不同复垦方式下土壤无机磷的空间分布特征

Spatial Distribution Characteristics of Soil Inorganic Phosphorus Under Different Reclamation Modes

以济宁地区引黄充填复垦、引湖充填复垦和预复垦3种复垦方式样地土壤为研究对象,通过分层采样和室内分析,研究不同复垦方式下土壤无机磷（Ca2-P、Ca8-P、Al-P、Fe-P、O-P、Ca10-P）的空间分布情况,并找出影响复垦土壤速效磷偏低的原因。结果表明：（1）3种复垦方式下的复垦土壤全磷含量在0.42-0.77g/kg之间,土壤速效磷含量在0.65-5.22mg/kg之间,复垦土壤全磷含量丰富而速效磷含量偏低;（2）复垦土壤中各无机磷形态以难被植物利用的Ca10-P和O-P含量最高,易被植物利用的Ca8-P和Ca2-P含量最少,不同复垦方式下的土壤各无机磷形态含量略有差别,与一般土壤相比,复垦土壤中第二磷源Ca8-P含量占到3%,比重相对降低,难利用磷源O-P含量占到32%,比重大幅升高;（3）复垦土壤无机磷总量和各形态无机磷含量在表层积累,随土层加深,其含量和有效性呈逐渐降低的趋势,其中引黄充填复垦和引湖充填复垦无机磷含量和有效性优于预复垦;（4）复垦土壤中速效磷含量与土壤压实度呈显著性负相关,相关系数r=-0.554＊（p〈0.05）,与难溶性Ca10-P呈极显著性正相关,相关系数r=0.650＊＊（p〈0.01）。复垦土壤压实度偏高和有效磷源含量缺乏造成复垦土壤全磷含量丰富而速效磷偏低,比较而言,预复垦方式受到更多的机械碾压而磷素状况更差。

Taking the soil under three different reclamation modes,i.e.reclamation filled by Yellow River sediments,reclamation filled by lake sediments,and beforehand reclamation,in the Jining region as the research objects,studying spatial distribution characteristics of various forms of inorganic phosphorus（Ca2-P,Ca8-P,Al-P,Fe-P,O-P,Ca10-P）in soil under different reclamation modes,and discussing reasons for low phosphorus availability in reclaimed soil.The result shows that：（1）Total phosphorus content in reclaimed soil under different reclamation modes was between 0.42 and 0.77g/kg,and available phosphorus content was between 0.65 and 5.22 mg/kg,total phosphorus content was higher in reclaimed soil,but plant-available phosphorus content was lower.（2）In reclaimed soil,contents of sparsely plant-available inorganic phosphorus（Ca10-P and O-P）were the highest,while the contents of Ca8-P and Ca2-P,which are plant-available,were the lowest.For the contents of various forms of inorganic phosphorus,there were slight differences among different reclamation modes.Compared with normal soils,the proportion of Ca8-P in reclaimed soils decreased,accounting for about 3% of total phosphorus,but the proportion of sparsely plant-available O-P increased,accounting for about 32% of total phosphorus.（3）Total inorganic phosphorus and various forms of inorganic phosphorus accumulated in surface soil,while contents and availability decreased besides increasing soil depth,besides the content and availability in soil under the modes of reclamationfilled by Yellow River sediments and reclamation filled by lake sediments were higher than those in soil under the mode of beforehand reclamation.（4）There was a significant negative correlation between plant-available phosphorus and soil compactness,r=-0.554＊（p〈0.05）,and there was an extremely significant positive correlation between plant-available phosphorus and Ca10-P,r=0.650＊＊（p〈0.01）.In reclaimed soil,a greater compactness and a lack of effective source of phosphorus could account for the lower phosphorus availability.In comparison,phosphorus conditions in soil under the mode of beforehand reclamation were worse because this mode got greater mechanical compaction.