中国作物的收获指数

 本文对中国300个农业气象试验站各种作物的收获资料进行统计分析，计算了收获指数、谷草比和有关的统计参数。结果指出：1.各作物的平均收获指数差别较大，主要粮食作物的收获指数在0.35—0.45之间，谷草比在0.55—0.80之间。2.收获指数和谷草比的变动范围较大，对于同一作物，绝大多数样本的谷草比都分布在平均值附近，而少数的可以偏离平均值较远。3.由粮食产量推算秸秆量，对于大面积的估算有较满意的结果，而对于个别地块，其误差可能较大。4.一些主要作物谷草比的频率分布曲线接近正态分布，而多数则属正偏类型。5.同一作物在丰、平、歉年的平均谷草比各不相同，一般丰年大，歉年小，平年介于其间。6.谷草比与产量水平有关，随着产量的提高而增加，其关系可用一元回归方程表示。

HARVEST INDEX FOR VARIOUS CROPS IN CHINA

Based on the harvest data of crops from 300 agrometeorologieal experimental stations in China, the authors calculated and analysed the harvest index (C_H), the ratio of grain to straw(G_s), and some relevant statistical parameters. The result indicates that:1. The difference of the average value of C_H(or G_s) for every kind of crops is significant, for main crops, the value of C_H are about 0.35-0.45, the value of G_s are about 0.53-0.80.2. The fluctuation of the values of C_H or G_s is considerable. For most sample, these values deviate not far from the mean value, but for a few sample, they have great departures from the mean value.3. The estimation of straw yield from the yield of grain and the ratio of G_s is satisfactory for a large area, but for some small plots, the estimations may cause significant errors.4. The frequency distribution curves of G_s for some crops are near noraml distribution, but for most crops the distribution curves appear positive skewness.5. The ratios of G_s for a certain crop in good years, common years and lean years are different. Generally speaking, in good years the ratios are greater, in lean years they are smaller and in common years they are medium.6. The ratio of G_s is closely related to the grain yield level. It increases with the growth of yield. Their relationship may be expressed by a single regression equation.