Growth dynamics of winter wheat in the field with daily fertilization and irrigation

In a field experiment with fertilized and irrigated winter wheat the above-ground crop was sampled once a week. Phenological development, plant density and canopy height were recorded and the green surface areas of leaves, stems and ears were measured. Soil mineral nitrogen was sampled and the field climate monitored. There were four treatments. The daily irrigated/fertilized (IF) and daily irrigated (I) treatments were both irrigated by a drip-tube system. Liquid fertilizer was applied to IF following a logistic function according to calculated plant uptake. A total of 200 kg N ha⁻¹ was applied. Treatment I, control (C) and drought (D) were all fertilized once in spring with 200 kg N ha⁻¹. In treatment D transparent screens were used to divert rainwater. Dry matter production ranged between 1400 in D and 2352 g m⁻² in IF. The corresponding amount of nitrogen uptake ranged between 15.8 and 24.6 g m⁻². After harvest, soil mineral nitrogen was lowest in IF.
An increase in the availability of nitrogen and water enhanced total biomass production as well as grain yield and leaf area. The daily supply of nitrogen according to crop demand delayed nitrogen uptake and increased total uptake. The results suggest that when the nitrogen is supplied in accordance with crop demand, the efficiency with which the applied fertilizer is utilized increases and the risk for nitrogen leaching decreases.     

Simulating the vegetation-producing process in small watersheds in the Loess Plateau of China

Small watersheds are the basic composition unit of the Loess Plateau in China. An accurate estimation of vegetation net primary productivity (NPP) is of great significance for eco-benefit evaluation in small watershed management in this region. Here we describe the development and testing of a vegetation-producing process model (VPP) of a small watershed in the Loess Plateau. The model couples three modules: radiation adjustment; soil hydrological processes; and vegetation carbon assimilation. Model validation indicates that the VPP model can be used to estimate the NPP of small watersheds in the region. With the VPP model, we estimated the spatial NPP distributions in the Yangou watershed for 2007. The results show that in the Yangou watershed the NPP is relatively low, averaging 168 g C/(m 2 ·a). Trees and shrubs have a higher NPP than crops and grasses. The NPP is larger on the partly shaded and shaded slopes than on the partly sunny and sunny slopes. The NPP on the slopes increases gradually on 0-20° slopes and decreases slightly on slopes steeper than 20°. Our simulation indicates that the vegetation type is the most important factor in determining the NPP distribution in small watersheds in the Loess Plateau.     

西藏东南部原始森林夏-秋季节鸡类的栖息地利用

本文报道了1995年夏-秋季节西藏东南部原始森林鸡类栖息地的利用方式.记录有7个物种,这些物种大多喜欢在阳坡环境,而回避相对潮湿的阴坡环境.在这一鸡类群落中,白马鸡(Crossoptilon crossoptilon)与藏马鸡(C.harmani)的杂交类型在数量上是最丰富的,其次是血雉(Ithaginis cruentus)和斑尾榛鸡(Bonasa sewerzowi).随后于2001年的调查表明,由于地处偏僻,这些鸡类依然没有遭受人类狩猎和栖息地干扰的影响.     

额济纳旗宜牧土地载畜量研究

本次研究选用莫斯模型法(Moss)对额济纳旗宜牧土地生产力进行了研究,在此基础上估算出载畜量,为该旗的牧业可持续发展和生态环境保护提供理论依据。     

ADAMTS17 mutation associated with primary lens luxation is widespread among breeds

Primary lens luxation (PLL) is a well-recognized, painful and potentially blinding inherited ocular condition in dogs. We screened PLL-affected dogs of 30 different breeds, to identify those which carried a previously described c.1473+1 G>A mutation in ADAMTS17 that is associated with PLL in Miniature Bull terriers, Lancashire Heelers, and Jack Russell terriers. This ADAMTS17 mutation was identified in PLL-affected dogs from 14 additional breeds. PLL-affected dogs from some breeds (most notably the Shar pei and the Brittany spaniel) did not carry the G1473+1A ADAMTS17 mutation, indicating they must suffer from a genetically distinct form of the condition. We also estimated the frequency of this ADAMTS17 mutation in some of the breeds. Our findings indicate the mutation segregates in a large number of different breeds of dog, many of which are terriers or breeds with terrier co-ancestry, but some of which have more diverse origins. Our results also indicate that the mutation is present at high frequency within most of the breeds in which it segregates. In the miniature bull terrier breed estimates of mutation frequency ranged from 0.27 to 0.39, corresponding to 7.3-15.2% PLL-affected dogs in this breed. We also identified an increased risk of PLL associated with heterozygosity at ADAMTS17, suggesting that carriers carry a low risk of developing PLL.     

西宁市耕地利用变化及其驱动力研究

以西宁市地区为例,以耕地为研究对象,运用特尔斐法、相关分析和主成分分析法对2000～2008年耕地数量变化相关的社会、经济、农业驱动力进行定量分析,并将定量分析结果与专家对西宁市以往的研究结果结合进行探讨。结果表明,社会发展、经济投资、农业科技进步及人口因素对耕地利用变化产生很大影响,并据此提出西宁市合理利用保护耕地的建议。     

禽流感H9亚型SD696株疫苗生产工艺改进试验

分别采用10日龄和12日龄SPF鸡胚增殖禽流感H9亚型SD696株病毒,并改变后孵化温度,将死亡高峰期、最终死亡率、平均单胚收获量、尿囊液血凝价HA、病毒含量EID50进行对比,结果表明用12日龄SPF鸡胚比用10日龄SPF鸡胚增殖禽流感H9亚型SD696株病毒,死亡高峰期推迟12-24 h,最终死亡率、尿囊液的HA和EID50无差异,平均单胚收获量提高了2-3mL。35℃培养比37℃培养鸡胚死亡高峰期延迟、最终死亡率降低、平均单胚收获量提高、尿囊液的血凝价HA及病毒含量EID50偏高。选择12日龄SPF鸡胚,35℃培养温度为生产工艺,既提高疫苗产量,降低成本,又能够提高产品的质量。     

中国基层公共文化服务平台政社共建研究

[目的/意义]各级政府鼓励和支持社会力量参与公共数字文化服务建设,为政社合作共建公共文化服务平台提供了良好契机.[方法/过程]文章梳理了基层公共文化服务平台政社共建的相关文献,结合政府与社会力量的角色作用、平台资源与服务的建设导向,分析了基层公共文化服务平台的政社共建模式,并结合政社共建平台的实践案例,分析其政社共建现...