Controlled‐release urea improved rice yields by providing nitrogen in synchrony with the nitrogen requirements of plants

Abstract

BACKGROUND Excessive application of nitrogen (N) fertilizer and low nitrogen‐use efficiency (NUE) are prevalent problems in rice production. Controlled‐release urea (CRU) is widely adopted to increase rice yields, but the synchronicity of N release from CRU with uptake of N by plants has rarely been studied. A 2‐year field experiment involving CRU and urea applications at three different N rates (240, 192 and 144 kg N ha−1, equal to 100%, 80% and 60% of the recommended rate, respectively) was performed to compare their effects on N uptake, soil N content and rice yields. RESULTS The successive release curves of CRU in the soil matched the corresponding N uptake curves of rice plants, and significant linear correlations were observed. Grain yield and N uptake under the CRU treatment increased by 5.25–7.88% and 7.13–17.94% than urea treatments, at the same N rate, and no obvious difference was found between CRU60% and Urea100%. CRU80% and CRU60% presented the highest NUE. The contents of ammonium‐nitrogen (NH4+‐N), nitrate‐nitrogen (NO3‐‐N), and total N and the chlorophyll relative value – SPAD (Soil Plant Analysis Development) values – of the leaves under the CRU treatments were significantly higher than those under the urea treatments from heading to harvest. The contents of exchangeable sodium ion (Na+) and calcium ion (Ca2+) and the cation exchange capacity increased in response to CRU. CONCLUSION CRU increased rice yields by providing N strongly in synchrony with the N requirements of the plants, and applying CRU at 192 kg N ha−1 was an effective strategy to conserve N fertilizer, increase soil N contents and enhance NUE. © 2021 Society of Chemical Industry

Highly active biostimulant Paecilomyces variotii extracts reduced controlled‐release urea application while maintaining rice yield

“…Soil NO 3 − ‐N and NH 4 + ‐N were extracted by 0.01 mol L –1 CaCl 2 , 29 and analyzed by the AA3 auto‐analyzer (Model AA3‐A001‐02E, Bran‐Luebbe Ltd., Germany). Soil‐available P was extracted by 0.5 mol L –1 NaHCO 3 at pH 8.5, 29 and analyzed by the Discrete Auto‐analyzer (Smart Chem 200, Alliance Ltd., France). Soil available K was extracted by 1 mol L –1 CH 3 COONH 4 at pH 7, 29 and analyzed by the flame photometer (Model 410, Sherwood Ltd., England).…”

“…Soil‐available P was extracted by 0.5 mol L –1 NaHCO 3 at pH 8.5, 29 and analyzed by the Discrete Auto‐analyzer (Smart Chem 200, Alliance Ltd., France). Soil available K was extracted by 1 mol L –1 CH 3 COONH 4 at pH 7, 29 and analyzed by the flame photometer (Model 410, Sherwood Ltd., England).…”

Combining Organic Fertilizer With Controlled-Release Urea to Reduce Nitrogen Leaching and Promote Wheat Yields

“…The total precipitation amounts in 2018 and 2019 were 966.3 mm and 864.6 mm, respectively, and the average temperatures were 14.83°C and 14.43°C during the first and second growing seasons, respectively (Figure 1). The study area has cold winters and hot summers, and the rainy season generally spans from June to August (Yang et al, 2021). Before this study, the field was previously managed as a winter wheat/summer maize rotation system and had been continuously cultivated for more than 6 years.…”

“…The fertilizer NUE included the apparent recovery N use efficiency (ARNUE, %), agronomic nitrogen use efficiency (ANUE, kg kg −1 ) and partial factor productivity (PFP, kg kg −1 ). These data were calculated as described by Yang et al (2021) using the following formulas:…”

Gene Expression, Enzyme Activity, Nitrogen Use Efficiency, and Yield of Rice Affected by Controlled-Release Nitrogen

“…13 Controlled-release urea has been applied to a variety of crops, resulting in numerous advantages. 14,15 They are coated with a polymer to control or lessen the release rate of nitrogen, which reduces nutrient losses and groundwater pollution while increasing nitrogen use efficiencies and grain yields at the plant's physiological level. 16,17 Many studies have proved that it is because the nitrogen release patterns and rates from controlled-release urea match well with the crop plants' requirements.…”