清代团体土地所有权探析——以义田制度为中心的考察

以义田为代表的清代团体土地,是清代土地所有权的重要形式之一,对清代社会的长期稳定具有重要价值。清代团体土地所有权在宗族、书院、寺庙等主体上的设立过程,体现了民间力举与国家力推的特征;清代团体土地所有权以交易安全为第一宗旨,其采用的要求苛刻之运行模式,是封闭主义与回避原则的作用结果,避免了社会动荡对其产权稳定的冲击;宗族法与国家法二元色彩的合力,则形成了清代团体土地所有权的保护源泉。

基于义田制度的清代团体土地所有权考辩

以义田为代表的清代团地土地,是清代土地所有权的重要形式之一。清代法律对团体土地所有权的规制,主要从设立途径、运行模式、保护源泉三个方面着手。清代团地土地所有权在宗族等主体上的设立过程,体现了民间力举与国家力推的特征。清代团体土地所有权采用近乎苛刻之运行模式,是封闭主义与回避原则的作用结果。宗族法与国家法的二元合力,则形成了清代团体土地所有权的保护源泉。清代团体土地在发挥稳定基层社会、促进宗族和睦的作用同时,也阻碍了商品经济在封建社会中的发展。研究清代团体土地所有权,不仅具有构建中国传统物权制度的理论价值,而且对于我国当前正在进行的农村集体土地承包经营权流转制度改革,具有重要的现实借鉴意义。

Effects of Tillage Practices and Land Use Management on Soil Aggregates and Soil Organic Carbon in the North Appalachian Region,USA

Promoting soil carbon sequestration in agricultural land is one of the viable strategies to decelerate the observed climate changes. However, soil physical disturbances have aggravated the soil degradation process by accelerating erosion. Thus, reducing the magnitude and intensity of soil physical disturbance through appropriate farming/agricultural systems is essential to management of soil carbon sink capacity of agricultural lands. Four sites of different land use types/tillage practices, i） no-till （NT） corn （Zea mays L.） （NTC）, ii） conventional till （CT） corn （CTC）, iii） pastureland （PL）, and iv） native forest （NF）, were selected at the North Appalachian Experimental Watershed Station, Ohio, USA to assess the impact of NT farming on soil aggregate indices including water-stable aggregation, mean weight diameter （MWD） and geometric mean diameter （GMD）, and soil organic carbon and total nitrogen contents. The NTC plots received cow manure additions （about 15 t ha-1） every other year. The CTC plots involved disking and chisel ploughing and liquid fertilizer application （110 L ha-l）. The results showed that both water-stable aggregation and MWD were greater in soil for NTC than for CTC. In the 0-10 cm soil layer, the 〉 4.75-mm size fraction dominated NTC and was 46% more than that for CTC, whereas the 〈 0.25-mm size fraction was 380% more for CTC than for NTC. The values of both MWD and GMD in soil for NTC （2.17 mm and 1.19 mm, respectively） were higher than those for CTC （1.47 and 0.72 mm, respectively） in the 0-10 cm soil layer. Macroaggregates contained 6%-42% and 13%-43% higher organic carbon and total nitrogen contents, respectively, than microaggregates in soil for all sites. Macroaggregates in soil for NTC contained 40% more organic carbon and total nitrogen over microaggregates in soil for CTC. Therefore, a higher proportion of microaggregates with lower organic carbon contents created a carbon-depleted environment for CTC. In contrast, soil for NTC had more aggregation and contained higher organic carbon content within water-stable aggregates. The soil organic carbon and total nitrogen stocks （Mg ha-1） among the different sites followed the trend of NF 〉 PL 〉 NTC 〉 CTC, being 35%-46% more for NTC over CTC. The NT practice enhanced soil organic carbon content over the CT practice and thus was an important strategy of carbon sequestration in cropland soils.

Impact of Land Use and Soil Fertility on Distributions of Soil Aggregate Fractions and Some Nutrients

The size distribution of water-stable aggregates and the variability of organic C,N and P contents over aggregate size fractions were studied for orchard,upland,paddy,and grassland soils with high,medium,and low fertility levels.The results showed that > 5 mm aggregates in the cultivated upland and paddy soils were 44.0% and 32.0%,respectively,less than those in the un-tilled orchard soil.Organic C and soil N in different size aggregate fractions in orchard soil with high fertility were significantly higher than those of other land uses.However,the contents of soil P in different size aggregates were significantly greater in the paddy soil as compared to the other land uses.Soil organic C,N and P contents were higher in larger aggregates than those in smaller ones.The amount of water-stable aggregates was positively correlated to their contribution to soil organic C,N and P.For orchard and grassland soils,the > 5 mm aggregates made the greatest contribution to soil nutrients,while for upland soil,the 0.25-0.053 mm aggregates contributed the most to soil nutrients.Therefore,the land use with minimum disturbance was beneficial for the formation of a better soil structure.The dominant soil aggregates in different land use types determined the distribution of soil nutrients.Utilization efficiency of soil P could be improved by converting other land uses to the paddy soil.

Aggregate Development and Organic Matter Storage in Mediterranean Mountain Soils

Soil aggregation and organic matter of soils from the pre-Pyrenean range in Catalonia (NE Spain) were studied,in order to assess their quality as carbon sinks and also to select the best soil management practices to preserve their quality.Aggregate stability,organic carbon and micromorphology were investigated.The highest amount of organic carbon was found in alluvial,deep soils (228 Mg C ha -1 ),and the lowest was in a shallow,stony soil with a low plant cover (78 Mg C ha -1 ).Subsurface horizons of degraded soils under pastures were the ones with smaller and less-stable aggregates.Fresh residues of organic matter (OM) were found mostly in interaggregate spaces.Within the aggregates there were some organic remains that were beginning to decompose,and also impregnative nodules of amorphous OM.Although OM was evenly distributed among the aggregate fractions,the larger blocky peds had more specific surface,contained less decomposed OM and had a lower organic/mineral interphase than smaller crumb aggregates,which were also more stable.Soil carbon storage was affected primarily by the OM inputs in the surface horizons.In order to store organic carbon over the mid- and long-term periods,the mechanisms favouring structuration through biological activity and creating small aggregates with intrapedal stable microporosities seemed to be the most effective.