棉花生理时间估测及其与害虫防治决策关系的研究

A Preliminary Study on Estimating Pbysiological Time of Transplant-ing Cotton Related to the Pest Control Decision Made in the CoastalRegion of Jiangsu

对育苗移栽棉苗期的生理时间研究结果表明：育苗移栽棉由于播种提前和苗床覆膜合计增温约１１．５个ＰＤ。苗床日增温效应受苗床人为管理与天气情况的双重影响，平均苗床期较气温日增温８．５９℃，较床外土表日增温４．８℃，其增温主要是通过提高苗床日最高温度。根据苗床内外温度的相关性与函数关系，建立了利用日气温、日有效积温估计苗床温度与生理时间的公共回归方程。并探讨了棉花生理时间与害虫防治决策的关系。

The methods of estimating physiological time for transplanting cotton is different from direct sowed cotton. In direct sowed cotton the physiological time(physiological day PD)can be estimated from the meteorological data by the summation of daily average tempera-ture minus 12℃ and divided by 14 starting from the sowing date. But for transplanting cotton it is needed to estimate the effect of temperature increase in the seed bed which is covered with polyethylene membrane before transplanting. Experiment showed that the physiological day increasing in the seed bed was 11, 5PD which included 5.3PD due to the earlier sowing date and.2PD due to the temperature increasing under the polyethylene membrane. The air tem-perature in seed bed was 8. 59℃ in average higher than in the open air while the temperature of soil surface in seed bed was 4. 8℃ in average higher than that outside the bed. The degree of temperature increase in seed bed was mainly affected by the daily maximum temperature. The co-equations of line regression for estimating the temperature and physiological day of cotton seedling in seed bed with the air meteorological temperature data and temperature accu-mulation were established and a more accurate physiological day for transplanting cotton can be obtained which may be beneficial in making pest control decision.