Performance of Sulfur‐Coated Urea Under Intermittently Flooded Rice Culture in Peru

Abstract

Short‐statured, high yielding rice (Oryza sativa L.) varieties grown extensively in northern Peru require extremely high rates of conventional N sources to achieve maximum yields. The recovery of applied N is extremely low due to the use of intermittent flooding. This water management system results in heavy N losses even with properly timed split applications. In search of simpler and more efficient methods of N management, eight field experiments were conducted in the region to evaluate sulfur‐coated urea (SCU), an experimental, slow‐release N sources supplied by the Tennessee Valley Authority. Rice yields were increased an average of 59% more by pretransplant‐incorporated SCU than by urea or ammonium sulfate applied in the same manner. SCU produced an average of 20% higher grain yield response than topdressed applications of urea or ammonium sulfate. SCU applications increased panicle production, N uptake at harvest, and the apparent recovery of added N. Beneficial effects of SCU were more pronounced in sites where check yields were low, especially less than about 4.8 ton/ha. In sites with high N supplying capacity, SCU produced excessive vegetative growth which resulted in yield reductions at high N rates.Regardless of an assumed 48%‐higher unit N cost in SCU, the overall benefits of pretransplant‐incorporated applications of SCU were favorable since there was a decrease of 40% in the optimum rate of N and the need for precise timing of application was eliminated.

Studies on the Mineralization of Urea, Coated Urea, and Nitrification Inhibitor Treated Urea in Soil

“…Sulphur-coated urea (ICI) having 30 per cent S nitrified more slowly than sulphur-coated urea (TVA), which had only 16 per cent S. Thus the reported efficiency of sulphur-coated 4 results con K rm the suggestion made by Bains et al (1971 . Sulphur urea (TVA) in crop production (Furata et al, 1968;Allen et d., 1971 ;Sanchez et al, 1973) may partly be due to nitrification inhibitory properties of associated S. Nitrification inhibitors have been reported to increase the efficiency of urea applied to rice (Prasad et al, 1970;Rajale and Prasad, 1973).…”

Growth, Yield and Nitrogen Use Efficiency of New Rice Variety under Variable Nitrogen Rates

“…The efficiency of applied nitrogen is only 30% -50% [4] and in many cases even less than that proportion [5]. The efficient use of nitrogen is recognized as an important production factor for rice but it has always been a problem to raise the utilization rate of the rice plant and to increase efficiency of absorbed nitrogen for grain production.…”

Effect of nitrogen fertilization on the nutritional quality of wheat variety, Yecora Rojo

“…18) and the two UF fertilizers (treatment No. 20,21). The increase in grain protein with N-application is in line with previous reports in literature [11,14,15].…”

“…For this reason, the government in the Kingdom of Saudi Arabia invested heavily in the agriculture production in general and in wheat production in particular. In the past few years, wheat production increased several times largely due to the introduction of high-yielding wheat varieties and through enhancing the fertility of the soil by the application of fertilizers, Slow-release nitrogen fertilizers are claimed to be more effective in enhancing the efficiency of N-fertilizers especially in coarse-textured calcareous sandy soils such as those encountered in Saudi Arabia [7,20]. A number of slow-release N fertilizers are currently evaluated under local environmental conditions on wheat crops.…”