Effects Of Phosphorus Application Rate And Variety Characteristic To Phosphorus Uptake And Utilization And Grain Yield Of Wheat And Maize

How to improve the utilization of phosphorus fertilizer is a challenge for nowadaysagricultural phosphorus nutrient resource management, variety improvement isconsidered to be an effective way to improve the utilization of phosphorus fertilizer,but it is lack of information for cropland experiment and especially experiment underthe wheat-corn double cropping system in the North China Plain. In this study, acombination of traditional high-yielding varieties Shijiazhuang8(wheat)-Nongda108(maize) was chosen as control sample to research the yield formations,phosphorus absorption and utilization characteristics of high phosphorus acquisitionefficiency varieties combination which contains Kenong9204(wheat) and NE15(corn), the root form of the distribution, acid phosphatase activity and pH was studiedto explore its mechanism, and the impact on the environment was studied as well. Themain results were as follows:(1)With the increase of the phosphorus application rate, the biomass and grainyield of each crop in the rotation system were increasing,there was no significantdifferences between variety combination, in the other words, the grain yield ofefficient varieties combination(Kenong and NE) were not small than traditionalvarieties combination(Shimai and Nongda) in the intensive cropping system,1000-grain weight of the efficient varieties combination were significantly lower thantraditional varieties combination in the grain yield formation factors.(2)The absorption efficiency of efficient varieties combination were significantlyhigher than traditional varieties combination in the rotation system, but the utilizationefficiency were lower than traditional varieties combination, with the increase ofphosphorus application rate, the absorption efficiency were increased, and theutilization efficiency were decreased, the phosphorus supplied by the soil were significantly increased with the increase of phosphorus application rate, there were nosignificant difference between the two combinations.(4)The root length of efficient wheat varieties were significantly higher thantraditional varieties, the root volume and root diameter of efficient maize varieties wassignificantly lower than traditional varieties, with the increase of phosphorusapplication rate, root surface area and root volume increased significantly in the2010wheat and maize season. There was no significant difference between efficientvarieties and traditional varieties in root biomass and root to shoot ratio. As thephosphorus application rate increased, the root biomass increased significantly and theroot to shoot ratio were not significantly changed. There was no significant differencebetween efficient varieties and traditional varieties in profile distribution, and it didn’tchange significantly with the increase of phosphorus application rate.(5)The acid phosphatase activity of efficient variety were significantly lower thantraditional variety in the vegetative twelfth leaf stage of maize, and there was nosignificant difference between efficient varieties and traditional varieties in the milkstage of maize, as the phosphorus application rate increased. The acid phosphataseactivity was decreased in the vegetative twelfth leaf stage of maize and increased inthe milk stage of maize, there were no significant difference between the phosphorusapplication rate. There was no significant difference between the pH of rhizospheresoil and bulk soil between both varieties of combination and phosphorus applicationrate. It showed that the change of acid phosphatase activity and rhizosphere pH maybenot the mechanism how the efficient varieties absorb large amount of phosphorus withlarge supply of phosphorus fertilizer.(6)The effect of two-year experiment to the soil phosphorus pools were as follows:with the increase of phosphorus application rate, the inorganic phosphorus content ofthe soil increased, some kinds of organic phosphorus fractions increased either, thetotal inorganic phosphorus content of efficient varieties combination was higher thantraditional varieties combination, it’s helpful for the sustainable utilization of the soil.When the phosphorus application rate increased, the environmental risk increasedsignificantly, but the environmental risk of the soil which the plant efficient varietiescombination is lower than these plant the traditional varieties combination.These results suggest that the absorption efficiency of efficient varieties is higherthan traditional varieties, but the utilization efficiency were lower than traditionalvarieties combination. The mainly mechanism for higher absorption efficiencyprobably is the increase of root length and decrease of root diameter. The grain yield ofefficient varieties combination was similar to the traditional varieties combination, it was lower environmental risk than the traditional varieties combination, the content ofinorganic phosphorus fractions and the total inorganic phosphorus content wereincreased.