| The changes of the light environment plays a decisive role on crop productivity, light use efficiency and water consumption. In order to study the change of light condition how to effect the growth,yield, grain quality and water consumption, the reaserch used black shading nets to control the light idensity, respectively set the reduction quantity 20%,40%,60%,80% of natural light idensity, recorded as L20,L40,L60;L80 with no shading as control group.The winter wheat which is widely planted in the central Shaaxi plain was taken as the research object. Through field experiments and data collection and analysis, the main conclusions are as follows:(1)The effect of different light conditons on microclimate in the field. Shading treatments resulted in the change of temperature in experimental plots. The temperature of CK was higher than other shading treatments. With the incresement of shading degree, the temperature gradually decreased; and the humidity showed the opposite law of temperature. Shading treatmens made large effects on the ground temperature of 5 and 10 cm. Since 15cm, the difference in ground temperature of L20 was not obvious with CK, and the difference of the ground temperature among L40, L60 and L80 was not obvious. The ground temperature in each treatment was close at 25cm, and there was no significant difference.(2) Shading treatment resulted in the delay and extension of different growth stages of winter wheat. For plant height, during the jointing stage and heading stage, the growth rate of CK treatment was faster than that of other treatments. After heading, the differences of height between treatment groups was gradually reduced. Different degrees of shade had no significant differences on the ultimate height of winter wheat. Shading treatment showed inhibitory effect on spike length. Under different light conditions, the leaf area of winter wheat showed a trend of increasing first and then decreasing, showing L80>L60>L40>L20>CK rule at the peak value.The change of light conditions inhibited the accumulation of dry matter in winter wheat to some extent, and reduced the dry matter accumulation rate. Shading treatment affected the distribution of dry matter.(3) There were no significant differences between the yield of L20 and CK, and the other shading treatments results in the decreasment of the yield.The regression equation about yield was established with grains per spike, 1000-kernel weight, spike length had a high significance.Shading treatment had no significant effect on grain protein content, and had a certain reduction effect on the formation of starch content, and played a very weak role in reducing sugar content.(4) The water consumption of winter wheat under different shading treatments showed:CK>L20>L40>L60>L80. To some extent, shading reduced the amount of the soil evaporation. For soil moisture content, shading treatment can effectively enhance the soil water retention.(5)For the comprehensive analysis of yielde and water consumption, the water productivity fo L20 reached the highest, and then the water productivity of the other shading treatments decreased. The utilization of L20 can reduce the consumption of water effcetively, but also make no significance effect on yield, which has a guiding significance for production practice. |
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