探析毛泽东、邓小平治理国家策略之异同

毛泽东和邓小平是我们党第一和第二代领导集体的核心。他们以马克思主义为指导,对治理国家有着共同的方略。但是,邓小平继承、丰富和发展了毛泽东的治国方略。比较研究他们的治国方略,比较他们之间治国方略之异同。对于提高党的执政水平,巩固社会主义制度具有十分重大的意义。     

State of Art and Knowledge of Urban Forestry in the Philippines

1 INTRODUCTIONUrban Forestry is an emerging science and art in thePhilippines. Its concepts and principles are quite similarwith traditional forestry being both resourcemanagement systems. However, urban forestrysobjectives are more focused on the protective,ameliorative, aesthetic and amenities rather than onproductive roles.As a resource management strategy, urban forestryinvolves wise use, management and/or manipulationof the resources that include individual trees and otherplants com…     

论默顿《社会研究与社会政策》之制度分析

笔者通过细读罗伯特.金.默顿的《社会研究与社会政策》一书,着重分析了默顿三个层面的制度问题,即科学的四类制度性规范,制度化利他主义和制度变迁。笔者认为,在当代社会,默顿的制度理论将继续在人类的科学研究中发挥重要的指导作用。     

红树林植被对大型底栖动物群落的影响

大型底栖动物是红树林生态系统的重要组成部分,从红树林大型底栖动物种类、红树林与其周边生境大型底栖动物群落的比较,以及生境变化对动物群落的影响等方面阐述了红树林植被与大型底栖动物群落的关系.从物种数量上看,软体动物和甲壳类动物构成了红树林大型底栖动物的主要部分.影响大型底栖动物分布的环境因素包括海水盐度、潮位和土壤特性等,但在小范围区域,林内动物的分布更多地与红树林植被特性和潮位有关.因此,由于红树林植被破坏或者恢复引起的生境变化,将导致大型底栖动物群落和常见物种种群的变化,尤其对底上动物影响明显;随着人工恢复红树林的发育,林内底栖动物的多样性相应增加,优势种也发生变化.相比位于相同潮位的无植被滩涂,红树林可促进潮间带生物多样性.     

以科学发展观引领社会主义新农村建设

本文分析了建设社会主义新农村的历史必然性,阐述了建设社会主义新农村的伟大历史意义,剖析了社会主义新农村建设的战略方针及其内在联系,并在科学发展观的指导下,指出了“坚持以经济建设为中心和综合改革,全面推进社会主义新农村建设”的必要性和迫 切性以及农村改革和体制创新的若干关键领域。     

Effect of manures and fertilizers on soil physical properties,build-up of macro and micronutrients and uptake in soil under different cropping systems: a review

Combined application of manures and fertilizers played a pivotal role in the improvement in soil physico-chemical properties, macro and micronutrients distribution and their transformations under different cropping systems. Based on a cropping system, the different levels of manures and fertilizers were used to study improvement in physico-chemical properties of soil. The aim was to explore the appropriate application of organic manures and inorganic fertilizers for improved sustainable yields of a cropping system. Intensive cropping systems lead to N, P, K, Zn, Cu, Fe, and Mn deficiencies in surface and subsurface soil, which could be refreshed with combined application of manures and fertilizers. The application of manures and fertilizers controls the pH and electrical conductivity of soil. Moreover, manures and fertilizers showed improvement is soil physical conditions viz. bulk density, particle density, porosity, and water holding capacity etc. Manuring coupled with fertilization helped to great extent for macro and micronutrient transformations in the soil. Under these transformations, the soil solution and water soluble component (fractions/pools) of soil is enriched with macro and micronutrients. There was a consistent declining trend of DTPA-extractable Zn, Cu, Fe, and Mn in the sub-surface soil in comparison to the surface layer, which may be ascribed to increase in pH with increase in depth and decrease of organic matter with depth. Similarly, manures reduced the concentration of residual macro and micronutrients in soil. Recently, integrated nutrient management system (INMS) is gaining importance vis-a-vis maintaining the soil fertility with conjunctive use of chemical fertilizers plus organic manures.     

我国农产品食品质量安全问题:特点、症结及对策

中国农产品和食品质量安全问题依然严峻,总体呈现出广泛性和复杂性、市场的非对称性、分布的地域性、加工品的低安全性、设施生产的高风险性和污染物的嬗变性等突出特点。从思想观念、发展方式、生态环境、劳动者素质、法规制度与科学技术方面,分析了现阶段中国农产品食品质量安全危机的主要诱致因素。提出了增强质量安全意识、转变农业发展方式、强化农业资源环境保护、提高生产经营者素质、完善法规政策与制度、加快科技创新与进步等对策建议。     

Temporal Variations in Primary,Secondary, and Micronutrient Contents in Soil of Litchi Orchard

Litchi is one of the important subtropical fruit crops in the state of Jharkhand, occupying around 33,000 ha with production of about 165,000 metric tons. Considering the importance of soil analysis in litchi crops, the present investigation was carried out in an established orchard (begun in 1979) at the Horticulture and Agroforestry Research Program, Indian Council of Agriculture Research Complex for Eastern Region, Plandu (Ranchi), Jharkhand, India, to study the nutrient concentrations in soils of litchi and the interrelationships among available nutrient concentrations present in soil, and crop productivity in order to develop a sound fertilizer management program. Periodic collection of soil samples from the established orchard was carried out on the second week of every month during 2006–2007. Analysis of soil samples were carried out for macro- and micronutrients in soil. Mean soil nutrient contents for nitrogen (N), phosphorus (P), and potassium (K) were 232 kg ha^?1, 53 kg ha^?1, and 420 kg ha^?1, respectively. The greatest contents of N and K were observed at full canopy distance, whereas for that for P was at one-third and two-thirds the canopy distance. Mean soil nutrient contents were 1.52 C mol (P⁺) kg^?1, 1.11 C mol (P⁺) kg^?1, and 23 ppm for calcium (Ca), magnesium (Mg), and sulfur (S), respectively. The greatest contents of Ca and Mg were observed at one-third the canopy distance whereas that for S was at two-thirds the canopy distance. However, mean soil nutrient contents were 1.03, 53, 65, and 1.42 ppm for copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn), respectively. The greatest content of Fe was observed at two-thirds the canopy distance whereas that for Cu was at one-third the canopy distance. The greatest Mn content was observed for both two-thirds and full canopy distance whereas Zn contents had no significant differences among the canopy distances. However, soil sampling at two-thirds canopy distance from the trunk was observed to be ideal for soil analysis.     

Nutrient Utilization Indices of NPK and Drought Management in Groundnut under Sandy Soil Conditions

ABSTRACT

In arid zones, farmers are obligated to reduce water amounts used in irrigating their lands. Consequently, reduction in final yields is realized. Thus, dealing with such a case became a decisive act. We tried to investigate the acceptable degree of lowering irrigation water with sustaining the productivity of groundnut as a way for managing drought conditions. Therefore, in summer seasons of 2016 and 2017 at the Experimental Research and Production Station, National Research Centre, Egypt, field trials were conducted with growing groundnut plants under three irrigation levels, i.e., 50%, 75%, and 100% of crop evapotranspiration (ET_c), denoted as I₅₀, I₇₅, and I₁₀₀, respectively. N, P, and K contents in seed and shoot and their yields in addition to harvest and partitioning indices were estimated. In spite of irrigating groundnut plants by normal water amounts, I₁₀₀, caused the maximum weight of seed biomass yield ha?1 and seed N and P contents, I75 was similar to I₁₀₀ for producing shoot biomass yield ha?1 and seed K content. Moreover, N and P yields (for shoots and seeds) and k yield (for seeds) showed the maximum values with I₁₀₀. Differences in all nutrient harvest indices (NHI, PHI, and KHI) between I₁₀₀ and I75 were not significant. Furthermore, I75 statistically leveled with I₁₀₀ in nutrient partitioning indices, viz., NPI, PPI, and KPI. In conclusion, groundnut straw residues produced by 25% less water supply than normal may share in managing drought stress by releasing nutrients and saving irrigation water in arid areas.     

Macronutrient-Use Efficiency and Changes in Chemical Properties of an Oxisol as Influenced by Phosphorus Fertilization and Tropical Cover Crops

Cover crops are important components of copping systems due to their beneficial effects on soil physical, chemical, and biological properties. A greenhouse experiment was conducted to evaluate influence of phosphorus (P) fertilization on nutrient-use efficiency of 14 tropical cover crops. The P levels tested were 0 (low), 100 (medium), and 200 (high) mg kg^?1 of soil. The cover crops tested were Crotalaria breviflora, Crotalaria breviflora, Crotalaria spectabilis Roth, Crotalaria ochroleuca G. Don, Crotalaria juncea L., Crotalaria mucronata, Calapogonium mucunoides, Pueraria phaseoloides Roxb., Pueraria phaseoloides Roxb., Cajanus cajan L. Millspaugh, Dolichos lablab L., Mucuna deeringiana (Bort) Merr., Mucuna cinereum L., and Canavalia ensiformis L. DC. Agronomic efficiency (shoot dry weight per unit P applied), physiological efficiency (shoot dry weight per unit of nutrient uptake), and apparent recovery efficiency (nutrient uptake in the shoot per unit nutrient applied) were significantly varied among cover crops. Agronomic efficiency decreased with increasing P levels. Overall, physiological efficiency of nutrient uptake was in the order of P > sulfur (S) > magnesium (Mg) > calcium (Ca) > potassium (K) > nitrogen (N). Similarly, apparent recovery efficiency was in the order of N > K > Ca > Mg > P > S. Different recovery efficiency in cover crops can be useful in selecting cover crops with high recovery efficiency, which may be beneficial to succeeding crops in the cropping systems. The P × cover crops interactions were significant for soil extractable Ca²⁺, P, cation exchange capacity (CEC), Ca saturation, Ca/K ratio, and K/Mg ratio, indicating that cover crops change these soil property differently under different P levels. Thus, cover crops selection for different P levels is an important strategy for using cover crops in cropping systems in Brazilian Oxisols. Optimal values of soil pH, soil Ca and Mg contents, hydrogen (H) + aluminum (Al), P, CEC, base saturation, Ca saturation, Mg saturation, and K saturation were established for tropical cover crops grown on an Oxisol.