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Effects Of Straw Mulching On Soil Water And Salt Distribution And Crop Growth Regulation Under Drip Irrigation

Posted on:2018-09-02Degree:MasterType:Thesis
Country:ChinaCandidate:T T BaiFull Text:PDF
GTID:2370330518490589Subject:Crop Cultivation and Farming System
Abstract/Summary:PDF Full Text Request
In order to elucidate the effect of straw mulching on the distribution of soil water,salt and the regulation of growth of wheat and corn under drip irrigation,winter wheat AK58,summer corn Zheng Dan 958 as the experimental materials,two-factor fractal plot tests were designed,Straw treatment(covering T,not covering T0)and field water holdings of four irrigation levels,40%(WI),50%(W2),60%(W3),70%(W4)(summer corn at this level plus 10%),through the large-scale mobile shelter under the test pit test.The effects of straw mulching on soil water and salt distribution,crop growth and development,grain filling characteristics and yield were studied systematically under drip irrigation.The main conclusions are as follows:Straw mulching under drip irrigation can significantly reduce crop water consumption,increase soil water storage capacity and improve water use efficiency.Straw mulching has a significant effect on preserving deep soil moisture,under the conditions of W1 and W2,moisture retention time up to 20 d,crop utilization and regulation of water can be as deep as 100 cm below;Under the condition of high water content,the water content of soil under straw mulching was 2%-5% higher than that of not cover,and the utilization of water was only 100 cm.The water consumption of straw mulching in the soil layer of 0-100 cm decreased by 7.45%-36.17% under the condition of drip irrigation:the amount of evaporation decreased by 9.14%-49.33%,soil water storage was increased 4.30%-6.23% than straw not covered.So that the water is mainly concentrated in the surface soil,the surface soil moisture content increased.Straw mulching is not conducive to the vertical direction to reduce salt,but can effectively increase the horizontal direction of salt suppression effect,the soil salt to the horizontal direction of the migration occurred mainly in the range of droplets 0-20 cm range,and the condition of not cover,the main occurred in the distance from the droplet 0-10 cm,the range of salt leaching can be increased by straw mulching,and the accumulation of salt in the horizontal direction of the root zone can be reduced.The treatment of W3 can effectively reduce the accumulation of salt in soil surface: the spatial migration distance of soil salinity under drip irrigation shows an increasing trend with the increase of irrigation amount,and the peak position of soil salinity is decreasing.During the whole growth period of winter wheat,drip irrigation can reduce the accumulation of 25.7%-31.5%,straw mulching and soil relative water content interaction can reduce the conductivity of 25.0%-51.0%.The salt concentration of TW4 treatment group was the lowest(384.88?S / cm before harvest: 324.13?S / cm after harvest),which was significantly lower than that of other treatments throughout the growth period.The plant height and leaf area index of winter wheat and summer maize could be significantly increased by straw mulching under drip irrigation.Under different coverage modes,the effects of straw mulching on the height of each treated crop were better than those in the early stage;Leaf area index coverage is opposite.Compared with the straw cover is not covered,under the condition of straw cover,plant height increased by 2.11%-20.93%(winter wheat)and 9.15%-16.41%(summer maize),leaf area index increased by 23.84%-49.46%(winter wheat)and 18.73%-46.77%(summer maize).Under different water gradients,the plant height of winter wheat straw was higher than that of not covered,but with the increase of water gradient,the difference gradually decreased.On the condition of straw mulching the plant height was better than that of low water under treatment of W3 and W4 in summer maize.Straw not covered plant height changes significantly under W1 treatment in the late row of pumping row of silk.Straw mulching could significantly improve the yield and water use efficiency of winter wheat and summer maize under drip irrigation.Under different coverage patterns,winter wheat increased by 11.15%-18.43% due to the increase of 1000-grain weight,summer maize by increasing the number of rows of particles,reducing bald tip length,the output increased by 14.60%-29.82%.Under different coverage modes,the water use efficiency was 4.28%-15.85%(winter wheat)and 20.35%-82.98%(summer maize);Water use efficiency is increased by 4.28%-15.85%(winter wheat)and 20.35%-82.98%(summer maize)than straw not covered;Under different water gradients,the water use efficiency was highest under W3 treatment in winter wheat and summer maize.Simulation of Grain Filling Process of Winter Wheat under Straw Mulching and Moisture Control Using Richards Growth Model,the results show that: the filling process of winter wheat was in accordance with the "S" growth curve,R2 from 0.9775 to 0.9996.Therefore,Richards can accurately reflect the straw mulching and moisture regulation and interaction of winter wheat grain filling process of weight gain.Through the interaction of straw mulching and water regulation,the characteristics of grain filling characteristics during the grain filling period of winter wheat were analyzed and compared: TW3 treatment had the maximum values of filling duration T,51.91 d,medium-term duration of grain filling T2,15.23 d,late duration of grain filling T3,26.56 d,medium grain filling rate R2,0.897 mg/d and late grain filling rate R3,1.365 mg/d.Water use efficiency and yield are not synchronized with trends in water consumption,the best combination of the two theoretically at 240mm(winter wheat)and 360mm(summer maize).Thus we can see that,the yield and water use efficiency double high effect in the water consumption of 240-270mm(winter wheat),summer corn at 340-370 mm.Straw mulching and soil relative water content of 60%(TW3)treatment combined with the highest water use efficiency(29.02%),the relative water content of soil70%(TW4)was increased by 5.30%,The yield was 7097.7 kg / hm2,There is no significant difference between the combination of TW4.So it can be drawn: TW3 is the best water-saving and high-yielding irrigation combination under this test condition.
Keywords/Search Tags:Winter wheat, Summer maize, Straw mulching, Drip irrigation, Water and salt distribution, Grouting characteristics, Yield
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