滴灌水热调控对土壤温度及白菜生长和产量的影响

在日光温室内开展白菜滴灌试验,研究不同土壤温度调节方式和施氮量对土壤温度、白菜生长、氮素吸收和产量的影响。土壤温度调节方式设灌溉水加温、覆膜、覆膜后灌溉水加温和无调节4个水平,施氮量设置0、135和270kg/hm2 3个水平。结果表明:灌溉水加温能使灌水过程的土壤温度明显增加,且气温越低,增温效果越明显,在苗期、莲座期和结球期的灌水过程中增温幅度最大分别达到3.9、4.8和7.0℃,但在灌后土壤温度下降较快,对生育期内积温的提高效果有限。覆膜的保温作用在气温较高的生育前期和深层土壤中更为明显。将覆膜与灌溉水加温相结合可以取得很好的增温效果,在10、20和30cm土壤中整个生育期内的积温比无调节措施处理分别增加136、128和120℃。土壤温度调节措施对白菜株高和球形指数均无显著影响。覆膜和覆膜后灌溉水加温都能使生育前期的干物质累积量显著增加,施氮量较高时,土壤温度调节措施的影响也更加明显。不同的土壤温度调节措施都会带来白菜产量的显著增加,灌溉水加温、覆膜以及覆膜条件下灌溉水加温处理的产量分别比无调节处理增产3.9%、10.6%和11.1%。在秋冬白菜生产中,采用覆膜与灌溉水加温处理相结合的土壤温度的调节方式可以起到有效的增温和增产作用。

Effects of Water-heat regulation on Soil Temperature,Chinese Cabbage Growth and Yield Under Drip Irrigation

Field experiments were conducted in solar heated greenhouse to investigate the effects of nitrogen rate and regulating meth-ods for soil temperature on the change of soil temperature,Chinese cabbage growth,nitrogen uptake and yield.Four regulating methods were used,including irrigation water heating,mulching,irrigation water heating with mulching and control treatment. Three nitrogen levels of 0,135 and 270 kg/hm2 were tested.The results indicated that irrigation water heating apparently increased soil temperature during the irrigation process,and temperature increase 3.9,4.8 and 7.0℃ in the seeding stage,rosette stage and heading stages respectively.But when the irrigation process was over,soil temperature will drop rapidly.The effect of mulching was more obviously in the early stage and deeper soil.Irrigation water heating with mulching could achieve more effective soil tempera-ture increase,and accumulated temperature increase during the whole season were 136,128 and 120 ℃ in 10,20 and 30 soil layers respectively.Both irrigation water heating and that with mulching could increase the aboveground dry matter and nitrogen uptake significantly,especially with a higher nitrogen rate.All treatments of water-heat regulation could apparently increased cabbage yield with a range of 3.9% to 11.1%.For Chinese cabbage production,irrigation water heating with mulching were recommended to im-prove soil water and heat condition.