Continuous Cropping On Physiological Characteristics In Proso Millet And Soil Environment Effect

The proso millet was irreplaceable in arid regions of northern China food production. Inthe practical production, the farmers found that the proso millet is impatience on continuouscropping. However, due to the restrictions of the arable land, the specific environmentalconditions in production area and traditional cropping systems, the continuous cropping inproso millet is very a common phenomenon. To study continuous cropping obstacle of prosomillet, the long-term experiment of minor grain crops at the the First Station of Northwest A&F University as the platform,“Neimei5” were planted as test material with four rotations:every two years (T1), continuously two years (T2), continuously three years(T3) and the byrotation (CK). The photosynthetic characteristics, dry matter accumulation above ground, theleaves’ active oxygen metabolism, the activities of soil enzyme, and the soil physical andchemical properties were measured at the growth stage of proso millet. To Provides atheoretical basis for the high-yield of proso millet, the correlation between the measurementindicators mentioned above and the yield were anlysised.And the result as follows.(1) With Continuous cropping, proso millet flag leaf net photosynthesis (Pn), the flagleaf chlorophyll content, the chlorophyll b content and green leaf area of plants main stem inproso millet were decreased, and showed obvious difference at heading stage and floweringstage. The aging process was speeded up, the grain filling termination were forced ahead.These effects make plant dry matter accumulation quantity reduce, grain yield decline.(2) The soluble protein content, chlorophyll content, SOD activity and POD activity weresignificantly reduced, however the MDA content was increased of continuous cropping prosomillet, and the degree intensified with the years of continuous cropping increasing.Continuous cropping can cause active oxygen metabolism in disorders, then the otherphysiological metabolic disorders took place, results in a proso millet aging process inadvance and accelerate, thus affecting dry matter accumulation and yield formation of prosomillet.(3) The activities of catalase, urease and invertase were decreased with the increasing years of continuous cropping, but the result of polyphenol oxidase activity was reverseactually, and the alkaline phosphatase activity was lowest in the second year of continuouscropping. So the soil enzymes were changed by continuous cropping, that makes the soilhumification and amelioration degree slowed down, the toxicity of broomcorn millet rootsystem increased, soil fertility declining and plant growth and development affected. Theseeffects makes grain yield decline.(4) The effective panicle per plant, spikelet number, the main spike length and1000-grain weight are the important factors of yield components in proso millet. The mainspike length of and1000-grain weight of proso millet were significantly reduced withcontinuous cropping, resulting in a decline in the yield, and the longer continuous croppingyears was, the more lower yield.So should pay attention to the reasonable rotation crops in cultivation and use rationalfertilization and other measures to improve the soil environment, thereby slowing thesuccession cropping obstacle and achieving a high yield and quality on proso millet.