Effects Of Growing Grass On Soil Nutrients In Orchards And Study On The Model Of Growing Grass

In order to clarify the soil condition of grassy orchards in Hebei Province,and try to find out the modern technology of grassy orchards which can effectively improve soil nutrients in Hebei Province.Firstly,based on Meta analysis,the effect of grass on soil nutrient content in orchards in China was analyzed,and the status of grass in orchards and typical natural grass orchards in Hebei Province was analyzed by field investigation and sampling.The effect of grass on Soil Nutrient in typical orchards in Hebei Province was confirmed by positioning experiment of artificial grass.The main results are as follows:(1)The results of Meta analysis showed that grass-planting can significantly improve the content of organic matter and total nitrogen in orchard soil,with an average growth rate of over 20% and over 13%,respectively.The average growth rate of soil organic matter and total nitrogen in natural sward mode was higher than that in artificial sward mode.Among the typical artificial sward,ryegrass had better effect on improving soil organic matter,and white clover had better effect on improving soil total nitrogen content.The contents of total phosphorus,total potassium,alkali-hydrolyzed nitrogen,available phosphorus and available potassium in soil has increased after growing grass,however the contents of some nutrient elements has decreased under different growing methods and grass species selection.(2)The results of investigation in Hebei apple orchard showed that there were 23% survey sample orchard used sward technology,75% of which adopted the natural way of grass and 25% of which adopted the artificial way of grass.Artificial grass varieties can be divided into two categories: gramineae and leguminous herbage,mainly including alfalfa,white clover,bluegrass and ryegrass.The variety of natural grass is diversified,which is different in different regions.A trend of more in the south and less in the north was showed in Hebei province,and the main varieties were found including Chinese milkweed,dog tail grass,horse tang,carp intestines,numerous ray,dandelion,ground,hyssop chrysanthemum,small feigong,purslane(3)The data of natural grass-growing orchards showed that the content of soil organic matter and major elements under the new cultivation mode were better than that under the traditional cultivation mode,and the soil alkali-hydrolysis nitrogen under traditional cultivation mode was generally deficient.The low content of soil available manganese is the common characteristic of the orchards.The content of soil available zinc under new cultivation mode were better than that under the traditional cultivation mode.The content of soil available iron and available copper were similar under two cultivation modes.(4)The results of positioning tests in typical orchards with artificial sward showed that years of grassing could increase the content of soil organic matter and organic carbon,and the rate of organic matter increase was between 9.17% and 27.4%.The content of nitrogen in the soil was increased,especially under leguminous white clover.The C/N of the surface soil were increased under the gramineous plants and decreased under the leguminous plants.The contents of available p and available k in soil were increased by grassing white clover and ryegrass respectively.The change of soil available iron content was not significant after growing grass.The content of available manganese in soil increased significantly.The content of available zinc and available copper in soil decreased significantly.The effective boron content in soil was increased under different treatments,but the difference was not significant.The contents of exchangeable calcium in soil were significantly increased under the treatments of white clover and bluegrass.The content of exchangeable magnesium in soil was significantly decreased under all the treatments.(5)In the natural sward mode,the grass which grows by creeping or has thin or hollow stalks such as dandelion,goshen,coccyx can be cultivated.In the artificial sward model,it is recommended to choose rye grass,bluegrass and alfalfa and clover of legume.Malignant weeds should be removed and dominant grass communities should be cultivated in the natural sward mode.Orchard sward demonstration was carried out within the scope of Xingtai county,and the grass growing effect was evaluated by the coverage degree.To sum up,orchard grass can increase the content of soil organic matter,total nitrogen,phosphorus,potassium and available nutrients.In Hebei orchards,it is suitable to popularize artificial grassland models mainly consisting of white clover,alfalfa,ryegrass and bluegrass,and natural grassland models mainly consisting of dandelion,goblin grass and setaria.