Evaluation of varietal difference and N-P-K fertiliser combinations on the effectiveness of BioGro in rice cultivation and on rice quality

摘要

Field experiments to statistically evaluate the effects of BioGro and common rice varieties on rice yield were conducted during the spring and summer seasons of 2006 at Thanh Tri in Hanoi province, Vietnam. BioGro in combination with 50% nitrogen (N) and phosphorus (P) fertiliser gave similar grain yields as those obtained with application of 100% N and P fertiliser without BioGro, indicating the beneficial effect of BioGro in reducing fertiliser inputs. The individual effects of both factors were significant (P<001); however, the interaction effect of BioGro and rice variety was absent in the spring crop but significant in the summer crop, indicating possible seasonal impacts on the effectiveness of BioGro. The beneficial effect of BioGro was observed with four common rice varieties but not with two other varieties. In Nam Dinh province at Hai Hau, the response to BioGro was evaluated of two high-priced, quality sticky rices, LT3 and Tam Xoan, that were grown mainly with farmyard manure. Different combinations of N, P and K fertilisers were tested with and without BioGro to evaluate their benefits and the effectiveness of BioGro in reducing fertiliser inputs. The experiment was conducted in four consecutive seasons (spring 2005, summer 2005, spring 2006 and summer 2006). A statistically significant beneficial effect of BioGro in reducing N and P fertiliser requirements to 50% was observed in only one season (summer 2005). From these results, it is recommended that the N fertiliser rate be reduced to a maximum 90 kg N/ha in the experimental site of Nam Dinh province for these high-quality rices. When comparing 100% N and P fertiliser treatments with 50% treatments with BioGro in harvested common rices, no difference was observed in quality parameters such as the percentages of unhusked grain, amylose and protein. However, a combination of BioGro and farmyard manure improved the glutinous grade and other quality parameters of Tam Xoan, a trademarked rice.