A Study On The Succession Of Soil Nematodes Driven By Crop Planting

Nematodes,one of the micro-metazoans with the highest species diversity in and occupying the central position of soil food web,which plays an extremely important role in maintaining the stability of soil ecosystem and promotes material circulation and energy flow.Therefore,studying the succession law of soil nematode community and driving factors under crop planting conditions is not only of great significance to reveal the occurrence mechanism of plant-parasitic nematode diseases in agricultural production,but also provides some theoretical guidance for formulating appropriate prevention and control measures,and ensuring the sustainable development of agriculture.The main composition of the paper:(1)the laboratory soil indoor tomato potting experiments were carried out using different land use patterns(forest soil,grassland soil and farmland soil),to explore the effects of tomato planting on the succession of nematode under different land use patterns.(2)The laboratory soil were different vegetation types(tomato and pepper),to explore the changes of crop types and growth stages on the number and succession of nematode community structure.(3)On the basis of previous studies,we will further explore how vegetation types drive the succession of nematode community structure.The laboratory soil were different resistant tomato varieties,to explore the effects of adding different resistant tomato root exudates into the soil on the number and community structure of soil nematodes and the differences of root exudates of different resistant tomatoes.(4)Exploring the influence of community structure of soil nematodes after RSD-treated on planting tomato soil,it took nematode disease soil of Huanian Town in Yunnan Province as experimental material.The main results were showed below:1: There were significant differences in the number and community structure of soil nematodes under different initial nematode.The Land use was the key factor to decide the structure of nematode community in soil.And,community structure of soil nematode had different responses under different initial nematode.The abundance and diversity of nematodes in grassland soil is the highest,followed by forest soil,and the lowest in farmland soil.With the increase of planting time,the abundance and diversity of nematodes in the three soil types all showed a decreasing trend,indicating that nematodes that nematode had a certain tendency to crops.2: The species and the growth stage of crops had significant influence on nematode population and the succession of community structure.Planting tomatoes had a greater effect on soil nematodes community structure than chilies,and,the changes of nematode trophic groups were significant in different growing stages,especially the number of plant-parasitic nematode increased significantly in tomato fruit stage.3: The root secretion components of tomato with different resistance were significantly different.The root secretion contents of carbohydrate,amino acid and amino compounds beneficial to plant growth and development were the highest in the resistant cultivars,the middle in common varieties and the least in susceptible varieties.It is worth noting that the content of 3,4-dihydroxycinnamic acid in susceptible varieties is abundant.The root exudates of resistant,common and susceptible cultivars could inhibit the total number of nematodes and plant-parasitic nematodes in the soil,and the root exudates of resistant tomatoes had the most obvious inhibition effect.So,the difference of root exudates was the decisive factor affecting the change of nematode community structure.4: Reductive reduction disinfestation(RSD)could improve the growth and development environment of tomato,and the number of nematodes and plant-parasitic nematodes in the soil were significantly reduced after RSD.Different RSD treatments had different inhibitory effects on plant-parasitic nematodes.Compared with CK treatment,the number of plant-parasitic nematodes decreased by 46%,75% and 69%in soluble sugars(SS),molasses(MO)and sugarcane bagasse(SB)treatments,respectively.RSD treatments had different effects on nematode flora at different growth stages of crops.During the growth of tomato,the number of bacterial-feeding nematodes increased,and at the same time,the number of phytophagous nematodes increased in the fruiting stage,but it was still significantly lower than that in untreated soil(CK).Therefore,it is concluded that RSD can effectively inhibit the number of plant-parasitic nematodes in the soil,increase the number of free-living nematodes,improve the structure of soil nematode community,and ensure the normal growth of crops.