Efficiency of Soil and Fertilizer Nitrogen in Relation to Variety and Application Time, Using N-15 Labelled Fertilizer. Part of a Coordinated Programme on Agricultural Nitrogen Residues with Particular Reference to Their Conservat

摘要

A series of experiments with flooded rice were carried out on 36 locations to study the influence of rice variety, fertilizer source, frequency of fertilizer application and soil conditions on the uptake of fertilizer N and grain yield. exp 15 N-labelled fertilizer was used in this study. The results show that (i) urea is a better source of N than ammonium sulphate on saline soils and also for the leading local rice variety (Milyang 15). The new variety Tongil utilized ammonium sulphate more efficiently; (ii) Fertilizer was more efficiently utilized on high organic matter soils; (iii) Varieties differed in fertilizer use efficiency; (iv) Hybrid Tongil lines gave higher grain yields than the local varieties, and made better use of fertilizer N, especially on saline soil, when applied at transplanting; (v) Sulphur-coated urea gave higher yield than urea on saline soils (27-39%), virgin soils (20%) and unmatured soils. (Atomindex citation 11:541193)