杉木人工林土壤磷素形态及其有效性研究

P Fractions in Soils and Their Availability in Chinese Fir Plantations in South China

对几种主要杉木人工林土壤Ｐ素形态及其有效性进行研究，结果表明：（１）无机Ｐ是赤红壤、红壤、黄红壤Ｐ素的主要形态，其中Ｏ－Ｐ含量最高，Ｃａ－Ｐ和Ｆｅ－Ｐ次之，Ａｌ－Ｐ含量最低。Ａｌ－Ｐ、Ｆｅ－Ｐ、Ｏ－Ｐ和Ｃａ－Ｐ在赤红壤中分别占无机Ｐ的２．７４％、４．７０％、８４．７４％和７．８１％；在红壤中分别占２．４６％、１１．９０％、７７．２４％和７．８０％；在黄红壤中分别占２．７４％、１０．６３％、７８．０４％和８．５９％。山地黄壤Ｐ素以有机Ｐ为主，无机Ｐ占全Ｐ的３０．５６％，Ａｌ－Ｐ、Ｆｅ－Ｐ、Ｏ－Ｐ和Ｃａ－Ｐ分别占无机Ｐ的１．５４％、１５．６７％、７８．８５％和３．９４％。（２）在供试土壤区内Ａｌ－Ｐ、Ｆｅ－Ｐ、Ｏ－Ｐ和Ｃａ－Ｐ表现出明显的地带性规律。但在红壤区内，Ｆｅ－Ｐ、Ｏ－Ｐ和Ｃａ－Ｐ呈现出一定微域内Ｐ素形态的复杂性和不均一性的变化，Ａｌ－Ｐ表现出明显的过渡带土壤特征。（３）在不同Ｐ素形态中，Ｆｅ－Ｐ是杉木人工林土壤有效Ｐ的一个重要来源。

P fractions and their availability in soils of Chinese fir plantations in South China were studied. I P (inorganic P) was a major component of total P and it accounted for 72.48% in lateritic soil, 73.20% in red soil, and 63.77% in yeillow red soil. Al P, Fe P, O P, and Ca P accounted for 2.74%, 4.70%, 84.74% and 7.81% in lateritic soil, 2.46%, 11.90%, 77.24%, and 7.81% of inorganic P in red soil, 2.74%, 10.63%, 78.04% and 8.59% in yellow red soil, respectively. Organic P in mountain yellow soil was a major composition of P, and I P only accounted for 30.56% of total P. Al P, Fe P, O P, and Ca P in inorganic P accounted for 1.54%, 15.67%, 78.85% and 3.94%, respectively. The distributions of Al P, O P, Fe P and Ca P in the four kinds of soils mentioned above had an obvious zonality and Al P appeared the characteric of transitional soil, while those of O P, Fe P and Ca P in the red soil region showed the complicated characteric and no homogeneity of P fractions. The regression analysis indicated that there was a significant relationship between Fe P and available P.