A field experiment was carried out during the rainy season (June-October) of 1998 at the Research Farm of the Indian Agricultural Research Institute, New Delhi, India to study the effect of coating prilled urea with eco-friendly neem (Azadirachta indica A. Juss.) formulations in improving the efficiency of nitrogen use in hybrid rice. The experiment was laid out in a split-plot design with three replications. Two rice cultivars, hybrid rice (NDHR-3) and Pusa Basmati-1, formed the main plots, with the levels of nitrogen (0, 60, 120 and 180 kg N ha-1) and various forms of urea at 120 kg N ha-1 in the sub-plots. The results obtained in this study showed that the rice hybrid NDHR-3 performed significantly better than the scented variety Pusa Basmati-1 for almost all the agronomic traits tested (growth, yield attributes, grain and straw yields, nitrogen uptake and apparent N recovery) The advantage of grain yield in hybrid NDHR-3 was nearly 16 q/ha over Pusa Basmati-1. Increasing levels of nitrogen significantly increased the number of effective tillers hill-1, panicle length, panicle weight, grain and straw yields and nitrogen uptake, thereby revealing a significant decline in agronomic nitrogen use efficiency (NUE). Among the sources of N, Pusa Neem Golden Urea proved to be significantly superior to other sources with regards to panicle length, grain yield, N uptake, agronomic nitrogen use efficiency and apparent N recovery (%), indicating that coating urea with neem formulations not only increased the grain yield, NUE and apparent N recovery, but also helped to reduce the environmental hazards associated with the use of large amounts of urea.
A field experiment was carried out during the rainy (kharif) season of 2001 at the experimental farm of the Indian Agricultural Research Institute, New Delhi, India, to study the effect of date of transplanting and nitrogen on yield attributes, yields, nutrient accumulation and nitrogen use efficiencies in hybrid and non-hybrid aromatic rice. The experiment consisted of 9 treatments with 2 varieties (Pusa Basmati 1 and Pusa Rice Hybrid 10), 3 transplanting dates (3, 10 and 17 July, 2001) and 4 nitrogen levels (0, 60, 120 and 180 kg N ha-1). Pusa Rice Hybrid 10 had significantly higher values of yield attributes (panicles hill-1, panicle weight, spikelets panicle-1, filled grains panicle-1, 1000-grain weight), yields and nutrient accumulation than the non-hybrid Pusa Basmati 1. There were significant reductions in yield attributes, yields and nutrient accumulation after delayed transplanting. Timely transplanting on 3 July led to 8.4 and 19.1% higher grain yield than transplanting on 10 and 17 July, respectively. Successive nitrogen levels had a significant effect on yield attributes (except 1000-grain weight), yields and nutrient accumulation up to 120 kg N ha-1. The maximum grain yield (5.87 t ha-1) was recorded at the highest level of N nutrition (180 kg Nha-1) and was 4.2, 15.5 and 39.3% higher than in the 120 kg, 60 kg N ha-1 and control treatments, respectively. Pusa Rice Hybrid 10 also had significantly higher values of agronomic nitrogen use efficiency (ANUE) (12.5 kg grain kg-1 N applied), apparent nitrogen recovery (27.4%), physiological NUE (44.2 kg grain kg-1 N uptake), N harvest index (62.7%), N efficiency ratio (119.6 kg dry matter kg-1 N uptake) and physiological efficiency index of nitrogen (47.4 kg grain kg-1 N uptake) than non-hybrid Pusa Basmati 1.
A field experiment was carried out to study the effect of K nutrition and genotypic variation on the dry matter (DM) accumulation, and the K concentration, accumulation, uptake and utilization efficiency in barley (Hordeum vulgare L.). Successive increases in potassium nutrition had a significant effect on the dry matter and K accumulation either in the total or in various plant parts of barley at the tillering, stem elongation, heading and maturity growth stages. K nutrition also led to significantly higher grain yield with each unit K application than without K application. The yield increase due to K application was mainly due to the improvement in spike development from tillers. Dry matter and K accumulation in various plant parts varied significantly between genotypes at the main growth stages. Among the various plant parts, the stem contained the highest K concentration, had the highest K accumulation at maturity and changed considerably with the K level, while other plant parts remained relatively unchanged. Among the eleven genotypes, genotype 98-6 had the highest grain yield and the K use efficiency of this genotype was 10.4 kg grain per kg K applied. It could thus be used as a breeding line to breed barley varieties for higher productivity under rainfed conditions with low available soil potassium.
Use of high analysis fertilizers such as diammonium phosphate in place of ordinary superphosphate and urea in place of ammonium sulphate over years, sulphur application to crop fields has considerably decreased, which has led to widespread sulphur deficiency in Indian soils. Hence, considering this into account a field study for two years was conducted at the research farm of ICAR-Indian Agricultural Research Institute, New Delhi to evaluate sulphur-coated urea (SCU) as a source of sulphur (S) and an enhanced efficiency of nitrogen fertilizer. Prilled urea (PU) coated with 4 to 5% S significantly increased wheat grain yield to the tune of 9.58 to 11.21% and nitrogen 19.06 to 23.94% and sulphur uptake 21.76 to 29.29% over prilled urea alone by wheat. However, net return and benefit: cost ratio was the highest and significant at 5% S coating onto PU. Five % SCU supplied 50% of the sulphur needs of the wheat crop and enhanced nitrogen recovery efficiency by 60% and is therefore recommended as sulphur as well as enhanced efficiency of nitrogen fertilizer for wheat in Indo-Gangetic plains of India. This is an important finding considering the environmental safety by increased nitrogen recovery and also productivity in present scenario.