Economizing nitrogen fertilizer in wheat through combinations with organic manures in Kashmir, Pakistan.

摘要

Integrating fertilizer N with organic manures is an important management strategy for sustainable agriculture production systems in subhumid, rainfed soils low in organic matter. A 2-yr (2007-2008, 2008-2009) field experiment with rainfed wheat (Triticum aestivum L.) was conducted in the state of Azad Jammu and Kashmir (Rawalakot), Pakistan to evaluate the effects of combined use of farmyard manure (FYM), poultry manure (PM), and urea nitrogen (UN) on crop productivity, nitrogen use efficiency (NUE) and soil properties. The experiment was conducted in a randomized complete block design with three replications. Treatments included one full N as UN, six combined treatments of UN, FYM and PM in 75:25, 50:50 and 25:75 ratios and a control, applied at equivalent rate of 120 kg N ha-1. The results showed that UN with FYM and PM decreased soil bulk density (4-11%), increased organic carbon (10-22%), total N (9-25%), available P (13-26%) and available K (13-23%) compared to the control. Combined application of UN, FYM and PM in 75:25 ratios produced comparable grain yields to UN treatment. However, total N uptake in the combined treatments was higher (83 and 89 kg ha-1 vs. 77 kg ha-1, respectively). The NUE in UN+FYM, UN+PM (75:25 and 50:50) was 44, 49, 41, and 44%, respectively compared with NUE of 39% in UN treatment. Results of this study confirmed that UN+FYM and UN+PM in 75:25 ratios saved ~25% (30 kg) of N fertilizer and represented a successful and sustainable management strategy for wheat production in the mountainous ecosystems.