Effect of Phosphorus Fertilizer Application Rate on Biomass Accumulation and Phosphorus Absorption of Alfalfa in Planting Year
To explore the effects of phosphorus fertilizer application on biomass accumulation and phos-phorus uptake of alfalfa(Medicago sativa L.)in Horqin Sandy Land,four phosphorus fertilizer application rates were set up,including 0 kg/hm2(P0),81 kg/hm2(P1),162 kg/hm2(P2)and 243 kg/hm2(P3).The plant height,aboveground biomass and phosphorus concentration of alfalfa'Knight T'were measured during the whole growth period,and the phosphorus uptake are calculated.The results showed the follow-ing:1)From initial bloom stage to full bloom stage,P2 and P3 significantly increased plant height by 13.03%-18.64%than P0(P＜0.05).2)From bud stage to full bloom stage,P2 significantly increased biomass by 34.08%,50.21%,and 63.25%compared with P0(P＜0.05).During the full bloom stage of alfalfa,P2 and P3 increased biomass by 63.25%and 54.21%than P0(P＜0.05),with no significant dif-ference between P2 and P3.The effectiveness of phosphorus fertilizer on biomass was the highest at full bloom stage under all phosphorus application treatments.3)From the prebranching stage to the embryonic stage of alfalfa,both phosphorus concentration and phosphorus absorption increase continuously with the increase of phosphate fertilizer application,and the effectiveness of phosphorus fertilizer for alfalfa phospho-rus absorption under various phosphorus fertilizer treatments was highest during the embryonic stage.The phosphorus uptake during the full bloom stage of alfalfa showed a trend of first increasing and then decreas-ing with the increase of phosphorus application rate,and P2 treatment was the turning point.4)With the increase of phosphorus application rate,the phosphorus utilization efficiency and phosphorus partial productiv-ity of alfalfa decreased at each growth stage.In summary,compared with the application rate of 81 kg/hm2 and 243 kg/hm2,162 kg/hm2 was the appropriate amount of phosphorus for alfalfa planting in the Horqin Sandy Land,and the embryonic stage and full bloom stage was the key periods for phosphorus fertilizer appli-cation.This study can provide reference for improving alfalfa productivity and efficient utilization of phospho-rus nutrition.
Phosphorus application rateAlfalfaBiomass accumulationNutrient absorptionHorqin Sandy Land
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