Ammonia volatilization losses from applied urea in flooded alkali soils.

摘要

A laboratory study was conducted to evaluate the effects of different factors on ammonia volatilization losses in flooded alkali soils (ESP [exchangeable sodium percentage] 26 and 82). Incubation studies in these soils showed that the losses were largely governed by the pH/alkalinity of the system. The duration of pre-submergence decreased the cumulative ammonia volatilization losses from 19.2-13.5% in ESP 26 soil and 22.5-16.0% in ESP 82 soil at 0.5 and 10 cm floodwater depths, respectively. Flooding of the soil decreased the soil pH resulting in lower losses from 23.9-16.9% in ESP 26 soil and 27.8-19.3% in ESP 26 soil and 27.8-19.3% in ESP 82 soil. The cumulative ammonia losses were maximum in the control treatment followed by Dhaincha straw. Farmyard manure, rice husk and wheat straw varied from 8.1-16.9% in ESP 26 soil and 9.0-20.5% in ESP 82 soil, respectively. The floodwater NH4, pH and CO3 + HCO3 in all the experiments followed the same trend in which the losses occurred.