Effects of different types of fertilizers application on rice grain quality

As expected, applications of organic fertilizer and controlled-release fertilizer are gradually varying traditional fertilization, being considered as important channels for substitution of conventional chemical-fertilizer. However, information regarding their effects on rice (Oryza sativa L.) grain quality remains limited. A field experiment was conducted to investigate the effects of combined application of bio-organic fertilizer and conventional fertilizer (BOF+CF), combined application of organic fertilizer and conventional fertilizer (OF+CF), and application of controlled-release fertilizer (CRF) on rice processing quality, eating quality and nutritional quality with conventional fertilizer (CF) and no fertilizer (NF) as controls. The protein content of OF+CF treatment was increased by 4.67%, 3.29%, 2.61% and 22.66% when compared to BOF+CF, CRF, CF and NF. These results imply that, among all treatments, NF produced the highest rice eating quality followed by CRF and BOF+CF, and OF+CF made the highest nutritional quality followed by CF and CRF. When compared to CF, BOF+CF and NF treatments decreased protein content by 1.96% and 16.34%. Compared to CF, BOF+CF treatment markedly reduced aspartic acid, serine, glutamic acid, glycine, alanine, histidine, arginine, and proline contents in milled rice by 17.31, 14.71%, 16.39%, 16.67%, 20.69%, 11.77%, 18.42%, and 18.75%, respectively. The nutritional quality under NF and BOF+CF was significantly decreased when compared with CF, due to the reductions in protein content of milled rice and most amino acids contents of brown and milled rice. These results suggest that a kind of suitable fertilizer could be chosen from them as alternatives according to desired goal in high-quality rice production.