Can the Nitrogen and Silicon Increase the Productivity and Yield in Rice Crops in the Rainfed Environment?

There is much doubt as to whether, in fact, the combination of nitrogen and silicate fertilization can increase yield and post-harvest yield in rainfed rice. The objective of this study was to investigate the effect of silicate and nitrogen fertilization on the development, quality, yield and post-harvest yield of rice cultivated in the rainfed environment. A field experiment was carried out in the 2014/2015 harvest in a 4 × 4 randomized block design with four replications. The first factor corresponded to the nitrogen doses (0; 50; 100 and 200 kg ha-1 of N), in the form of urea, and the second factor at silicon doses (0; 7.5; 15 and 30 kg ha-1 Si), in the form of calcium silicate. Si affected the chlorophyll content at 45 days after sowing (DAS) suggesting being important in floral differentiation. The increase in N doses caused higher levels of chlorophyll in rice leaves at 55, 65 and 85 DAS, regardless of whether they supplied Si. Plant height, number of tillers, weight of one thousand seeds, total grain yield and of whole grains were not influenced by the Si supply. However, Si doses reduced the yield of broken grains, thus reducing postharvest losses and, consequently, improving grain quality in the beneficiation process.