Effect of fallow frequency, flexible rotations, legume green manure, and wheat class on the economics of wheat production in the Brown soil zone

Abstract

Producers in the semiarid Brown soil zone of Saskatchewan have historically produced spring wheat (Triticum aestivum L.) in fallow-based rotations because these cropping systems are profitable and risk efficient; however, their use has also been most damaging to soil quality. New wheat types and management methods have been developed that may offer wheat producers opportunities to enhance economic returns, while improving environmental sustainability. This study compares the economic merits of reducing fallow (F) frequency, using an annual legume green manure (LGM) crop as a summer fallow replacement, adopting a flex-cropping approach based on available soil water reserves (if water) or the need to control problem weeds (if weeds), and the production of Canada Western Red Spring (CWRS) wheat (W) versus the higher yielding Canada Prairie Spring (CPS) wheat class (HY). The results are based on 15 yr of data from seven crop rotations included in an ongoing experiment being conducted on an Orthic Brown Chernozem at the Semiarid Prairie Agricultural Research Centre at Swift Current, Saskatchewan. The crop rotations included F-W-W, LGM-W-W, F-HY-HY, F-W-W-W, continuous W (Cont W), Cont W (if water), and Cont W (if weeds). Cropping systems were managed using conservation tillage practices. They were fertilized with recommended rates of N and P based on soil tests, and crop residue was maintained as tall as possible (usually > 30 cm) to enhance snow trapping. The 1988–2002 study period was characterized by above normal growing season precipitation; thus, grain yields were also above average for this region. Results showed that producers will earn the highest net return with Cont W ($41 ha-1), despite this rotation having the highest production costs. Net returns ranked second highest for F-W-W-W, F-HYHY, and the flex-crop rotations (about $15 ha-1 less than Cont W), and ranked lowest for F-W-W and LGM-W-W (about $25 ha-1 less). However, since 1993, when the LGM was managed more effectively than in the first 6 yr, LGM-W-W was more profitable than F-W-W. On average, it was more profitable to produce CPS compared with CWRS wheat when the CPS/CWRS price ratio was greater than 0.8. Producers who are highly averse to risk would still choose cropping systems that included some summer fallow, while those with lower risk aversion would choose Cont W, but with all-risk crop insurance. In the absence of an all-risk crop insurance program, producers would typically choose Cont W (if water), F-W-W-W, or F-W-W. We concluded that area producers, who practice conservation tillage management and use tall stubble for snowtrapping, can enhance farm income by moving to more intensive cropping systems, and while doing so, they will foster improved environmental sustainability. Key words: Crop rotations, wheat, summer fallow, legume green manure, flex-cropping, production costs, net returns, income variability