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。     

河北省康保县主要农作物收益比较分析

河北省康保县位于省西北部的坝上高原,是农业县。2010年笔者通过比较康保县种植的各种农作物的成本、收益,得出不同农作物收益存在显著的差异。当年康保县农作物商品率从大到小的排列依次为:红豆>马铃薯>胡麻>菜籽>莜麦>小麦>豌豆;而农作物的纯收益最高的是马铃薯(14 645元/hm2),其播种面积仅占总耕地面积的4.35%,其次是红豆(6 028元/hm2),其播种面积仅占总耕地面积的2.82%。因此,今后应扩大马铃薯与红豆的种植面积。由从事农业生产者的着眼点分析,当代农民仍有很重的自给自足的思想,耕地的利用率不够理想,没能使土地收益最大化。一般农户用48%的土地生产口粮,而没有尽可能地把土地用于生产比较效益较高的作物,生产小麦、莜麦农户数占总农户数的比例分别为78.57%、67.86%。因此,农业管理部门应加强对农民的基础教育与宣传工作,调整农业种植结构,提高农民收益改善全县的农业生产状况。同时应大力推广农业机械租赁形式的农机化运作模式,以解决农村劳动力不足问题,扩大生产,提高劳动生产率,提高农户的家庭收入。     

Wheat Straw Biochar Increases Potassium Concentration,Root Density,and Yield of Faba Bean in a Sandy Loam Soil

ABSTRACT

A greenhouse experiment was conducted to study the effect of different irrigation levels (100%, 75%, and 50% of water requirement) and wheat straw biochar levels (0%, 1.25%, 2.5%, 3.75%, and 5% w/w) on faba bean yield, water productivity, root length density, and different ions concentration in soil solution, using a factorial arrangement in complete randomized design with three replications. Results showed that application of high level of biochar (5% w/w) destroyed the plants before they reached maturity. The maximum yield was obtained in 1.25% w/w biochar under full irrigation, while the maximum water productivity was obtained in 2.5% w/w biochar and 50% of water requirement. Further, the root length density in soil top layer (0–8 cm) was significantly more than those in 8–16 cm, due to holding more water content in top layer and no drainage from the pots. Sodium, potassium, calcium and magnesium ions’ concentrations in soil solution were significantly increased by increasing biochar levels; however, the rate of increase in potassium was higher than other ions due to high potassium concentration in biochar in comparison with the soil. In conclusion, application of biochar in the level of 1.25% w/w is suggested as a suitable agent to decrease water consumption and improving the crop performance.     

A Critical Review of the Water Balance and Agronomic Effects of Conservation Tillage under Rain‐fed Agriculture in Ethiopia

About 80% of Ethiopia's population is involved in rain‐fed agriculture. Moisture stress coupled with traditional tillage with breaking ard plough, locally known as ‘Maresha ’ are the major limiting factors for agricultural production. Soil erosion, low infiltration and decline agricultural productivity because of conventional tillage implement have been frequently reported. In order to curve this situation and meet the huge food demand of the growing population, different conservation tillage systems have been implemented. However, there is limited information about the impacts of the practices. This review paper therefore aimed at providing adequate information concerning the impacts of the practices on water balance and crop yield. Systematic, best evidence and narrative review techniques were used. Results revealed that the application of conservation tillage had brought significant improvement on water balance and agricultural production. Researchers found over 50% decreased in surface runoff, 9 to 40% improvement in water productivity and good crop transpiration (T = 53 mm season⁻¹), compared to conventional tillage T = 49 mm‐season⁻¹ because of conservation tillage implement. Moreover, doubled grain yield was obtained from ridging, subsoiling and wing plough (1076, 1044 and 1040 kg ha⁻¹, respectively) compared to traditional tillage which resulted in 540 kg ha⁻¹. Improving water balance and agricultural production in rain‐fed agriculture need to reduce evaporation and surface runoff through improving moisture retention and transpiration. This could be achieved by the adoption of conservation tillage which can improve on‐farm water balance, yields and water productivity among smallholder farmers in Ethiopia. Copyright © 2016 John Wiley & Sons, Ltd.     

小鼠小肠上皮细胞的分离培养研究

通过组织块培养法进行胎鼠原代细胞培养,采用刮除法和相差消化及相差贴壁法对细胞进行纯化,用0.05%的胰蛋白酶进行消化传代对小鼠小肠上皮细胞进行了原代分离培养、传代、纯化及鉴定。结果表明:组织块培养法得到了小鼠生长状况良好的细胞,经过纯化,得到了较纯的小肠上皮细胞;形态学观察和免疫组化检测显示得到的细胞为小鼠上皮细胞。用组织块培养可以分离纯化出增殖能力较强的上皮细胞,并能进行传代纯化,通过免疫组化鉴定,证明分离出的小鼠IEC为阳性,即为小肠上皮细胞。     

氨化麦秸全氮损失研究

２种不同处理方式的麦秸，按照麦秸：水：尿素比例１００：３０：４制作的氨化饲料，用凯氏定氮法测定含氮量。Ⅰ、Ⅱ号料含氮量分别为１．１３１７％、１．３７１８％，比麦草提高１６１．９１％、２１７．５５％。２种料经过１￣１３０ｄ室内堆放，分４个阶段测定，１号料１￣４０ｄ全氮损失９．８９％，占全期全氮损失１５．８１％的６２．６０％，Ⅱ号料４０￣６０ｄ全氮损失８．１３％，２０ｄ占全期损失２９．８５％的２６．３