氮肥用量对江淮粳稻稻米品质及主要矿质元素含量的影响

通过田间试验,研究了3个氮肥水平下(0 kg/hm2、150 kg/hm2、300 kg/hm2)江淮粳稻(镇稻88、南粳44)主要稻米品质指标和精米中主要矿质元素含量的变化。结果表明,氮肥用量对稻米主要品质指标和矿质元素含量的影响显著,两个品种的变化趋势基本一致。随着氮肥用量的增加,水稻的出糙率、精米率、整精米率、垩白大小、垩白米率、垩白度均呈现下降趋势,但米粒的长宽比升高,外观品质改善的效应高于加工品质的下降效应,且在高氮水平下,整精米率、垩白米率显著下降,长宽比显著增加。籽粒中直链淀粉含量随氮肥用量的增加而下降,而蛋白质含量相反,且在高氮水平下,蛋白质含量明显提高。精米中的主要矿质元素(Mg、Ca、P、Fe、Mn、Zn、Cu)含量,除Mn之外,均随施氮水平的提高而呈现下降趋势,但有些矿质元素受到氮肥的影响程度因品种而异。上述结果表明,施氮量增加,将影响稻米的加工品质和矿质营养水平,但外观品质可以得到明显改善。在施氮水平确定中,不仅要考虑水稻高产与氮肥高效的协调,还应该兼顾产量与矿质营养品质的同步提高!。

Impacts of nitrogen application amounts on grain quality and mineral elements concentrations of Japonica rice in Jianghuai River area

Field experiments on two Japonica rice varieties(Zhendao 88 and Nanjing 44) were conducted to study the impacts of nitrogen(N) application amounts(0 kg/hm2,150 kg/hm2,300 kg/hm2) on grain quality and mineral concentrations.Similar impacts of N application levels were found on the varieties.Grain quality indicators of brown rice rate,milled rate,head rice rate,chalkiness size,chalky grain rate,chalkiness decreased and length-width ratio increased along with the increase of N application amount.The head rice rate,chalky grain rate declined significantly and length-width ratio increased significantly in high-nitrogen-level treatment.The effect of nitrogen fertilization was bigger on appearance quality than on processing quality.Grain amylose content dropped,while protein content rose in the grain as N application amount went up,and protein content increased significantly in high nitrogen level.The contents of most mineral elements(Mg,Ca,P,Fe,Zn,Cu) except Mn in milled rice decreased with N application rates,and the contents of other elements varied among rice cultivars.The results demonstrate that N application may sacrifice the processing quality and mineral nutrition,but improve the appearance quality of Japonica rice in Jianghuai River area.Determining the optimal N application rate for a rice crop requires comprehensive consideration of all the aspects of production,including the integration of high yield and high nitrogen use efficiency,and simutaneous improvement of yield and mineral mutrition.