Simulating the Impact of Nitrogen Management on Rice Yield and Nitrogen Uptake in Irrigated Lowland by ORYZA2000 Model

This paper considers the implications of ORYZA2000 model in simulating physiological traits of rice at different nitrogen concentrations. The experiment was conducted over the course of the growing season in 2012 and 2013 in Rice Research Institute, Deputy of Mazandaran, Iran. The variety used was Shiroudi as a high yielding variety. The considered factors were the amount of nitrogen at four levels (40, 80, 120, 160 kg N ha^?1 and control) and nitrogen splitting in four levels. We compared simulated and measured grain yield, biomass, grain nitrogen, total plant nitrogen uptake, and leaf area index (LAI) by Student’s t-test of means and by absolute and normalized root mean square errors (RMSE). Results showed that grain yield was simulated with an RMSE of 411–423 kg ha^?1 and a normalized RMSE of 6%. RMSE was 671–910 kg ha^?1 for biomass on harvesting date. RMSE were 7–11 for grain nitrogen, and 10–13 for total plant nitrogen uptake. LAI was simulated with a normalized RMSE of 17–23%. Generally the model simulated LAI, an exceeded measured value for different nitrogen treatments. The most obvious finding that emerged from this study was that ORYZA2000 model can be applied as a supportive research tool for selecting the most appropriate strategies for rice yield improvement at various nitrogen fertilization concentrations.     

Two years of a field study on sesame growth and yield,nutrient uptake by PGP bacteria application and capsule type

Abstract

A two-year field experiment was conducted to study PGP bacteria on growth and yield productivity of sesame. Factors were control, Nitroxin, Biophosphor, and an equal combination of biofertilizers along with sesame capsule type. 1000-seed weight and oil content increased in the second year, but, seed yield reduced (-12.6?g m²), which represented a negative relationship between seed weight and yield. The effect of year on No. of single and multi-cap node plant^?1 was reversed. Seed yield, chlorophyll, protein, and N increased in the multi-cap seed, whereas, 1000-seed weight and seed weight plant^?1 was decreased. Maximum yield and yield components were achieved in the second and first year, respectively, along with the multi-cap seed. Nitroxin, after the equal combination, was approximately showed the maximum enhancement of growth and yield productivity of sesame. The most seed yield (4261 k ha^?1) was performed in the first year, combined biofertilizers and multi-cap seed, whereas, the highest oil content was gained in the second year and single-cap that it was due to the higher N and P use efficiency in the first year. No. of node plant^?1 and capsule No. plant^?1 showed the most correlation with the other parameters. Seed yield was correlated with No. of node plant^?1 (r?=?0.925) and leaf dry weight (r?=?0.885). The N and P use efficiency had been higher in the first year, multi-cap, and equal combination. Nitrogen Use efficiency was higher compared to phosphorous. The uptake of N and P by sesame increased with the integrated application of different bacteria.