| In recent years,the excessive application of chemical fertilizer has not only caused the decline of cultivated land quality in China,but also had negative impact on food security,which seriously restricted the sustainable development of agriculture in China.Legume green fertilizer can not only release large number of nutrients into the soil after decompression,but also provide sufficient nitrogen for crop growth due to the unique symbiotic nitrogen fixation system between legumes and Rhizobium.Therefore,planting legume green fertilizer can become one of the effective methods to reduce chemical fertilizer and improve soil fertility.Tea tree as an important traditional economic crop in China,this crop is easy to form a continuous cropping obstacle due to its perennial fixed cultivation,thus resulting in a decline in tea quality and loss of tea plantation soil fertility,although by intercropping leguminous green manure with tea trees can alleviate slightly soil problems,but some stress factors such as soil acidification severely limiting the leguminous plants,Rhizobium in complex tea plantation soil environment is vulnerable to all sorts of bacteria,fungi,which reduces the strain activity and led to the decrease of the efficiency of biological nitrogen fixation.However,Bacillus as an important member of plants growth promoting rhizobacteria,it not only can promote plant growth,enhancing plant stress resistance and increasing crop yield,some Bacillus strains can also cooperate and interact with Rhizobium to enhance the symbiotic nitrogen fixation ability of the latter with legumes.In addition,the early stage of the laboratory work results show that although planting green manure and summer tea tree intercropping can improve the tea plantation soil fertility in short time,but tea tree root in the process of growth will continue to acid secretion and absorb soil nutrients,resulting in single season green manure’s economic benefits in tea plantation is limited,so this article in tea tree intercropping mode of green manure,through the way of green manure crop rotation in order to make full use of green manure resources and improve its value in tea plantation.The results of this study are as follows:(1)With kidney bean,Chinese milk vetch and hairy vetch as host plants,interaction experiment was conducted between 9 strains of Bacillus isolated in laboratory bacterial library and corresponding host Rhizobium.Because bean has obvious biological characteristics and is easy to observe different treatment group differences in physiological indexes,thus preferable beans as a host plants grows,preliminary screening of Bacillus,after 9 strains of Bacillus respectively with cowpea Rhizobium CFN42(Rhizobium etli)interaction,found the RF-2,ZSZ-6,ZC4-1,RC-3 and BTSD-1,5 strains of Bacillus which can increase the number of bean nodule and nitrogenase,which also have an obvious effect on promoting plants growth;Follow-up choosing Chinese milk vetch and hairy vetch as host plants,preliminary screening will get 5 strains of Bacillus respectively with Mh93(Mesorhizobium huakuii)and Vic5(Rhizobium leguminosarum)interaction,plants experimental result shows that the effect of promoting nitrogen fixation ability is obvious which is inoculated with ZC4-1(Bacillus amyloliquefaciens).Compared with the single treatment of Rhizobium,the nitrogenase activity of host plants with inoculation of ZC4-1was increased by 10.8% and 36.3% respectively.In addition,the interaction of ZC4-1 with corresponding host Rhizobium can effectively promote the development of shoot and leaf of Chinese milk vetch and hairy vetch,improve the physiological indexes of plant height and fresh weight of shoot.Through three rounds of interaction experiments between Bacillus and Rhizobium,we find one Bacillus strain ZC4-1 which with the best growth-promoting effect on three kinds of leguminaceous plants was finally screened out for subsequent field application in tea plantation.(2)In tea plantation for test site,select Chinese milk vetch,Trifolium pratense,hairy vetch intercropped with tea tree,and inculate Rhizobium and ZC4-1 at the same time for exploring the effect of ZC4-1 on promoting plant biomass,yield and nodule nitrogenase activity.The results show that compared with inoculating Rhizobium alone,the plant height,aboveground biomass and yield of the three kinds of leguminous green fertilizer crops were significantly increased after inoculating with Bacillus,and ZC4-1 had the best growth-promoting effect for vetch.In addition,three just appear hairy vetch root nodules of leguminous green manure,through to the hairy vetch nodule number and nitrogenase activity test,find the interaction of ZC4-1 and hairy vetch Rhizobium can obviously enhance plant nitrogen fixation ability of nodules.Compared with the single receiving Rhizobium group,the number of hairy vetch nodule was increased by 10.7% on average,individual nodule nitrogenase activity increases by 14.7%,but also further enhance the hairy vetch and the symbiotic nitrogen fixation efficiency of Rhizobium in tea plantation.The results showed that the soil fertility of the three kinds of leguminous green fertilizers increased to different degrees after extra inoculation with ZC4-1 and timely turning over,compared with the non-inoculated group and the single-inoculated rhizobia group at the same period.Which Chinese trumpet creeper and root and bacillus and timely after the double pressure to improve soil fertility effect best,compared with before planting green manure soil total nitrogen,organic matter,available phosphorus content were 26.6%,15.9%and 18.1%,respectively,at the same time Chinese trumpet creeper dual inoculation group after turned down the highest amino acids in tea,tea polyphenols and caffeine content is the lowest.It was suggested that vetch inoculating rhizobia and bacillus at the same time and pressing them in good time could improve the quality of tea.(3)In tea plantation for test site,select the winter green manure hairy vetch and Chinese milk vetch respectively with mung bean crop rotation,green manure crops in summer and returning flowering turned down in early green manure,explore green manure crop rotation system compared with quarterly green manure in improving the effect of soil fertility,improve the quality of the tea,and Chinese milk vetch to mung bean crop rotation and hairy vetch to mung bean crop rotation on the tea plantations of comprehensive benefit.Using monocropping tea as the control,no nitrogen fertilizer was applied during the experiment.Soil samples of different treatment groups at different stages were collected to determine the physical and chemical properties,and the quality of tea leaves at different stages was compared.The results showed that the activities of total nitrogen,organic matter,available phosphorus,available potassium,urease and soil p H in the initial soil samples of green manure rotation group were increased to different degrees compared with those of tea tree monoculture and green manure monoculture group.In mung bean early flowering green manure and rotten turned down after a month,compared with single culture of tea tree in the initial soil total nitrogen content(0.8376 g/kg),Chinese milk vetch to mung bean crop rotation and hairy vetch to mung bean crop rotation group,soil total nitrogen content up to 1.0816 g/kg and 1.1543 g/kg,and at the same time was the soil total nitrogen content of mung bean group is 1.0362 g/kg,and green beans turned down a month later,found that hairy vetch-mung bean crop rotation group compared with the same period was a tea soil p H is about 0.9;In addition,compared with Chinese milk vetch-mung bean rotation and single-cropping mung bean group at the same period,the contents of available phosphorus,available potassium and urease activity in soil of hairy-mung bean rotation group were higher,which increased by 8.8%,314.07%,55.3%,and the contents of caffeine and tea polyphenols in tea were significantly lower than those in monocropping tea group,and the quality of tea was also improved.Comprehensive the above results,this study screened one Bacillus strain ZC4-1 which can promote leguminous green manure crop Chinese milk vetch and hairy vetch nodular nitrogen-fixing and growth through the intercaction of Rhizobium with Bacillus under laboratory conditions,after that we choose ZC4-1 for tea plantation field application resources.Then based on the climatic conditions of testsite tea plantation,we apply leguminosae green manure-Rhizobium-Bacillus interaction system in tea plantation,compared with leguminosae green manure single root nodule bacteria and Bacillus interaction can promote leguminosae green manure after growing in the tea plantation,and effectively improve leguminosae green manure nodule number and nitrogenase live,Thus further improve the physical and chemical properties of the tea plantation soil and tea quality,initially achieve the effect of reduction on chemical fertilizer.On the other hand,choose different green manure in winter and summer respectively mung bean crop rotation,green manure crops and returning flowering turned down in early green manure,through testing the quality of tea and tea plantation soil physical and chemical indexes each period,found the green manure in winter with mung bean crop rotation system which had the best effect on improving the quality of the tea plantation soil fertility and tea quality,which can aslo reduce the phenomenon of tea plantation soil acidification and provide good environment for tea tree. |
PDF Full Text Request