Effects Of Leguminosae Green Manure Inoculated With Rhizobia On Crop Growth And Chemical Fertilizer And Pesticides Reduction In Tea Tree Intercropping And Strawberry Rotation System

Agriculture is one of the pillars of our country’s economy,but not proper use of chemical fertilizers has been not only affecting the healthy growth of plants,but also restricting the sustainable development of agriculture for many years.Therefore,modern agriculture should be combined with traditional farming methods.In order to improve ecological environment,prevent and control plant diseases and eliminate pests,we should take local conditions into account,choosing the suitable rhizobia leguminous green manure and crop-rotation which can not only improve soil fertility,but also protect ecological environment of farmland,make soil microbial community rich,and save economic expenses.Because all of those,reducing the use of fertilizers and pesticides can be achieved.The perennial tea tree is an important cash crop in China,and intercropping between tea trees and legumes can alleviate continuous cropping obstacles caused by continuous monoculture to some extent.In order to select the best combination,two kinds of summer green manure-soybean and mung beans,three winter green manure-milk vetch,trifolium pretense and Chinese trumpet creeper were combined.Then,the corresponding rhizobia were inoculated,and the intercropping system of legume crops and tea with both ecological and economic benefits was selected.In recent years,strawberry diseases have been seriously threatening strawberry quality and yield in practical production.In order to improve the utilization rate of land and increase the efficiency of nutrients,this paper proposes constructing a green and ecological strawberry planting system,the rhizobialegumes-strawberry rotation system.In this experiment,according to the actual situation of strawberry greenhouses,heat-resistant mung beans were selected as green manure in summer to study their effects on the occurrence of soil-borne diseases of strawberry and the improvement of soil and crop quality.Therefore,this paper firstly isolated,purified and collected rhizobia of legume green manure in different growing seasons to provide strain resources for subsequent experiments.The efficient rhizobia-legume crop combinations were screened in the laboratory.The interaction between rhizobia-leguminous green manure with tea tree intercropping and strawberry rotation was studied.The comprehensive effects of legume green manure on improving soil environment,disease and insect pests,crop quality and yield,soil microbial stucture change were studied.The results are as follows:（1）Through 16S rRNA sequencing and analysis,a total of 16 strains named TQ,GX,XXK,DY,QH,GC,YX,JQ,HS,XXSZ,DY,JP,ZYY4,ZYY6,ZYY10,DS were isolated from Astragalus sinicus nodules and rhizosphere soil.Through the determination of symbiotic nitrogen fixation capacity,a total of 4 strains of isolated Astragalus sinicus rhizobia can nodulate on "Minzi 9",which were respectively named as ZYY6,ZYY10,DS and JQ,belonging to Mesorhizobium huakuii.However,rhizobia Mh93,112 have better nodulation and nitrogen fixation effects.After that,in order to screen the rhizobia that can form nodules and fix nitrogen on "Sulv No.4" mung bean,34 strains of rhizobia provided by the laboratory were inoculated on mung bean,4 strains of Bradyrhizobium japonicum USDA110 and Vig2,Rhizobium GB4,Bradyrhizobium elkanii Vig3,were screened out.Finally,Vig2 were selected as the test strains for the subsequent experiment.（2）The rhizobia-soybean/mung bean-tea tree intercropping system was selected in the tea plantation to study and different kinds of green manure were put in soil.After that,returning crop stalks to the field was done during the flowering period,and single cropping tea tree was designed as the control.During the experiment,no chemical nitrogen fertilizer was applied,and soil samples from different periods were collected to determine total nitrogen,organic matter,soil pH and soil microbiome.Then investigation the incidence of pests and diseases was carried out in the high incidence period in summer.The results showed that after planting green manure in the flowering period and the flowering period,the soil nitrogen content turned down.Leguminous green manure of soybean,mung bean and rotten soil total nitrogen were 0.8324 g/kg and 0.8884 g/kg,more than tea three soil during the same period（0.5842 g/kg）by 42.49%and 52.08%,more than the results of monoculture.That means symbiotic nitrogen fixation of rhizobia and legumes can be effectively fixed in the growth process of leguminous green manure and provide consumed crops nitrogen;Compared with the perennial single-cropping tea trees,the content of organic matter in the soil of leguminous green fertilizer in the flowering period decreased somewhat,but the content of organic matter in the soil of leguminous green fertilizer increased significantly after 2 months of turning over and composting.The organic matter in the soil was 22.3119 g/kg and 24.0215g/kg,respectively,which were 63.93%and 76.49%respectively higher than that in the soil before planting（13.6108 g/kg）.Compared with monoculture tea,making tea intercropping soybean and mung bean as green fertilizer can improve soil carbon and nitrogen ratio to a certain extent and make soil environment more conducive to tea growth.The soil pH value of green manure,especially after mung bean planting,increased by 0.8 compared with that of single cropping,which alleviated soil acidification.In addition,there was almost no weed growth in the green manure between the tea lines,which could realize zero use of herbicide.Compared with the treatment of monoculture alone,the disease levels of the tea plants intercropped with leguminous green fertilizer in summer were reduced,and the disease levels of the tea trees intercropped with soybean,intercropped with mung bean and monoculture were 4,2,12,respectively.Compared with monocultured tea trees,the number of insect eyes of tea trees intercropped with soybean and mung bean decreased by 14.88%and 14.83%respectively,and the insect population density decreased by 63%and 43%respectively.The contents of caffeine and polyphenols in tea were tested,and the results showed that the contents of caffeine and polyphenols in tea under the condition of intercropping green fertilizer,especially the intercropping mung bean,were significantly lower than those of the single-cropping tea,which was conducive to the improvement of tea quality.The richness and diversity of soil microbial community were improved after leguminous green fertilizers were turned over.Especially,the proportion of microbial groups in these bacterial taxa,such as Gemmatimonadetes,Cyanobacteria,Actinobacteria and Nitrospirae,which were involved in nitrogen cycle,material decomposition and improvement of soil aggregate structure,was increased,and the proportion of Acidobacteria,a microorganism related to soil pH,was decreased.Moreover,through the sequencing of eukaryotes,I found eukaryotic animal species richness increased,the ecological system complexity increases made tea plantation habitat more stable,resistant to diseases and adversity stress increases.Intercropping green manure tea tree in rhizosphere soil samples of eukaryotes taxa of Phragmoplastophyta.Chlorophyta,Annelida,Vertebrata.etc.and tea tree pest related groups have obvious difference with control group,the insect species richness increased;The relative contents of Ascomycota,Basidiomycota and Phytophthora decreased.In addition,the increase of Rhizophagus was beneficial to improve the resistance of tea plants to biological stress,which was consistent with the investigation trend of field disease mitigation.In conclusion,the comprehensive benefits of tea intercropping mung beans are better,which can effectively reduce the application of the chemical nitrogen fertilizer and the use of pesticides,herbicides.（3）The rhizobia-mung bean-strawberry rotation system was selected from the strawberry greenhouse for research,and compared with the rice-strawberry rotation model.After mung beans in the strawberry greenhouse were planted in summer and crop staws were put in soil at the mung bean flowering period,soil samples of different periods were collected to determine the total nitrogen,organic matter,soil pH,after that investigating the occurrence of diseases in the high incidence period of strawberry,plant growth,fruit sweetness and yield of strawberries.During the experiment,each treatment was treated with equal amount of organic fertilizer.The results show that:Compared with the rice crop rotation,rotation mung bean with strawberry in the growth period of leaf area（52.16 cm2）and plant height（20.85 cm）,the results of leaf area（61.76 cm2）and plant height（22.45 cm）,which were significantly higher than rice-strawberry rotation treat’s leaf area（37.75 cm2）and plant height（15.93 cm）in strawberry growth period,Leaf area（47.77cm2）and plant height（18.31cm）in the fruit mature stage;But there was little difference in fruit sweetness.The mung bean-strawberry rotation system was effective in inhibiting soil-borne diseases,and the incidence of verticillium wilt was reduced by 63.5%in the growing period of strawberry,the incidence of verticillium wilt was reduced by 31.6%when strawberries have matured.At the same time,with strawberry greenhouse soil total nitrogen compared to the initial value CK0（0.7406 g/kg）,on planting green manure and soil total nitrogen content increased significantly after straw decomposition,the rotation of mung bean root during the period of treatment of soil total nitrogen was 0.8629 g/kg,increased by about 16.5%compared to CKO,and greenhouse soil total nitrogen of rice rotation only increased by 3%.Each processing application amount of fertilizer before transplanting strawberry,makes strawberries grow antecedent soil nitrogen,through the crop growth and development,and consumes part of nitrogen,eventually rotation mung bean and rice rotation after the three treatment in strawberry mature period of soil total nitrogen content were 0.8474 g/kg and 0.7872 g/kg,compared with CKO,increased by 14.4226%and 6.2838%respectively.Compared with the initial value of soil organic matter（24.6803 g/kg）in the strawberry greenhouse before sowing green manure,the soil organic matter（29.9320 g/kg after planting green manure）could be increased by about 20.08%after planting green manure（29.6253g/kg after planting mung beans in rotation）.The organic matter content in the strawberry greenhouse of rice in rotation inoculation was 26.6316 g/kg in the same period,and the organic matter was increased by about 7%.The soil organic matter contents of mungbean-strawberry rotation and rice-strawberry rotation were 32.4035g/kg and 29.3033g/kg,respectively,which were 31.2930%and 18.7316%higher than that of CKO.After rotation of mung beans,the C/N ratio of strawberry at the fruit stage remained at 22,which increased by about 4 compared with the original CKO（18）,and was closer to the C/N ratio of 25 which was the most suitable for crop growth.PH increased from 5.51 to 5.82 after rotation of green beans,and increased by about 0.3.The pH of greenhouse soil in rotation rice fluctuated.When it came to the strawberry fruit period of the same year,the pH was maintained at about 5.6,increased by about 0.1.The analysis of soil microbiome in different periods showed that the species richness and diversity of eukaryotes in rhizosphere soil samples were higher than that in rhizosphere soil samples of healthy strawberry.Rotation could change the microbial community in the soil of strawberry greenhouse,especially the soil eukaryotic community was more abundant after the rotation of rice.Rotation of mung beans and rhizobia inoculation can improve the diversity and quantity of beneficial bacteria,reduce the abundance of pathogenic microorganisms,and have better inhibitory effect on soil pests than rotation of rice.After rotating mung beans,pathogenic microorganism and harmful animals like the Nematoda,Chytridiomycota,Ascomycota pathogenic etc.decreased significantly.In addition,Annelida population abundance increase,which can improve soil organic matter decomposition and aggregate structure of soil.Rotation of mung bean can improve the soil microbial diversity,increase the beneficial microbes,inhibition of strawberry diseases occurs,promote the growth of strawberry plant,and increase ecological benefit and economic benefit.Based on the above results,it can be seen that according to the comprehensive analysis.tea tree intercropping mung beans have better effects on improving soil fertility,adjusting pH,reducing disease and improving tea quality,and tea tree intercropping soybean has better effects on controlling insect pests.Rhizobia-leguminous green manure intercropping with tea tree can increase the tea plantation soil organic matter and total nitrogen content,as well as make soil microbial population diversity greater,improve soil pH value,provide a good soil environment for tea tree growth.The effects of selecting mung bean green manure to be put in soil in the flowering period are optimal.Preliminary achievements to reducing the effect of chemical fertilizers and pesticides in tea plantation can be made.Rotating green manure and applying organic fertilizer in strawberry greenhouse could not only improve the content of soil nitrogen and organic matter,balance the ratio of C/N,effectively reduce the incidence of soil-borne diseases of strawberry in later crops,but also promote the growth of strawberry.By the comprehensive analysis of crops,green manure and the soil,it can be seen that the interactive relationship between rhizobia,leguminous and green manure can be preliminarily judged.The effects of various combinations of green manure and crops by using different cultivation modes are also evaluated.This paper provides methods for screening the suitable intercropping system of rhizobia-leguminous green manure-crops,and expand the application range of leguminous crops as green manure.However,the actual effect of rhizobia-legume green fertilizer application is related to geographical location,environmental climate,bacterial strain activity and other factors,which requires long-term observation and further research and analysis to reach a more accurate conclusion.