The Effect Of Nitrogen Fertilizer Forms On Growth, Yield And Grain Quality Of Rice (Oryza Sativa L.)

Issues surrounding rice quality are increasingly more demanding and complex for producers, millers, manufacturers of conventional and convenience foods, rice ingredient users, marketers and consumers alike. Factors influencing quality greatly depends on the genetic make up of rice. However, with the effective use of fertilizers, good quality grains can be produced. Moreover, environmental awareness worldwide has led to greater concerns regarding the effects of inorganic fertilizers on the quality and safety of agricultural products and the environment. It is against this background that this research was conducted to compare the effect of organic and inorganic fertilizers on yield and grain quality. The research was conducted in the experimental farm in Hua Jia Chi campus of the Zhejiang University in Hangzhou, China during the period 2002-2003. Two varieties of rice, Yixianyou 1577 (hybrid rice) and Chunjiang 16 (normal japonica rice) were used and directed sown with population densities of 750000 plants/hm2 (4 plants/pot, area of a pot is 0.053m2) in 1st June. Seeds were directly planted in pots. There were three treatments (Inorganic Nitrogen fertilizer (N), Organic manure + Inorganic Nitrogen fertilizer (N+O) and Organic manure only (O)) with ten replications. 360kgN/hm2 of total nitrogen were applied in different fertilizers. Results from the research indicated that plants treated with N+O in both varieties and in both years had the highest actual yields followed by O and then N with the least yield. For the hybrid variety in 2002, N+O gave a 5.1% increase over N and 0, and a 10.8% increase over N that doubled that in the first year and a 3% increase over 0 in 2003 respectively. For the normal variety in 2003, N+O had a 16.2% increase in yields over N and O. The effect ofdifferent treatments of fertilizers on head milled rice rate (HMRR) for the hybrid variety showed that the N+O treatment had 17.3% increase of HMMR over O treatment and 36.3% increase of HMMR over N treated plants. For the normal variety, O treated plants had an increase of 21.5% over N+O and had an increase of 36.5% over N treated plants. The treatment with N+O and O fertilizers has been useful for higher protein and lower amylose content than treatments with N. The amount of amino acids however increased for N treated plants followed by O with N+O having the least in terms of quantity. Overall results indicate that the normal variety was more sensitive than the hybrid variety to the treatments of fertilizers and the results suggests that organic fertilizers can improve apparent rice grain quality.