Economics of spring wheat production systems using conventional tillage management in the Brown soil zone – Revisited

Producers in the semiarid Brown soil zone of the Canadian Prairies have historically used fallow (F)-based cropping systems with mechanical tillage methods to produce spring wheat (Triticum aestivum L.) (W). However, in the past two decades government policies and programs have changed, as have cropping practices, market opportunities, and weather patterns. This study re-examines the economic merits of these conventional cropping systems under today’s conditions in regard to the optimal cropping frequency, value of applying N and P fertilizer at soil test rates, and the possible advantage of replacing monoculture wheat with lentil (Lens culinaris Medikus) (Lent) or flax (Linum usitatissimum L.) (Flx) grown in mixed rotations. The analysis draws on data from a long-term crop rotation experiment that was established in 1967 on an Orthic Brown Chernozem at the Semiarid Prairie Agricultural Research Centre at Swift Current, Saskatchewan. All cropping systems were managed using conventional tillage practices, which attempted to conserve as much surface crop residue as possible (i.e., stubble mulch tillage techniques were used). The findings for 1985–2002, a period characterized by above normal precipitation, were compared with those reported previously for the 1967–1984 period when growing conditions were less favorable but more typical for this area. Net returns during 1985–2002 were highest for W-Lent ($93 ha-1 yr-1) and lowest for F-Flx-W ($38 ha-1 yr-1). Net returns for well-fertilized F-W, F-W-W, F-W-W-W-W-W, and Cont W during this same period were similar, averaging about $52 ha-1 yr-1 or 44% less than for W-Lent. These results contrast with those reported for the previous 18-yr period when F-W and F- W-W generally produced higher net returns than Cont W. Within the F-W-W systems, the application of both N and P fertilizer increased the 18-yr (1985–2002) mean net returns by $18 ha-1 yr-1 compared with application of N only, and by $32 ha-1 yr-1 compared with application of P only. For Cont W the application of N and P fertilizer increased the mean net returns by $71 ha-1 yr-1 compared with application of P only. These economic benefits from N and P fertilization were much higher than those reported in 1967–1984 due to the more humid growing conditions and the increased rate of N fertilizer prescribed by the soil testing lab since 1991. Further, our findings showed that only if producers were highly risk averse, do not subscribe to all-risk crop insurance , or if the price for wheat was high or price for lentil low, would the monoculture wheat systems be preferred to W-Lent. However, producers who are highly risk averse would still opt for the cropping systems that included some summerfallow. Our findings support the recent trends in land use practices by area producers towards more diversified and intensive cropping systems which are less reliant on frequent fallowing. Key words: Crop rotations, wheat, lentil, flax, summerfallow, production costs, net returns, income variability

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