| Object:To address the problem of residual film pollution in agricultural fields caused by polyethylene mulching films,in order to vigorously develop water and fertilizer-saving agriculture,we accelerate the promotion of the practical application of degradable mulching films and guarantee the sustainable development of agriculture in irrigated arid oasis areas.This study investigates the effects of water-fertilizer interactions on the yield and growth characteristics of drip-irrigated maize covered with degradable films.To explore whether degradable films can replace ordinary polyethylene mulching films in the arid zone of Xinjiang,and provides a theoretical basis for the screening of suitable degradable mulching film types and optimization of water and fertilizer management of drip-irrigated maize in the region.Methods:A field plot experiment was carried out for the corn variety"Jinguyu No.6"in the operation and management station of the Ili River Irrigation District Management Office in this experiment.A total of 5treatments were set up in the test in 2020:black and white oxidative biodegradable mulching films(BO,WO),black and white ordinary polyethylene mulching films(BP,WP)and Non-mulching films check(CK).In the experiment in 2021,the amount of drip irrigation and fertilization under oxidative biodegradable mulching film was set as two variable factors for a random complete combination design.Three irrigation quotas were set in this experiment:3700 m~3/hm~2(W1),4300 m~3/hm~2(W2),and 4900 m~3/hm~2(W3).Three nitrogen application levels were set:200 kg/hm~2(F1),240 kg/hm~2(F2),and 280 kg/hm~2(F3),in which both diammonium phosphate and potassium sulfate were 300 kg/hm~2.At the same time,under the local conventional irrigation conditions,three nitrogen application levels were set by ordinary polyethylene mulching film:F1,F2,and F3 as the control group of oxidative biodegradable mulching film,and a total of12 treatments,and all treatments were repeated three times.Results:(1)Covering with different mulching films can improve the soil moisture status of 0～60cm.In the later stage of drip-irrigated maize growth,compared to BP,WP,and CK,BO treatment could increase soil moisture by 2.26%to 11.34%(P<0.05),and WO treatment could increase soil moisture by 3.93%to 8.00%(P<0.05).The overall performance of each mulching films treatment was WP>BP>BO>WO>CK,and the BO treatment had better moisture retention than the WO treatment.Under the coupling conditions of water and fertilizer,the change of soil water content was mainly affected by the amount of irrigation,the higher the amount of irrigation,the higher the soil water content.Different mulching films mainly affected the soil water content variation pattern in the 0-40 cm soil layer,while it had less effect on the soil water content variation in the 40-60 cm soil layer.(2)The insulation effect of each mulching films treatment was generally comparable in 2020 and 2021.The overall performance of each mulching films treatment was WP>BP>BO>WO>CK,and BO treatment had better thermal insulation than WO treatment.Under the coupling conditions of water and fertilizer,the variation trend of soil temperature in the 5～15 cm and 15～25 cm soil layers was the same,however the degree of fluctuation of soil temperature in the 5～15 cm soil layer was greater,the difference of soil temperature between different irrigation treatments were more obvious,and soil temperature decreased with the increase of irrigation quotas.(3)After 20 days of maize sowing,the overall trend of soil nitrate nitrogen content in each water-fertilizer combination treatment was decreasing with increase soil depth,and the majority of soil nitrate nitrogen concentrated in the soil surface layer.After 60 days of maize sowing,the trend of soil nitrate nitrogen under each water-fertilizer combination treatment was decreasing,and then elevated and then dropped as the soil depth increased.After 100 days of maize sowing,the change trend of soil nitrate nitrogen under each water and fertilizer combination treatment was nearly the same as that after 60 d of sowing.After 130 d after sowing,in the 0-50 cm soil layer,the variation trend of soil nitrate nitrogen under each combination of water-fertilizer increased with the depth of soil layer.The change of nitrate nitrogen content at the place is as follows:F3>F2>F1.In the late growth stage of maize,the soil nitrate nitrogen contained in BO treatment was lower than in BP treatment,due to the degradation of the degradable mulching films.(4)Compared with BP and WP treatments,the plant height of drip irrigation maize under mulching under BO and WO treatments decreased by 3.2 cm,2.1 cm(P>0.05)and 10.3 cm,9.3 cm(P<0.05),respectively,and both were significantly increased by 9.9 cm and 2.8 cm,compared with CK treatments;stem diameter,leaf area index(LAI)and dry matter accumulation all showed the same performance.The overall performance was BP>WP>BO>WO>CK.Under the coupling conditions of water and fertilizer,the change trend of each growth morphological index of drip-irrigated maize increased with the increase of irrigation quota,while with the increase of fertilization amount,it showed a trend of first increasing and then decreasing gradually.The expression was:W3>W2>W1,F2>F3>F1.All indicators and parameters reached the highest level in the mature stage.The maximum values of all growth form indicators of maize were appeared in the high water and medium fertilizer(W3F2)treatment and the minimum values were appeared in the low water and low fertilizer(W1F1)treatment.(5)The yield of BO treatment decreased by 0.33%compared to BP and increased by 2.70%compared to WP treatment.The yield of WO treatment decreased by 5.35%(P<0.05)and 2.44%compared to BP and WP treatment,but both BO and WO treatments increased yield by 29.39%and 22.88%,compared to CK.The overall performance was:BP>BO>WP>WO>CK,and the water use efficiency had the same performance.Under the coupling conditions of water and fertilizer,the change trend of yield and water use efficiency of drip-irrigated maize increased with the increase of irrigation quota,while with the increase of fertilization amount,it showed a trend of first increasing and then decreasing gradually.The expression was:W3>W2>W1,F2>F3>F1.The maximum value of maize yield in the whole growth period was 14589.82kg/hm~2 in the high water and medium fertilizer(W3F2)treatment,and the minimum value appeared in the low water and low fertilizer(W1F1)treatment was 12044.36 kg/hm~2.(6)The results of the 2a test showed that the ordinary polyethylene mulching films did not degrade during the whole growth period of maize,The degradation process of the oxidative biodegradable mulching films were basically similar,but it underwent different degrees of degradation.The speed and intensity of degradation varied from WO>BO>BP>WP,and the white oxidative biodegradable mulching film had the best degradation.After excess expenses for residual film recycling were removed,the net benefit of BO treatment was not significantly different from the ordinary polyethylene mulching films.Conclusion:Considering indicators of drip-irrigated maize growth index,yield,water use efficiency,in order to ensure maize yield and alleviate the residue of mulching films in farmland,the research believes that the black oxide biodegradable mulching film and the W3F2 treatment which a nitrogen content of 240 kg/hm~2and the irrigation quota was 4900 m~3/hm~2 was the optimal planting mode for maize under drip irrigation in the oasis of the Ili River irrigation area in Xinjiang. |
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