Through pilot experiment,it is found that the cotton yield is obviously influenced by multi-stage water logging;the degree of water logging can be described by the water logging factors such as SFW,SEW_50,and SFEW_50;there is a significant linear relationship between the cotton relative yield Ry and the water logging factors such as SFW,SEW_50,and SFEW_50.

Soil alkali-hydrolyzable N were classified as very low(<50%relative yield ),low(50%～75%relative yield ), medium(75%～90%relative yield ),high(90%～95%relative yield ) and very high(>95%relative yield ) based on the relative yields.

relative yield and salt mass per unit area vs.

The output fluctuation and control of continous polyester plant;

A study of grain yield fluctuation in view of mitigation of meteorological disasters in Jiangsu;

Based on the hybrid midseason rice regional trial in Hubei province from the year 1990 to 2004 and the data of weather station in Jingzhou、Wuhan and Xiangfan city,the influence of various meteorological elements on the yield fluctuations of hybrid midseason rice was analyzed.

This paper introduces the major mathematic models of synthetic prediction of crop yield, including separation of trend factor and trend yield,simulation of trend yield;,extension of trend yield;,prediction of fluctuating yield, revision of predicting errors, multi-result s synthetic integration .