桑苗圃和桑园的化学除草

用氟乐灵和精稳杀得或高效盖草能进行桑苗圃除草，用草甘磷和乙草胺混合进行桑园除草，可有效地防除杂草。     

福建省林业国有苗圃花卉产业发展的思考

从福建省国有苗圃花卉产业发展的优势入手,针对当前的生产现状及存在问题,提出了加强领导、合理布局、调整所有制结构、加大投入等5项措施。     

黑杨无性系日CO2固定总量的测定及与苗木生产潜势的相关性研究

通过对不同基因型黑杨无性系植株净光合速率日变化曲线与光合主体叶面积在时间和光强上进行累计积分来计算植株日CO2固定总量P。由于净光合速率日变化曲线不易准确测得，故以光响应曲线和光强的日变化来推测净光合速率日变化。对P值和生物量的相关性研究表明，二者的相关性很高。且认为可以用计算出的P值作为评估苗木生产潜势的指标之一，这为育种中生产力的早期选择提供了有力的证据。     

Observations of Phytophthora spp. in Water Recirculation Systems in Commercial Hardy Ornamental Nursery Stock

Samples of water and sediment were taken from drains, reservoirs and wells from four commercial hardy ornamental nurseries with water recirculation systems. The samples were taken on seven different dates throughout a single year from August 1994 to July 1995. The samples were screened for Phytophthora species using five different methods: direct plating, three bait tests (using lupin seedlings, apples and Rhododendron leaves) and a DAS-ELISA (double-antibody sandwich enzyme-linked immunosorbent-assay) with two antisera. In the nurseries with old water recirculation systems, Phytophthora species were detected in the drains and in the reservoirs. In the nursery with a new recirculation system, the pathogens were only present in the drains. None of the water samples from wells in any of the nurseries were contaminated. Phytophthora species were present in the water as well as in the sediment samples from drains and reservoirs. They were detected in the water recirculation systems irrespective of the season. The number of isolates increased about sevenfold between late summer and spring. At least 12 different Phytophthora species were identified: some isolates were previously unrecorded species. The epidemiology of the pathogens in outdoor water recirculation systems as well as the importance of the results for commercial nurseries is discussed.     

Pest Management in Traditional Tropical Agroecosystems: Lessons for Pest Prevention Research and Extension

Based on current agroecological theory and IPM practices, this review explores the role of traditional practices, involving site selection, soil management, timing of planting and harvesting, crop resistance, intercropping, weed management, harvest residue management, post-harvest management, natural enemies management, mechanical control, repellents and traps in the natural regulation of potential pests. In synthesis, the literature suggests that although pest management professionals focus their efforts on pest control, the preventative approach taken by traditional farmers is more effective. Potential constraints to the implementation of this preventive pest management approach include:(1) lack of integration of ecological theory and pest management, (2) lack of cooperation among social and biological scientists, and (3) lack of real efforts to work with farmers as equals and support mechanisms that protect their knowledge. This revised version was published online in July 2006 with corrections to the Cover Date.     

非自然越夏区小麦白粉病模拟鉴定病圃

作者于1990～1995年根据陕西省关中麦区小麦白粉病侵染循环特点,人工模拟自然发病条件,在非自然越夏区杨陵(省农科院试验地)成功地建立起白粉病菌可周年存活,且秋、春季均能充分诱发感染的混合菌系病圃,宜对小麦种质材料进行全生育期抗白粉病鉴定。利用该病圃已对陕西省1000余份小麦品种(系)及部分国内外抗源亲本材料做了抗病性鉴定和利用评价。     

银中杨人工林抚育采伐技术研究

采用标准地调查方法,对初植密度为2 m×2m的银中杨人工林的抚育采伐开始期和采伐强度进行调查研究,确定抚育采伐开始期为8年生时,采伐强度为50%。研究确定了银中杨人工林的经营密度表,以期为生产经营提供依据。     

Simulating farming practices within a region using a stochastic bio-decisional model: Application to irrigated maize in south-western France

Agricultural is a major contributor to environmental resource management problems. Modelling the distribution of agricultural land use to evaluate current situations or scenarios is an important issue for policy-makers and natural resource managers. A promising approach is the use of bio-decisional models based on decision rules. However, at the regional scale, the large number of farmers makes it difficult to identify decision rules, and the diversity of farmers' decisions is rarely considered. To this end, we developed SIMITKO, a spatialised and stochastic bio-decisional model, able to simulate the spatial and temporal variability in farming practices. We focused on the choice of varietal earliness and sowing practices of maize (Zea mays L.) in the Baïse sector (south-western France). Model development was based on statistical analyses of surveys of farmers’ practices to identify their current strategies, the best variables to describe the practices and the probabilities associated with the values of the variables for each strategy. We tested SIMITKO by simulating the dynamics of areas sown with maize. Comparing model predictions of practices to observed data showed generally good predictions of sowing dynamics but less satisfactory predictions of varietal earliness choices. Possible improvements are suggested.     

Soil organic carbon stock variability in the Northern Gangetic Plains of India: interaction between agro‐ecological characteristics and cropping systems

Soil organic carbon (SOC) content and its spatial distribution in the Northern Gangetic Plain (NGP) Zone of India were determined to establish the cause–effect relationship between agro‐ecological characteristics, prevailing crop management practices and SOC stock. Area Spread Index (ASI) approach was used to collect soil samples from the NGP areas supporting predominant cropping systems. Exponential ordinary kriging was found most suitable geo‐statistical model for developing SOC surface maps of the NGP. Predicted surface maps indicated that 43.7% area of NGP had 0.5–0.6% SOC, while the rest of the area was equally distributed with high (0.61–0.75%) and low (< 0.5%) SOC content levels. Averaged across cropping systems, maximum SOC content was recorded in Bhabar and Tarai Zone (BTZ), followed by Central Plain Zone (CPZ), Mid‐Western Plain Zone (MWPZ), Western Plain Zone (WPZ) and South‐Western Plain Zone (SWPZ) of the NGP. The SOC stock was above the optimum threshold (> 12.5 Mg/ha) in 97.8, 57.6 and 46.4% areas of BTZ, CPZ and MWPZ, respectively. Only 9.8 and 0.4% area of WPZ and SWPZ, respectively, had SOC stock above the threshold value. The variation in SOC stock was attributed largely to carbon addition through recycling of organic sources, cropping systems, tillage intensity, crop or residue cover and land‐use efficiency, nutrient‐use pattern, soil texture and prevailing ecosystem. Adoption of conservation agriculture, balanced use of nutrients, inclusion of legumes in cropping systems and agro‐forestry were suggested for enhancing SOC stock in the region.