Effects Of Different Tillage Systems On Farmland Weed In North Henan

Weeds and crops constitute the farmland ecological system. In this system, weeds have strong adaptability and reproductive capacity, compete with crops for water and nutrients in the soil, influence the growth and development of crops, and then make the crop yield and quality decreased. In China, about10%crop failure roots in weeds every year. Therefore, the control of weeds in farmland is very important in increasing grain yield. With the rapid development of biological science and interdisciplinary mutual infiltration, the research of weed biological control gradually goes deep. Compared with other control methods, biological control has many advantages. Research shows that, rational rotation mode can reduce the dominance of some weeds in farmland. In this paper, through the investigation of weeds in different rotation field, using inverted " W " nine points sampling method to determine weed species, quantity, distribution,calculate weed abundance, importance value and dominance, and weed species diversity and similarity index in different farmlands. Draws the following conclusions:See through the relative abundance and importance value of weeds:Kochia scoparia, Echinochloa crusgali, Descuminia sophia, Alopecurus aequalis Sobol are the preponderant weeds in wheat field of rice-wheat rotation; Rotala indica, Cyperus difformis L., Monochoriavaginalis, Sagittaria pygmaea Miq. are the preponderant weeds in rice field of rice-wheat rotation. Kochia scoparia, Descuminia sophia, Polypogon monspeliensis are the preponderant weeds in wheat field of soybean-wheat rotation; Digitaria sanguinalis, Setaira viridis, Gramineae, Cyperus iria L. are the preponderant weeds in soybean field of soybean-wheat rotation. Echinochloa crusgali, Descuminia sophia, Chenopodium album are the preponderant weeds in wheat field of maize-wheat rotation; Cyperus rotundus L., Sorghumsudanense(Piper)Stapf., Digitaria sanguinalis (L.)Scop, Gramineae are the preponderant weeds in maize field of maize-wheat rotation. Echinochloa crusgali, Descuminia sophia are the preponderant weeds in wheat field of peanut-wheat rotation; Digitaria sanguinalis, Setaira viridis(L.)Beauv, Gramineae, Cynodondactylon(Linn.)Pers.are the preponderant weeds in peanut field of peanut-wheat rotation. Relative abundance and importance value are coincident in the reaction of weed’s dominance.The number of weeds in rice-wheat rotation field is the most, followed by peanut-wheat rotation, soybean-wheat rotation, maize-wheat rotation. Peanut-wheat rotation and soybean-wheat rotation have the highest similarity in weeds species, followed by maize-wheat rotation and soybean-wheat rotation, maize-wheat rotation and peanut-wheat rotation, rice-wheat rotation and peanut-wheat rotation, the similarity of rice-wheat rotation field and soybean-wheat rotation is the lowest. According to the species diversity index, peanut-wheat rotation> maize-wheat rotation> rice-wheat rotation field> soybean-wheat rotation.Analysis by synthesis, can conclude that the harm of weeds is greater in rice-wheat rotation field and peanut-wheat rotation field weed. Maize-wheat rotation and soybean-wheat rotation show certain control ability in the type and quantity of weeds.