Sustainable Crop Rotations for Alberta s Brown Soil Zone

Transcription

1 Otober 2003 Agdex Sustinble Crop Rottions for Albert s Brown Soil Zone C rop prodution on the Cndin Priries hs historilly foused on spring whet. In reent dedes, rops suh s brley nd nol hve inresed in res where there is suffiient preipittion. However, in the Brown soil zone of southestern Albert, summerfllow nd monoulture whet systems remin the primry ropping prtie. In the Brown soil zone: the verge nnul preipittion is pproximtely 350 mm (13.8 in) nd growing seson preipittion is bout 150 mm (6 in) pproximtely 46 per ent of the ultivble lnd is seeded into whet nd 35 per ent is summerfllow ( totl of 81 per ent together) Wht is the onern? The study In 1992, the Long-Term Drylnd Crop Rottion Study in the Brown Soil Zone study begn t the Albert Crop Diversifition Centre South s Bow Islnd substtion. This long-term study ws imed t determining the vibility of existing nd lterntive rops nd ropping systems under differing rtes of inorgni fertilizers nd mnure. The study looked t the effets of ropping prties nd the eonomis of vrious rop rottions With suh low preipittion, retining soil moisture through summerfllowing hs been n importnt griulturl prtie in the semirid regions of the Priries. However in the long term, summerfllowing n led to deline in soil qulity s result of the following ftors: orgni mtter loss sliniztion wind nd wter erosion depleting soil nitrogen nd other nutrient reserves Produers hve mintined soil produtivity by pplying hemil fertilizers nd in fllow yers, by using herbiides rther thn ultivtion to ontrol weed growth. However, the long-term environmentl sustinbility of ropping systems tht inlude summerfllow remins in question. The study ws designed to do two things: to determine the effets of different ropping prties on soil qulity in the long-term nd to determine the eonomi performne of the vrious rop rottions tht inluded: redued summerfllow use legumes in the rottion inorgni fertilizers mnure pplitions Erlier reserh pertining to soil qulity found tht: reduing the frequeny of summerfllow improved orgni rbon (mesure of soil orgni mtter) nd totl nitrogen, both of whih re potentil mesures of soil qulity dding legumes to the rottion or using mnure or ompost helped improve soil qulity The study lso hd n eonomi omponent where frmlevel eonomi risk model ws used to simulte deisions mde by non-risk-tking produers fing vrible nnul returns. The net returns nd vribility for eh tested rottion under different fertilizer tretments were lulted, inluding mnure. The nlysis inluded the effets of hnges in rop pries nd input osts.

2 Experimentl dt nd design The soil series t the study site is Chin ly lom, dominnt soil type in southestern Albert. Tretments of vrying levels of hemil fertilizers were pplied to the following rop rottions estblished in 1992: 1. fllow-whet (FW) 2. fllow-whet-whet (FWW) 3. ontinuous whet (CW) 4. nnul legume (pe)-whet (LW) 5. flx-whet-fllow ( ) 6. grss (G) Other design fetures: mnure tretment of the rop rottions fllow-whet nd ontinuous whet the nnul legume in the legume-whet rottion ws field pes; the grss rottion onsisted of pubesent whetgrss tht ws plnted in spring 1992 the whet nd flx phses of the fertilized rottions were fertilized with 0, 18 or 36 lbs nitrogen (N) per re per yer nd with 0 or 18 lb phosphte (P 2 O 5 ) per re per yer fertilized grss reeived 90 lbs P 2 O 5 per re t the time of estblishment in 1992 nd n nnul spring brodst pplition of 36 lb N per re per yer Eonomi nlysis The frm-level eonomi risk model developed for this study lulted the following: the best rottion nd fertilizer ombintions for given set of risk-tolerne levels (where risk-tolerne is mesured by tolerble vribility in nnul returns, i.e., low tolerne or high version would be hrterized by produer who nnot tolerte osionl low returns in exhnge for higher verge returns) expeted net frm inome (NFI) nd nnul vribility for eh ombintion expeted net rottionl inome (NRI) for ll rottion nd fertilizer ombintions in the study, i.e., the inome remining ($/re) fter pying ll sh osts nd depreition of mhinery nd interest on outstnding lons for eh rottion under test NRI nnul vribility A representtive frm ws set t 1,600 res. A mhine omplement typil for rop frm of this size ws speified. Mhinery requirements, sizes, pries, ges, depreition shedules, repir shedules, fuel use, nd effiieny were inluded in the estimtion. Fuel use nd other mhine osts were tbulted for eh hour of mhine use. Where required, the osts of pre-seeding tillge, seeding, erly summer weed ontrol, lte summer tillge nd hy hrvesting, fll hrvest nd post-hrvest tillge opertions were inluded for eh rottion. All-risk rop insurne (whih overs yield loss due to drought, hil, frost, nd other environmentl ftors) ws inluded in the nlysis for ll rops exept hy. Crop insurne ws set t the 70 per ent individul overge level, nd premiums were set t yer 2000 levels. Expeted osts nd returns for eh of the test fertilizer tretments nd rottions re shown in Tble 1. The verge nnul pries nd the verge nnul test plot yields for eh rop were used to lulte returns (see Tble 2 for period verges). Net rottionl returns At the onlusion of the study, the expeted nnul net rottionl inome nd stndrd devitions were determined for eh rop rottion nd fertilizer tretment. This nlysis led to the following results, rnked in the order of expeted returns, from highest to lowest (exept where indited, the results refer to the se with rop insurne). The highest expeted returns, in terms of net rottionl inome, me from the nnul legume (pe)-whet (LW) rottions. However, these rottions lso showed high vribility in returns. This vribility ws only exeeded by hy nd two ontinuous whet (CW) tretments (Tble 3). The inresed vribility is result of reltively higher input osts nd returns s ompred to the other rottions (Tble 1). Of the remining rop rottions in the series, the ontinuous whet (CW) rottion with fertilizer tretments of 36 lbs per re of N (CW(36,0)) gve the next gretest expeted net rottionl inome, followed losely by CW() nd fllow-whet-whet FWW(). The se without rop insurne obtined somewht different outome. The highest rottionl inome me from the nnul legume (pe)-whet (LW) rottions. Then in desending order of net rottionl inome me the fllow-whet-whet (FWW) rottion with fertilizer tretments of 36 lbs per re of N nd 18 lbs per res of P 2 O 5 (FWW()). This rottion ws followed by fllow-whet (FW(18,18)) nd FW() (Tble 4). 2

3 Tble 1. Averge nnul prodution osts nd returns ($ per re per yer) Continuous whet Fllowwhet Fllow-whetwhet Legumewhet Flx-whet- fllow ( CW) ( FW) ( FWW) ( LW) ( ) Seed osts Fertilizer osts (N, P , b , Herbiide osts Mhinery repirs Fuel osts Averge returns: 0, , Hy Hy b 0, , mnure Note tht herbiide nd seed osts for hy re inurred in the first yer only. Empty ells orrespond to tretments not pplied to the rottion. Tble 2. Averge yields for eh rop by rottion nd fertilizer tretment (ton per re) Tretments ((N, P ) nd mnure) 2 5 ( 0,0) ( 36,0) ( 0,18) ( ) ( 18,18) (Mnure) CW (whet) FW (whet) FWW (whet) LW (whet) LW (pes) (flx) (whet) Hy Empty ells orrespond to tretments not pplied to the rottion. 3

4 Continuous whet CW(), whih ws the most profitble CW tretment, rehed n expeted net rottionl inome tht ws $2.53 per re lower thn the best fllow-whet (FW) rottion; however, the vribility ws higher. All-risk rop insurne redued the vribility of net rottionl inome for ll rottion nd fertilizer tretment ombintions. With the insurne, the expeted net rottionl inome of the ontinuous whet (CW), legumewhet (LW), nd flx-whet-fllow ( ) rottions inresed, while it deresed for fllow-whet (FW) rottions, nd results were mixed for the fllow-whetwhet (FWW) rottions (ompre Tbles 3 nd 4). Crop insurne of this sort fvored the ontinuous ropping rottions beuse those rottions showed greter vribility from yer-to-yer. Tble 3. Expeted nnul net rottionl inome w ith rop insurne ($ per re per yer) Fertilizer pplition ((N,P) nd mnure) 0,0 36, 0 0,18 18,18 Mnure CW ( 28.15) ( 31.41) ( 39.54) ( 33.73) ( 34.82) (33.57) FW ( 20.76) ( 25.55) ( 21.61) ( 24.41) ( 24.37) (24.04) FWW b ( 24.03) (31.53) LW ( 35.19) (31.65) ( 24.43) (30.45) Hy ( 59.66) (61.44) Vlues in prenthesis re vrines. b Empty ells orrespond to tretments not pplied to the rottion. Bsed on dt from only. Tble 4. Expeted nnul net rottionl inome w ithout rop insurne ($ per re per yer) Fertilizer pplition ((N,P) nd mnure) 0,0 36, 0 0,18 18,18 Mnure CW ( 36.25) ( 46.17) ( 46.81) ( 45.97) ( 43.24) (41.07) FW ( 21.88) ( 25.54) ( 21.63) ( 24.41) ( 24.38) (24.44) FWW b ( 27.12) (35.98) LW ( 43.82) (40.87) ( 23.86) (23.78) Hy ( 59.66) (61.44) Vlues in prenthesis re vrines. b Empty ells orrespond to tretments not pplied to the rottion. Bsed on dt from only. The ontinuous whet (CW(mnure)) tretment performed poorly, but ws not money loser. Fllowwhet (FW(mnure)) only modertely underperformed FW(18,18) by $2.70 per re. The flx-whet-fllow ( ) rottions performed poorly. The hy yields of grss (G(36,0)) nd G(0,0)) were very poor in this drylnd test, nd lthough the expeted net rottionl inome ppers vrible, this result is misleding. The 1993 yields were bnormlly high s result of high preipittion while the remining yers provided little yield. If the nlysis hd inluded only the yers , hy would be the lest vrible rop. Even so, the returns were very low or negtive. 4

5 Combintions The nlysis lso evluted how produers might ombine the rottions under test to mximize their verge nnul returns nd redue their exposure to risk (or vribility in returns from yer-to-yer). Without the introdution of the legume-whet (LW) rottions, the results from the eonomi risk nlysis suggested tht only ombintions of the ontinuous whet (CW(36,0)) nd fllow-whetwhet (FWW()) would be plnted s risk version is vried. With inresing risk version (i.e., the se where produer nnot tolerte osionl low returns in exhnge for higher verge returns), the FWW() rottion begn to supplnt CW(36,0), but even t very high risk version, only 30 per ent of the lnd ws plnted in FWW() with the reminder in CW(36,0). Without rop insurne, the results from the eonomi risk nlysis suggested tht only ombintions of the fllowwhet (FW) nd fllow-whet-whet (FWW) rottions would be plnted s risk version is vried (Tble 5). The only exeptions were t very high risk-version levels (i.e., the se where produer nnot tolerte osionl low returns in exhnge for higher verge returns). These results re onsistent with the ropping prties of produers in this re nd my indite why produers hve so predominntly used the FWW nd FW rottions. When legume-whet (LW) rottions were inluded, rop insurne redued the vribility in the net rottionl inome for these rottions. Vribility ws redued to the point tht only under very high risk-version ws ny other rottion inluded in the optiml mix (fllow-whet (FW(18,18)) t only 150 res or bout 9 per ent of the ropped lnd). Similrly, without rop insurne, the LW rottion ws mjor omponent of the optiml rottionl mix, even t very high risk-version levels (see Tble 6). Sensitivity of the results ws tested by: 1. vrying whet, pe, flx, nd hy pries 2. vrying fertilizer pries 3. lowering interest rtes As long s pe pries remin t lest 70 per ent of their verge prie for the period, the legume-whet (LW(0,0)) net rottionl inome remined bove the next best rottion in the study. However even t this level, the results indited tht risk-verse produers would still mix the LW rottion with fllow-whet (FW(18,18)) to obtin their optiml prodution hoie. They would not just reple it with the FW rottion. Tble 5. Frm-level optiml rottions nd eonomi performne under risk version (without legume rop, ) Optiml rottions Mesured s perentge of totl ultivted lnd * St. dev. = stndrd devition Low Levels of risk version Medium High Very high Continuous whet () Whet-fllow (18,18) Whet-whet-fllow () Expeted net returns ($ per re) St. dev.* of returns ($ per re) Tble 6. Frm-level optiml rottions nd eonomi performne under risk version (with legume rop, ) Optiml rottions Mesured s perentge of totl ultivted lnd * St. dev. = stndrd devition Low Levels of risk version Medium 5 High Very high Whet-fllow () Legume-whet (18,18) Expeted net returns ($ per re) St. dev.* of returns ($ per re)

6 Alterntively, whet pries would need to inrese by 35 per ent before the expeted net rottionl inome for nother rottion would exeed tht of legume-whet (LW(0,0)). Beuse of the low net rottionl inome with flx-whet-fllow ( ), even resonble inreses in flx pries would not be enough to get risk-verse produers to dd the rottion to their optiml mix. Fertilizers The study suggested tht s hemil fertilizer osts rise, produers would be more likely to shift towrd rottions with redued hemil fertilizer tretments. The whetfllow ((0,18)) rottion, for exmple, provides some solutions, but only fter 50 per ent inreses in hemil fertilizer pries. For fllow-whet (FW) or ontinuous whet (CW) mnure tretments to beome ttrtive to produers, the pries on hemil fertilizers would need to inrese by 80 per ent over the period verge in the study. This is the point t whih fllow-whet (mnure) finlly entered the solution. Although there re good resons to pply mnure s n orgni fertilizer, it is ostly to do so. In ddition, the yield response, t lest in this short-term study, does not ompre to tht obtined from hemil fertilizers. Applying mnure t hevier rtes lso introdues set of environmentl problems ssoited with phosphorous loding. Additionl reserh is required to determine if some ombintion of mnure nd hemil fertilizers ould be profitble. The study results lso suggest tht orgni soil mendments, in the form of mnure, re profitble. However, the dt implies tht mnure use on wide sle is not likely beuse it is more profitble in the short-term to use hemil fertilizers. Summerfllow nd monoulture whet systems hve been the most widely epted ropping systems in the semirid regions of southern Albert. These systems retin soil moisture nd therefore experiene less vribility from yer-to-yer. However the long-term environmentl sustinbility nd impt on soil qulity of ontinued summerfllow in the rottion is onern. Informtion prepred by: Alln M. Wlburger, Ph.D., P.Ag Deprtment of Eonomis University of Lethbridge Lethbridge, Albert T1K 3M4 Phone: (403) Ross H. MKenzie, Ph.D., P.Ag Crop Diversifition Division Albert Agriulture, Food nd Rurl Development Lethbridge, Albert T1J 4V6 Phone: (403) This ftsheet is bsed on pper by: Wlburger, A.M., MKenzie, R.H., Sewrd, K. nd Ulrih, K The Eonomis of Sustinble Agriulture Alterntives on the Semirid Cndin Priries. Journl of Sustinble Agriulture (Aepted). Conlusions The results of the Long-Term Drylnd Crop Rottion Study in the Brown Soil Zone indite tht introduing legumes into drylnd rottions in southern Albert would inrese produer profits. Legumes would lower prodution osts s their bility to fix nitrogen in the soil would redue or eliminte the need for hemil fertilizers. Risk-verse produers would be expeted to plnt ombintion of pe/whet (LW(0,0)) nd fllow whet (FW()) or FW(18,18). The reltive rtes would depend on eh produer s degree of risk-version nd level of rop insurne. With this ombintion of rottions, produer expeted net frm inome ould be expeted to inrese from $5 to $8 per re. 10/03/500 6