锐齿栎、油松茎流养分输入和树干基部土壤特性初步研究

Nutritive Input of Stem flow in Chinese Pine and Sharp tooth Oak Forests and Its Effect on Characteristics of Soil Nearby the Base of the Tree Stems

研究了锐齿栎、油松茎流化学性质及其树干基部土壤特性，结果表明：油松茎流的ｐＨ值为４．９７，呈酸性；锐齿栎茎流ｐＨ值为６．６０，呈微酸性；茎流中无机态化学物质的总质量浓度油松为３３．４８８ｍｇ／ｋｇ，锐齿栎为２６．１０５３ｍｇ／ｋｇ，其中Ｋ、Ｃａ、Ｎａ、Ｍｇ、ＮＨ＋４－Ｎ５种元素浓度占总浓度的９７％以上，构成了茎流无机态化学物质的主体；树干基部土壤由于受茎流的影响，其ｐＨ值，油松为５．７，比土体低０．５，锐齿栎为５．９，比土体则高０．３；全氮、水解氮和速效钾含量均高于土体，而全磷和速效磷则与土体差异不大；土壤酶活性，两个树种均是树干基部土壤高于土体，特别是脲酶活性油松干基比土体高７１６．６７％；锐齿栎高２９７．６２％。

Chemical properties of stem flow in Chinese pine and sharp tooth oak forests as well as its effect on the characteristics of soil nearby the base of tree stems in the two forests were studied. The stem flow of Chinese pine forest was acidic with a pH value of 4.97; and that of sharp tooth oak forest showed a weaker acidity with a pH value of 6.60. The total content of inorganic chemical compounds from stem flow was 33.488mg/kg for Chinese pine forest, and 26.107 mg/kg for sharp tooth oak forest, respectively. The inorganic chemical materials obtained from stem flow consisted mainly of the following five elements:K, Ca, Na, Mg and NH + 4 N, which took up over 97.0% of the total content.Two types of soil were sampled respectively from the two forests studied, and analyzed. The first was the soil close to the base of tree stems (within a range of 0～5cm). The second was the soil body beyond 30cm of tree stems and used as control. It was shown that stem flow had an influence on the features of the soil nearby the base of tree stem. The pH value of the soil nearby the base of tree stem in Chinese pine forest was 5.70, being 0.5 scale lower than its control. That in sharp tooth oak forest was 5.90, being 0.3 scale higher than its control. The contents of total nitrogen, hydrolyzable nitrogen and available potassium were higher in the soil nearby the base of tree stem than in the soil body used as control in the two forests; however, no large differences in total phosphorus and available phosphate were found between the two types of soil. The enzymatic activities of the soil nearby the base of tree stem were higher than those of the soil body used as control. Urease activity of the first type of soil in Chinese pine and sharp tooth oak forests was 716.67% and 297.62% more than that of the second type of soil, respectively. The results meant that the soil nearby the base of tree stem showed a better supply of nitrogen because of stem flow.