Effects of slow-release fertilizers on nitrate leaching, its distribution in soil profile, N-use efficiency, and yield in potato crop

Abstract

The purpose of the present study was to study the effect of slow-release fertilizers on nitrate leaching, its distribution in soil profile, N-use efficiency (NUE), and yield in potato cultivation in the years 2012 and 2013. The treatments included nano-nitrogen chelate (NNC), sulfur-coated nano-nitrogen chelate (SNNC), sulfur-coated urea (SCU), and urea (U) at three levels of nitrogen input (46, 92, and 138 kgN/ha). For this purpose, a factorial experiment in completely randomized designs (CRD) was designed and conducted with three replicates. The results of variance analysis showed that each treatment had significant effects on yield, leaching, and soil nitrate. Comparison of nitrate leaching values due to the treatments showed that NNC, SNNC, and SCU fertilizers led to reduced nitrate leaching levels by 35.72, 41.56, and 9.94 % compared to U fertilizer application. In contrast, potato yield increased by 56.10, 59.61, and 49.76 % with NNC, SNNC, and SCU fertilizers, respectively, compared to U fertilizer application. The highest NUE value in both years was observed in 46 kgN/ha of nitrogen input treatment. This value in the years 2012 and 2013 was 1056 and 793 kg/kg and belonged to the SNNC and SCU treatments, respectively. Moreover, the maximum tuber nitrate concentration (228 mg/kg) was recorded with the third nitrogen level of urea.