A study on the effects of incorporated manure compost with chemical fertilizer on nitrate leaching and grain yield under canola-soybean-wheat crop rotation in sandy soils

Innovative strategies are needed to improve water and nitrogen use efficiencies in sandy soils. The objectives of this study were to quantify the amount of nitrate leaching losses under conventional and integrated nutrient management of canola and wheat. The experiment was carried out using a randomized complete-block design, with three replications. Fertilization treatments including: urea (CF), urea + zeolite (CF-Z), urea + composted manure (IF), urea + composted manure + zeolite (IF-Z) and control (CK). The maximum water deep percolation was occurred after irrigation in November and May. The average of annual nitrate leaching losses for CF, CF-Z, IF, IF-Z and CK were 53.64, 41.21, 33.16, 25.59 and 9.23 kg.ha-1, respectively. The maximum and minimum annual nitrate leaching factor were achieved with the CF (47%) and IF-Z (10%) treatments, respectively. Annual nitrate leaching losses and annual nitrate leaching factor showed positive and significant correlations with the amount of water inputs in the months. The IF-Z fertilizer treatment produced the highest grain yield for canola (3661.5 kg.ha-1) and wheat (4058.9 kg.ha-1). The results showed that application of manure compost and zeolite could be a useful methods for decreasing chemical fertilizer application rates and improving the sustainability of agricultural systems.