东北平原14个地点杨树防护林和农田土壤全磷及其组分差异研究

土壤磷素差异是科学评价农田防护林土壤养分管理的基础之一。本研究在富裕、兰陵、明水、肇州、宋站、杜蒙、赤峰、通辽、奈曼、四平、长岭、白城、德惠和泰来14个地点采集杨树防护林和配对农田表层(0～40 cm)土壤样品共84个，使用Tiessen和Sui修正的Hedley磷素分级法测定土壤9种磷组分，使用配对样本T检验法研究农田、杨树防护林土壤全磷及磷组分含量差异。结果表明：(1)东北平原14地点土壤全磷范围在122～594 mg·kg^-1,均值为266 mg·kg^-1;9种组分中，稀盐酸无机磷(HCl-Pi)占全磷(TP)含量的52.7%,其次是氢氧化钠有机磷(NaOH-Po)占14.8%、浓盐酸有机磷(conc.HCl-Po)占11.2%,闭蓄态磷(Re-P)、浓盐酸无机磷(conc.HCl-Pi)、氢氧化钠无机磷(NaOH-Pi)占比在5%～6%之间，而水溶性磷(H₂O-Pi)、碳酸氢钠无机磷(NaHCO₃-Pi)、碳酸氢钠有机磷(NaHCO₃-Po)占比在0.5%～3%之间。(...

Differences of soil total phosphorus and its 9 fractions between poplar shelterbelts and adjacent farmlands in 14 locations of Northeast China Plain

The difference of soil phosphorus(P)is one of the guidelines for soil nutrient management of farmland shelterbelt forest.In this paper,total 84 soil samples were collected from 14 sites(Fuyu,Lanling,Mingshui,Zhaozhou,Songzhan,Dumeng,Chifeng,Tongliao,Naiman,Siping,Changling,Baicheng,Dehui and Tailai counties)in Northeast China Plain at the depth of 0~40 cm soil layer.The Hedley method modified by Tiessen and Sui was used to determine 9 P components in soil,and the paired T test was used to study the differences of total P and P components between farmland and poplar shelterbelt soil.(1)Soil total P in 14 sites ranged from 122 to 594 mg·kg^-1,with an overall average at 266 mg·kg^-1.In all 9 fractions,the peak was dilute hydrochloric acid inorganic phosphorus(HCl-Pi),contributing 52.7%of the total soil P(TP),followed by sodium hydroxide organophosphorus(NaOH-Po)(14.8%)and concentrated organophosphorus hydrochloride(conc.HCl-Po)(11.2%).Closed state of phosphorus storage(Re-P),concentrated hydrochloric acid inorganic phosphorus(conc.HCl-Pi)and sodium hydroxide inorganic phosphorus(NaOH-Pi)took a proportion of soil total P at 5%~6%,while water soluble phosphorus(H2O-Pi),sodium bicarbonate inorganic phosphorus(NaHCO3-Pi),sodium bicarbonate organophosphorus(NaHCO3-Po)took a proportion ranged from 0.5%to 3%.(2)On average across the 14 sites,the soil total P content in poplar shelterbelt was 20.9%lower than that in the neighboring farmland.In the nine P components,the NaHCO3-Pi in poplar forest decreased 30.9%compared with the farmland;The proportion of NaOH-Pi to total soil P in 11 out of the 14 sites was lower in poplar forests compared with farmland,and the average in poplar was significantly lower.(3)The HCl-Pi,NaOH-Po,conc.HCl-Po fractions were also the main drivers for soil total P reduction in poplar forests,and the HCl-Pi contributed 54.1%of the total reduction.Our data manifested that poplar afforestation induced soil total P reduction with different reduction among the nine fractions.Soil total P and different fractions varied at over 10-fold in different locations,while only<2-fold variations were found between farmlands and poplar forests.Our finding highlighted that large area soil P variations from land uses should fully exclude inter-site variations,and our results provide basic data for the evaluation of soil P changes in Northeast China Plain.