杉木林取代阔叶林后土壤生物学活性变化的研究

通过对福建省南平市溪后安曹下取代阔叶林的70a生杉木车产林（山坡）、32a生杉木“青年林”（山坡）及前茬阔叶林（山脊）土壤生物学活性连续2a的比较研究结果表明，与山脊上前茬的阔叶林相比，70a生杉木丰产林土壤微生物总数、生理类群的数量减少、活性下降；土壤酶活性减弱；呼吸作用强度（内源）及添加基质的外源呼吸作用强度降低，土壤中有机质分解和腐殖质再合成程度降低．32a生杉木“青年林”土壤生物学活性下降则更为明显，说明从杉木取代阔叶林（头耕土）起，土壤生化活性及土壤肥力就存在明显下降现象，轮伐期缩短或林地连栽杉木代数增加，而不采取恢复地力措施，杉木林地地力衰退将更为明显．     

"三高"农业与土肥作用及对策——以梅县为例

"三高"农业与土壤和肥料有密切关系。地力是作物产量和质量的重要基础,要取得高产、优质、高效,就必须坚持不懈地培肥地力。土壤中营养元素的含量,肥料类型和施肥技术,都对农产品产量和品质有很大的影响。因此,培肥地力、因土种植、合理施肥能提高经济效益、生态效益和社会效益。忽视土肥工作,将影响"三高"农业的发展。     

市场经济与土肥科技

土肥的基础地位是不随社会性质或社会经济类型的变化而变化的，它既具重要性，又具长久性．市场经济是仍然需要土肥科技的．土肥科技的教学、科研和推广的力度必须加大，局面必须改观，且宜快不宜迟．土肥科技工作者一定要将培肥地力作为中心工作．根据广东的实际，增施有机肥是培肥地力的主要措施，因而抓秸秆还田和发展冬绿肥是我们工作的重点．     

全球环境变化国际人力因素计划推出的工业转变研究举措

本文侧重于全球环境变化国际人力因素计划（ＩＨＤＰ）工业转变项目（ＩＨＤＰＩＴ）———一个以当前工业体系向可持续工业体系转变的机制为重点的国际研究举措———迄今为止所取得的结果和进展．这个ＩＨＤＰＩＴ项目研究从三个角度分析了工业转变：宏观体系，包括工业体系、金融体系和自然体系；生产体系；和消费体系     

朱森林省长重视地力建设

朱森林省长重视地力建设土壤是人类赖以生存和发展的重要物质基础，土壤肥力对农业发展具有决定性的意义．有关研究表明，广东省５０％以上的农田的地力在下降，影响着农业的持续发展．这个问题引起了广东省土壤肥料科技专家的极大关注．１９９５年９月１８日，１５位知名...     

土肥基础与持续发展农业

论述土肥基础与持续发展农业的基本内涵和特征；从历史的经验教训、片面发展经济的现实、地力监测的情况等方面，论证了土肥基础对持续发展农业的重要性；分析了广东省土肥基础的现状，提出了一系列加强土肥基础的对策：建立健全有关法规、有计划地扩大耕地面积、加强地力建设、改造中低产田和保护耕地环境等．     

广东省土壤肥力监测总结

广东省土壤肥力监测总结广东省土壤肥料总站（广州５１０５００）土壤肥力监测（又称地力监测）是对农业区主要耕地类型的土壤理化性状和生产力进行监测，以便了解和掌握不同的耕作措施对地力的影响及其变化规律，为合理利用土地、保护和提高地力、指导农业生产提供科学依...     

利用IBSQ－69型驱动耙进行稻草还田的优点和方法

利用ＩＢＳＱ－６９型驱动耙进行稻草还田的优点和方法张育灿（广东省土壤肥料总站，广州５１０５００）据广东省近年来的地力监测结果表明，全省耕地地力普遍呈下降趋势。增施有机肥料是提高耕地地力最有效的措施，而利用稻草还田又是增施有机肥料直接有效的办法之一。它...     

"九五"期间广东省土肥工作回顾与未来展望

“九五”以来,广东省土肥系统紧紧围绕农业增效、农民增收和农业可持续发展的目标,以提高地力、肥效统揽全局,充分发挥职能、技术、手段     

乳源县稻田地力状况与改造中低产田的建议

乳源县稻田地力状况与改造中低产田的建议项若驹，黄居甲，李少灵（乳源瑶族自治县农业局，乳源５１２７００）改革开放以来，随着农业政策的落实和技术的进步，我县粮食生产已提高到一个新水平，总产增长２１．７％，单产提高４２．７％．但自１９８３年以来，我县耕地地...     

重金属污染高风险农用地水稻安全种植技术研究

在农田土壤污染较为严重的情况下生产安全高品质的稻米是目前农业生产面临的一大挑战。重金属低积累水稻品种,不但能有效降低水稻稻米中重金属的含量,而且有经济成本低、且环境友好等特点,但在重金属高风险污染区仅仅使用低积累品种无法达到安全生产的目的。以重金属污染高风险农田土壤为研究对象,开展重金属低积累水稻品种筛选和化学修复手段结合的农田安全利用技术研究。结果表明:通过对23个不同品种水稻在高风险重金属污染农田土壤中种植重金属含量比较分析,表明不同水稻品种对Cd吸收能力差异较大,五优321、广8优占、丰优428、粤晶丝苗2号、粤金银占、合美占等6个水稻品种对Cd吸收能力较弱,但在该地区土壤重金属含量水平下,Cd质量分数仍高于0.2 mg·kg^-1,Pb和As含量均不超标;在此结果基础上结合土壤污染特点,采取3种污染物控制技术降低稻米中Cd含量,五优321品种与石灰、石灰Se配施等配合施用均有较好的效果,可以作为此类污染区域重点推广品种;喷施Se叶面肥能显著增加稻米中Se含量,提升稻米品质,且Se与石灰配合施用,增Se效果要好于单独施Se肥。采用化学钝化剂联合低累积水稻品种,稻米中Cd含量降低40%-70%。该研究采用大田原位试验,其结果可以对当地污染农田土壤的安全利用更具指导意义。     

The role of agri‐environment schemes in conservation and environmental management

Over half of the European landscape is under agricultural management and has been for millennia. Many species and ecosystems of conservation concern in Europe depend on agricultural management and are showing ongoing declines. Agri‐environment schemes (AES) are designed partly to address this. They are a major source of nature conservation funding within the European Union (EU) and the highest conservation expenditure in Europe. We reviewed the structure of current AES across Europe. Since a 2003 review questioned the overall effectiveness of AES for biodiversity, there has been a plethora of case studies and meta‐analyses examining their effectiveness. Most syntheses demonstrate general increases in farmland biodiversity in response to AES, with the size of the effect depending on the structure and management of the surrounding landscape. This is important in the light of successive EU enlargement and ongoing reforms of AES. We examined the change in effect size over time by merging the data sets of 3 recent meta‐analyses and found that schemes implemented after revision of the EU's agri‐environmental programs in 2007 were not more effective than schemes implemented before revision. Furthermore, schemes aimed at areas out of production (such as field margins and hedgerows) are more effective at enhancing species richness than those aimed at productive areas (such as arable crops or grasslands). Outstanding research questions include whether AES enhance ecosystem services, whether they are more effective in agriculturally marginal areas than in intensively farmed areas, whether they are more or less cost‐effective for farmland biodiversity than protected areas, and how much their effectiveness is influenced by farmer training and advice? The general lesson from the European experience is that AES can be effective for conserving wildlife on farmland, but they are expensive and need to be carefully designed and targeted.     

粮食增产寄希望于中低产田改造

广东省增加粮食产量的关键是提高单产，改造中低产田是提高单产的最有效途径．本文回顾了一年来广东省农建改低的工作，指出今后应进一步提高认识，高标准搞好农田基本建设，为广东农业实现现代化打下坚实的基础．为搞好农田基本建设，必须切实加强领导．有计划有步骤地认真做好各方面的工作．     

绿肥在现代农业中的地位──论广东绿肥的发展前景

绿肥可以解决有机肥源不足的困难，减少化肥用量，节省成本和能源消耗，改善土壤环境，提高土壤肥力和地力；提高作物产量和产品质量；促进畜牧业的发展。本文根据广东的实际，指出广东的现代化农业需要大种绿肥，也可以大种绿肥。要使广东的绿肥生产得到恢复和发展，必须抓好如下的措施：从战略高度来认识绿肥的重要性；加强领导，把它提到重要的议事日程上来；广泛开展试验示范，并加强宣传发动；增加经济投入，省、市、县各级要设立绿肥种子繁育和经营风险金。     

Farmland size,chemical fertilizers,and irrigation management effects on maize and wheat yield in Mexico

ABSTRACT

Farmland size is a key factor in debates over agricultural land use, food security, agrochemical pollution, and the future of smallholder systems. This paper examines relationships between farmland size, chemical fertilizers and irrigation management, and maize and wheat yield in Mexico. We used agricultural census data to estimate the mean farmland areas and crop yields of 5.5 million farms and nine million agricultural plots in 2,455 Mexican municipalities. We also derived indices of socio-environmental and management factors to examine relationships with yield. Using multiple regression models, we found that although mean farmland area positively relates to maize and wheat yield, the relationships depend critically on the management contexts of chemical fertilizers and irrigation, which vary widely across farm size gradients. Smallholder yield gaps were associated with deficits in irrigation, rather than chemical inputs. Findings highlight the growing need for expanded irrigation access and/or water management assistance for smaller farms.     

Qualität und Verwertungsmöglichkeiten von Holzaschen aus naturbelassenen Hölzern

Background, aim and scope The increasing use of wood for generating heat and electricity requires that more and more fuels be obtained directly or indirectly from the forest. Sound, sustainable recycling management calls for the return of any generated wood ash back to the forest to make use of the nutrients it contains. Similarly, recycling this ash in other locations such as agricultural land or private gardens can serve equally well as fertilizer. At the same time, it is critical that no accumulated pollutants be introduced into the nutrient loop. Wood ash that is heavily laden with such pollutants must not be considered for recycling. As part of this research project, commissioned by the Ministry for the Environment and Conservation, Agriculture and Consumer Protection of the State of North Rhine-Westphalia in Germany (MUNLV), ash samples of 209 wood-fired appliances generating between 10 and 4000?kW of heat performance were taken from throughout the federal state of North Rhine-Westphalia. Untreated wood, either forested or scrap, was used as the sole fuel for these appliances. Materials and methods All course ash and fly ash samples were analyzed to determine their composition of main nutrients, heavy metals, and the elements Fe, Cl, Si, Al and Na. The purpose of this analysis was to evaluate the suitability of this wood ash for reintroduction to forest soils or as fertilizer in other types of soil. Results The majority of the wood ash samples in this study contained sufficiently high amounts of nutrients to match the requirement for stand-alone fertilizers (PK-fertilizer, potash fertilizer). However, the heavy metal content was highly variable, with a mean content high enough to prohibit them from being classified per se as PK- or potash fertilizer for agricultural land. Due to the high quantities of cadmium, application of this ash to garden soils would likewise be ill-advised. Discussion On forest soils German law permits application of a mixture of potash fertilizer containing, at most, 30?% wood ash (course ash). Because of the high amounts of cadmium and copper, wood ash from our samples can only comprise a maximum of 28?% when added to typically used potash fertilizers. Higher percentage of wood ash would exceed the cut-off value established by the German Fertilizer Ordinance (Düngemittelverordnung – DüMV). Conclusions The application of wood ash on agricultural land and in private gardens is, rightfully so, highly regulated by law. However, the rules governing application of wood ash in the forest are much more lax. Determination of heavy metal content in wood ash cannot be used to determine compliance with DüMV standards because of the high content and fluctuating nature of heavy metals found. Recommendations and perspectives Presently an alternative approach for classifying the ecologic risk of wood ash recycling is being developed.     

Farmers' perceptions of constraints to plantain production in Ghana

SUMMARY

Plantain (Musa AAB), a primary food crop in Ghana, is a key component in sustainable agricultural systems in high rainfall zones. Recently, there has been a substantial yield decline and reduction in plantation life. To elucidate the context in which intervention strategies should be developed, a Participatory Rural Appraisal (PRA) was conducted at five villages in the major plantain-producing belt of Ghana. The importance of plantain as a preferred food was confirmed, although farmers tended to sell plantain for cash income, using cheaper, less preferred alternatives for home consumption. Farmers identified decreasing soil fertility, the high cost of labour for weeding, pests and diseases, lack of good quality planting material and marketing-related issues as the major production constraints. Due to declining productivity in less fertile regions, plantain has been replaced with other food crops such as cassava and maize. Farmers overestimated the importance of insect pests but were unaware of the extensive damage that could be caused by nematodes and the foliar disease, black sigatoka. They observed, however, that pest damage is more severe when soil fertility is poor. Clearly, integrated pest management is likely to be most effective when practiced within the context of cropping systems management; sustainable strategies that are being developed for resource-limited plantain farmers in Ghana are discussed.     

Population Declines and Range Contractions among Lowland Farmland Birds in Britain

We used extensive atlas and census data to assess trends in the distribution and population levels of birds on lowland farmland in Britain between the late 1960s and early 1990s. Many species of farmland birds have become less widespread or have declined in numbers, or both, but few have become more wide-spread or have increased. Of the 28 species classified as farmland birds the distributions of 24 contracted between 1970 and 1990. Of the 18 farmland species for which it was possible to assess population change, 15 were less abundant in 1990 than in 1970. Seven of the species were estimated to have undergone population decreases of at least 50%. Farmland species showing the largest population declines tended also to show substantial range contractions. Farmland species underwent an appreciably larger contraction of distribution than species associated with any other habitat. Furthermore, farmland species tended to decrease in abundance, whereas woodland species tended to increase. Population declines among farmland birds became evident in the mid- to late 1970s, a period when several fundamental changes were taking place in British agricultural practices. These included a great reduction in the spring sowing of cereals, a simplification of crop rotations, increased use of chemical pesticides and inorganic fertilizers, and more-intensive grassland management. We suggest that the declines of farmland bird species have been caused or aggravated by this pervasive intensification of agriculture. Existing research on declining farmland birds, however, indicates that there is no single mechanism underlying the population changes. We identify priorities for research, focusing mainly on relationships between bird populations and agricultural practices, but we also recognize a need for a better understanding of the role of predation.     

生态茶园建设与病虫害综合防治

综述了在茶树病虫害综合防治中生态学原理和农田生态系统科学理论的运用。强调以生态防治，即农业防治和生物防治为主，借助于各种农业技术和现代生物科学手段，在综合防治中尽量少用化学农药，以减少对环境的污染、农药残留及对天敌的伤害，维持茶园生态平衡。