Selection Of The Available Weeds And Studies On Their Characteristics In Shanxi Orchards

Grass in the orchard has become a basic measure of fertile soil, but due to a lack of selecting study of suitable native weeds, resulting that the management has many problems.This research mainly through the survey of wild weeds in the northern orchards, which suited the native weeds, to understand the morphological and physiological characteristics, through the introduction form the advantage of local weeds. The results of the study are as follows:1.This research through the survey of wild weeds in the northern orchards(Jinzhong, Yuncheng, Linfen), weeds were found in the distribution of frequency include:Capsella bursa-pastoris, Setairaviridis(L.)Beauv, Herba Taraxaci, Chenopodium album, Amaranthus tricolor L., Portulaca oleracea L, Calystegiahederacea Wall, Convolvulus arvensis L., Digitaria sanguinalis(L.)Scop, Plantago asiatica, Lagopsis supina (Stiph.) IK.-Gal, Viola yedoensis Makino and so on. According to competing with fruit trees for the overground and underground space, to select the suitable weeds:Capsella bursa-pastoris, Setairaviridis(L) Beauv, Portulaca oleracea L, Herba Taraxaci, Viola yedoensis Makino.2. Selected weeds Herba Taraxaci, Capsella bursa-pastoris, Portulaca oleracea L, Setairaviridis (L.)Beauv, Viola yedoensis Makino are seed breeding, under the condition of natural growth, mainly by high seed setting rate, a kind of high quantity to increase fertility, form the weed community. Researching on seed fertility, the results show that Herba Taraxaci, Plantago asiatica, Lagopsis supina (Stiph.) IK.-Gal, Viola yedoensis Makino's suitable germination temperature is 15-25?, germination percentage is more than 50%, no the phenomenon of physiological dormancy. Light is beneficial to Herba Taraxaci, Plantago asiatica, Viola yedoensis Makino's germination. Capsella bursa-pastoris, Portulaca oleracea L, Setairaviridis(L.) Beauv are not germinating, there are the phenomenon of physiological dormancy.3. Through analysis of the physiological characteristics of Herba Taraxaci, Capsella bursa-pastoris, Portulaca oleracea L, Setairaviridis (L.)Beauv, Viola yedoensis Makino, the result shows that their root can produce the secretions to reduce pH. The leaves of Portulaca oleracea L is high water content, water storage ability, large accumulation of overground biomass, small underground biomass, small root-shoot ratio, small transpiration water rate, and water use efficiency utilization rate is high. The results show that Portulaca oleracea L has the strong drought resistance, strong water storage ability. The Pn of Setairaviridis (L.)Beauv is high, roots are the number of fibrous roots and water use efficiency utilization rate is also high. Portulaca oleracea L and Setairaviridis (L.)Beauv are summer weeds in the orchord, large biomass, these can improve organic matter content. Capsella bursa-pastoris is autumn and spring weeds,to extend the orchard coverage period. Herba Taraxaci and Viola yedoensis Makino have developed roots, strong tillering fertility, turning-green early next spring, long green period, strong the negative resistance, they are good groundcover plants as orchord grass.4. Viola yedoensis Makino belongs to the perennial herbaceous plants, low plant, long green period, high coverage rate, and strong trampling resistance, at present distribution in orchard is less, so this paper studied Viola yedoensis Makino about seed multiply and management in the field, the photosynthetic characteristics of different environments, the result shows that the sowing in the spring, Viola yedoensis Makino in se edling stage are susceptible to other weeds, so we should strengthen field management. The photosynthetic characteristics of Viola yedoensis Makino of shade and sun environments show that shade Viola yedoensis Makino has large leaves, high chlorophyll content, low light saturation point (LSP) and light compensation point (LCP), strong ability of taking advantage of weak light. So it belongs to one of the suitable orchard grass.