基于土地利用和覆被变化的黄河三角洲土壤质量预警研究

该文通过1987和2002年黄河三角洲土地利用和覆被变化与土壤肥力变化的对比分析，探讨土地利用和覆被变化对土壤肥力的影响。研究结果表明：土地利用和覆被变化对土壤肥力变化有直接影响，耕地转为林草地、建设用地、盐荒地和沙地，土壤肥力均有下降趋势；林草地转为滩涂的土壤肥力明显下降，转为盐荒地的略有下降；沙地转为耕地的土壤肥力明显提高，转为林草地有下降趋势，转为盐荒地的略有提高或不变；盐荒地转为耕地的土壤肥力有较大的提高，转为林草地的保持不变或稍有下降，转为沙地的稍有提高，转为建设用地的略微下降；滩涂转为盐荒地的土壤肥力保持不变或略微下降，转为林草地的稍有提高。     

Soil nutrient changes due to land use changes in Northern China: a case study in Zunhua County, Hebei Province

Abstract. Since the 1980s, land use in rural areas of China has changed greatly as the result of political initiatives. These changes have caused soil nutrient changes which are examined in this paper for Zunhua County, northern China from 1980 to 1999. The areas of farmland, grassland, and paddy decreased greatly and were replaced by increases in forest and residential land. The soils under forest in 1999 transformed from farmland in 1980 increased in organic matter by 21%, total nitrogen by 18%, available nitrogen by 65%, available phosphorus by 17% and available potassium by 17%. Similarly, in the area which was converted from farmland in 1980 to grassland in 1999, soil organic matter, total nitrogen, available nitrogen, available phosphorus, and available potassium increased by 38%, 37%, 71%, 2% and 28%, respectively. Changes from farmland to forest and grassland not only changed land cover but also improved soil fertility and probably reduced soil nutrient losses.     

甘肃省几种主要农田土壤肥力监测结果

对甘肃省几种主要耕种农田土壤肥力连续5年的定位监测结果进行分析。结果表明:农田土壤耕层有机质、全氮、速效磷均比第二次土壤普查值增加,速效钾均比普查值下降;施肥结构不合理,土壤耕层养分盈亏量为氮盈余,磷富积,钾亏缺。     

不同培肥方式对西藏中部退化土壤的影响

对西藏中部土壤复退过程中土壤物理、化学 (养分 )、生物变化及其效应进行了探讨 ,初步结果表明 ,在西藏高原生态条件下 ,有机肥 ,特别是有机—无机肥配合施用在短期内对降低土壤容重 ,提高土壤孔度 ,增加 1～ 3 mm水稳性团聚体数量 ,提高土壤养分和有机质含量 ,促进土壤生物繁殖具有显著作用 ,并呈随有机肥投入量递增而显著增加的趋势 ,化肥 (包括化肥平衡施用 )的综合效应则相对较低。大幅度提高土壤有机质含量及供钾水平是退化土壤肥力恢复过程中面临的重要问题。不同培肥方式的土壤微生物数量构成中细菌均占绝对优势 ,对作物营养具较大贡献 ;化肥、有机—无机肥配合施用不利于土壤真菌、放线菌数量的提高     

Crop management effects on soil carbon sequestration on selected farmers’ fields in northeastern Ohio

Soil organic carbon (SOC) pool is the largest among terrestrial pools. The restoration of SOC pool in arable lands represents a potential sink for atmospheric CO₂. Restorative management of SOC includes using organic manures, adopting legume-based crop rotations, and converting plow till to a conservation till system. A field study was conducted to analyze soil properties on two farms located in Geauga and Stark Counties in northeastern Ohio, USA. Soil bulk density decreased with increase in SOC pool for a wide range of management systems. In comparison with wooded control, agricultural fields had a lower SOC pool in the 0–30 cm depth. In Geauga County, the SOC pool decreased by 34% in alfalfa (Medicago sativa L.) grown in a complex rotation with manuring and 51% in unmanured continuous corn (Zea mays L.). In Stark County, the SOC pool decreased by 32% in a field systematically amended with poultry manure and 40% in the field receiving only chemical fertilizers. In comparison with continuous corn, the rate of SOC sequestration in Geauga County was 379 kg C ha⁻¹ year⁻¹ in no-till corn (2 years) previously in hay (12 years), 760 kg C ha⁻¹ year⁻¹ in a complex crop rotation receiving manure and chemical fertilizers, and 355 kg C ha⁻¹ year⁻¹ without manuring. The rate of SOC sequestration was 392 kg C ha⁻¹ year⁻¹ on manured field in Stark County.     

Direct and Residual Effects of Fly Ash-Based Integrated Fertilization on Rice (Oryza sativa L.) and Rapeseed (Brassica camprestris L.)

Integrated effects of fly ash (FA), farmyard manure (FYM), and chemical fertilizers recommended dose of fertilizer (RDF) on the performance of rice (Oryza sativa L.) and their residual effect on rapeseed (Brassica camprestris L. vartoria) were studied for two years in loamy acidic inceptisol of Assam, India.

The FA was generated from a bituminous and lignite coal-based captive thermal power plant of Hindustan Paper Corporation Ltd (HPCL), Assam. Rice yields were higher when FA, FYM, and RDF were used collectively vis-à-vis sole application of RDF reflected also in rapeseed under residual effect . FA effect on mean rice equivalent yield of the rice–rapeseed system was the highest (24.4%) under integrated application. Nickel (Ni) and cadmium (Cd) contents in rice decreased with increasing FA, while arsenic (As) was just the opposite. Integration of FA, FYM, and RDF was effective in lowering Ni, Cd, and As in rice compared to 100% RDF alone or together with FA. The residual effect on rapeseed was similar for Ni and As while the Cd content increased. Blending of FA, FYM, and RDF also positively altered the residual soil pH, organic carbon (C), and nitrogen, phosphorus, and potassium (NPK). Thus, FA can be an integral component of integrated plant nutrition system (IPNS) in augmenting crop yield and residual benefits in loamy acid inceptisol.     

炭化生活污水污泥对酸化红壤的改良效果

从南京市、马鞍山市和丹阳市的3个污水处理厂采集污泥,在500℃下热解制备炭化污泥,测定了污泥和炭化污泥的性质和重金属含量,研究了污泥和炭化污泥对酸性红壤改良效果,并探讨了炭化污泥中重金属的环境风险。结果表明,污泥和炭化污泥中含有一定量的碱,添加炭化污泥可提高红壤的p H和交换性钙、镁和钾含量,降低土壤交换性铝和交换性H+含量。但污泥中大量铵态氮的硝化作用释放质子,抵消了污泥对红壤酸度的改良作用。添加污泥和炭化污泥提高了土壤有机碳、有效磷和速效钾的含量,提高了土壤肥力。污泥炭化后重金属含量有所增加,但大部分重金属的有效态含量下降,说明热解过程可以降低部分有毒重金属的活性。与对照相比,添加炭化污泥会增加土壤中部分重金属有效态含量,特别是有效态锌含量显著增加,因此炭化污泥农业利用存在一定的环境风险。建议将炭化污泥用于酸化的森林红壤的改良。     

榨菜叶还田对土壤肥力的影响研究

利用盆栽试验和田间试验研究了榨菜叶还田对土壤养分肥力的影响,结果表明,榨菜叶还田处理土壤碱解氮、速效磷、速效钾含量在水稻整个生长期变化较小,水稻生长后期土壤速效N、P、K含量都高于化肥处理;而化肥处理氮磷钾含量变化较大,说明榨菜叶养分供应能够与作物的吸收相互协调,养分供应持续稳定,能满足水稻生长后期对NPK养分的需要,是一种天然的缓释肥料。在水稻生长期,榨菜叶还田能明显的提高土壤肥力,与对照相比,水稻收获后不同处理土壤有机质含量、土壤氮、磷、钾含量,均有所上升,以榨菜叶及其配施化肥处理上升的幅度较大,培肥效果较好。     

分形理论在土壤肥力研究中的应用与前景

分形理论的提出对于定量描述复杂的、高度不规则的系统特征与机理提供了方法.本文从土壤腐殖质、土壤微生物、土壤团聚体等方面回顾了分形理论在土壤肥力研究中的主要结果:土壤腐殖质胶体在不同条件下形成不同分形特征的聚合物;同一种微生物可能形成具有不同分形特征的结构;土壤中的有机无机胶体在不同条件下凝聚成不同的团聚体,从而形成不同的土壤结构并对其肥力功能产生影响.我们认为分形理论在探索土壤的形成过程和肥力功能上将具有重要的应用前景:如团粒结构体的形成可能是由土壤胶体分形凝聚而成;土壤中的活性有机质有逐渐老化的现象,可能和腐殖质胶体由结构疏松的分形结构向普通团聚体过渡的过程有关;土壤微生物在不同微环境下具有不同的分形特征,可以推测在各种土壤过程(包括物理、化学以及生物化学过程)中它们的功能也可能是不一样的.此外,土壤结构的开放程度决定孔隙、水分以及空气的分布,从而决定了微生物的生存空间.所以土壤结构体对微生物空间分布的影响也是将来该领域值得研究的内容之一.     

Physical activation of biochar and its meaning for soil fertility and nutrient leaching – a greenhouse experiment

The slow alteration of the surface of charred biomass (biochar) over time may contribute to an improved nutrient retention and thus fertility of tropical soils. Here, we investigated soils from temperate climates and investigated whether a technical steam activation of biochar could accelerate its positive effects on nutrient retention and uptake by plants relative to nonactivated biochar. To this aim, we performed microcosm experiments with sandy or silty soil, mixed with 2.0, 7.5 and 15.0 g/kg soil of fine (<2 mm) or coarse‐sized (2–10 mm) biochar from beech wood (Fagus sp.). After initial fertilizer (NPK), ashes and excess nutrients were leached with water, and the microcosms were planted for 142 days with Italian Ryegrass (Lolium multiflorum ssp. italicum). Thereafter, leachate, soil and plant samples were analysed for their nutrient contents. The results showed that biochar additions of ≤15 g/kg soil left elevated contents of available P and N in the surface soil but reduced their uptake into the plants. As a result, total biomass production was unchanged. Different particle size and application amounts influenced these findings only marginally. Nitrate leaching was enhanced in the sandy soil (+41% for nitrate, but reduced in the silty soil ?17%) and P was immobilized. Hence, the fertility of the temperate soils under study was only marginally affected by pure biochar amendments. Steam activation, however, almost doubled the positive effects of biochars in all instances, thus being an interesting option for future biochar applications.