| Red-fleshed Pitaya(Hylocereus polyrhizus Britt.&Rose cv.'soft branch dahong')introduced from Taiwan planted in Langqi Rongsheng Leisure Farm in Mawei District of Fuzhou city Fujian province was used as experiment material.Four different sod culture treatments were carried out for pitaya fruit cultivated in greenhouse,i.e.? set of alfalfa,?sets of white clover,? sets of Cassia rotundifolia and IV sets of natural grasses,and contrasted with clean tillage.The differences of microenvironment,yields,quality and economic benefit of pitaya orchard under different sod culture designs were compared.The main results were as follows:1.These 4 kinds of sod culture treatments could significantly reduce the temperature and raise the air humidity in summer pitaya orchard.When the average temperature in June was below 30 C,cassia rotundifolia(Chamaecrista rotundifolia)had the best cooling and humidifying effect.The highest reduction range of temperature could be 1.95?,and the air humidity could be increased by 10.2 percentage points.When the average temperature in July and August was above 30 ?,the effect of white clover(Trifolium repens)on cooling and humidifying was the best.The maximum temperature could be reduced by 1.70?,and the air humidity could be increased by 12.9 percentage points.2.Compared with clean tillage,these 4 kinds of sod culture treatments could significantly reduce soil temperature and soil bulk density in 0 cm-20 cm soil layer in summer,increase soil water content,total porosity and capillary porosity,but the effects of different sod culture treatments were different.Soil temperature could be lowered by 3.63? by sod culture,but there was no significant difference between different grasses.Soil water content of natural grasses was the best,which could increase 6.79 percentage points.White clover(Trifolium repens)treatment had the best effect of reducing bulk density,the increment was 12.33%.Alfalfa(Medicago sativa)treatment had the best effect of increasing total porosity and capillary porosity,which increased total porosity and capillary porosity by 11.80 and 13.47 percentage points,respectively3.Sod culture could significantly increase the soil organic matter content in 0 cm-20 cm soil layer in pitaya orchard,but the effect on soil pH was not significant;after 0.5a and la of grass growing,the soil organic matter content increased,white clover treatment had the best effect,which could increase the content of soil organic matter by 0.36 and 0.84 percentage points,respectively4.Soil total nitrogen content,total phosphorus content,total potassium content,alkali-hydrolyzed nitrogen content,available phosphorus content and available potassium content in 0 cm-20 cm soil layer of pitaya orchard were significantly increased by the other 3 sod culture treatments except that natural grasses treatment slightly reduced the total phosphorus content in soil.Cassia rotundifolia treatment had the best effect on improving soil total nitrogen content,with an increment of 96.72%compared with clean tillage.White clover treatment had the best effect on improving soil total phosphorus and alkali-hydrolyzed nitrogen,with an increase rate of 79.82%and 130.05%,respectively.Alfalfa treatment had the best effect on improving soil total potassium and available phosphorus,with an increase rate of 12.82%and 30.24%,respectively.Natural grasses treatment had the best effect on increasing soil available potassium,with an increase of 77.43%.5.Compared with clean tillage,sod culture treatments could significantly increase the contents of Ca,Fe and Zn in 0 cm-20 cm soil layer of pitaya orchard.Cassia rotundifolia treatment had the best effect,with the increasement of 20.16%,25.51%and 52.94%respectively,there was no significant difference in Ca content between other sod culture treatments and clear tillage treatments.Natural grasses and alfalfa treatments could significantly increase soil Fe content,while white clover treatment has no significant difference with clean tillage treatment.Natural grasses and white clover treatments had the most significant effect on improving soil Zn content,soil Zn content of alfalfa treatment had no significant difference compared with clean tillage treatment.There was no significant difference in the content of Mg in the soil between the different sod culture treatments and the clean tillage6.The activities of soil urease,invertase,catalase and alkaline phosphatase in 0 cm-20 cm soil layer of pitaya orchard were significantly increased by these 4 kinds of sod culture when compared with clean tillage.Among them,Cassia rotundifolia treatment had the best effect on increasing soil urease activity,with an increment of 51.05%.Alfalfa treatment had the best effect on increasing the activities of sucrase,catalase and alkaline phosphatase,which increased the activities of various enzymes by 82.69%,131.40%and 120.00%,respectively7.The average single fruit weight,edible rate and fruit firmness of pitaya fruit were improved by four kinds of sod culture,and the thickness and fruit shape index of peel were decreased.Among them,alfalfa treatment and natural grasses treatment had the most significant effect in increasing average single fruit weight,edible rate and reducing peel thickness,the average single fruit weight could be increased by 32.66%,the edible rate increased by 5.36%,the longitudinal diameter increased by 10.08%,the transverse diameter increased by 15.24%,and the peel thickness decreased by 29.33%,white clover treatment had the most significant effect on reducing fruit shape index,up to 6.60%,natural grasses treatment had the best effect on improving fruit firmness,up to 31.25%8.The content of soluble solids,soluble sugar,soluble protein,vitamin C and pectin in pitaya fruit could be increased by these 4 kinds of sod culture treatments.In July,the effect of interplanting Cassia rotundifolia treatment was the most remarkable.The contents of soluble solids,soluble sugar,soluble protein,Vc and pectin increased by 4.74%,25.42%,56.39%and 25.89%respectively compared with that of clean tillage.In August,the effect of Interplanting Alfalfa treatment on the soluble solids,soluble sugar,soluble protein,Vc and pectin content of pitaya fruit was the most significant,with the increase of 7.99%,6.67%,13.02%and 10.12%,respectively.In July,there was no significant difference in titratable acid content between sod culture treatments and clear tillage.In August,interplanting Cassia rotundifolia treatment could significantly reduce the titratable acid content of pitaya fruit by 18.22%.In August,white clover treatment increased Vc content by 5.22%compared with clear tillage,while other sod culture treatments increased Vc content slightly but not significantly9.Sod culture could inhibit the growth of weeds in pitaya orchard,and significantly reduce the number of weeds.Alfalfa treatment had the best weed control effect,with the highest reduction of 84.09%.Meanwhile,sod culture could significantly reduce the proportion of withered branches in the pitaya orchard which caused by high temperature.After interplanting alfalfa,the dried-up rate of Pitaya branches were the lowest,which decreased by 48.30%compared with clear tillage,thus directly affecting the number of fruit hanging and fruit yield.In August,which was most affected by high temperature,the treatment of alfalfa increased by 48.37%compared with that of clean tillage.However,sod culture significantly increased the damage rate of plants to Helicoverpa armigera and Spodoptera litura larvae in Huolong orchard,the alfalfa treatment had the highest damage rate,reaching 8.03%and 11.63%,respectively10.In the actual production of this experimental base,grass cultivation in summer(from July to August)could spent about 100-305 CNY on grass seeds,insecticide and seeding,spraying and other labor costs,saved about 270 CNY on herbicide and herbicide labor costs,and increase the output value of pitaya orchard by 2920-5672 CNY per 667 m2.The results showed that sod culture could significantly improve the economic benefits of pitaya orchard,among which interplanting alfalfa treatment had the best effect,the economic benefits could be increased by 5757 CNY per 667 m2 in summer(from July to August). |
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