Tillage and residue management effects on soil properties and yields of rainfed maize and wheat in a subhumid subtropical climate

Minimum tillage in conjunction with crop residue mulch may be a promising practice of soil management to improve soil properties and crop production in the subtropical climate of north-western Punjab. Therefore, a 5-year field experiment was conducted to study the effect of tillage and crop residue mulch on some properties of a sandy loam soil (Fluvisol) cropped to rainfed maize (Zea mays L.)–wheat (Triticum aestivum L.) sequence. Three main treatments investigated were minimum tillage (consisting of making a small trench for seed placement) with 3 Mg ha−1 crop residue mulch of the previous crop (MTR), minimum tillage without residue mulch (MT), and conventional tillage (involving two diskings followed by a planking) without residue mulch (CT). Subtreatments consisted of five rates of fertilizer N (0, 40, 80, 120 and 160 kg ha−1) applied to wheat. Maize received 80 kg N, 17 kg P and 16 kg K ha−1. Soil quality in terms of increased organic matter content, water retention, infiltration of water and aggregation, and decreased bulk density of the surface soil was improved in the MTR relative to other treatments. Pooled grain yield in the MTR treatment remained below the CT treatment during the first 2 years (1993 and 1994) but was subsequently greater than the CT. However, grain yield in the MT treatment was lower than CT treatment throughout the study period. The results indicated the necessity of using residue mulch in conjunction with minimum tillage in order to improve soil quality and sustain/improve crop production.