Library Earth and Environmental Sciences

A field experiment was conducted at farmer’s field of Anandapur, Mangalpur VDC-3, Chitwan, Nepal during winter season from September 2006 to February 2007 to study the effects of nitrogen and plant population on maize. Fifteen treatment combinations consisting of five levels of nitrogen: 0, 50, 100, 150 and 200 kg N/ha and three levels of plant population; 55555 plants/ha (60 cm × 30 cm spacing), 66666 plants/ha (60 cm × 25 cm spacing) and 83333 plants/ha (60 cm × 20 cm spacing) were tested in factorial randomized complete block design (RCBD) with 3 replications. “Rampur Composite” variety of maize was planted on sandy silt loam and strongly acidic soil having medium in total nitrogen (0.123%), high in soil available phosphorous (77.56 kg/ha) and low in soil available potassium (23.25 kg/ha). The research findings revealed that each level of nitrogen significantly increased grain yield upto 200 kg N/ha. The grain yield (6514.48 kg/ha) obtained under 200 kg N/ha was significantly higher than that of 0, 50, 100 and 150 kg N/ha. The percent increment in yield due to application of 50, 100, 150 and 200 kg N/ha was to the extent of 62.11, 104.74, 135.68 and 154.74%, respectively over control. Significant effect on grain yield due to different levels of plant population was observed. The grain yield (5113.46 kg/ha) obtained under 66666 plants/ha was statistically at par with that under 83333 plants/ha, but significantly superior over that under 55555 plants/ha. The interaction between different nitrogen levels and plant densities on grain yield showed that the highest grain yield (6925.79 kg/ha) was obtained under treatment of 200 kg N/ha + 66666 plants/ha. The yield attributes namely number of cobs/plant, cob length, cob diameter, number of grain rows/cob and 1000 seed weight significantly increased with increasing N levels and decreasing plant population levels. The number of barren plants/ha decreased with increasing levels of N but increased with increasing levels of plant population. The net return (Rs. 42188.74/ha) and benefit:cost ratio (1.67) obtained under 200 kg N/ha were significantly highest than that obtained under other levels of nitrogen (150, 100, 50 and 0 kg N/ha). The plant population of 66666 plants/ha gave the highest net returns (Rs. 25812.28) which was 10.19 and 49.64% higher than that of 83333 plants/ha and 55555 plants/ha, respectively. The benefit: cost ratio (1.44) obtained under 66666 plants/ha was significantly higher than that of 55555 and 83333 plants/ha. The interaction between different nitrogen levels and plant densities on economics of maize production showed that significantly highest net return (Rs.48606.98) and B:C ratio (1.78) were under treatment of 200 kg N/ha + 66666 plants/ha. The highest grain yield and maximum profit were obtained when maize variety “Rampur Composite” was planted with 200 kg N/ha and plant population level of 66666 plants/ha (60 cm × 25 cm spacing).

Jiban Shrestha earned a Master Degree in Agriculture (M.Sc. Ag) from Institute of Agriculture and Animal Sciences, Rampur, Chitwan under Tribhuvan University, Nepal in 2007. He is working in the capacity of Scientist (Plant Breeding and Genetics) at National Maize Research Programme, Rampur, Chitwan under Nepal Agricultural Research Council, Nepal since 2010. Mr. Shrestha has been involved in basic and applied research on maize mainly related to development, maintenance and improvement of hybrid and open pollinated maize varieties as well as soil nutrient management for maize grown in various production systems. He has played vital role for development and release of Rampur Hybrid-2, three early varieties (Arun-3, Arun-4, Arun-6), two pipe line hybrids and one yellow quality protein maize (QPM) variety. He has published 50 peer reviewed articles in both national and international journals, 10 proceeding papers, 12 scientific abstracts, 18 scientific reports, 10 magazine articles, two leaflet, one newsletter article and two book. He has been affiliated to more than 100 journals [including "European Journal of Agronomy" (Elsevier)] and national publications as editor or reviewer. Before embarking on his career as Scientist, he had worked as Project Officer at Support Activities for Poor Producers of Nepal (SAPPROS) under Education for Income Generation (EIG) in Nepal Program funded by USAID/Winrock Int’l Institute for Agriculture Development, Nepal. He is member of Society of Agricultural Scientist Nepal (SAS-N) and Agronomy Society Nepal (ASON). He has also joined as member of Asian Council of Science Editors (ACSE), European Association of Science Editors (EASE) and reviewer committee member of many international conferences.He has guided agricultural graduate and postgraduate students for their thesis research.