基于灰色关联的浙江省各地级市农业生产力分析

采用灰色关联法,对浙江省各个地级市的农业生产力进行评价,详细介绍了灰色关联法在农业生产力评价中的分析过程.结果表明,浙江省各地级市的农业生产力与参考系的关联度排序为:宁波市＞杭州市＞台州市＞绍兴市＞嘉兴市＞金华市＞温州市＞舟山市＞湖州市＞衢州市＞丽水市,即浙东北的农业生产力大于浙西南.     

Performance of a small-scale chipper for professional rural contractors

The study determined the productivity, fuel consumption and product quality obtained with a new tractor OWered drum chipper, designed to reduce the gap between industrial chippers and small-scale chippers. The machine as tested with poplar logs and beech slabs, considered as representative of the raw material commonly used for ergy wood production. After accounting for accessory work and delays, productivity of green chips ranged between and 6 tons per scheduled machine hour, which was very good for a tractor-powered unit. Specific fuel consumption f oven-dry chips varied between 2.5 and 3.0 L per ton, or 0.6 L per m_3. These figures compared favourably with those btained from previous studies of both smaller and bigger chippers. Chip quality was very good. Samples contained no versize particles, qualifying for use in small-scale plants. The average size of beech chips was significantly larger than r poplar chips, possibly due to the higher strength of beech wood.     

Agricultural Policy, Climate Factors and Grain Output： Evidence From Household Survey Data in Rural China

This paper estimates a stochastic frontier function using a panel data set that includes 4 961 farmer households for the period of 2005-2009 to decompose the growth of grain production and the total factor productivity (TFP) growth at the farmer level. The empirical results show that the major contributor to the grain output growth for farmers is input growth and that its average contribution accounts for 60.92% of farmer’s grain production growth in the period of 2006-2009, whereas the average contributions sourced from TFP growth and residuals are only 17.30 and 21.78%, respectively. The growth of intermediate inputs is a top contributor with an average contribution of 44.46%, followed by the planted area (18.16%), investment in fixed assets (1.05%), and labor input (-2.75%), indicating that the contribution from the farmer’s input growth is mainly due to the growth of intermediate inputs and that the decline in labor inputs has become an obstacle for farmers in seeking grain output growth. Among the elements consisting of TFP growth, the contribution of technical progress is the largest (32.04%), followed by grain subsidies (8.55%), the average monthly temperature (4.26%), the average monthly precipitation (-0.88%), the adjusted scale effect (-5.66%), and growth in technical efficiency (-21.01%). In general, the contribution of climate factors and agricultural policy factor are positive and significant.     

三黄鸡羽毛紧凑度选育指标可行性分析

以三黄鸡为试验材料,分析了个体、家系间羽毛密度、干毛比例、主翼羽长度、尾巴长度的差异,同时对羽毛紧凑度选育方法进行验证研究。结果表明,羽毛密度、干毛比例、主翼羽长度在个体间差异很大,家系间差异达到显著水平。羽毛密度与主翼羽长度、尾巴长度呈显著负相关;干毛比例与主翼羽长度、羽毛密度相关不显著,但与冠高有极显著相关。双向选择效果分析表明,以主翼羽长度和干毛比例为指标进行直接选育效果好,但以羽毛密度为指标进行直接选育效果较差。通过半同胞法估算出羽毛密度、干毛比例、主翼羽长和冠高的遗传力分别为0.198、0.339、0.491、0.549。     

Sustainable productivity and profitability of diversified rice-based cropping systems in an irrigated ecosystem

An experiment was conducted at ICAR Research Complex for Eastern Region, Research Farm, Sabajpura, Patna (longitude 85°13′N and 1atitude 25°37′E), Bihar, India for four consecutive years 2004–05 to 2007–08 to develop a diversified cropping system for an irrigated ecosystem in Bihar by introducing pulse/oilseed/vegetables as a second or third crop in 10 rice-based cropping systems. Four crop cycles have been completed for all the cropping systems. During all years of the experiment there were significant variations among the cropping systems. Maximum paddy yield equivalent was recorded in rice–tomato–bottle gourd (40.44 t ha^?1) followed by rice–potato–onion (28.47 t ha^?1), rice–coriander–lady's fingers (26.79 t ha^?1), rice–carrot–cowpea (24.59 t ha^?1) and rice–mustard–tomato (24.44 t ha^?1). A higher value for the diversification index (DI) represents a higher level of crop diversification. It is evident from the results, that DI varies from 0.299 on a medium-sized farm to 0.903 on a small farm, with an average DI value of 0.643 among all farm categories. A survey revealed that the average DI value for small-scale farmers was highest (0.741) compared with the medium- (0.591) and large-scale (0.626) categories, and the differences were negligible. This seems reinforce the view that the smaller the farm, the higher the level of crop diversification.     

丰宁邓栅子林场森林生产力预测

森林生产力是评价森林生长的重要指标,但以往的研究主要是以林木实际生长量进行测定,没有考虑环境因素对其生长潜力的制约,本文就环境对林木生长潜力在数量上进行了探讨。结果表明：森林最大生产量和木材最大生产量的数值受气象条件的影响不大,而实际森林生产量和木材生产量却受到气象条件的限制,达不到最大值。     

Site, plot, and individual tree yield reduction of interior Douglas-fir associated with non-lethal infection by Armillaria root disease in southern British Columbia

Root pathogens are one of the principle factors affecting forest productivity in many forests, but few estimates of impact are available. Non-lethal root infections associated with Armillaria root disease were studied to determine their effect on stem volume yield in seven planted Douglas-fir stands and a naturally regenerated stand in British Columbia's southern interior. Trees were removed from the soil and the infection date of a random selection of trees was determined. The volume reduction attributable to disease was determined as a comparison of diseased to disease-free trees over time since infection. Volume reductions per tree ranged from 0 to 30 dm³ (0-27%) depending on the tree age and disease duration. Yield reduction reached 27 m³/ha, averaging 15 m³/ha for the three oldest planted sites by age 30 (7-15%), but was lower at the naturally regenerated site. Yield reduction at the site level correlated best with the number of diseased trees and an unknown site factor. Sites with slow juvenile growth had the least yield reduction owing to their lower incidence of disease over time. Yield was less affected by the proportion of diseased primary roots per tree than by the cumulative time since infection. A few of the diseased trees maintained growth rate after infection similar to disease-free trees; interestingly, these trees were smaller than average to begin with. Overall, trees suffer accumulating growth reduction without recovery. Root diseases prevent full expression of site potential even without mortality. Minimizing disease impact in respect to other forest management goals is also discussed.     

新型城镇化背景下创新基层社会管理的探索

本文全面分析了新型城镇化背景下基层社会管理面临的挑战,进而提出创新基层社会管理的有效途径.     

猪饲料原料净能测定方法及其影响因素

净能体系是唯一能在相同基础上体现能量需要和饲料能值的能量体系，以净能体系为基础，准确测定生长肥育猪饲料原料净能值，建立预测其饲料净能值的模型，有利于提高饲料能量利用效率，降低饲料成本。文章综述了猪饲料原料净能的测定方法，分析了不同测定方法的优缺点及其影响因素。     

显脉金花茶无菌体系建立及增殖培养研究

以显脉金花茶幼嫩带芽茎段作为外植体,开展外植体灭菌、启动培养及增殖培育试验,结果表明:3月采集的外植体最易灭菌,其最佳灭菌方案为先用75%酒精浸泡20 s后用0.1%升汞浸泡9 min;最佳启动培养基配方为WPM+6-BA 7 mg.L-1+NAA 0.25 mg.L-1;最佳增殖培养基配方为:改良WPM(NO3-∶NH4+=2∶1)+6-BA 5 mg.L-1+NAA 0.05 mg.L-1。