寒地稻区水稻裂纹米发生机理及其防御对策的研究 Ⅱ栽培措施和收获加工措施对裂纹米率的影响

Study on Occurrence Mechanism and Preventive Measure of Crackle-Rice in Cold Region Ⅱ The Influence of Cultivation,Harvest and Processing Methods on the Rate of Crackle-Rice

旨在研究出栽培措施和收荻加工措施对裂纹米率影响的量化关系，结果表明在一定的范围内，随着氮肥的增加裂纹米率有降低的趋势，裂纹米率最低的纯氮量为12．18kg／667m^2；对于寒地水稻晚燕品种来说，降低裂纹米率的最佳撤水时间为齐稳期后35d左右，最佳收获时间为齐穗期后53d左右，延后收割比提前收割、提前撤水比延后撤水裂纹米率高；对于北方粳稻来说，稻谷含水量在15％～17％之间时，不易产生碎米；水稻收割晾晒后，要厦时码上圆垛，尽量减少穗暴漏在外的面积，码圆垛的最佳时间应在10月中下旬；脱粒方式尽量用小型脱粒机或人工脱粒机，用大型机械收获时要防止转速过大过猛。

the relations between cultivation , harvest and processing methods and the rate of crackle-rice were studied. The results indicated that the rate of crackle--rice was decreased when the amount of nitrogenous fertilizer was increased, and the rate was the lowest when the amount was 12.18kg/667m^2. As far as mid maturing and late-maturing variety in cold region were concerned,the optimal drainage period was the date past 35 days after full heading time , the optimal harvest period was the date past 53days after full heading rime ,and the later harvest date produeed higher rate than the earlier harvest date. For northern rice , the rate was low when the water content of paddy was between 15% and 17%. After harvest ,a round stack of rice which few ears was exposed was advantageous to decrease the rate ,and the optimal time was the second and last ten days of October. Proper methods of threshing were helpful to decrease the rate, little and manual threshers were the optimal methods of threshing ,and when big threshers was used rotating speed should be lowered.