Study On The Effects Of Mineral Conditioner On Soil Phosphorus Retention And Plant Nutrient Uptake

Phosphorus is an important nutrient for crops,and application of phosphate fertilizer is one of the main ways to provide phosphorus to crops.However,phosphorus is easily fixed in soil,which resulted in a low utilization rate of the fertilizer.Moreover,the ministry of land and resources claimed after 2010 the existed phosphorus mineral resource was one of the minerals that cannot meet the demands of national economy for consumed in large quantities.Therefore,it is of great strategic significance to reduce the fixation contents of phosphorus in soil,increase the effectiveness of phosphorus and improve the utilization rate of phosphate fertilizer for agricultural sustainable development and efficient utilization of phosphorus resources.In this study,a weakly alkaline and full of various nutrients elements?potassium,calcium,magnesium,silicon and sulfur?mineral conditioner was used to improve soil,which was the calcined product of proper matching mixture of potassium feldspar,dolomite and limestone powder.During the study,the effect of conditioners on adjusting soil acidity and phosphorus availability was studied through field experiment and soil culture experiment.Under condition of reduction of the applied chemical fertilizer content,pot experiment were conducted to discuss the effect of amendment on the nutrient elements absorption and yields of plant.Besides,The adsorption and desorption characteristics of phosphorus for modified soil were further explored.The results showed that applying mineral conditioners together with chemical fertilizer can not only improve soil nutrient contents and the environment for crop growth by effectively enhancing soil acidification resistance,increasing soil phosphorus availability and replenishing soil mineral elements,but also can increase crop nutrition absorption and yields,so as to improve the utilization rate of phosphate fertilizer and reduce the dosage.Specific conclusions of this study are as follows:?1?The contents of K₂O,CaO,MgO,SO₃,SiO₂ and Al₂O₃ in mineral conditioners were3.84%,36.46%,4.18%,10.2%,30.05%and 7.47%,respectively.It can improve the pH of soil.After one month of soil spiked,under applying same amount of fertilizer,soil pH value rose from 5.02 to 5.31-5.61 when the dosage of mineral conditioners was 1-2 g/kg.While the soil pH increased from 5.66 to 5.93-6.34 when only application of 0.5-2 g/kg mineral conditioner.?2?The application of mineral conditioners supplemented the effective mineral elements such as calcium,magnesium and silicon in the soil.When the dosage of addition mineral conditioners was 0.5-2 g/kg,soil effective calcium contents increased by 13.43%-30.65%,effective magnesium contents increased by 33.38%-69.63%,and the effective silicon contents increased by 16.35%-46.27%.?3?The application of conditioners can obviously improve the effectiveness of phosphorus in the soil,which can increase the level of soil phosphorus supply.The results of field trial of acid red soil show that the percentage of effective phosphorus in total phosphorus increased by 5.70%,10.43%and 18.95%with the applied conditioners contents at 525 kg/ha,750 kg/ha and 975 kg/ha,respectively.The results of indoor culture experiment of paddy soil show that when the dosage of mineral conditioners was 0.5-2 g/kg,the fixed rate of phosphate fertilizer applied to soil was delayed and the effective phosphorus contents increased by34.54%,21.49%,24.17%for soil cultured 15 days and increased by 35.86%,22.09%,23.84%for soil cultured 22 days.?4?The application of appropriate amount of mineral amendment can promote nutrient uptake by crops and improve crop failure resulting from fertilizers reduction.In the pot experiment,under condition of applied chemical fertilizer reduced by 15%,with applying0.5-2 g/kg mineral conditioner,the uptakes of nitrogen,phosphorus,potassium,calcium and magnesium in plant increased by 14.69%-44.26%,15.28%-52.89%,16.28%-42.43%,26.99%-33.25%and 28.40%-41.04%,respectively,and the crop yields increased by10.47%-33.33%.When soil treated with 0.5 g/kg conditioners,plant yields equaled to which obtained under the conventional fertilization;When applying 1g/kg conditioners,compared to conventional fertilization,the yields did not decrease,but increased significantly by 15.81%.?5?Freundlich models and pseudo-second-order kinetic model could well fit the adsorption processes of phosphorus by the modified soil.Moreover the adsorption process of phosphorus contains physical adsorption and chemical adsorption,and the latter is the main one.At low phosphorus concentration,the modified soil increased the adsorption of phosphorus;While at high phosphorus concentration,the adsorption capacity of modified soil to phosphorus was affected by many mechanisms without obvious law of adsorption contents.And part of the absorbed phosphorus can be desorbed to a certain extent,still maintaining a certain degree of effectiveness within a short time.