A Root Crop Growth And Water Use Efficiency Of Research

The experiments were made to analyse the root cutting influence on the crop growth and the water use efficiency by pots and root observing boxes and plots. The results showed:1. The leaf photosynthetic rate was improved by moderate root cutting in seedling stage, and the leaf transpiration rate and stomatal conductance of millet were depressed. But, the leaf photosynthetic rate was depressed and the transpiration rate and stomatal conductance of millet were improved if the root cutting was serious in seedling stage or the root cutting in elongation stage or boot stage.2. The individual plant hight was decreased in Most of treatments of root cutting, and the shrinking rate of leaf area of millet was slower than the check during the bearing anaphase,that is to say, root cutting has definite function to leaf area of millet in preventing premature senility and prolonging ability during the later stage. 15 days later after root cutting, the aboveground biomass of the treatment of root cutting was lower than the check.At the 80% field capacity,the aboveground biomass of millet improved between 1.5~24.7%,and the biomass degraded between 2.9~19.0% at the 50% field capacity.But, three kinds of treatments of root cutting increased the aboveground biomass in maize experiment. 3. Most of millet roots distributed between 0~50cm in the soil profile, the root quantity in root cutting treatments was less than the check between 0~15cm,however, more than the check below the 15cm depth.The total root quantity in root cutting treatment was more than the check. During the short term after root cutting,the root growth was restrained,but later,the root in root cutting treatment was continuing growing,and its root ablity was stretched. Compared the two kinds of root quantity in different water condition,it is easy to produce the new root and hair root in high water condition,and its root growth better than in low water condition evidently.4. At the 80% field capacity,when the root was cutted more seriously and more later,the seed yield of millet dropped;while at the 50% field capacity,moderate root cutting in prophase increased the seed yield (the treatment of "fm" is the highest),but it reduced the seed yield when the root cutting was serious and in boot stage. The seed yields of maize are all increased when they were root cutted,and the order is I2D >I6S> I2S> CK. In all treatments of root cutting at 50% field capacity, thousand grain weight was increased.5. The leaf WUE of millet was increased when root cutting in seedling stage,and only the treatment of I2D of maize increased the leaf WUE; The biomass WUE of millet and maize were increased excepting the root cutting treatments of "TM" and "sl"; At the 80% field capacity, when the root was cutted more seriously and more later,the seed yield WUE of millet were dropped; While at the 50% field capacity, the seed yield WUE of millet was increased when the root cutting is moderate in prophase,and have no reduction of output or increase the production at the same time ,while the benefit of saving water didn't evidently at the later stage root cutting.