Controlled-release N fertilizer to mitigate ammonia volatilization from double-cropping rice

Controlled-release nitrogen fertilizer (CRNF) can effectively enhance crop yields and raise the efficiency of nitrogen fertilizer in agroecosystems. In the present study, the volatilization of NH3 was determined by airflow enclosure chamber technique after the application of different CRNF rates in double-cropping rice fields in southern China for continuous 3 years. The early and late season rice (ESR and LSR) were cultivated each year. The results showed that the total NH3 volatilization losses ranged from 25 to 56 kg N ha−1 in ESR and from 32 to 61 kg N ha−1 in LSR. The loss of N to the total applied N ranged from 12 to 29% in ESR and from 12 to 27% in LSR. The application of CRNF significantly reduced the cumulative NH3 volatilization losses by 20–43% for ESR and by 20–32% for LSR compared with conventional urea application. CRNF in LSR was less effective to reduce NH3 volatilization than that in ESR. Furthermore, the application of 80% of N rate in the form of CRNF gave higher grain yield and apparent nitrogen recovery efficiency (ANRE) than that of application of 100% of N rate from conventional urea. CRNF can effectively reduce NH3 volatilization, and increase rice yield and ANRE. Considering higher price of CRNF, the application of CRNF at lower (20% applied N) rate than conventional urea in LSR may be a reasonable fertilization strategy for improving N use efficiency, environment effectiveness, and sustaining the development of rice production systems in double-cropping rice.

Efficiency of Nitrogen Fertilization of Winter Wheat Depending on Sulfur Fertilization

Optimization of fertilization enables to obtain a yield of high quality and quantity, brings economic profits, and reduces environmental threats. The aim of the three-year field experiment was to determine the efficiency of fertilization with a new fertilizer available on the Polish market and containing nitrogen (N) and sulfur (S) in proportions designed for cereals cultivation (30% N and 6% S as ammonium nitrate and ammonium sulfate). Other treatments included no fertilization; fertilization with ammonium nitrate (34% N); fertilization with standard nitrogen and sulfur fertilizer with N supplementation with ammonium nitrate. Nitrogen doses were 150, 200, and 250 kg N ha−1. Sulfur was applied in doses of 30, 40, and 50 kg S ha−1. A beneficial effect of using fertilizer containing N and S in proportions designed for cereals cultivation was observed. The highest mean optimal nitrogen dose and maximum winter wheat yield were recorded for the new fertilizer (217 kg N ha−1 and 8251 kg ha−1, respectively). Sulfur supplementation with the new fertilizer significantly increased apparent nitrogen recovery (mean values 48.9%, 44.6%, and 40.6% for doses 150, 200, and 250 kg N ha−1, respectively), agronomic efficiency (11.1 and 8.6 kg kg−1 N for doses 200 and 250 kg N ha−1, respectively), and physiological efficiency (24.7 kg kg−1 N for dose 200 kg N ha−1).

Biomass, Efficiency of Nitrogen Conversion and Nitrogen Recovery in Millet Cultivars Under Nitrogen Fertilization

The objective of this study was to evaluate the production of green mass (GM), dry mass (DM), nitrogen contained (NC), bromatological composition, apparent nitrogen conversion efficiency (NCE), and apparent nitrogen recovery (ANR) of millet cultivars (ADR-500, ADR 7020 and LABH 70732) that received different doses of nitrogen (N) (0, 50, 100, 200 kg.ha-1). The experimental design was randomized blocks in a 3x4 factorial scheme (three cultivars and four N rates) with four replications. About biomass, only GM showed an interaction between N and millet cultivars. The DM production showed difference only between N doses. The NCE and ANR differed between N doses with decreasing mean values, due to the increase of nitrogen fertilization. The best conversion efficiency was 54.06 kg DM/kg N applied. The best rate of recovery of N occurred with the application of 50 kg N.ha-1. The values of NC varied in the fertilized plots. NCE and ANR differed between millet cultivars. The bromatological composition variables did not differ as a function of the N doses evaluated. In the conditions of the present study, nitrogen fertilization did not influence the production and bromatological composition of millet cultivars. The three cultivars present satisfactory characteristics for use in ruminant feed.