| As the main cultivation technique in arid and semi-arid areas,plastic film mulching has been widely used.In order to find out the temporal and spatial changes of soil water and temperature and their effects on the formation of crop yield in dry land covered with plastic film,a field experiment was carried out in the dry land agricultural experimental station of Northwest University of agriculture and forestry science and technology in Pengyang County,Guyuan City,Ningxia Hui Autonomous Region from 2020 to 2021.The single factor randomized block design was adopted,including four treatments: full film double ridge and furrow sowing(D),half film spreading(PM),half film ridge and furrow(R)and bare land flat planting(PZ),The changes of soil moisture and temperature,the accumulation and distribution of photosynthetic products and the differences of nutrient uptake in different organs of spring maize under different film mulching planting methods were studied,which provided a reference for the optimization and application of film mulching planting technology in dryland.The main results are as follows:(1)Effects of plastic film mulching on soil water temperature in spring maize fieldFilm mulching significantly increased the soil temperature of 25 cm soil layer and affected the soil moisture content during the growth period of spring maize.Compared with half film paving(PM),half film furrow(R)and bare land flat planting(PZ),the soil temperature of full film double ridge sowing(D)increased by 1-2 ℃,and the warming effect was better in 10 cm and 20 cm soil layers.The soil moisture content of 0-200 cm in the two-year maize growth period from high to low is PM(16.5%)> d(16.2%)> PZ(16.0%)>R(16.0%).Due to the comprehensive effect of crop growth consumption and rainfall,the soil water content of different mulching methods in different growth periods and different soil layers showed a large spatio-temporal dynamic change.(2)Effects of film mulching on Photosynthetic Characteristics and dry matter accumulation of Spring MaizeFilm mulching significantly improved the photosynthetic performance of spring maize and promoted the accumulation of dry matter.Compared with PZ,the two-year average net photosynthetic rate(Pn)of film mulched D,PM and R treatments increased by 12.6%,8.9%and 5.8%,SPAD increased by 12.3%,3.2% and 2.2%,leaf area index increased by 43.3%,33.4% and 48.0% respectively,and dry matter accumulation increased by 55.7%,44.1% and50.0% respectively.(3)Effects of plastic film mulching on nutrient absorption and distribution of Spring MaizeThe positive effects of plastic film mulching on soil moisture and temperature promoted the transport of more nutrients to grains at grain filling maturity.The law of nitrogen and phosphorus uptake by plants under different film mulching methods at maturity stage was the same,from high to low,d > PM > R > PZ.The two-year average nitrogen uptake content of D,PM and R treatments was 30.7%,29.5% and 8.1% higher than that of PZ,respectively.The two-year average phosphorus uptake content of D,PM and R was 41.0%,21.9% and15.3% higher than that of PZ.Under different film mulching methods,the absorption of nitrogen in various organs of the plant showed the following: grain(67.3%)> stem(12.9%)> leaf(11.0%)> others(8.8%).(4)Effects of plastic film mulching on Yield and production benefit of Spring MaizeCompared with PZ,the ear length of D,PM and R increased by 20.1%,13.3% and8.4%,respectively;Ear diameter increased by 9.5%,8.0% and 7.8%,respectively;The number of grains per ear increased by 31.5%,10.63% and 21.2%,respectively;100 seed weight increased by 36.0%,39.0% and 32.2%,respectively;The yield increased by 85.0%,67.7% and 59.8%,respectively.Although film mulching increased the production cost,it improved the economic benefit of dryland spring maize.Compared with PZ,the production investment ratio of D,PM and R increased by 21.2%,21.9% and 16.7%,respectively.In conclusion,compared with PZ,full film double ridge and furrow sowing significantly improved the photosynthetic performance of crops(14.0%),soil temperature in10cm-20 cm soil layer(7.6%),dry matter accumulation(55.7%),and nitrogen absorption of plants(30.7%),and promoted the transformation of photosynthetic products into grains during grain filling maturity,thus significantly improving the yield(85.0%)and the yield input ratio(21.2%),which is the most economically effective film mulching method in maize production in semi-arid areas. |
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