Wheat and Maize Yields in Response to Straw Management and Nitrogen under a Bed Planting System

Abstract

In the Yaqui Valley, northwest Mexico, the crop sequence that is becoming more common consists of planting wheat (Triticum aestivum L.) as a winter crop on a raised bed followed by maize (Zea mays L.) as a summer crop. In this area, straw of both winter and summer crops is commonly burned. The consequences of burning crop residues on crop yields in the Yaqui Valley have not previously been documented, and alternative practices have not been proposed. A 5‐yr study was conducted at the CIANO (Centro de Investigaciones Agrı́colas del Noroeste) experiment station in Sonora, Mexico, to compare the effects of burning with other straw management strategies on wheat and maize yields. We tested two tillage systems (conventional‐tilled bed, CTB, and permanent bed, PB), five straw management treatments (incorporated with CTB and straw as stubble, partly removed, removed, or burned with PB), and seven N treatments, five applied preplant (0, 75, 150, 225, and 300 kg N ha−1) and two at the 1st node stage (150 and 300 kg N ha−1) of wheat. Maize following wheat received a uniform application of 150 kg N ha−1. The combination of PB and straw as stubble produced superior maize and wheat grain yields in high‐yielding environments; in low‐yielding environments, PB–straw burned produced greater wheat grain yields. Nitrogen fertilizer application of 150 and 300 kg N ha−1 at the 1st node stage of wheat increased grain yields compared with preplant N fertilizer applications. Permanent beds combined with retaining all crop residues in the soil as stubble have the potential to increase both wheat and maize yields in the Yaqui Valley.