Study Of The Effect Of Three Techniques To Overcome Apple Continuous Cropping Obstacles

Preventing the apple replant disease was an important factor for restricting the sust ainable development of apple industry and exploring the method of overcoming the ap ple replant disease had become the current pressing issue. Our research was based on the reason for the apple replant disease and compared the adaptability of resistant stoc k under the continuous cropping stress and analyzed the influence of different interrow crops on apple rootstock. Furthermore, we also studied the influence of saccharides for apple rootstock and soil, which provided the theoretic foundation for solving the apple replant disease. The following results are obtained.1. The plant height, diameter, leaf chlorophyll content and root vigor of plant L31 had a little differences before and after continuous cropping stress, and the decreasing amplitude were 4.3%,2.6%,1.4% and 3.9%, respectively. Our results showed that no remarkable changes in each part of the light and parameters, dry fresh weight and root characteristics of the L31 leaves. It had the strongest tolerance, followed by L20、L19 and L24, respectively.2. The plant growth of Malus hupehensis Rehd and Malus zumi had no significant difference before and after continuous cropping stress when the shallot was used as interrow crops. Moreover, the root vigor of plant had the lowest decreasing amplitude (6.2% and 9.5%, respectively), which confirmed it had the best improvement effect. Furthermore, the activity of POD, SOD and CAT of apple rootstock had the lowest increasing amplitude and had no remarkable difference before and after continuous cropping stress, which indicated the shallot could effective to alleviate the harm of the apple replant disease.3. Our results also showed that the root extract of shallot could recover the flow rate of rhizosphere effectively compared with chili, coriander and fennel. The order of improve the plant growth under continuous cropping was shallot> chili> coriander> fennel.4. Our results showed that the height, diameter and leaf chlorophyll content of seedling of Malus hupehensis Rehd increased with the increase of saccharides concentration in the continuous cropping soil. Application of saccharides could increase the number of soil bacteria and actinomycetes, reduce the number of fungi.5. In addition to glucose, low concentration of fructose, maltose and Arab sugar could effectively increase the number of bacteria in the soil and soil bacteria increased by 94.2%, 30.2% and 101.2% respectively when applied the concentration of 50 mg/kg. The actinomyces quantity in soil was the highest when applied the fructose and maltose concentration of 50 mg/kg and 111.1% and 117.0% respectively higher than CK. And the actinomycetes quantity in soil was the highest when applied the glucose concentration of 100 mg/kg and 203.9% higher than CK. Moreover, the actinomycetes quantity increased by 66.7%, 222.9% and 266.7% respectively with the increase of arabinose concentration. The lower saccharides concentration could effcctive to reduce the number of soil fungi and the largest decreasing amplitude of soil fungi appeared when applied the maltose concentration of 50 mg/kg and decreased by 71.7% than CK.