Nitrogen is one of the key factors for higher grain production of hybrid maize (Zea mays L.). The use of improved varieties and optimal use of nitrogen (N) fertilizer is important for exploiting yield potential of maize. This work was carried out to evaluate the effects of N rates on grain yield and yield attributing traits of hybrid maize. Two hybrids (RML-86/RML-96 and RML-95/RML-96) and five levels of nitrogen (120, 150, 180, 210 and 240 kg N/ha) were evaluated at research field of National Maize Research Program (NMRP), Rampur, Chitwan, Nepal in spring season of 2017 and 2018. The experiments were conducted in two factorial randomized complete block design (RCBD) with three replications under rainfed condition. The pooled analysis (2017 and 2018) showed that the highest grain yield 10.5 and 10.5 t/ha were given by hybrids RML86/RML96 and RML95/RML96, respectively with the use of 150 kg N/ ha in 2017. The hybrids RML-86/RML-96 and RML-95/RML-96 produced the highest grain yield 7.49 and 7.68 t/ha, respectively with the use of 150 kg N/ha in 2018. The mean grain yield (2017 and 2018) showed that both maize hybrids produced the highest grain yield 10.5 t/ ha in 2017 and 7.58 t/ha year in 2018 with the application of 150 kg N/ha. The application of nitrogen fertilizer on grain yield was found significant (P<0.05) in both years. Therefore, the application of 150 kg N/ha has significantly increased grain yield of maize, Therefore, this dose of nitrogen can be recommended for higher maize production in Chitwan, Nepal in spring season under rainfed condition.

Nitrogen (N) response by maize differs due to growing seasons, growth stages, duration and growing domain as N losses is higher due to leaching as well as volatilization. Objective of this study was to know the response of split applications of N and growing seasons on maize under Chitwan environments. Field experiments were conducted for two consecutive years at the research field of NMRP Rampur during the winter, spring, and summer seasons of 2012/013 and 2013/014. Experiments were laid out in factorial randomized complete block design with four replications for all the seasons. Early maturing maize genotype Arun-1 EV was used for the experiments. Five splits of recommended dose of N were tested. Grain yield, days to flowering, plant height, ear height, kernel rows per ear, no. of kernels per row, ear length and thousand grain weight significantly differed due to growing seasons and split applications of N. Significantly higher grain yield (3911 kg ha -1 ) was obtained with the application of 30 kg N ha -1 each at 30, 45, 60, and 75 days after sowing as compared to control (2801 kg ha -1 ). Regarding the growing seasons, highest grain yield was obtained in winter (4393 kg ha -1 ) followed by spring (3791 kg ha -1 ) and summer (2468 kg ha -1 ) season, respectively. Results of these studies revealed that four splits of N viz. application of 30 kg N each at 30, 45, 60, and 75 days after sowing respectively, would be more economical to minimize N losses from the soil and efficient use of N at critical growth and development stages of maize.

In a pot culture experiment, five different species of Brassica (Brassica juncea, Brassica campestris, Brassica carinata, Brassica napus, and Brassica nigra) were grown for screening possible accumulators of heavy metals, viz. Zn, Cu, Ni, and Pb. The plants were grown to maturity in a soil irrigated with sewage effluents for more than two decades in West Delhi, India. The soil analysis showed enhanced accumulation of Zn, Cu, Ni, and Pb in this sewage-irrigated soil. Among all species, B. carinata showed the highest concentration (mg kg(-1)) as well as uptake (microg pot(-1)) of Ni and Pb at maturity. Although B. campestris showed a higher concentration of Zn in its shoots (stem plus leaf), B. carinata extracted the largest amount of this metal due to greater biomass production. However, B. juncea phytoextracted the largest amount of Cu from the soil. In general, the highest concentration and uptake of metal was observed in shoots compared to roots or seeds of the different species. Among the Brassica spp., B. carinata cv. DLSC1 emerged as the most promising, showing greater uptake of Zn, Ni, and Pb, while B. juncea cv. Pusa Bold showed the highest uptake of Cu. The B. napus also showed promise, as it ranked second with respect to total uptake of Pb, Zn, and Ni, and third for Cu. Total uptake of metals by Brassica spp. correlated negatively with available as well as the total soil metal concentrations. Among the root parameters, root length emerged as the powerful parameter to dictate the uptake of metals by Brassica spp. Probably for the first time, B. carinata was reported as a promising phytoextractor for Zn, Ni, and Pb, which performed better than B. juncea.

A field experiment was conducted to study the effect of Azotobacter on growth and yield of maize (variety Rampur composite) . Analysis of variance showed that grain yield, plant height, ear height, ear length, kernel per rows and 1000 grain weight were significantly affected with treatments. Only inoculation of Azotobacter increased 15 to 35% grain yield over non inoculated treatments. The benefit of Azotobacter inoculation was higher in the absence of chemical fertilizer application.

Maize ( Zea mays L.) v arieties differ in their response to nutrient supply . Optimum fertilizer dose is necessary to explore the yield potential of a v ariety . A field experiment w as conducted at Rampur , Chitw an, during winter season of 2012/13 and 2013/14 to study the productivity of hybrid maize RML-32 X RML-17 to different lev el of nitrogen, phosphorus and potash. T reatment factors -1 -1 included tw o lev els of potash (40 and 60 kg K O ha ) and phosphorus (60 and 90 kg P O ha ) and 2 2 5 -1 -2 -1 four lev els of nitrogen (120, 160, 200 and 240 kg N ha ). Number of ears m , kernel rows ear , kernels -1 -1 row , grain and stov er yield ha w ere increased with increased nitrogen lev els. Increased phosphorus doses significantly decreased days to 50% tasselling and silking. Soil analysis results indicated that increased N and P doses had increased av ailable N, P and soil organic matter , but -1 -1 decreased soil pH. The highest mean grain yield of 9.35 t ha w as obtained when 200 kg N ha -1 -1 applied with 60:40 P O :K O kg ha . Application of 200:60:40 kg N: P O K O ha gav e the highest net 2 5 2 2 5 : 2 -1 returns of Rs 1,34,696 ha with the highest benefit cost ratio of 1.9. Farmers of Chitw an are -1 suggested to apply 200:60:40 N:P O :K O kg ha for grain production of hybrid maize RML-32 × RML-17