Effects Of Newspaper Mulches On Soil Temperature And Humidity And Tomato Traits In Greenhouse

Mulching is an important agronomic measure for regulating temperature,preserving soil moisture,saving water and increasing production.In order to improve the defects of polyethylene film which is difficult to degrade and straw mulching which has toxic side effects and easy to breed pests and diseases,using paper instead of plastic is one of the effective ways to solve the problem of soil pollution.However,different mulching conditions will have different effects on the physical and chemical properties of soil and the growth characteristics of crops.The effects of different mulching amounts on tomato growth characters and quality under paper mulching conditions were studied,and the most suitable mulching amounts were explored to provide theoretical basis for facility tomato cultivation.With Provence tomato as the experimental variety,0.114 kg·m^-2（P1）,0.229kg·m^-2（P2）,0.458 kg·m^-2（P3）coverage treatments were set and compared with 0 kg·m^-2（CK）treatment.The infiltration,water retention and water loss of different newspaper coverage amounts were studied by double-ring infiltration method and immersion and water loss method.Soil moisture sensors were used to measure the soil temperature and humidity at the depth of 0-10,10-20 and 20-30 cm.Plant height,chlorophyll,leaf nitrogen content and fruit yield of tomato plants were measured regularly.Sugar acidity meter and hardness tester were used to measure fruit sugar acidity and hardness.The effects of newspaper coverage on soil moisture and heat change and tomato growth in greenhouse were studied.The results show that:（1）Under different newspaper mulching amounts,the soil infiltration rates were P3>P2>P1>CK in descending order,and soil infiltration rate increased with the increase of coverage thickness.After 24 hours of water absorption,the cumulative water absorption was P1>P2>P3,and the water absorption rate decreased with the increase of time.The cumulative water loss was P1>P2>P3 after 24 hours of water loss,and the water loss rate decreased with time.After the whole immersion and water loss experiment,the final water holding capacity of the three newspapers was P1>P2>P3.Through regression fitting,it was found that there was a significant logarithmic relationship between cumulative water holding and immersion time,and between cumulative water loss and water loss time,and the fitting degree of the three coverings was good.The relationship between water absorption rate and immersion time and water loss rate and water loss time is a significant power function.Among them,the newspaper of P3 has good permeability.Therefore,P3 can increase soil moisture and reduce surface runoff under the condition of flood irrigation and severe rain.P1 has the best water retention,which is beneficial to soil water retention in areas where sprinkling irrigation,drip irrigation and moderate and light rain prevail.The results can provide a basis for improving soil physical and chemical properties and soil water use efficiency under organic mulches.（2）Paper mulches can reduce soil temperature,and with the increase of soil depth,soil temperature increases with P2（2.11℃）the largest,P3（0.23℃）the smallest.The soil temperature of different treatments was CK>P3>P2>P1 from high to low.Compared with CK treatment,the soil temperature of P1,P2 and P3 decreased by 0.34℃,0.29℃and 0.28℃,respectively,and there was no significant difference in soil temperature among different treatments.Paper mulches can improve soil moisture.With the increase of depth,soil moisture increases by 5.73%in P2 and 0.07%in CK.The soil moisture of different cover amounts was P1（23.31%）>P2（22.82%）>P3（22.56%）>CK（21.92%）from high to low.The soil water consumption was CK（307.38 mm）>P1（304.35 mm）>P3（302.44 mm）>P2（296.70 mm）.The Hydrus-1D model was used to simulate the variation of soil water and heat during the whole growth period of tomato.The model could better reflect the variation process of soil water and temperature in all soil layers during the whole growth period of tomato.Although there were some deviations at some observation points,the simulation results were well fitted to the experimental results.（3）Compared with no mulching treatment,plant height,chlorophyll,leaf nitrogen content,yield,fruit weight,hardness and sugar-acid ratio of three different mulching treatments increased,while acidity and taste index decreased.In terms of water use efficiency,water use efficiency of P1 was the highest,followed by P2,and water use efficiency of P3 was lower than that of CK.The results showed that the growth characteristics and fruit quality and storage quality were improved under mulching treatments.In terms of chlorophyll,leaf nitrogen content,yield and water use efficiency,P2 treatment had the highest hardness,P3 treatment had the highest plant height,sugar degree and sugar-acid ratio,and CK treatment had the highest acidity and taste index.Through principal component analysis of each quality index,it was concluded that the comprehensive score of tomato growth traits and quality under P1 treatment was the highest.The effects of three mulching amounts on soil moisture and heat change,tomato plant and fruit quality were comprehensively compared.Paper mulches could reduce soil temperature and improve soil moisture,water use efficiency,yield and quality.The effect from high to low was 0.114 kg·m^-2,0.458 kg·m^-2and 0.229 kg·m^-2.The results showed that the treatment with 0.114 kg·m^-2 coverage had good water-saving,moisturizing and yield-increasing effect,and was more advantageous in this area.