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Effects Of Water And Nitrogen Regulation On Soil Water,Nitrogen And Salt Distribution And Growth Characteristics Of Sunflower Under Plastic Film Mulching And Furrow Irrigation

Posted on:2020-11-26Degree:MasterType:Thesis
Country:ChinaCandidate:Y L BaiFull Text:PDF
GTID:2370330596985847Subject:Agricultural Soil and Water Engineering
Abstract/Summary:PDF Full Text Request
China's terrain is complex,climate is diverse,water resources are unevenly distributed in time and space,cultivated land is scarce,and agricultural productivity areas are significantly different.Therefore,it is particularly important for the protection and development of cultivated land in some areas.Saline-alkali land is a kind of cultivated land that can be developed in China.It has a wide distribution range and huge potential for utilization.At the end of the20th century,most areas provided suitable growth environments for crops by irrigation and quantitative fertilization of saline-alkali land.However,the traditional extensive agricultural management methods have caused the waste of water resources and the deterioration of soil conditions to some extent,coupled with the long-term unreasonable irrigation and fertilization,which has led to the expansion of the area of salinized land.Therefore,the use of efficient water-saving irrigation methods and reasonable control of fertilization can provide a sustainable development direction for agricultural planting in saline-alkali land.This experiment studied the reasonable irrigation methods and water and nitrogen control of the farmland in Datong Basin from 2017 to 2018.Three factors were set in the experiment:two irrigation methods:horizontal irrigation(Q)and film furrow irrigation(G).Two types of irrigation:high irrigation volume 340 mm(W1)and low irrigation volume 300 mm(W2).Four nitrogen levels:nitrogen application rates were 156 kg/hm~2(N1),260 kg/hm~2(N2),364 kg/hm~2(N3),and no nitrogen(N0)treatment.Among,W1 irrigation was used for irrigation,and W1 and W2 irrigation were used for furrow irrigation.The effects of different water and nitrogen on the conductivity,water content and nitrogen change of salinized soil under the irrigation of irrigated and covered furrow were analyzed.The effects of plant height,disk diameter,1000-grain weight and other growth traits,as well as crop yield,water consumption and water and nitrogen use efficiency,resulted in efficient irrigation methods and fertilization levels.The research results can provide an effective scientific basis for improving the utilization efficiency of water resources and nitrogen,increasing grain yield,preventing secondary salinization of soil and preventing deterioration of ecological environment.The test has reached the following conclusions:(1)Under different water and nitrogen treatments,the volume watercontent has obvious stratification:the variation of water content of 0-40 cm soil layer is relatively large,and the variation is up to 15.00%.The water content of the soil layer of 40-100 cm soil layer has always maintained a relatively stable state.It is basically distributed between 15.00%and 20.00%.The surface variability of water content in 2017-2018 under different water and nitrogen treatments is about the same.Under different nitrogen application rates,the moisture content in the furrow irrigation conditions in 2017 was in the seedling stage,N0<N1<N2<N3.N0,N1,N2and N3 are 15.27%,15.82%,17.25%and19.23%,respectively.During the flowering period,N2>N1>N3>N0,N0,N1,N2and N3 were 13.83%,16.22%,16.42%and 15.39%,respectively.The water content of furrow irrigation was lower than horizontal irrigation at the seedling stage,and the flowering stage was higher than horizontal irrigation.Under different nitrogen application rates in 2018,the water content under furrow irrigation conditions showed N2>N1>N3>N0,before flowering N0,N1,N2 and N3 were 15.56%,18.96%,18.93%and 16.49%,respectively.The water content after the flowering period was about 12.00%.(2)Under different water and nitrogen treatments,the conductivity changes are also relatively large.From the overall point of view,the conductivity of 0-10 cm is close to 3000?S/cm.Conductivity of 40-100 cm soil layer,which is basically between 200-800?S/cm.The 40-100 cm soil layer serves as a potential reservoir of water and salt for crops.After applying nitrogen fertilizer,the soil conductivity also increased slightly,but within a certain range,with the increase of nitrogen application rate,it will not affect the change of soil total salt content.The effect of fertilizer application on the conductivity of 0-40 cm soil layer is greater than that of 40-100 cm soil layer.The amount of irrigation mainly changes the conductivity of the 0-40 cm soil layer.Under the conditions of furrow irrigation in 2017,the conductivity of 0-40cm soil layer is GW1N3>GW1N2>GW1N1>GW1N0.The conductivity of 0-10cm is 1560,1854,2012 and 2293?S/cm.The conductivity is significantly greater than the N0 condition in the 40-100 cm soil layer.The conductivity values of the soil layers N1,N2 and N3 are all around 500?S/cm,which is 200?S/cm larger than the conductivity of N0.The distribution of conductivity under W2 irrigation is roughly the same as that of W1.The conductivity of the furrow irrigation under low nitrogen conditions is lower than that of the irrigation.In2018,the conductivity of 0-40 cm soil surface layer is about 4000?S/cm,which is much larger than the conductivity of soil surface in 2017.In 2018,the conductivity of 40-100 cm soil layer was not significantly different under various nitrogen treatments,and the size was about 500?S/cm.There is no increase compared to 2017.(3)Fertilization and irrigation have significant effects on the content and distribution of nitrate nitrogen and ammonium nitrogen.Under certain nutrient conditions,the content of nitrate nitrogen in the soil increased significantly with the increase of nitrogen application rate(p<0.05).The effect of irrigation amount on nitrate nitrogen was different in soil layers.It is known that the greater the amount of irrigation,the nitrate content of soil in the 0-40 cm soil layer is significantly reduced,but the effect of irrigation on the nitrate content of 40-100 cm is not significant.Under N2 treatment,the nitrate nitrogen in the 0-40 cm surface of the soil is GW2N2>QW1N2>GW1N2.It can be found that under same irrigationmode,the larger the irrigation amount,the smaller the nitrate nitrogen content,and the GW2N2 ratio is more GW1N2 than 2.00mg/kg.Under the same water and nitrogen conditions,the nitrate nitrogen content in the 40-60 cm soil layer was less than that in the water irrigation.The difference between W1 and W2 is mainly reflected in the fact that under W1 conditions,the nitrate content of the 60-100 cm soil layer will incre ase as a whole because of the relatively large amount of irrigation.In 2017,the effects of different water and nitrogen treatments on soil ammo nium nitrogen were different under different soil depths,and the effect on soil nitrate was much greater than that in soil depth.The ammoniumnitrogen content in the farmland soil at a depth of 0-20 cm is larger than20-100 cm.Under the condition of N2,the soil 20-100 cm showed so me difference under different irrigation amount and irrigation mode,and it s ammonium nitrogen content basically showed GW1N2>GW2N2>QW1N2.It can be known that under the appropriate amount of nitrogen,theammonium nitrogen content in the depth of 20-100 cm in the furrowirrigation is larger than that under the irrigation condition,and the am monium nitrogen content also increases with the increase of irrigation a mount.As the depth of the soil increases,the ammonium nitrogen content decreases slightly.Under the state of irrigated,the ammonium nitrogen content was stable at 4.00 mg/kg along the soil depth of 20-100 cm.In2018,the distribution of ammonium nitrogen in the soil along the soil layer showed a certain difference under the different treatments in 2017.Under W1 conditions,a minimum occurs at 40-60 cm because the soillayer is sand,the soil water holding rate is low,and the retention of ammonium nitrogen is weak under continuous rainfall.Under W2irrigation,the ammonium nitrogen content in the soil at 0-20 cm depth is 20.01%higher than W1.Under the condition of irrigated irrigation,ammonium content of 20-100 cm was about 4.0 mg/kg,while the amm onium content of 20-100 cm in the furrow irrigation was 35.20%higher than that under the condition of irrigating.(4)Properly increase the amount of irrigation and nitrogen application,and change the irrigation method to promote sunflower growth.Under the condition of nitrogen application,the planting of furrows was higher than that of alfalfa-irrigated plants,indicating that the furrow irrigation was beneficial to the elongation of stems between sunflower seedlings and buds,and the height of different nitrogen plants under ridge and furrow cultivation.The conclusion is N3>N2>N1>N0,where GW1N2 has the highest plant height,and its value is about 156.0 cm.Under the nitrogen application rate,the diameter of the furrow irrigation is obviously larger than that of the rice irrigation,which is not proportional to the diameter of the sunflower.Under the same nitrogen application conditions,the disk diameter will increase when the amount of irrigation increases.Under the treatment of nitrogen application,the furrow irrigation of the film is more important than the 1000-grain.The effect of plastic film furrow irrigation on the increase of sunflower grain yield was significant(p<0.05).Under the condition of more nitrogen application,the effect of lifting was more obvious.In 2017,under the condition of N2,the yield of furrow irrigation was 329.2 kg more than that of horizontal irrigation.The effect of nitrogen application rate on sunflower grain yield was significant.When the nitrogen application rate was about 260.0 kg/hm~2,the yield of sunflower was the largest.The change of nitrogen application rate caused a significant difference in the agronomic utilization rate of nitrogen fertilizer and the partial productivity of nitrogen fertilizer(p<0.05).The irrigation amount had no significant effect on the agronomic utilization rate of nitrogen fertilizer and the partial productivity of nitrogen fertilizer(p>0.05).The irrigation method would make a significant difference in the agronomic utilization rate of nitrogen fertilizer(p<0.05).Under each nitrogen application condition,the effect of irrigation method on partial productivity was not significant(p>0.05).Compared with the mulching irrigation,the mulching irrigation can control the water and nitrogen in the soil during the whole growth period of the crop within a reasonable range.Therefore,the crop yield is increased,so the furrow irrigation is more scientific and reasonable.Covering furrow irrigation and tilling irrigation,crops can be applied with nitrogen fertilizer within a certain range,and the 1000-grain weight and the diameter of the disk will be significantly improved.However,excessive application of nitrogen fertilizer will inhibit the absorption of nutrients by the crop,and reduce the 1000-grain weight and the diameter of the disk.In the saline-alkali land,the furrow irrigation planting can significantly increase the plant height compared with the sloping irrigation.It is good for photosynthesis of crops,making sunflower seeds more full,thus increasing 1000-grain weight and increasing yield.
Keywords/Search Tags:sunflower, mulching furrow irrigation, irrigation amount, nitrogen application rate, water and salt, yield
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