Impact of Nitrogen Forms and Levels on Yield and Quality of Rice in Kirinyaga and Kisumu Counties Kenya

Abstract

Nitrogen is one of the most limiting elements in crop production. The lack of nitrogen is even more pronounced in Sub-Saharan African as farmers are poor and cannot afford the required amount for crop production. Depending on form, nitrogen is known to affect the uptake of other nutrient elements. It is therefore important to understand strategies that can enhance the availability of N as well as other element. The N content is also a putative precursor for protein, an important component of rice quality. An experiment was therefore carried out to evaluate the effects of nitrogen forms and levels on yield and quality of rice grain in Ahero Kisumu county and Mwea Kirinyaga county. The trial took place during the main growing seasons of July to December. The Experiments were laid out in Randomized Complete Block Design (RCBD) in a factorial arrangement with three replicates giving a total of 36 plots, with each plot measuring 3 m by 4 m.  Two nitrogen forms, including urea and ammonium sulphate were applied in three levels (0, 25 and 50kgha-1 respectively). The results showed a positive relationship between levels of nitrogen and the measured parameters. There were observed increase in yield, grain crude protein, as well as more zinc and iron accumulations. Ammonium sulphate supplied at 50kgha-1 recorded an increase in grain zinc concentration of 163.8 mgkg-1and 195.5 mgkg-1 in Ahero and Mwea respectively.  A similar trend was observed in both crude protein and iron accumulation in the rice grain.  The unfertilised plots had the lowest accumulation and uptake of the two elements and lower quality of tested aspects. Proper application of nitrogen with the recommended rates has the potential of eliminating the challenges of hidden hunger, hence enhancing food insecurity and reducing malnutrition through increased yield and quality of rice.