs oIf fat tt probllemis, suc-h as oumtstantdinig (de-bts anit erttciest paymtnits, couildl hinderi giro)wth. 'I'lt( ec-onomtically realistic poss5ibility of, Litrit gi-owth wxas btiased npwSSardI li the 'nio isk, farmo pl atns (descried bs the NI P modeti ~l. Inicr-eas ing det-1tto-as set ratios tinder all sitmiationis tindicatedl a posit ivec relaitionship b etween(-i farm growssth anid niet wVorth. -HIoss ver, hight debut-to-asset sittuatins led to seriouis in- albility ti) mieet c-ash floss nieeds as they c-atei diuc-. Tius is par ticitlar Is ti-tic be- c-aus i s gireatert )1)) pr opo t of f arm as se t s is Ih-ld in the- fot-t of itllt-Iliuid assets, siuc-I as litnd atd t m tachtiner-, wh14ici ca-a itot qutickly be sld ini ot-cer- to mteet casht flosw requtiremoents. 'H ie fact th at cexpec-tedl incomte play de- xviat(- fromn r ealizedI iiicome indicatces titat a c-ost is associatced wxith an inc-orrect de- cisioti. The moel-itng appr-oach dce - opcdi itt this stutdy addlresses risk mtan- agemtu-it resea-ch whitch should prov5 ile a tisftil gideh fini- Alahama aicutlturet iti par ticitlar atnd( for Ui itedl States agiculi I- tttrt itt genteral.- Kolajo is. 14,-a-at A-ssocttiatc- and Slat i is Pro- T OI 101.1 the Southeast, doule cIroppinig ry fc or wintei grazing wsith summer annuals su ch as cotton, corni soybI eans, and graini sorglnit is a coimmon practice. Since earl\ p~lanti ng of' ry~e is critical for ade- quI ate fall and xwiniter grazing, uin g disk- in g-onl 1 land pie paraftio after h arsvest common11)1 plract ice. fit sonic( areas, wintr girazing crops are no~i-t ill planted into su n er cropj s tiibhle wxi th no- tillage girainl drills or 1)y seeinig with aircraft. During the past 6 sears, data from stuldlies coinduicted hy the Alabaina Agri- cu lttiral I'\pei ient Station at seven Io) cationiIs ini the S tate iiidicate that sonie 1ft1riii oif deep t ilIlage is necessary foi wxheat grain prod)(uictioni. In the fall oft 1986, the wxinter crop was changed fromt wxheat to ry e at the Wiregirass Suibstatioi in H eadlland and at the B~rewton and \lom oes ille Experimeint Fields to detei- mine if deep tillage also wxas needed fot is e. Soils on the expeimiiental sites were D~othaii fine sandy lo~aii at Ifeadland, Benildale colarse sandx loam at Brewton, and I aicedalc fine sandy loam at Mon- roexvillk. The tillage tireatmeits, originally es- tab~lished~ for wxheat ini the fall of 1980, counsisted of no tillage, disk o)n1l, chisel p~lows, and~ tuii p1jlows prior tol planting wxheat. FEach main plot was dhivided inmto twoi sublolts for- the summler crops. One sublpltot xxas plaiited withouit iln-ross sub- souiliing anid the other was planted with in- iowx subsoiling. In 1984, suibsoiling with shanks sp)acedl at 24 to) :36 ini. priolr to p~lantin1g wxheat was add~edl as ain addi- tioiial main plot. Ry ewxas drilled in the fall of 1986 after harsesting grain sor- ghum. Seed(ing rate was 9(011b. per acre, and~ it wxas cut for forage y ieldls ii) earls Mlarch . Osven-dry wxeighits are listed ini the table. Rve forage y ields fol lowsed thle same rends( as wxheat grain y ieldls ini that ino- tillage resulted in the lowest y ields. D~iskinig-olnly imnproved yields oiver no- tillage, hbut resulted iin lowxer yiel(ds thani dleep tillage, amid no onme form oif dleep til- lage wxas generally smiperiolr to alolther. In-ross shubsoiling prior to) plan~ting the sumim ier crop impnIrovedl yields at Brew- toni (1,320 and 940111b. per acre xwith and wsithomt ini-ro ss ~oilintg, resplectiv ely) 1buit nolt at the o~ther locations. Althoumgh in- row subSlsoliling for the summer crop imlprovxed y ields at Breswton, the itm- provselments pri~marily occurr-ed within Alabaoma Agricultural Experiment Station S."V. ' ".1 1 _i .'x ,9* -itt, -*" - 7 ;o <, r _ ~ ~~~ .. .m . . .:fSa. ' . . .1 t "i .- J.T. TOUICHTON, J.R. AKRIDGE, and H.W. IVEY the no -tillage and disk-tillage sy steins, andl it wold~ nmot substitute for dleep) til- lage prior to planting ry e. Although strict ito-tillage did not re- sult iii acceptable x ields, high y ields can he imainmtainedl swith cioniservation tillage. Oni most fields in Alabama, the chisel plow55 shoulId 1 he an adeoquate conii5(r5a- tion-mtillage priactice foi irye protdutctioni pr1ovxided a drag hat rather than multip)1e dliskinig oper ationts is used to level thme solil. Suibsoiling, (36-ini. shank spaciing) is certainly an acceptale practice and may even he a better coniservation-itillage ss- tem thtan strict no-till age. The results from the first year of this test strongly indicate that no-tillage is not an accep~tab~le production practice for rye on Sandy Coastal Plain soils, espe- cially when the cost of 'a no-till grain dhill is figuredl into produlction costs. When purchase price of (equpipmenmt and cost of til lage operations are cotisid~ered, the most economical sy stemn appears to he chisel plowing. -\k idge is Superin11tend(filt of 13I iXtoii andf Mouroe- (hil of wiicgi is Subs)tationl. Olxi.N-m 1)11 r: FURI)X(. Y'Iii 1)s Ns AXljii Ii n TILLAGEm PloI 0 PLAN IIN. R)E %N I) IN -BN% SSi.IINCa PRoo It 1S1ArN xs111: liiiFI St St. s MEH SOW;I.tm Ai (:1O)1 VI TIll :h Locmo \IN,s Ii Cms(hx, Ii.O~ 1 OI Ai.A Tillagi at S! roinig for Yicl per( afre at1 itc til ocation) Lb). Lb) 1. No-till .. . . . . .. . . . . v s :3,87ff 1,170f 1,730 Mi) -5:3ff 1,79ff D)isk ... . . . .. . . . .. S .1,96ff 1,22ff 2 52ff Inl 66ff 2,69ff Chiscli................................5,69ff I tt 2,68f nil 1,0 Iff3,1I 1f Tun................ yes 5,32ff 1,37t0 2,94ff no -860f 2,89f Subsoil..........................sts 5,32ff 1,45ff 2,7f(f Mo I 124f0 2,78ff liiie in-rowx iuisoifif anid tiousihsoifud plots5 were niot harv e sted separ ately at Hedland.~ Conservation Tillage Changes Quantity and Quality of Surface Runoff K.H. YOO, J.T. TOUCHTON, and R.H. WALKER CONSERVATION TILLAGE is the "in thing" as farmers seek farm- ing methods that control erosion while maintaining crop yield. It is esti- mated that over 90% of U. S. farmland will be under conservation tillage by the end of this century. For this to succeed, however, there is a need for information about how such non-inversion tillage sys- tems influence the quantity and quality of surface and subsurface runoffs from fields. A soil erosion study site at the Ala- bama Agricultural Experiment Station's Tennessee Valley Substation is being used to evaluate and compare three til- lage systems for cotton production. Sur- face runoff, soil erosion, and plant nu- trient and pesticide losses under natural rainfall conditions in the Tennessee Val- ley region are being determined under tillage systems described as follows: Tillage systems No-tillage without cover crop (NT) Reduced- tillage with wheat cover crop (RTC) Conven- tional tillage (CT) Fall tillage none/crop stubble disk, chisel plow/plant wheat 11-7-84 disk, chisel plow/fallow 11-7-84 Spring tillage none/ plant 4-22-85 none/ plant 4-22-85 Summer tillage none none disk/ 3 culti- plant vations 4-22-85 5-21-85, 5-31-85, 6-21-85 There were 15 rains during the 1985 growing season (April 22-November 7) which generated measurable surface runoff. The growing season was divided into two periods for data analysis, before and after the last cultivation of the CT system (June 21 or 2 months after plant- ing). As shown by data in the table, there were variations among the tillage sys- tems in surface runoff, soil erosion, and plant nutrient losses. During the early part of the growing season, total surface runoff was about equal from the NT sys- tem and the CT system; however, soil loss from the CT system was twice that of the NT system. The early growing pe- riod is often called a "critical period" in terms of soil erosion when the crop has not yet developed full canopy. After the critical period, the soil loss was low from all treatments, with the lowest from the RTC system. More than 85% of the total soil losses from all treat- ments occurred during the 2-month crit- ical period. However, there was more rainfall but less surface runoff during the later, noncritical growing period than during the critical period. Sediment con- centration during the noncritical period remained relatively low for all treat- ments even during high runoff events. Heavy crop coverage during the non- critical period plays a major role in pre- venting soil erosion by reducing the ero- sive forces of raindrop impact on the soil surface. The RTC system had the lowest level of surface runoff and soil loss throughout the growing season. This may have been the result of a combina- tion of the enhanced infiltration and the protection of the soil surface by the wheat stubble against raindrop impact. The summer cultivation in the CT sys- tem helped reduce surface runoff during the summer months without increasing soil erosion. The overall mean concentration of ni- trate nitrogen (NO 3 -N) in the runoff water from all three tillage systems was well within the 10 p.p.m. upper limit recommended for drinking water. How- ever, the concentrations of ammonium nitrogen (NH 4 -N) averaged well above the 0.5 p. p.m. standard for public water supplies. There were several runoff oc- currences where the NH 4 -N concentra- tions even exceeded the 2 p.p.m. level considered to be toxic to fish. The percentage of the applied pesti- cides-pendimethalin (Prowl?) and al- dicarb (Temik?)-that left the field was lower than 0.5% from all tillage systems. The first runoff after the application of pesticide carried the highest concentra- tion, and the concentration level rapidly decreased thereafter. The pendime- thalin was detected throughout most of the growing season. The CT system gave the highest loss of the plant nutrients and pes- ticides, whereas the RTC system gave the lowest. - An important concern about conservation tillage is its effects on crop yield. Seed cotton yields from all three tillage systems were com- parable for the 1985 season: 3,225 lb. per acre from the NT system, 2,920 lb. from the RTC system, and 2,775 lb. per acre from the CT system. Yoo is Assistant Professor of Agricultural Engineering and Touchton and Walker are Professor and Associate Professor of Agron- omy and Soils, respectively Alabama Agricultural Experiment Station RUNOFF AND POLLUTANT LOSSES IN RUNOFF-GENERATING STORM EVENTS DURING 1985 GROWING SEASON OF COTTON Tillage Runoff Runoff losses/acre systems Inches Pct. of rain Soil NH 4 - N NO-N N' p2 Lb. Lb. Lb. Lb. Lb. Critical period (8.89 in. rain) NT ..................... 1.90 21.4 842 0.31 0.92 2.00 0.25 RTC .................... .81 9.1 203 .16 .42 .56 .14 CT ..................... 2.18 24.5 1,877 .38 2.83 2.51 .47 Noncritical period (12.6 in. rain) NT ..................... 1.68 13.3 110 .22 .25 .63 .13 RTC .................... .55 4.4 28 .10 .08 .22 .04 CT ..................... 1.26 10.0 120 .58 .24 1.02 .10 Total (21.5 in. rain) NT ..................... 3.58 16.6 952 .54 1.12 2.63 .38 RTC .................... 1.36 6.3 232 .26 .50 .73 .19 CT ..................... 3.44 16.0 1,997 .96 3.07 3.53 .57 'Total Kjeldahl nitrogen. 2 Total phosphorus in water and sediment. rer 14 S it I I 'I A t N~m \ N () . ( I i s ;(Iii'T IIlt-timil1)1 weed (((I i I i NeciII h t s iiiu Ihi b'tui mti t (, at) the i cubii 1 tNtsull a( i ivepar Ii ts~th ofi uth1ill to fdiii I otlcI l '11 (\ vvt ii' (I sorrel b i nconsitent1 1( cot2 t hiitsl b LI iI(((h c~i. Bicitiil test N t (ihlN XXiiil Niill XXieII I ijiI(I eilunll Statin citt- In Iii. c tesN t (II t li i OIt I- ILNil- tiuitilii atI IBiit', (IiII N I n (1 ( (IN NX t i lilli tnd dNal in Nt1(1r((XIII it NI N liiiilt IN wereh)I appiei li(' ctobr tho 3 l-in. s( i]cI patcn rc\c nan r \I I it Evaluation of Preemergence -Applied Herbicides for Control of Southern Yellow Wood Sorrel in a Pine Bark Medium D.L. BERCHIELLI-ROBER