【作者】 张玉革；

【导师】 张玉龙；

【作者基本信息】 沈阳农业大学 ， 土壤学， 2005， 博士

【摘要】 为探索土地利用方式变更对土壤营养元素剖面分布的影响,本文对中国科学院沈阳生态实验站(41°31′N, 123°22′E)的水稻田、玉米地、撂荒地和人工林地0～150 cm土体10 个土层中土壤营养元素含量的剖面分布、储量等进行了比较研究。四种供试农田或林地均发育于潮棕壤,以不同方式利用已经达14 年时间。所得主要结果如下: 土壤有机C、全N、全S 含量剖面分布因土地利用方式不同而产生明显的差异,林地剖面土壤有机C、全N 含量较撂荒地、玉米地、水稻田高。0～20cm 土层,林地和撂荒地土壤有机C 和全N 储量高于玉米地和水稻田,而土壤全S 储量无显著差异。0～100cm 及0～150cm 土层,土壤有机C、全N、全S 储量均为林地>玉米地>撂荒地>水稻田。土壤有机C 与全N 极显著相关,且林地和撂荒地土壤C 与N 的相关性略高于水稻田和玉米地。土壤剖面中C/N,无论水田、玉米田,还是林地和撂荒地,均随深度而下降,但同一深度层次比较,林地最高,稻田最低,玉米地与撂荒地居于中。土壤全P 含量在不同深度土层基本呈现出林地>撂荒地>玉米地>水稻田的趋势,0～20 cm 土层土壤全P 储量水田、玉米地、撂荒地和林地间差异不显著,但在0～100cm和0～150cm 深度,林地和撂荒地土壤显著高于玉米地和水稻田土壤。林地、水田、玉米地和撂荒地土壤C/P 均随剖面深度增加而降低,在40 cm 以下有林地和玉米地高于撂荒地和水稻田的趋势。土壤交换性阳离子储量以林地为最高,但不同利用方式间差异不显著。4 种土地利用方式比较,土壤交换性Ca/Mg 水田最高,林地最低; 水稻田和玉米地土壤交换性Ca/K明显大于的撂荒地和林地。在东北平原南部的气候条件下,经过十几年的时间土壤交换性盐基离子的种类、数量剖面分布等方面差异已经相当明显。土壤DTPA 浸提态Fe、Mn、Cu、Zn 含量剖面分布特点是随土层深度增加其含量降低,且在林地、撂荒地、水稻田和玉米地间也出现明显分异。除DTPA 浸提态Fe 的这一差异主要发生在较深土壤层次外,DTPA 浸提态Mn、Cu、Zn 含量在大多土层中均差异明显。DTPA 浸提态Fe、Mn、Cu、Zn 含量与SOC、全N、碱解N、全S 含量等存在显著的相关关系。更多还原

【Abstract】 This paper studied the storage and dynamics of soil nutrients at the Shenyang Experimental Station of Ecology, Chinese Academy of Sciences (41°31′N, 123°22′E), aimed to explore the nutrients distribution in soil profile under four land use patterns over 14 years. The four land use patterns are paddy field (PF), maize field (MF), fallow field (FF) and woodland (WL). In each profile at 0～150 cm depth, soil samples were collected from the layers 0～5, 5～10, 10～20, 20～30, 30～40, 40～60, 60～80, 80～100, 100～120, and 120～150 cm. The four test farmlands and woodland are originated from aquic brown soil. Following results were obtained. The profile distribution of SOC, total N and S were differed with different land use patterns. Soil organic C and total N contents in each soil layer were higher in WL than in FF, MF and PF. At the depth of 0～20 cm, the storage of SOC and total N were higher in WL and FF than in MF and PF, but no significant difference was found for soil total S. At the depths of 0～100 cm and 0～150 cm, The sequence of SOC, total N and S storages was WL >MF> FF > PF. Soil organic C had a significant correlation with soil total N, and the correlation was slightly closer in WL and FF than in PF and MF. The C/N ratio in the profiles of PF, MF, FF and WL decreased with soil depth, and was comparatively higher in WL and lower in PF. Soil total P contents in different soil layers were WL> FF> MF> PF. At the depth of 0～20 cm, soil total P storage had no significant difference among PF, MF, PF and WL, but at the depths of 0～100 cm and 0～150 cm, it was significantly higher in WL and FF than in MF and PF. The C/P ratio was decreased with depth in WL, PF, MF and FF, but tended to be higher in layers below 40 cm in WL and MF than in FF and PF. The storage of soil exchange base cations was tended to be higher in WL than PF, MF and FF, but the difference was not significant. Generally, soil exchangeable Ca/Mg and Ca/K ratios were in the sequence of PF>MF>FF>WL, and were significantly higher in PF and MF than in FF and WL. Under the climate conditions in South Northeast Plain of China, the effects of land use on the sorts and contents of soil exchangeable base cations in the profiles were obvious over more than a decade. DTPA-extractable soil Fe, Mn, Cu and Zn were decreased with increasing soil depth, and the differentials were obvious among WL, FF, PF and MF. The differences of DTPA-extractable soil Fe under different land uses were mainly occurred in deeper layers, while DTPA-extractable soil Mn, Cu and Zn varied significantly in most layers. The DTPA-extractable soil Fe, Mn, Cu and Zn were positively correlated with SOC, total N, alkali N and total S in WL, FF, PF and MF. Cluster analysis and principal component analysis showed that soil chemical properties could be classified into three groups, of which, SOC, total N, alkali N, NO3--N, Olsen-P, and total S were clustered in group one, NH4+-N, exchangeable Ca and the sum of exchangeable base cations were in group two, and soil pH was in group three. Of the principal components affecting the profile distributions of SOC and nutrients under different land uses, plant cycling, including the accumulation and turnover of organic matter and the uptake and transport of nutrients, was considered as the leading foctor that affecting the profile distributions of C, N, S and microelements, and leaching and anthropogenic disturbance were the secondary factors that influence the profile distributions of soil exchangeable base cations and pH. The effects of land use change on the profile distributions of SOC and nutrients were obvious. Woodland had obvious advantages in improving SOC storage and maintaining soil fertility. Compared with maize field, fallow field could significantly increase SOC content in topsoil (0～20 cm), but had no significant difference in SOC storage at the depth of 0～100 cm. The results obtained could potentially provide theoretic support for understanding the effects of land use change on soil eco-environment, nutrient use efficiency, and establishment of sustainable land use models. Moreover, it could be helpful for nutrient biogeochemical cycling.更多还原