The positive relationship between soil quality and crop production: A case study on the effect of farm compost application

In order to ensure sustainable agriculture, and for evaluating the effects of management practices on soil processes, tools for assessing soil quality are required. The development and use of a multiparameter index, which includes a wide range of soil properties, have been tested and found useful by several studies. However, soil quality measurements are ‘stand-alone’ tools unless they are either linked to important soil functions, used to characterize (agro)ecosystems or used to predict sustainability or productivity. In our study, the relationship between crop production and soil quality was assessed in a six year old field experiment studying the effect of farm compost (FC) amendment in a crop rotation of potato, fodder beet, forage maize and Brussels sprouts. To justify the hypothesis that repeated FC amendment results in both improved soil quality and consequently higher crop yields, a wide range of chemical, biological and physical soil properties were measured and integrated into a soil quality index (SQI). Next, crop yields were used as a functional goal to verify the causal relationship between SQI and crop production. Our results showed that there were significant changes in chemical, physical and biological soil quality as a result of repeated FC amendment. This was evidenced for example by a remarkable increase in both soil organic carbon (SOC) and total N content. Microbial biomass, the relative amount of bacterivorous nematodes and earthworm number were significantly increased as well and, together with SOC and total N, indicated as the dominant factors in assessing soil quality. The integration of these key indicators into the SQI revealed higher SQI values when FC was applied. In addition, crop yields were increased in all FC treated plots by which SOC was pointed out as the most important indicator influencing crop production. Finally, a causal relationship was observed between soil quality and the yield of potato and fodder beet. We conclude that our SQI may be a promising and useful tool to compare different (soil) management practices in relation to a strategic, regional goal, e.g., sustainable high yields. Before generalizing, we recommend a thorough validation of our SQI in other long-term field experiments.     

广东郁南51年生灰木莲生长研究

研究以广东省郁南林场大东坑工区内 51 年生灰木莲 Manglietia conifera 为研究对象，对灰木莲树高、胸径、材积、树干通直度、侧枝生长习性等指标进行调查和分析。结果表明：51 年生灰木莲生长良好，胸径平均为 44.28 cm，最大为 79.60 cm，树高平均为 20.79 m，最高为 27.00 m，单株材积平均为 1.48 m3，最高为 3.65 m3。可见，灰木莲引种在广东郁南适应性强，能够生长良好，具有生长速度快，树干通直，自然整枝好等特点，是该地区可以推广种植和培育大径材的优良树种。     

暖冬对漯河小麦生产的影响

本文利用漯河市召陵区姬石镇区域站大田物联网冬季温度、湿度、积温等的气象数据,分析了漯河麦区冬季变暖气象条件下对小麦播种时期、播种量、群体发育,个体发育、产量三要素、病虫害发生及危害的影响,提出了应对暖冬的栽培管理技术措施。     

从实验室能力考核看试验的精确度控制

以本实验室参与的两次果蔬农残能力考核情况为例,通过对实验室两次考核结果的精确度控制的比较,对引起试验误差、导致试验质量失控的原因进行剖析,为农产品质量安全检测实验室的质量控制工作提供参考。     

农机工业必须依靠科技创新走新型工业化道路

分析了农机工业在新形势下不能适应我国农业发展和全面建设小康社会要求的现状，指出走新型工业化道路势在必行；系统论述了农机工业走新型工业化道路必须依靠科技创新，提高农机企业的管理水平和农机产品的科技含量，提升市场综合竞争力，开发新型农机技术和产品，保持农机工业和现代农业的可持续发展，发展先进技术装备和劳动力资源相结合的组合技术等主要方向和任务；提出了建设农机科技创新体系、支持农机创新活动等政策性措施和建议。     

帽儿山林场4类天然次生林碳储量研究

运用森林生态学典型样地法设立标准地并获取野外数据,采用重铬酸钾-硫酸氧化湿烧法测定植物、土壤中的碳。通过对帽儿山林场4类天然次生林碳素密度及储量的比较研究,结果表明:1)天然次生林主要树种不同器官中碳素密度变化范围在0.331 6~0.501 4 gc/g之间,枯立木、林下植被、枯枝落叶和半分解的有机残体(A00层)各层的碳素密度差异不大,土壤各层的碳素密度的排列顺序为腐殖质(A0层)>表土层(A层)>亚表土层(B层)。2)硬阔叶林生态系统总的碳储量为261.31 tc/hm2,山杨林生态系统总的碳储量为195.20 tc/hm2,蒙古栎林生态系统总的碳储量为196.41 tc/hm2,白桦林生态系统总的碳储量为143.18tc/hm2。3)天然次生林年平均净碳固定量为4.647tc/hm2.a。     

Technical efficiency in the spice based agroforestry sector in Matale district, Sri Lanka

Spices constitute an important sub-sector of the economy of Sri Lanka. Most perennial spices are cultivated in agroforestry types of farming systems. A field survey was conducted covering 127 agroforestry farmers in six divisional secretariats in Matale district during the period of October to December 2002. Technical efficiency of spice based agroforestry systems was estimated in order to identify the potential increase in production without incurring additional costs for farm inputs. The factors affecting technical efficiency and constraints and potential of the agroforestry system were also investigated. According to a stochastic frontier production function using a Cobb–Douglas model, hired labour, organic fertilizer, inorganic fertilizer, land size, and soil conservation measures showed significant positive effects on the agroforestry production. The mean technical efficiency of the spice based agroforestry systems was 84.32%. According to the inefficiency model the efficiency increased significantly as a result of farm visits by extension officers, participation in farmer training, less sloping lands, more experience, and higher diversity of the agroforestry system. Technical efficiency decreased, however, with higher education level of the farmer and with higher off-farm income. Unsustainability of the agroforestry system is seen as a result of a␣range of constraints related to productivity, market, technology and institutions.     

Improving adoptability of farm forestry in the Philippine uplands: a linear programming model

In the Philippines, smallholder farmers have become major timber producers. But the systems of timber production practiced have several limitations. In intercropping systems, the practice of severe branch and/or root pruning reduces tree-crop competition and increases annual crop yields, but is detrimental to tree growth and incompatible with commercial timber production. In even-aged woodlots, lack of regular income and poor tree growth, resulting from farmers’ reluctance to thin their plantations, are major constraints to adoption and profitable tree farming. In the municipality of Claveria, Misamis Oriental, the recent practice of planting trees on widely spaced (6–8 m) contour grass strips established for soil conservation suggests ways to improve the adoptability (i.e., profitability, feasibility and acceptability) of timber-based agroforestry systems. Assuming that financial benefits are the main objective of timber tree farmers, we develop a simple linear programming (LP) model for the optimal allocation of land to monocropping and tree intercropping that maximizes the net present value of an infinite number of rotations and satisfies farmers’ resource constraints and regular income requirements. The application of the LP model to an average farmer in Claveria showed that cumulative additions of widely spaced tree hedgerows provides higher returns to land, and reduce the risk of agroforestry adoption by spreading over the years labour and capital investment costs and the economic benefits accruing to farmers from trees. Therefore, incremental planting of widely spaced tree hedgerows can make farm forestry more adoptable and thus benefit a larger number of resource-constrained farmers in their evolution towards more diverse and productive agroforestry systems.     

森林经营方案实施效益计算机评价系统的研制与应用

本文论述“国营林场、采育场森林经营方案实施效益评价系统”的计算机程序设计思想以及程序实现的方法,介绍福建省来舟林业试验场及其森林经营方案概况,把各种量化的数据输入计算机,对该场森林经营方案实施效益进行了评价,并讨论分析了计算机输出的评价结果。     

崇州林场柳杉人工林空间结构研究

崇州林场的植被主要是柳杉(Cryptomeria fortunei)人工纯林。为了定量地描述林分的空间结构,调查共设置6个50 m×50 m固定标准样地,对样地中的林木进行每木检尺并绘出它们的坐标位置。研究运用了角尺度参数来量化林木分布的均匀性(即空间分布格局);大小比数来测度树木间的优势度分化,也为种群在林分中的相对地位提供了有益的信息。而混交度则通过参照树周围最近的几株相邻木与其不同种个体所占的比例,来表征林分的物种多样性。借此以单木为基础的结构参数所描述的林分空间混交度、林木大小(胸径)分化程度以及群聚程度,使得定量比较那些具有复杂结构的林分也变得简单易行。这无疑有助于林地的可持续经营和生态管护。