The forest nursery, nursery seedling breeding area, including seedling cultivation area, seedling cultivation area and seed tree area and other parts. Different functions of different partitions. Seedling propagation and seedling cultivation area is mainly used for seed breeding seedlings and cuttings, grafting, layering to cultivate seedlings; and the seedlings cultivation area and seed tree area is mainly used for directional cultivation must dry, crown Chupu seedlings and seed required for the cultivation of excellent female parent trees. In the process of seedling cultivation, weeds often have a great influence on seedling growth. Therefore, it is important to control the weeds in the nursery.
1 the degree of damage of weeds in field
Field weed is one of the most important sources of seedling quality. Nursery for weeding the cost of the total cost of about 80%[1]. Chen Lin et al [2] survey, Gansu Hexi field 84 dicotyledonous weeds, accounting for 77.78%, 22 monocotyledonous weeds, accounting for 20.37%, among them, the most common are: wild oats, quinoa, Convolvulus, thistle, barnyardgrass, Chenopodium glaucum, Amaranthus retroflexus, reed, Polygonum aviculare, Sonchus brachyotus etc.. Xie E cloud [3] also found that agricultural pests in Hexi Irrigation District main weeds Chenopodium album, wild oats, field bindweed etc.. But in the natural evolution of the co evolution, the local crops on the local weed generally have an inhibitory effect, the two sides have a balance point, will not cause the destruction of the nursery or crops. But exotic invasive weed may cause the failure of nursery seedling.
Chen Ye et al [4] shows that alien invasive weeds in Gansu Hexi area there are 5 dominant families were Gramineae, Leguminosae, Compositae, Amaranthaceae, Chenopodiaceae, a total of 25, accounting for 62 of the total 5%., Chenopodium album, Setaria viridis, Convolvulus arvensis, Datura appears the highest frequency, respectively, 55.2%, 64.5% 45.3% and 42.4%. these invasive weeds, due to inhibition of species evolution not cooperated once in the local invasion, often become the dominant species, causing serious damage to agricultural production.
The main methods and measures of weeding in nursery 2
2.1 chemical weeding
At present, the main use of chemical weeding in nursery weeding is manual weeding. The nursery seed sowing seedlings after germination to four or five leaves to go through a slow growth period, this period of seedlings to drought and other adverse environmental weed resistance is very weak, and the weeds grow very rapidly, such as artificial weeding, a fee of two artificial, easy injury seedlings, if not clear, often form small grass seedlings, serious impact on seedling growth. And the use of chemical weed control is very good. The chemical reagents for different seedling are also different.
The lock on the [5] et al seedlings before germination, spraying 40% b o mixture can effectively control the Fatong, rose and gongxiexiaobi leaves flowers in various shrubs, the duration of two months; sethoxydim of marigold, a string of red and other dicotyledonous seedlings in monocotyledonous weeds control excellent, a string of red shift planted 48% trifluralin better weeding effect. Sun Jiali [6] with trifluralin on the summer mulberry nursery weeding, concentration of weed control effect of 0.15g/m2 is best, with fluoroglycofen, trifluralin, Gaicaoneng weeding of f.velutina nursery weeding rate of 92.38%. He Yuexiang [7], results show that the best preemergence trifluralin herbicide efficacy, weeding rate reaches above 93.8%, seedling cover grass + oxyfluorfen herbicidal effect, as 85.2-92.3%. Chen Yongqing [8] weeding test of Chinese fir clones with 0.9ml/ M2 cuttage nursery Gedicao, 30d suppressive reached more than 99%. Yellow Shijian [9] with 0.06-0.75ml/ m2 in the nursery of Chinese fir fluoroglycofen EC spraying the best control effect, and has no effect on the growth of Chinese fir; Qiu Jianbo [10] uses 50% butachlor, 24% goal of cedar nursery weeding, weeding rate of more than 91%. In the control of weeds, the production has been used more one kind of drug is glyphosate. Found that the effect of weed control on trifoliate orange Chen Guihu et al [11] of glyphosate, glyphosate 10% times solution of 40~60 seedlings growth was not affected, but weed control rate reached more than 95%, residual period of 60d [12] with 0.3g/m2; Dong Shenglan of glyphosate on weeds in nursery, weeding rate of up to 85%, and the seedling is not affected by herbicide phytotoxicity; yellow [13] with glyphosate surfactant 10% 25 times liquid of spruce nursery, weeding rate was higher than 91.2%, and had no effect on growth of seedling; Huang Xiufeng et al [14] of apple, orange, sugarcane, grapes and other fruit and nursery weeding, found 0.225g/m2 glyphosate, up to 20d after the administration of weeding effect 100%, far better than prometryne diuron, and Nishi Matsu. Chemical control of pear orchard weeds also showed that spraying glyphosate 2kg+2,4-D butyl 50g per 667m2, in addition to the rash after administration of 15d can reach 100%, 25d after administration of 96.7%[15-17].
2.2 physical weeding
The use of chemical herbicides has also caused a series of problems, such as the emergence of herbicide resistant weeds, soil pollution, degradation of water quality, and the damage to non weed species (especially human, livestock). In order to reduce the damage of chemical herbicides, the nursery weeding also carried out a lot of physical weeding attempt. One of the more successful is the film mulching. A large number of experiments in the early twenty-first Century showed that the effect of the black film was the best. Xu Yunlong [18] of the citrus nursery weeding test found that black or silver black double color film of good. I found in the production line, advanced mulching, and soil covering, for most weeds can play a preventive role.
In addition to plastic film, the most commonly used method of physical weeding is manual weeding. Artificial weeding not only can reduce the pollution of pesticide, but also can use the weed to feed livestock, is the most economical and environmentally friendly way of weeding in thousands of years. But because of the rising cost of labor and the innovation of technology, artificial weeding has been replaced by other methods. Straw mulching, stocking, mechanical weeding and other new methods are gradually used in the production of.
The straw mulch for weed control in production is mainly used for orchard weed control. Liu Guangqin [23] found that orchard planting vulpia myuros can effectively inhibit the growth of weeds in summer; Zhao Jinyuan [24] in orchard planting in Mao, spring and summer, autumn 3 germination peak can suppress weeds, weed coverage by 35%, 50%, 90%, 0, reduced to 3% 5%. is a stocking a new approach of modern nursery weed control. The specific approach is in the seedling cultivation area and seed tree stocking area primarily herbivorous pig, chicken, ducks and other poultry, to inhibit the growth of weeds in nursery seedlings. Yang Zhaowu et al [25] study found that the chicken in the orchard, compared with the control group, 40 /667m2 stocking low-density group, 80 /667m2 group and high density herbaceous layer vegetation coverage were reduced by 25% and 96%, indicating the chicken has a significant role in controlling weeds forest nursery, orchard etc.. Woodland stocking, not only can control the growth of weeds, at the same time, bring a lot of livestock and poultry income, livestock and poultry manure is also organic fertilizer, can make the nursery nursery is shortened, more robust. Li Yan et al [19] try weeding machine design of nursery, nursery weed with bilateral furrow weeding weeding machine. In fact, as early as in the 60's, the German [26] has been used to control the forest lawn grass machine.
2.3 biological weeding
The investigation of plant pathogenic organisms in main weeds was carried out, and the single type strain was obtained from the isolation, purification, culture and reproduction of the weeds. So far, there are about 100 different species of infection was used to control about 80 kinds of weeds have economic significance [22]. focused on several genera: disc sp. (Colletotrichum) 18 species, Fusarium species (Fusarium) 13, Alternaria sp. (Ahernaria) and tail 12 sp. (Cercospora) 8. A total of 41 genera of fungi have been or are being considered as candidates for the biological herbicides. For example, Japan using Exserohilum lnonocera spores granules on barnyardgrass; using Epicocosorus nernatosorus control in paddy field is difficult to prevent wild water chestnut (Eleocharis koruguwai), has made new progress. It is also used to kill weeds in soil weed seed bank to control weeds. In addition, it can also use the mutual inhibition between different grasses to achieve the purpose of controlling the grass pests. For example, the grass can be very good to inhibit the growth of other weeds [20].
The feasibility and method of 3 nursery students
Grass is a kind of advanced technology of orchard soil management is widely used in developed countries in the orchard, the fruit row or the whole garden planting perennial grasses or legumes. To the nursery, also can improve the seedling survival and seedling quality by using the grass. The seedling breeding area and seedling cultivation area, mainly in the main weeds. According to the rules of our country city garden nursery seedling technology (CJ/T23-1999), seedling breeding area and seedling cultivation area can not have weeds; and the seedlings cultivation area and seed trees, grass, soil and water conservation can increase soil organic matter and soil fertility, improve tree growth environment and so on, especially the wide application of [21]. in the orchard in the development of
The whole grass orchard, interplanting grass or grass pattern between strains. The general soil deep, fertile, deep root distribution, the whole orchard; and shallow soil, barren, should adopt a row or strains of grass. Generally in the seedlings after the growth of 3A can be carried out on the grass. At present advocate of Interplanting grass and chemical weeding in the system. In the vertical projection of the tree crown, herbicides are used to remove weeds, and the soil is not required to be cultivated. It is advantageous to protect the soil structure and make the fruit trees make full use of the soil nutrients.
At present, the comprehensive evaluation expert good orchard grass varieties have 2 kinds, namely white clover and white clover genus [20]. in grass legume perennial herbaceous plants, fruit trees and shallow taproot, not fight fat, trampling resistance, high efficiency, strong ability of bio solid N, 1 5-8a. can be used in thatch adaptability, yield moderate natural death, upright and weak without manual cutting. The weed control is the key to the success of nursery seedling raising.
At present, chemical control is the main. Along with the progress of technology, the control of some environmental friendly, such as microorganism weeding, covering the weeding, the mechanical weeding, the antagonistic weeding and so on, will play an increasingly important role in the production. Along with the development of computer and electronic technology, the research on the technology of electronic or electric power plant is being studied by western researchers. This will have a huge impact on the agricultural production in the future.
If we can set up the related theory, the research on the influence mechanism of the electric field (especially the electromagnetic field) on the growth of plants, the test and analysis of the physical parameters of the main weeds in agricultural production, and the development of the Cheng Xinyi generation of electronic weeding machine, will occupy the commanding height of the technology.
Reference
[1] asked, Liang Songtang, Huang Lixiang. Application effect of chemical weeding in forest land. Guangdong forestry science and technology, 1999,15 (3): 47-49
[2] Chen Lin, Diao Shaodong, Gu Mingjie, et al. Common weed species and community composition in Gansu. Journal of Kasetsart University, 1997,25 (5): 55-58
[3] Chen Lin, Xie Eyun. Weed division of farmland in Gansu province. Gansu Journal of science, 1992,4:64-68
[4] Chen Ye, Samantha Ko, Zheng Tianxiang, et al. Investigation and hazard assessment of exotic weeds in farmland in Hexi region of Gansu province. Crop journal, 2013,1:120-123
[5] style lock, Qiao Jianguo, Cui Zhengkai. Study on 5 kinds of weed control technology in nursery. Journal of Hebei Forestry College, 1995,10 (2): 131-135