Influence of Modified Urea Compounds to Improve Nitrogen Use Efficiency under Corn Growth System

Abstract

Adopting new practices is an imperative need to increase the efficiency of nitrogen use (NUE), especially in selecting appropriate N-fertilizer sources and application doses. Regretfully, conventional urea’s ability to supply nitrogen to soils is quickly lost as a result of volatilization, leaching, and denitrification. Thus, this study’s main aim was to use various modified urea compounds with different doses and investigate their effect on mineral nitrogen release in the soil to improve nitrogen uptake and its use efficiency under the corn growth system. The field trial was conducted in a randomized complete block design (RCBD) by 28 experimental plots. Seven treatments including a control (C), urea (U100 and U200), urea + potassium humate (UPH100 and UPH200), and urea cocrystal (UC100 and UC200) with four replicates were used. The results reported that the treatments significantly (p < 0.05) affected grain yields. The urea treatments (U100 = 100 kg N ha−1, U200 = 200 kg N ha−1) increased the grain yields by 7.16% and 30.53%, respectively, compared to the control (C), while the urea + potassium humate treatments (UPH100 = 100 kg N ha−1, UPH200 = 200 kg N ha−1) and urea cocrystal treatments (UC100 = 100 kg N ha−1, UC200 = 200 kg N ha−1) provided a 30.51, 50.47, 39.23, and 56.63% increase in grain yields, respectively, compared to the control. The treatments had significant (p ≤ 0.05) effects on the fresh leaves and stems yield and the dry matter, fresh cob, and dry cob yields. Moreover, the use of modified urea as urea + potassium humate and urea cocrystal at high rates of 200 kg N ha−1 showed highly significant (p < 001) effects on the uptake in grain, stems, and total nitrogen uptake by corn compared to the control and urea alone. This study highlighted that modified urea fertilizers such as urea + potassium humate and urea cocrystal were better than conventional urea to improve corn yield productivity and N use efficiency.