No-Till with Optimum N Fertilization Produces High Cotton Lint Yield and Improves N Efficiency in Wheat-Cotton Cropping System

摘要

Excessive tillage and N fertilizer use increase production cost, reduce soil fertility and threaten sustainability of cotton production in wheat-cotton cropping system. This study was conducted to determine the desired tillage level and N fertilizer rate for cotton production in a wheat-cotton rotation in Northwestern Pakistan. A field experiment was carried out during 2010 and 2011 in which three tillage methods, namely, zero (NT, no tillage), reduced (RT) and conventional tillage (CT) as main plots and five N levels (0, 50, 100, 150 and 200 kg ha(-1)) as subplots were arranged in a randomized complete block design with split-plot arranegement. These treatments were superimposed on land previously occupied with NT, RT and CT wheat. Cotton lint yield was higher at 150-200 kg N ha(-1) under RT compared with other tillage methods. Almost all N efficiency indices decreased with increasing N rate, with the highest values recorded at 50 kg N ha(-1). Mean values for T x N interactions revealed that N agronomic, physiological and recovery efficiencies were higher in RT with 150 kg N ha(-1). The overall results revealed that N application of 150-200 kg ha(-1) under RT can optimize cotton yield and N efficiency at reduced cost of cultivation.