| Drip irrigation under mulch film is one of the methods to save water,reduce water evaporation and increase crop yield in arid and semi-arid regions.In order to further study field microclimate and crop growth differences between drip irrigation under film mulching and no mulching,to guide maize cultivation,the film mulching and no mulching plus a rain fed treatment was set in the northeast region.Each treatment was set 3 replicates in 2015-and 2016.The effect of mulching and no mulching on soil water and heat changes between air temperature and humidity and heat balance was analyzed,and observe the biological characteristics of crops,including plant height,leaf area and dry matter,the results are as follows:1.Effect of drip irrigation under Mulch on soil water and heat(1)Under the condition of drip irrigation under mulch film in the northeast of China,the soil moisture content of the main soil area decreased rapidly during the jointing stage,and that of the soil surface was greatly affected by rainfall.The moisture content of plastic film mulching treatment was as high as 38%,but when the rainfall was too long,the film mulching effect was not obvious.In addition,variation of water storage on the corn roots soil in maize was similar to soil moisture,decreased drastically from jointing to filling.Soil water storage of film mulching treatments was 20% higher than no mulching treatment.(2)During the whole growth period,the daily mean value of soil temperature changed with the change of air temperature,which showed the change trend of cosine function first increased and then decreased.The 0-20 cm temperature of soil surface soil had generally trend cosine function.Soil temperature of 45 cm soil layer was similar between 2015 and 2016,with the increase of depth,the time that soil diurnal variation temperature reaching the maximum value was delayed,and in the same depth,the time soil temperature of film reaching the maximum delayed compared with no mulching.2.Effect of drip irrigation under Mulch on air in Maize(1)There was no significant difference in the air temperature and humidity between the treatments(P>0.05).With the increase of height,the gap of air temperature and humidity between film mulching and no mulching decreased gradually.There was no significant correlation between the temperature and the air temperature between the 10 cm and the canopy,but there was a significant correlation between the temperature and the air temperature at the height of the half plants.With the increase of height,the relationship between the temperature of the crop was: crown > half of the plant height > 10 cm of soil surface,while the relationship between the moisture content of the crop was: 10 cm of soil surface > half of the plant height > crown.(2)The net radiation without film surface of the average value was 33.5% higher than treatments(2015).The net radiation on the crown present an inverted "U" trend,and the average value of net radiation without film was 5.6%(2015),1.6%(2016)higher than film.(3)The soil heat flux change in furrow of mulching was as similar as no mulching.In 2015,the treatment without plastic film mulching was 2.8W/m2 higher than film.The soil heat flux in middle between the treatments was the same.In 2015,the average value of film mulching was 0.06W/m2 higher than no film mulching treatment.In 2016,the average value of no film mulching was 0.69W/m2 higher than film mulching treatment.The middle ridge soil heat flux between film mulching and no mulching treatment had no significant difference in 2015 and 2016(P>0.05).3.Effects of drip irrigation under Mulch on biological characteristics of Maize(1)In 2015 and 2016,the relationship between plant height of Maize,leaf area index or dry weight and days after sowing accorded with the logistic model.The plant height of drip irrigation under film mulching treatment were 7.55%(2015),1.88%(2016)high than no mulching.In 2015,the leaf area index of film mulching was 22.15% higher than no film.In 2016,the leaf area index of no film mulching was 8.45% higher than film.The dry weight of film mulching were 21.7%(2015)higher than the treatment without film mulching.(2)The yield in 2015 was 10645.49-12482.37 kg/hm2,that of 2016 was 10466.07-12032.78 kg/hm2,and the yield of film mulching was higher than that of no plastic film production by an average of 8.8%(2015),7.9%(2016).(3)WUE of film mulching was higher than that of no plastic film mulching treatment by 1.1%(2015),6.9%(2016).WUE of Film mulching were 4.8%(2015),15.9%(2016)higher than the rainfed treatment.It was obvious that drip irrigation could improve water use efficiency. |
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