Effects Of Planting Patterns On Rules Of Water Consumption Based On Precision Irrigation System

The effects of planting patterns on rules of water consumption based on precision irrigation system were studied respectively in Yucheng ecological experiment station of the Chinese Academy of Sciences and experimental plot of Shandong Agricultural University in 2002-2004. The research analyzed changes of soil water and water use efficiency(WUE) in five different planting patterns that included winter wheat and summer maize rotation, straw mulching, furrow planting, bed planting and "20+40"planting pattern so as to select the proper planting pattern fit for the precision irrigation.The results were as follows. 1 Effects of planting patterns on soil water and water use efficiency In different planting patterns, dynamic change of moisture content was significant in soil surface layer of different irrigation treatments and became insignificant with soil layer deepening. The experiment in Yucheng ecological experiment station of the Chinese Academy of Sciences showed that the trend of moisture content changed on inverse "S"type with soil layer deepening. There were two inflexions(20cm and 110cm) in the soil layers of wheat-maize rotation pattern,but two inflexions were 20cm and 100cm respectively in the soil layers of straw mulching pattern. However, the experiment in Shandong Agricultural University showed that the trend of soil moisture content reduced gradually with the soil layer deepenning. Irrigation can change temporarily the soil moisture content but can not change the falling trend of soil water storage.The soil layer of water consumption of winter wheat was deeper than that of summer maize, but there was the primary water consumption layer on 0-100cm layer. Crop water consumption in different planting patterns increased significantly with the irrigation quantity increasing. Crop water consumption was influenced more significantly by irrigation quantity than by planting patter, but the effect of irrigation on crop water consumption was also reduced in the year of plenty of the precipitation. Between the irrigation treatments, water use efficiency(WUE) of the crop with no irrigation was usually the highest than others, but its crop yield was usually the lowest, therefore, Seemed on the better crop yield and WUE, two irrigations were more economical among five planting patterns. 2 Characteristics of the entironment in the field Temperature in the wheat field changed on inverse "U"type with the time of a day and there was the peak at 14 o'clock. Temperature in the wheat field was influenced significantly by irrigations but not by planting patterns.In the treatment of no irrigation, temperature had changed significantly in the vertical layers, that is, temperature improved gradually from bottom layer to top layer. However, temperature dispersion between the vertical layers became insignificant when influenced by irrigations. On the condition of no irrigation, there was the highest on relative air humidity in wheat field of bed planting pattern and the lowest on furrow planting pattern, furthermore, there was the significant arrangement character on the vertical distribution of wheat colony. The relative air humidity on different patterns and its arrangement character were changed by irrigations and there was insignificant on relative air humidity between different planting patterns at the results of irrigation. In daily changes of photosynthetic rate of flag leaf at wheat grain filling stage, the highest photosynthetic rate emerged at 14:00 o'clock or so, and the lowest value emerged at 18:00 o'clock or so. As a whole, photosynthetic rate of the treatment of two irrigations was always higher than that of no irrigation treatment. Photosynthetic rate in furrow planting pattern was always higher than other patterns before 14:00 o'clock on the condition of no irrigation, but there was no regulation based on two irrigations. Planting pattern had little effect of the activity of PSâ…¡in dark-adapted...