Effects Of Phosphorus Activator On Soil Phosphorus Availability And Plant Phosphorus Uptake In Jiaodong Apple Orchard

Phosphorus is one of the essential nutrients for Apple growth and development.Its fixed adsorption in soil leads to low availability of phosphorus in soil.To explore the ability of phosphorus activators to activate soil“Residual phosphorus”and improve the bioavailability of phosphorus components in soil,it is of great significance to promote the growth of apple plants and the efficient utilization of phosphorus.The experiment was conducted from February to December,2020,with M9T337 seedlings as the test materials,the effects of different phosphorus activators on phosphorus composition,phosphorus availability,growth,phosphorus uptake and utilization of apple rootstocks in acid apple orchard soil of Yantai were studied.The main results are as follows:1.Effects of three phosphorus activators（biochar,humic acid and zeolite）at 1.5%treatment level on plant growth,phosphorus utilization efficiency and phosphorus composition in soil:The results showed that the plant biomass increased significantly with the addition of 1.5%biochar,humic acid and zeolite as compared with that without phosphorus activator,The total root length,total surface area and the number of root tips increased,Increased root activity,increased soil organic matter content,The proportion of Na HCO₃-Pi and Na OH-Pi increased,while the proportion of HCl-P and Residual-P decreased,The content of available phosphorus was increased,the accumulation of phosphorus and the utilization efficiency of phosphorus were increased.The results showed that biological carbon treatment was the best,followed by humic acid and zeolite treatment.2.Effects of different concentrations of biochar on apple growth and phosphorus uptake and utilization:Compared without P application,P application significantly promoted the growth of shoot and root,and increased the content of available p and the accumulation of P.Compared with conventional phosphorus（P）application,20%（80%）phosphorus reduction significantly inhibited plant growth and decreased soil indexes.Compared with normal P application and P reduction by 20%（80%P）,increasing biological carbon significantly increased plant height,stem diameter,fresh weight and dry weight,promoted root development,enhanced root activity,and increased soil p H and organic matter content,the content of available phosphorus,the accumulation of phosphorus in plant and the apparent utilization rate of phosphorus fertilizer were significantly increased.The best effect was80%P+2.5%B（20%P reduction and 2.5%biochar application）.