番茄、玉米套种膜下滴灌条件下农田地温变化特征

The interplanting between tomato and maize of soil temperature dynamics under mulched drip irrigation

土壤水热状况是影响作物生长的重要因素,以膜下滴灌及套种双重效应为背景,针对番茄、玉米套种农田设置了高(番茄:180 mm,玉米:270 mm)、中(番茄:132 mm,玉米:202.5 mm)、低(番茄:84 mm,135 mm)3种不同的灌溉定额,采用定位监测法测定番茄带膜间裸地(A)、覆膜番茄行间(B)、番茄带与玉米带膜间裸地(C)、覆膜玉米行间(D)共4个位置的不同深度主根区含水率和地温动态变化,研究了地膜覆盖、土壤水分以及作物遮阴对套种农田不同行间,不同深度土壤温度的影响特征。结果表明:全生育期内,4个水平位置的地温大小顺序与土壤深度有关,10 cm以上的地温大小顺序为C>D>A>B,10 cm以下的地温大小顺序为D>B>A>C;从土壤温度场的分布情况来看,地温的最大变幅出现在C处,为8.10℃;最小变幅出现在B处,为4.71℃;含水率与地温的关系表现为:5 cm以上地温与含水率呈反比关系,20 cm以下地温与含水率呈正比关系。可见,套种覆膜滴灌农田合适的土壤水分状况将有利于根区良好水热的形成,从而更有利于作物的生长。研究结果将对西北地区滴灌农田管理有一定的参考价值。

It is very significant for maintaining the optimal soil moisture and soil temperature in the crop field, because that is the important foundation of developing an optimal irrigation system. The environment of reasonable soil moisture and temperature in the field will not only enhance the water use efficiency but also benefit crop growth and increase crop yield, especially for interplanting field with complex crop environments. In the experiments, the interplanting of tomato and corn under mulched drip irrigation were tested in Hetao Irrigation District in 2012. We set up three treatments which are the high irrigation quota （tomato： 180 mm, corn： 270 mm）, medium irrigation quota （tomato： 132 ram, corn： 202.5 mm） and low irrigation quota （tomato： 84 mm, corn： 135 mm）. The moisture content and soil temperature of different depths of root zone were measured in the middle of bare soil between tomatoes belt （ A）, the middle of mulched tomato lines （ B）, the middle of bare soil between tomatoes and corn belt （ C）, the middle of mulched corn lines （D） and crop growth, and yield were observed in different growing seasons. The effects of plastic film, soil moisture and crop shade on soil temperature at different rows and depths of inter-planting were studied by the experiment. The results showed that it had apparent effect of mulch on heat preservation under 15 cm soil depths, but the soil temperatures of whole root zone were influenced by crop shade and soil moisture; The soil temperatures of four horizontal positions were significant variation for different the soil depths （5 cm, 10 cm, 15 cm, 20 cm, 25 cm） , and the proper sequence of average soil temperature above 10 cm soil depth in different positions was： C〉D〉A〉B, the one under 10 cm soil depth was： D〉B〉A〉C; The study on distribution of the soil temperature in the interplanting field showed that the maximum variational amplitude of soil temperature appeared at the C position, and it would reach 8.10 ℃ ; the minimum variational amplitude of soil temperature appeared in the B position, and it was only 4.71 ℃. There was definitely some inverse correlation between the soil temperature and soil moisture above 5 cm soil depth, however direct proportion was observed below 20 cm soil depth. The study also found that there was strong temperature effect in the middle of lines between high and low crops （ such as C position ） during daytime, and the temperature can influence the crop of two sides, so mulched cultivation has obvious effects for restraining the loss of heat. It is thus clear that the optimal soil water and soil temperature are beneficial to form better soil moisture and temperature environment and high crop yield in the intercropping field under mulched drip irrigation. The study will be very meaningful for drip irrigation farm management in the Northwest Region.