Analysis on the Variation Law of Rice Irrigation Quota and its Correlation with Yield in Southern Guangxi
Water use efficiency of rice and field productivity were affected by irrigation quota.In order to explore the variation law of rice irri-gation quota and its correlation with yield,the experiment of water layer location monitoring and supplementary irrigation of paddy field was conducted for eight consecutive years from 2014 to 2021 in Nanning Irrigation Experimental Station,providing fundamental data for quantify-ing the irrigation quota of rice in the double cropping rice region of southern Guangxi.The upper and lower limits of the water layer in paddy fields were established in regreening stage,tillering stage,jointing and booting stage,heading and flowering stage,milk ripening stage,and yellow ripening stage.The water layer depth was monitored daily by measuring needles.Supplementary irrigation was performed when the depth was below the lower limit,and the cumulative irrigation amount was calculated.At the same time,the rainfall was measured by meteo-rological facility in Nanning Irrigation Experimental Station.In mature stage of rice,indicators such as panicle length,1 000-grain weight and yield were measured.The test results show that:① The amount and time distribution of rainfall were important factors influencing the ir-rigation quota of paddy fields,and the uneven distribution of rainfall during the growth periods of rice was the main factor causing significant differences of irrigation quota.The irrigation quota of early rice was 210.1～438.4 mm,while that of late rice was 243.9～477.5 mm.② When the irrigation quota was within the range of 200～320 mm,panicle length,1 000-grain weight and yield of rice increased with the increase of irrigation amount.While the irrigation quota was more than 320 mm,continued irrigation was not conducive to the increase of rice yield.It could be seen that the appropriate irrigation quota for rice was 320 mm during the experiment.Insufficient or excessive irrigation would affect rice yield and reduce the effective utilization rate of water resources.
万方数据
维普
