福建烟区土壤肥力状况

福建烟区 72 2个土壤样品的分析结果表明 ,土壤 p H平均为 5 .0 4.各成分的质量分数为 :有机质 2 8.93 g· kg- 1 、物理性粘粒 (<0 .0 1 mm) 3 3 %、全 N 1 .446g· kg- 1 、碱解 N 1 41 .9mg· kg- 1 、全 P 0 .482 g· kg- 1 、速效 P 2 0 .5 mg· kg- 1 、全 K2 0 .89g·kg- 1、速效 K1 2 2 mg·kg- 1、缓效 K2 94mg· kg- 1、交换性 Ca5 99.3 mg·kg- 1、交换性 Mg2 9.5 3 mg·kg- 1、有效S2 6.8mg·kg- 1、有效 Cu2 .1 1 mg·kg- 1、有效 B0 .2 42 mg·kg- 1、水溶性 Cl- 1 4.7mg·kg- 1 .烟区土壤 p H普遍偏低 ,应重视调节土壤酸度 ;注意适量施用 N肥 ;合理施用 P肥 ,减少土壤固定 ;重视施用 K肥 ;增加 Mg、B营养 ;施用石灰调节土壤酸度的同时应避免影响烤烟对 Mg、B的吸收     

广西靖西县新甲乡田七土壤肥力及重金属含量的调查与分析

对广西靖西县新甲乡田七土壤肥力及重金属（As、Hg、Cr、Pb、Cd）污染现状进行调查与分析。结果表明,在研究区域范围内,新甲乡田七土壤中有机质和速效钾养分达到 I级、II级,但区域2中速效钾是 III级,但3个区域土壤速效氮均为 IV级,处于缺乏状态。土壤重金属含量除 Cr达到轻微污染外,其他均未超出警戒范围。从综合污染指数结果可知,3个区域土样重金属含量已达到警戒线,土壤污染水平还处于尚清洁。     

沼肥不同施用方法对糯玉米根际土壤 肥力和微生物数量影响

【研究目的】本文通过基肥 追肥的施肥方法,研究沼肥的不同施用方法对糯玉米根际土壤肥力和微生物数量的影响。【方法】每小区五行,三次重复,完全随机区组设计,施肥方法分为基肥 追肥两阶段,两阶段施的量是一样的;【结果】单施沼肥和沼肥 菌肥玉米根际土壤N、P、K含量提高很明显,沼肥 菌肥、沼肥 化肥 菌肥、单施沼肥能明显降低土壤容重;施用沼肥使土壤中细菌、放线菌和霉菌的数量都有所增加;【结论】沼肥 菌肥、沼肥 化肥 菌肥、单施沼肥能明显降低土壤容重,很好改善土壤的结构,细菌、放线菌和霉菌的数量都有所增加。     

北京八达岭地区油松与灌丛林土壤肥力特征的研究

为探讨油松林土壤健康经营措施,该文对北京市八达岭低山区油松和灌丛林土壤的发生层厚度、物理性质、有机质和养分状况进行了研究. 结果表明:油松林的凋落物层为4.0 cm,高出灌丛林地96.30%; 油松林土壤的物理性质如粘粒、总孔隙度以及持水性能低于灌丛,但差异不显著; 在0～5 cm的土层中,油松林土壤的pH值低于灌丛0.3个单位,土壤有机质、全氮、碱解氮、有效磷和速效钾指标分别比灌丛土壤低31.86%、34.38%、22.28%、24.56%和22.86%,其差异均达到显著水平; 采用0～5 cm和0～20 cm土层厚度,比较油松和灌丛林土壤肥力指标的差异,所得结果不尽一致.研究认为,油松林能形成较厚的凋落物层,而灌丛植被有利于土壤有机质和养分的积累; 在经营油松纯林过程中应保留或补种一些灌木以达到改善林地生产力的效果.      

早稻施用控释氮肥的效果

为了探明控释氮肥在早稻上的应用效果，在不同肥力水平稻田进行控释氮肥、等氮量尿素、倍氮量尿素和不施尿素等处理，测定早稻各生育期干物质、成熟期经济性状及产量。结果表明：在较低、中等和较高肥力稻田上，施用控释氮肥的增产效果和经济效益依次递减；施用控释氮肥（施纯氮90kg/hm^2)比等氮量尿互分别增产9.6%，8.0%，5.6%,比无氮区分别增产74.5%,70.8%,49.5%。施用该肥促进了早稻生育中、后期对氮的吸收，氮素利用率达到72.6%-86.9%，比等氮量尿素平均高41.7%。干物质日生产量也高于等氮量尿素。经济效益比等氮量尿素平均增加763.35元/hm^2，比倍氮量尿素平均增加137.36元/hm^2。     

1979～1999年辽宁省耕地土壤养分肥力的变化分析

1979年土壤普查结束后 ,沈阳、锦州、朝阳等地又在耕地土壤上采集5551个监测土样 ,进行了土壤有机质、全氮、速效磷、速效钾等项目的测试分析。结果表明 ,在1979～1999年 ,全省耕地土壤有机质、全氮、速效钾呈下降趋势 ,速效磷呈上升趋势。有机质年递减率约为0.06%,全氮年递减率为0.47%;有效钾年递减率约为1.27%,平均下降20.6mg·kg-1 ;有效磷年递增率约为5.31%,平均提高7.3mg·kg-1。     

Modelling the Relationship Between Summer Maize NPK Uptake and Yield on the Basis of Soil Fertility Indices

Quantitative estimation of fertilizer requirements can help to increase maize （Zea mays L.） yields and improve the fertilizer use efficiency. The model for the Quantitative Evaluation of the Fertility of Tropical Soils （QUEFTS） was calibrated for maize by use of soil fertility data and fertilizer trials at different sites of the Huang Huai Hai river plain in China. The QUEFTS model accounts for interactions between nitrogen （N）, phosphorus （P） and potassium （K）. It describes the effects of soil characteristics on maize yields in four steps： （1） assessment of the potential supply of N, P and K based on soil chemical data; （2） calculation of the actual uptake of N, P and K, in function of the potential supply as determined in step 1 ; （3） draft the yield ranges as a function of the actual uptake of N, P and K as determined in step 2; （4） calculation of the maize yield based on the three yield ranges established in step 3. Data of field experiments with different fertilization treatments of various regions in China during the years of 1985 to 1995 were used to calibrate the QUEFTS model for summer maize. In step 1 the N, P and K recovered from their amount applied were described by new equations. The minimum and maximum accumulated N, P and K （kg grain kg^-1） in summer maize were determined as （21-64）, （126-384） and （20-90）, respectively. The simulated yields were in good agreement with the observed ones. It was concluded that the calibrated and adjusted QUEFTS model could be useful to improve fertilizer recommendations for maize in the Huang Huai Hai plain of China.     

Soil fertility management in the mid-hills of Nepal: Practices and perceptions

Sustaining soil fertility is essential to the prosperity of many households in the mid-hills of Nepal, but there are concerns that the breakdown of the traditional linkages between forest, livestock, and cropping systems is adversely affecting fertility. This study used triangulated data from surveys of households, discussion groups, and key informants in 16 wards in eastern and western Nepal to determine the existing practices for soil fertility management, the extent of such practices, and the perception of the direction of changes in soil fertility. The two principal practices for maintaining soil fertility were the application of farmyard manure (FYM) and of chemical fertilizer (mainly urea and diammonium phosphate). Green manuring, in-situ manuring, slicing terrace risers, and burning plant residues are rarely practiced. FYM usage was variable with more generally applied to khet land (average 6053 kg fresh weight manure ha^–1) than to bari land (average 4185 kg fresh weight manure ha^–1) with manure from goats and poultry preferred above that from cows and buffaloes. Almost all households (98%) apply urea to khet land and 87% to bari land, with 45% applying diammonium phosphate to both types of land. Application rates and timings of applications varied considerably both within and between wards suggesting poor knowledge transfer between the research and farming communities. The benefits of chemical fertilizers in terms of ease of application and transportation in comparison with FYM, were perceived to outweigh the widely reported detrimental hardening of soil associated with their continued usage. Among key informants, FYM applied in conjunction with chemical fertilizer was the most popular amendment, with FYM alone preferred more than chemical fertilizer alone – probably because of the latters long-term detrimental effects. Key informant and householder surveys differed in their perception of fertility changes in the last decade probably because of differences in age and site-specific knowledge. All key informants felt that fertility had declined but among households, only about 40% perceived a decline with the remainder about evenly divided between no change and an increase. Householders with small landholdings (< 0.5 ha) were more likely to perceive increasing soil fertility while those with larger landholdings (> 2 ha) were more likely to perceive declining fertility. Perceived changes in soil fertility were not related to food self-sufficiency. The reasons for the slow spread of new technologies within wards and the poor understanding of optimal use of chemical fertilizers in conjunction with improved quality FYM may repay further investigation in terms of sustaining soil fertility in this region.Colin Pilbeam graduated from the University of Oxford with an MA in Agriculture and Forest Sciences. He spent 11 years as a Post-Doctoral Research Fellow in the Department of Soil Science, The University of Reading researching nitrogen and water dynamics in cropping systems in Kenya, Syria, and Nepal. He is now the manager of research programs at Cranfield School of Management.Sudarshan Bhakta Mathema is a senior agricultural economist based in Kathmandu, Nepal. After serving the Ministry of Agriculture and Cooperatives, in Nepal for 23 years, he joined the UNs Food and Agriculture Organization as the Farming Systems Economist for 2years. Currently, Dr. Mathema is the Manager of the Hill Agriculture Research Project with the Department for International Development, UK. Dr Mathema has major expertise in the fields of farming systems research and development, participatory research and development, competitive grant systems, sustainable rural livelihoods, impact assessment, project management and implementation, agricultural extension methods, and various types of socio-economic research. He has worked as a consultant for various national and international institutes. He has published papers and reports in the field of agriculture, particularly focusing on Nepal.Peter Gregory has been the Professor of Soil Science at the University of Reading since 1994. His research focuses on the interactions between plant roots and soils and on the development of sustainable systems of crop production. He has worked in Australia, Syria, Nepal, India, and West Africa and is the chair of Global Environmental Change and Food Systems – an international research project on food security.Padma Bahadur Shakya is an Agricultural Economist who has worked for the Department of Agriculture under the Ministry of Agriculture and Cooperatives in Nepal for more than 20 years. He has also been a short-term consultant for various national and international organizations such as FAO, the UNs World Food Programme, Swiss Development Corporation, Asian Development Bank, JICA, HARP, and several local NGOs. Currently, he is affiliated with the Agriculture Perspective Plan Support Programme, implemented by the Ministry of Agriculture and Cooperatives.     

栽培沙打旺对沙荒地水肥状况影响的研究

本试验连续四年研究了北京地区在依靠自然降水的条件下，沙打旺在沙荒地上的生长情况。结果表明，沙打旺长势良好，每年可产干草１１２５０ｋｇ·ｈｍ＾－２。在沙打旺生长期间，遇干旱年份时，土壤水分状况０￣４０ｃｍ土层为干土层，０￣２００ｃｍ土层的土壤重量含水量低达３％；在雨季期间，土壤的水分状况得以恢复。土壤的肥力状况表现为全氮、全磷、碱解氮、速效磷以及土壤有机质含量都有减少；仅速效钾含量增加。本试验还研究