| Mulching film can save water and soil moisture,improve soil water and fertilizer conditions,greatly increase crop yield,and is widely used in facility agriculture.However,due to the fact that the thickness of most domestic mulching film is less than 0.008mm,its strength is low,it is easy to be broken,and the recovery rate is low,the residual amount of farmland mulching film increases year by year,and the negative impact on the production of facilities agriculture is increasingly prominent,which has threatened the sustainable development of agriculture.In this study,six residual film amount gradients(0,200,400,600,800 and1200kg/hm~2)were set by outdoor facility greenhouse test,corresponding to CK,T1,T2,T3,T4and T5 treatment,respectively.The effects of different residual film amounts on soil moisture,transpiration water consumption,root morphology,yield,quality and water use efficiency of tomato plants were studied in order to provide theoretical reference for formulating scientific and reasonable farmland management measures and preventing and controlling residual film pollution in the residual film area.The research conclusions are as follows:(1)Under this experimental condition,0 to 30 cm soil layer CK treatment of soil moisture content significantly lower than the residual film,film processing residue at different stages after the soil moisture content increased with the increase of soil depth first reduced,CK,after processing to reduce the processing of soil moisture content increased with the increment of the residual film to reduce after,have been reduced by the development of growth period after rising trend.The soil moisture content of 20-30cm with residual film treatment was the highest,which ranged from 22.38%to 24.40%.Soil water content of 0-30cm with residual film treatment at different growth stages was firstly increased and then decreased,and that of 30-60cm was firstly decreased and then increased,and that of CK treatment was increased with the increase of soil depth.The difference of soil profile moisture content between residual film treatment and no residual film treatment at different growth stages is the most significant at seedling stage.With the continuous increase of residual film content,soil profile moisture content tends to be closer to that of CK treatment.The peak value of soil water content in the 0-30cm soil layer fluctuated back and forth among the residual film treatments.The peak value of T1 was 22.53%higher than that of CK at the seedling stage,T3 was 15.61%higher than that of CK at the flowering and fruit setting stage,and T1 was 10.51%higher than that of CK at the fruit expansion stage.The soil moisture content of each treatment decreased first and then increased with the development of growth period.The residual film mixed into the soil had no significant effect on the overall trend of soil moisture content during the whole growth period.(2)The residual film had a great effect on the transpiration rate of tomato leaves at seedling stage and flowering and fruit-setting stage,but the effect of residual film was not obvious at fruit expansion and maturity stage.T5 treatment had the highest transpiration rates at seedling and flowering and fruiting stages,which were 9.91mmol/(m~2·s)and 9.80 mmol/(m~2·s),respectively,15.97%and 33.78%higher than CK treatment.With the increase of the amount of residual film,the transpiration rate of leaves decreased firstly and then increased at the seedling stage,and showed an increasing trend at the flowering and fruit-setting stage.The residual film had little effect on the water consumption and water consumption intensity of tomato in the whole growth period,more significant effect on the water consumption and water consumption intensity at flowering and fruit-setting stage,and little effect on other growth periods.At the flowering and fru It’setting stage,the water consumption of T4 treatment was 43.89±11.69mm,and the water consumption of CK treatment was 23.91±2.43mm.The water consumption and water consumption intensity of each treatment were T4>,T5>,T3>,T2>,T1>CK.With the development of growth period,the difference of water consumption and water intensity between CK treatment and residual film treatment became smaller and smaller.(3)Residual membrane had a certain effect on the root length and root surface area of tomato during the four growth stages,but it did not show a continuous and stronger inhibition effect.When the amount of residual membrane was too much,the root development of tomato was better.The residual film had a great effect on the vertical distribution of root length and root surface area at seedling stage and flowering and fruit-setting stage,and had a significant effect on the vertical distribution of root length and root surface area at 0-20cm soil layer at fruit expansion stage and maturity stage.The residual film had no significant inhibitory effect on the root volume of tomato at seedling stage and flowering and fru It’setting stage,and even had a certain promotion effect.The residual film had a significant inhibitory effect on the root volume of tomato at fruit expansion stage.The residual membrane had no negative effect on the growth of tomato root volume at mature stage,and even promoted the growth of tomato root volume.With the increase of residual film amount,the root length and root surface area density of tomato firstly increased and then decreased at seedling stage,firstly decreased and then increased at flowering and fruiting stage,firstly decreased and then increased at fruit expanding stage,and then increased and then decreased at mature stage.The root volume density of tomato showed a trend of firstly increased and then decreased at both seedling stage and flowering and fruiting stage.(4)Under the conditions of this experiment,the tomato yield of CK treatment was 28.95%and 19.08%higher than that of T1 and T2 treatment,respectively.However,with the continuous increase of residual film amount,the tomato yield did not show a stronger and stronger inhibitory effect,but first decreased,then increased and finally fluctuated.The results indicated that a certain amount of plastic film residue(200kg/hm~2)could reduce the yield of tomato,but the residual film had no significant effect on the growth and development of tomato as a whole.Under the experimental conditions,the soluble sugar content of T2 treatment was the highest,which was 59.05%higher than that of CK treatment.When the residual film amount was less than 400kg/hm~2,the soluble sugar content of tomato increased with the increase of the residual film amount.The organic acid content of tomato ranged from 0.62%to 84%.Although CK treatment was the highest,different residual film amount had no significant effect on the organic acid content.The residual film had a significant effect on the ratio of sugar to acid of tomato,and the nucleic acid ratio size of each treatment was T2>,T4>,T1>,T3>,T5>CK.The content of Vc in tomato ranged from 28.06 to 45.04%,the highest in T1 treatment and the lowest in CK treatment.Compared with CK treatment,the content of Vc in tomato under T1 treatment increased by 60.30%.The residual film had a significant effect on the nitrate content of tomato,and the nitrate content of T2 treatment was the highest,which was 73.53%higher than that of CK treatment.When the residual film amount was less than or equal to400kg/hm~2,the nitrate content showed an increasing trend,but with the accumulation of residual film(>400kg/hm~2),the soil moisture increased,and the nitrate content in tomato decreased.(6)The residual film had a great influence on the instantaneous water use efficiency of leaves at the seedling stage and flowering and fruit-setting stage.T4 treatment was 18.40%higher than CK treatment at the seedling stage,and CK treatment had the highest instantaneous water use efficiency at the flowering and fruit-setting stage.It was 12.19%,9.16%,20.62%,23.31%and 20.00%higher than that of T1,T2,T3,T4 and T5,respectively.With the increase of residual film amount,the instantaneous water use efficiency of leaves increased firstly and then decreased at the seedling stage,then decreased continuously at the flowering and fruiting stage,decreased firstly and then increased at the fruit expansion stage,and increased firstly and then decreased at the mature stage.Under the conditions of this experiment,CK,T3 and T5treatments had relatively high water use efficiency at yield level,and CK treatment was 15.64%,11.18%and 14.24%higher than Ti,T2 and T4 treatments,respectively.The WUE of tomato yield level fluctuated up and down with the increase of residual film amount,but did not show a gradual decrease.The results indicated that the residual film mixed into the soil could affect the WUE of tomato yield under the experimental conditions,but on the whole,the residual film had little effect on the WUE of tomato yield.The tomato quality was comprehensively evaluated by CRITIC weight method,and the ranking result was T1>T3>T4>T2>CK>T5(7)According to the analysis of principal component analysis,the comprehensive evaluation scores of the 6 treatments in this experiment ranked CK>,T5>,T3>,T4>,T2>T1.According to the results of different residual film amount on soil moisture,root morphology,yield,quality and water use efficiency of tomato in this experiment,it can be seen that a certain amount of residual film amount(≤400 kg/hm~2)is obviously not conducive to the growth and development of tomato,but with the accumulation of residual film amount(≥600kg/hm~2),the negative effect of residual film amount on tomato will gradually decrease. |
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