不同促根措施对皖南烤烟成熟期钾素代谢的影响

以大田正常施肥为对照（CK）,设置增施黄腐酸钾（TPFA）、γ-聚谷氨酸（TPGA）和豆浆灌根（TSRI）3个处理,研究不同促根措施对烤烟成熟期根系生理、烤后烟叶钾含量、烟株不同部位钾积累量、钾离子通道基因（NKT1、NtKC1、NtORK1、NtTPK1）和转运体基因（NtHAK1、NtKT12）表达量的影响。结果表明,处理的根鲜重、干重和体积均显著高于CK处理,TPFA和TSRI处理的根系活力显著高于TPGA处理;TSRI和TPGA处理可明显提高烤后烟叶的钾含量;不同促根措施可显著促进根、茎和中部叶的钾积累量;TSRI处理的根中NtORK1的相对表达量显著低于CK处理,TPGA和TPFA处理的上部叶和中部叶NtORK1的相对表达量极显著低于CK处理;TSRI处理根中NtTPK1的相对表达量极显著高于其他处理;3个处理根中NtHAK1的表达量极显著高于CK处理。综合来看,TPGA和TSRI处理不但能促进根系发育、提高钾积累量,而且成熟期烟株对钾的吸收和转运能力强,增加烤后烟叶的钾含量。     

Long-term changes in microbial community structure in soils subjected to different fertilizing practices revealed by quinone profile analysis

Quinone profile analysis of stored air-dried soils gave an approximation of the long-term changes in the microbial community structure in four soils subjected to different types of fertilizer application from 1987 to 1997: unfertilized soil (NF-soil), soil amended with chemical fertilizers (CF-soil), soil amended with chemical fertilizers and 40 t ha^-1 y^-1 of farmyard manure (CF+ FYM-soil), and soil amended with 400 t ha^-1 y^-1 of farmyard manure (FYM-soil). The carbon content increased, and the soil pH remained higher in the soils receiving farmyard manure. Principal component analysis of the quinone profiles of the soils indicated that the microbial community structure showed a high similarity among the four soils before the onset of cultivation and changed to a different community structure specific to the respective fertilizing practices except for the NF-soil. The specific quinone profile became stable after two cropping seasons in the FYM-soil, after 10 cropping seasons in the CF+ FYM-soil and after 15 cropping seasons in the CF-soil, respectively. The quinone profile of the NF-soil did not become stable, and no specific profile was developed. The specific quinone profiles in the FYM- and CF+ FYM-soils were both characterized by large mole fractions of menaquinone with seven isoprenoid units (MK-7). Farmyard manure itself contained a large mole fraction of MK-7. It was suggested that the amount of MK-7 increased due to the application of farmyard manure. MK-7 indicates the presence of Gram-positive bacteria with low guanine plus cytosine contents such as Bacillus and Gram-negative bacteria of the Cytophaga-Flavobacterium complex. The specific quinone profile in the CF-soil was characterized by the presence of menaquinone with seven isoprenoid units dihydrated (MK-7(H₂)and MK-7(H₄). Although Brevibacterium and Kocuria contain MK-7(H₂), no microorganisms are known to have MK- 7(H.) as major quinone. The common major quinones were MK-8, MK-10(H₄) and a mixture of MK-8(H₄) and MK-9, suggesting the predominance of Grampositive bacteria in all the soils. Mole fractions of Ubiquinone with 8 isoprenoid units (Q-8) and Q-10 increased at various times in all the soils, indicating the sporadic growth of Gram-negative bacteria.     

农业管理措施对中国不同农业区域土壤有机碳平衡的差异性影响

Improving management of soil organic carbon （SOC） has been considered as a substantial mitigation strategy to climate change. Management such as stubble retention （SR）, conservation tillage （ZT）, and fertilization are recommended for both promoting production and accumulating SOC. However, whether such management practices can cause net increase in SOC or just a slow-down of SOC decline largely depends on the current status of SOC for a given region. This paper synthesized the available SOC data in the croplands of China, and analysed the change of SOC in the top 20 cm soil as a result of management change. The results showed that, on average, SOC increased by 18.3% through SR, by 9.1% through ZT, and by 12.4%, 36.9% and 41.5% through application of inorganic （IF）, organic （OF） and combined inorganic and organic fertilizers （IOF）, respectively, compared to those under stubble removal, conventional tillage and no fertilization. Under SR, ZT, IF, OF and IOF, SOC increased by 16.0%, 10.2%, 8.2%, 32.2% and 41.3%, respectively, at the end of the trials compared with the initial values at the start of the trials. Our analysis also showed that in Northeast and Northwest China, SOC in agricultural soils is still decreasing due to cultivation. In North and South China, however, SOC appears to have reached a new equilibrium of low SOC state after a long cultivation history, and soils have greater potential to sequester C. Our analysis highlights the need of taking account of the baseline status to assess the net soil C balance over time and space.     

Assessing the Knowledge Level of Beekeepers on Improved Beekeeping Management Practices in Peri-Urban Areas of Southwestern Nigeria

The study was conducted to assess beekeepers' knowledge of improved management practices in peri-urban areas of southwestern Nigeria. A multistage sampling procedure was employed to select 90 respondents from the study area. Results show that beekeepers in southwestern Nigeria had inadequate knowledge of improved beekeeping management practices, which resulted in low skill in most of the practices. Most of the beekeepers encountered problems ranging from inadequate skill, drought, honeybee pests and diseases, and death of the colony. The authors recommend that farmers be well-trained in improved management practices so as to enhance food security.     

福建省海河划界方法的探讨

海河划界具有重要的实践意义和深远的历史意义,可以说是功在当代、利在千秋的事业。海河划界涉及很多方面、层次和学科,本文综合了国内外对海河划界的研究,主要从行政管理的角度,对我省海河划界的方式、方法进行初步探讨,旨在抛砖引玉、更好地为我省海洋综合管理和渔业生产服务。     

Initial Effects of Intensity and Severity of Balsam Fir Tip Harvesting on Harvesting Intensity at the Stand Level,Tip Production,and Tip/Foliage Removal at the Tree Level,and Harvesters’ Production and Productivity

Balsam fir (Abies balsamea [L.] Mill.), which is widely used for floral greenery, is an important source of nontimber forest products (NTFP) from the northern forests of North America. Nonetheless, additional information is needed to refine and revise commercial tip-harvesting management guidelines to promote sustainable forest management. Therefore, a study was initiated to: (a) examine the socioeconomic impacts of and anticipate the potential biological responses to four contrasting harvesting practices; (b) discuss the implications of the results for the relevance and applicability of some specifications of management guidelines; and (c) assess the compatibility of tip harvesting while pursuing an objective of timber production.     

管理模式对胶园土壤酸性磷酸酶活性动态的影响

对西双版纳割胶、未割胶条件下橡胶林土壤酸性磷酸酶活性动态变化特征及其对不同保护带种植方式(距瓣豆绿肥覆盖与野生杂草覆盖)的响应研究.结果表明,7～12月份橡胶林土壤酸性磷酸酶活性呈现先下降后升高的变化趋势,土壤酸性磷酸酶活性具有表层(0～20 cm)＞中层(20～40 cm)和底层(40～60 cm)垂直差异.不同管理方式下橡胶林土壤酸性磷酸酶活性表现为:割胶处理＞未割胶处理,距瓣豆绿肥覆盖土壤＞野生杂草覆盖土壤.橡胶林土壤酸性磷酸酶活性与全氮、全磷呈显著或极显著正相关.     

高海拔地区秸秆生物反应堆技术应用初探

摘要：针对高海拔地区冬季日光温室蔬菜生产中存在的问题及限制因素,介绍了秸秆生物反应堆技术及其原理、生物反应堆作用、应用形式、注意事项等,对秸秆生物反应堆技术应用效果进行了分析。     

浅析青海湖北岸生态环境存在问题及治理对策

摘要：通过论述青海湖北岸生态环境现状和生态环境恶化的原因,说明了青海湖北岸生态环境的重要地位和作用,针对环湖生态保护与管理存在的问题,提出了加大湖北岸生态环境执法力度、完善公众参与机制、恢复生态环境质量及功能、积极探索管理模式等建议。     

浙江省农民专业合作社经营机制研究

通过对浙江省淳安、龙泉等7县(市)的39家农民专业合作社和183名社员进行实地问卷调查,从组织机制、激励机制、营销机制3方面对合作社现有的经营机制进行分析研究,结果表明,现今合作社在理事会产生方式、品牌建设等方面已日趋完善,对促进农户增收起到了一定的作用。但在服务功能、差异化营销等方面还有待完善。提出了注重人才培养、加强民主管理、健全激励机制、综合运用4PS营销模式等完善合作社经营机制的对策建议。