Effects Of Different Mulching Patterns On Soil Moisture-nutrient Characteristics And Citrus Quality In Guangxi Citrus Orchard

It is of great significance to improve soil water and fertilization condition,enhance the ecological function of citrus orchards,and achieve an increased quality and efficiency.In this study,the goal is to explore the changes of soil moisture and nutrients,as well as the quality characteristics of citrus leaves and fruits under different mulching patterns.Three treatments,including spraying herbicide(CK),covered with grass-proof cloth,and natural grass mowing,respectively,were set up to analyze the effects of different mulching patterns on the characteristics of soil moisture-nutrient citrus quality in a citrus orchard.The primary conclusions are as follows:(1)The soil p H value was significantly lower under the grass-proof cloth and natural grass mowing treatments than that under the spraying herbicide.Compared with spraying herbicide treatment,soil organic matter content at 0-10 cm,10-30 cm,and 50-70 cm depth of the fields were significantly increased by 29.89%-54.70% under covered with grass-proof cloth treatment,and the content at 0-10 cm,30-50 cm,and 50-70 cm depth of the fields were significantly increased by 34.56%-55.17% under natural grass mowing treatment.The grass control cloth mulching and natural grass cutting treatment provided a better fertility basis for the soil of the citrus orchard,which was more suitable for the growth of citrus.(2)Compared with the spraying herbicide,the treatment of covered with grass-proof cloth and natural grass mowing significantly increased the soil moisture content in the0～70cm during the young fruit period and fruit expansion period of citrus.Moreover,inhibited soil moisture evaporation and effectively improved the water-holding ability of soil under these two treatments,which can reduce irrigation water capacity and save water resources.In the citrus expansion stage,the direction of the soil water flux in the 0～70cm soil layer of the natural grass mowing and spraying herbicide was upward,with higher upward soil water flux under the earlier one,which could transfer more deep soil water upward for absorption by citrus roots.However,the soil water flux in the 0-70 cm soil layer covered with grass-proof cloth was downward,and the soil moisture in the middle and upper layers could already meet the growth demand of citrus.(3)Compared to the spraying herbicide treatment,the contents of alkali-hydrolyzable N,available K,and available Mg in the soil for the covered with grass-proof cloth treatment were significantly increased by 29.23%,77.36%,and 66.34%,respectively,and the contents of alkali-hydrolyzable N,available K,total N,and available Mg in soil under natural grass mowing increased by 33.20%,56.38%,8.45%,and 78.13%,respectively.Additionally,the contents of soil alkali-hydrolyzable N and total N in natural grass mowing treatment were significantly higher than those in the covered with grass-proof cloth treatment.The soil nutrient condition could be improved by the covered with grass-proof cloth and natural grass mowing,and the effect of natural grass mowing was better.(4)In the terms of leaf mineral elements,the treatments of covered with grass-proof cloth and natural grass mowing significantly increased various mineral elements of the levels such as N,P,K,Ca,Mg,Zn,and the natural grass mowing had the most prominent effect on increasing the mineral elements in citrus leaves,followed by the covered with grass-proof cloth.As for the citrus quality,the treatments of covered with grass-proof cloth and natural grass mowing significantly improved the soluble solids content,edible rate,rate of fruit juice,total sugar,VC content,sugar-acid ratio and solidity-acid ratio,and significantly reduced the total acidity of the citrus.Our results also indicated that both covered with grass-proof cloth and natural grass mowing treatments could effectively improve the quality and flavor of citrus fruits.In terms of correlation,the quality indicators of citrus such as soluble solids content,total sugar,VC content,sugar-acid ratio,and solidity-acid ratio were significantly positively correlated with the indicators of soil such as moisture content,organic matter,alkali-hydrolyzable N,available K,and available Ca,available Mg,and of leaves such as N,K,and Zn.In summary,the covered with grass-proof cloth and natural grass mowing treatments were more effective than spraying herbicide treatment in increasing soil moisture content,organic matter and effective nutrients,which resulted into the high soil water holding capacity,and reduced soil p H value.It suggested that such effective methods could be sustainablely applied to the citrus orchard of Guangxi.