Study On The Effects Of Different Phosphate Sources On Transformation Of Inorganic Phosphorus In Calcareous Soil

Objective:Research and development for a new multi-functional efficient liquid drip irrigation fertilizer which is suitable for Calcareous Soil. Reveals the mechanisms of activating inorganic phosphorus fractions in soil and improving phosphorous nutrition of plant.Methods:1. simulation experiment:A simulation experiment was carried out for revealing the activation effects of yellow humic acid and phosphoric acid in liquid fertilizer on single inorganic phosphorus fraction:octa-calcium phosphate(OCP, Ca8-P),hydroxyapatite(HAP, Ca10-P),aluminum phosphate(Al-P),ferric phosphate(Fe-P). Studying the magnitude and changing trend of activators(yellow humic acid and phosphoric acid) on inorganic phosphorus fractions.2. Pot experiment:A pot experiment was carried out for studying the the influence of liquid and granular phosphorus fertilizer sources on calcareous soil pH, micronutrient availability (Fe,Mn, Zn,Cu), soil inorganic phosphorus fractions. Studying its effectiveness on phosphorous nutrition of processing tomato and enzyme activity about sucrose metabolism. Analysising of correlation between the content of soil inorganic phosphorus fraction and phosphorus uptake by processing tomato.3. Field experiment: A field experiment was carried out for studying the the influence of liquid and granular phosphorus fertilizer sources on calcareous soil pH, micronutrient availability (Fe,Mn,Zn,Cu), soil inorganic phosphorus fractions. Research to phosphorous nutrition of processing tomato and phosphate fertilizer utilization efficiency with different treatments. Analysising of correlation between the content of soil inorganic phosphorus fraction and phosphorus uptake by processing tomato.Results:1. simulation experiment:Yellow humic acid and phosphoric acid could activate different inorganic phosphorus fraction by dissolving parts of Ca8-P,Ca10-P,Al-P and Fe-P. The dissolved effect of treatment with phosphoric acid more than the treatment with yelloew humic acid.At 48h, the dissolution rate of Ca8-P,Ca10-P,Al-P,Fe-P of treatment with phosphoric acid is 22.2%,18.8%,28.8%,32.2% and treatment with yelloew humic is 17.4%,5.0%,8.8%,10.8%. The dissolved quantity increased gradually with time changing. The longer time of adding acidic material, the fewer dissolved quantity in unit time.2. Pot experiment:The treatment of liquid fertilizer top dressing application improved the efficiency of soil P by reducing soil pH,containing higher content of soil Ca2-P and Ca8-P(P=0.05), lower content of soil Al-P and Ca10-P(P=0.05). Liquid fertilizer applying could significantly increase the content of available Iron, Manganese, Zinc and Copper in soil. Compared with the treatment of granular phosphorus fertilizer base application, liquid fertilizer applying can significantly improve the phosphorus nutritions and dry matter accumulations of processing tomato. The biomass,content of P uptake,lycopene,soluble solid,soluble sugars in liquid fertilizer top dressing respectively increased 17.4%,40.2%,29.1%,21.1% and 8.19%(P=0.05). The treatment of liquid fertilizer top dressing could significantly influence enzyme activity about sucrose metabolism: acid invertase(AI),neutral invertase(NI),sucrose syntha(SS),sesucrose phosphate synthase(SPS). It is concretely represented that fertilizer applying can significantly increasing enzyme activity of SS and SPS, reducing enzyme activity of AI and NI. The correlation between the content of soil Ca2-P,Ca8-P and phosphorus uptake by processing tomato were significantly correlation. Correlation coefficient were 0.6522 and 0.7759. 3. Field experiment: The effect of dirrerent treatments on 0-20cm soil pH were not significant. Soil Ca2-P and Ca8-P content within 0-20cm soil depth decreased obviously with increasing application time, in contrast, Ca10-P increased gradually, which indicated there have an obvious phosphorus fixation after P fertilizer application. Ca2-P content in the topsoil (0-20cm) was substantially higher with the treatment of liquid fertilizer topdressing, and relative higher soil Ca8-P content was maintained in the 0-20cm depth topsoil as well during processing tomato growth stage. Compared with other treatments, soil P fixation could be reduce significantly and the percentage of soil sparingly P transformed from soil water soluble phosphorus decreased significantly under liquid P topdressing application, therefore it significantly improved soil Ca2-Pand Ca8-P content(P=0.05)in the 0-20cm depth topsoil as well as soil P bioavailability. Liquid fertilizer applying could significantly increase the content of available Iron, Manganese, Zinc and Copper in soil. Processing tomato yield and plant P content increased markedly under the treatment of liquid fertilizer topdressing, and tomato market yield increased 26.7%, compared with basal application granular P (CK1), and fertilizer recovery rate increased as well. The correlation between the content of soil Ca2-P,Ca8-P,Al-P and phosphorus uptake by processing tomato were significantly correlation. Correlation coefficient were 0.8700,0.8277 and 0.8919.