Studies On Sericulture Industry In Hills And Donga Of Southern Yulin City

Yulin city is situated in the North of Shaanxi province. Due to its serious erodibility of water and soil, our government has paid more concerns and more investment on the area since 1949. Thanks to the development of west China and the promotion for returning of farmland and grass to forestation and for building an environment of Beautiful Rivers and hills, the construction of ecological environment becomes the key strategy as well as the basic point for Yulin. In southern area of Yulin,where is boundary between Maowusu desert and loess plateau; it belongs to landforms with plateaus,hills and gullys, coupled with tattered massif, barren soil,and unrational cultivation. As a result, vegetation is destoryed; soil and water are eroding; all kinds of gullys interlock with each other; ecological environment is becoming frailty. Concurrently the agricultural development is greatly limited by frequent drought, rain shortage and windy climate.Mulberry with the functions of economy and ecology, has a good capacity to control the erodibilities of water and soil, and it can speed the development of economy by planting it and breeding silkworms. Moreover , the strategy can not only resolve the issues between"quilt"and"money", but creat an economic,ecological and social environment to consolidate the achievement from returnning of farmland and grass to forestation.According to the current situation of sericulture, a series of studies were carried out in Yulin city ecological demonstration, including graft modification on mulberry trees, researches on breeding silkworms and trails of applying biogas waste fertilizer on foliage. The data obtained are collected by conducting surveys from silk breeding breeders who live in Chenjiaping village Qingjian county and Zhaojia village Suide county.The results are demonstrated in the followings.(1) Analysis of properties on different mulberry varieties was shown that six varieties were obviously better than Shaanbei sweet mulberry (CK).Some varieties ,such as yellow wood 14,Xuan792,Yu71-1 and Boluo mulberry, are widely accepted by silkworm breeders,and used to update mulberrys. From the general evaluation on silkworm breeding,Xuan792 is particularly suitable for tender silkworm due to its eminent leaves.(2) The result of bud graft in spring is shown that this simple method was fit for 1-2cm thick stock to survive, especially for 1.5-2.0cm thick stock .(3) The income has increased by 40% by the fact that the sericulture experiment, the small silkworm raising together than average baby-raising method, silkworm horizontal inscribed board has raised Sangbianyu that has increased by 42.87% , having thrown into the good mulberry baby-raising ratio reality life than the heatable brick bed house raises the Zhang silkworm yearly income economizing 50%; As for the economic effect, the good mulberry raises have been 31.02% more compared with reality life Sangbianyu. The mulberries consume amounts of Shaanxi silkworm 305 understand 14.01% respectively lower than Qingsong X Haoyue and Suju X Minghu 8.72%, average cocoon is produce amounts but higher than 13.83%, the cocoon gross income has been high 13.97%.(4)The mulberry foliage became green and its foliage thickness increased after applying biogas waste fertilizer. The production of foliage rose up by 11.9% in the first year and by 11.4 in the second year. Compared to the CK, the increment was 45 kilograms with the treatment of biogas waste fertilizer per 666.7m2 .The pod yield increased by 18%-32.57%, and the average rate of pod was approximately 26%-27.40% with 7.3% increment with treated leaves to breed silkworms. (5) The mulberry treated by biogas waste fertilizer evidently grew better than those of mulberry untreated mainly in the person of the growth of tender branches, foliage area, and the upgrowth of winter branches. The result indicated that the application of biogas waste fertilizer was good for the growth of mulberry.(6)The compound planting model, with the rate of 1:7.1 between input and output, was adopted in the hills and donga of southern Yulin, which presented a marked economic benefit.Based on the investigation, some measures have been proposed in this thesis to develop sericulture of southern Yulin. The current task is to construct demonstration to consolidate existing mulberry garden under cooperative management. It's necessary to build up the construction of scientific facilities and spread new varieties and techniques and strengthen the training of silkworm breeders. In addition, favor policies should be made to formalize markets and improve breeders'profit, so sericulture association should be established to serve the industry effectively. The implement of industrial sericulture should be quicken , and the outgrowth of sericulture is also supposed to utilize to large extent.