The Study On Allellopathy Of Legume Forage Chamaecrista Spp To Paspalum Notatum

Chamaecrista spp is high yield, good quality and strong adaptability pasture which spreads all over the world. It is not only used as an important feed plant ,but also plays a key role in grass-field rotated, improving soil fertility and water-soil conservation, regularly interplant with fruit tree. It is well-adapted to hilly red soil in South China. The mixture sowing of Legumes pasturagee and Gramineous pasturage can increase yield. However, there are some technical problems which should be solved. For example ,the blind mixture sowing is bad for pasture growth ,and even leads to the reduce of production. The difference of Sowing Period, Quantity and interplanting mode may cause adverse effect to each other's growth. Usually, the mixture sowing of forage grasses and legumes could help each other, the rhizobia legumes that improve soil fertility are good for grasses and other types of pasture growth and development, finally get high production. For these reasons, the paper takes the allelopathy of leguminous Ch. Spp.to Paspalum notatum as research example, studies Ch. Spp. allelopathy which will be of great practical significance for mixed intercropping in the production.Eight kinds Ch. spp. pasturage introduced from abroad were researched as the test material: Chamaecrista rotundifolia CPI86134,CPI34721,CPI87178,CPI57503,CPI3248,ATF2232 and Chamaecrasta nictitans ATF2217,ATF2219. What's more, the author will use GC-MS machine to analysis chemical substances of the upper pasture Cassia leaf extracting liquids, and compare chemical differences between eight varieties of Cassia. By observing the effects of Ch. spp's different parts of the extracting liquids in different times on Bahiagrass seed germination and seedling growth, determines the allelopathic effect of Ch. spp and it's response to different environmental conditions, and compares allelopathic effects potential ablitity of eight breeds of Ch. spp to filter out the breed which has a strong sense of allelopathic effects. On the basis of observing, the author speculates the source and acting factors of allelopathic effects .The main conclusions are as follows:The main components of Ch. spp.pasturage is analyzed by GC-MS in blooming period. The components of Chamaecrista rotundifolia CPI34721 is most in the eight breeds, 31 belong to seven groups; whereas CPI86178 is 29.There is Phenos exist in most breeds extract,except for CPI86134, and ATF2217and ATF2232 contain most of all.The result shows that the extract from stem, root and rhizosphere soil of Ch. spp have a strong effect on the germination and seedling growth of P. notatum. The effect changes in different concentration , which low level extract can promote the growth, whereas high level inhibited, and it is of significant difference between each group. Same breeds and different position's extract have different allelopathy on receptor. The extract of 10% from soil inhibited P. notatum on germination and seedling length is in significant level. The extract of 5% and 7.5% is not in significant level. The extract of stem and root of 7.5% is only inhibited .P. notatum on germination and seedling length is in significant level, but promotes root growth, and with the concentration is lowing, the promoting effect shows. The soil extracting liquid has the worst Inhibiting effect on Bahiagrass, the second is root extracting liquid and the third is stem extracting liquid. In terms of Ch. rotundifolia ATF2232, the stem, leaf and root extracting liquid in the concentration of 5%,7.5%and 10% all have the inhibiting function to the seed germination of Bahiagrass, but have the promoting function to seedlings and root growth of Bahiagrass.The stems and leaves, roots and rhizosphere soil extracting liquid in flowering period and podding period of Ch. spp (eight breeds) have the inhibiting function to seed germination and seedling growth of Bahiagrass, but the extent of effect is different. Compared allelopathic effect of the same growth period and different species, the author can find out that each kind of Chamaecrista spp has the chemical inhibiting effect on the seed germination and seedling growth of Bahiagrass. Besides, the chemical inhibiting function of Chamaecrista rotundifolia ATF2232 and the CPI34721 is stronger than other species.ATF2232's stem and leaf extracting liquid in bloom have the inhibiting effect on seed germination of Bahiagrass ,but the effect is not obvious. On the contrary, extracting liquid has obvious inhibiting function to the seedling height and root length. ATF2232 in podding period has the strongest inhibiting effect on seed germination of Bahiagrass, but the effect in seeding period is not strong. Comparing the stem and leaf's extracting liquid in various growing period of the same breed, the author finds out that the impact which the stem and leaf's extracting liquid of Chamaecrista rotundifolia CPI34721, ATF2232, CPI86178 and CPI86178 and CPI57503 in flowering and podding period have on seed germination and seedling growth of Bahiagrass is obvious different. Excepting that the impact which the stem and leaf's extracting liquid of CPI57503 during flowering period in five breeds is stonger than it in podding period, the situation of other breeds is opposite. By the comprehensive evaluation on allelopathic effect of Chamaecrista spp (eight breeds), the test selects three breeds which have stronger allelopathic effect: CPI34721, ATF2232 and CPI57503.I concludes that sowing patterns affect extent of allelopathy. When the CPI86134, CPI34721, ATF2217 and ATF2219 are respectively sowed by 20 granules/dishs, 10 granules/dishs, 20 granules/dishs and 20 granules/dishs, They promotes growth of P. notatum seedlings at different degree.The allelopathy of Ch. spp on P. notatum isdifferent in stress. As the temperature increases, Ch. spp. promotes the growth of P.notatum in germination and growth stage. P. notatum grows best in 27℃.In different acidity conditions, the effect of Ch. spp.to P. notatum growth is also different. In the acidity condition Ch. spp. inhibited the growth of P. notatum, As the pH increases, the promoting action is showed. In neutral condition, it can promote the P.notatum's growth. P. notatum grows best in pH from6.5 to7.5. When the PEG concentration is 20%, the inhibition effect is most significant. The contrast of P.notatum grows best. Aluminum and Magnesium density also affects the allelopathy. The inhibition effect of Ch. rotundifolia is most significant in Atheluminum level is 0.7g/L. Chamaecradta nictitans inhibited the growth of P. notatum when concentration of Aluminum is 1.1g/L and concentration of Magnesium is 0.06g/L and 0.123g/L.