罗斯308肉鸡生长曲线拟合研究 及其生长规律预测

为了明确罗斯308 肉鸡的生长发育规律,用Logistic、Gompertz 和Von Bertalanffy 3 种生长模型对120 只 罗斯308 肉鸡进行生长拟合分析,并对不同周龄的平均周增重、相对增长率以及料重比进行测定。结果表明, Logistic、Gompertz 和Von Bertalanffy 3种模型的拟合度均高于0.99;从拐点体重、拐点周龄等指标分析,Logistic 曲线 的拟合值与实际测定值最为吻合,拟合度、拐点体重、拐点周龄分别为0.99、2 160.25 g、5.77 周;罗斯308 肉鸡料重比 在前后两期均为先高后低,6 周龄料重比为后期最低。综合分析,Logistic 曲线对罗斯308 肉鸡生长拟合度最高,罗斯 308 肉鸡最佳出栏时间为6 周龄。     

香稻栽培技术规程

从香稻品种选择,增香施肥措施,育秧和移栽,水分和病虫鼠草害防治管理,收获贮藏等方面介绍了香 稻栽培技术规程,以期促进香稻栽培实现增香优质、高产的目的.     

再生水灌溉下农田氮素转移规律研究

研究再生水灌溉条件下氮素在土壤中的转移规律,对于最大限度地利用再生水、减少水体污染具有重 要意义。研究表明,土壤中氮素的含量随再生水中氮素含量和灌溉量的增加而升高,在再生水灌溉条件下,土壤中铵 态氮浓度随着深度的增加而出现减小的趋势,而硝态氮和总氮随着深度的增加则出现了先增加后减小的趋势,并且 在70 cm 处出现了最大值。     

不同滴头流量及灌水定额下红枣树耗水规律

通过大田试验研究了不同滴头流量及灌水定额下红枣树的耗水规律,结果表明：各处理红枣树的全生育期耗水规律呈现单峰曲线变化,峰值出现在8月10日前后,各处理红枣树的日均最大耗水量在4.00～5.74 mm之间变化,各处理红枣树花期至成熟落叶期的作物系数在0.399～1.036之间变化,累积耗水量在287.0～413.5 mm之间变化;采用相同滴头流量时,红枣产量和WUE均随灌水定额的增大而增加,但增加的幅度逐渐减小;采用相同灌水定额时,增加滴头流量能够提高红枣产量和WUE,但在a=0.05水平下,未达到显著水平。     

黑龙江省大豆作物系数的确定

作物系数是计算作物需水量,合理进行灌溉和水分资源调配的重要参数。依据1991—2011年黑龙江10个典型农业气象站大豆农业气象观测记录,运用统计学方法,确定了大豆实际平均生育期,利用FAO推荐的Penman-Monteith公式和根层水分平衡原理,计算出了大豆作物系数,并进一步分析了大豆作物系数的变化规律。结果表明,近20年,黑龙江大豆平均播种时间推迟5 d,收获时间推迟10 d,平均生育期为5月1日到9月30日,生育期延长5 d。大豆作物系数在生育期内呈现出“单峰”变化趋势,结荚期的作物系数最大,为0.96,其次是开花期,为0.75,苗期和成熟期最小,为0.32;三叶期、分枝期和鼓粒期作物系数分别为0.60,0.62和0.71,全生育期平均作物系数为0.61。大豆的水分敏感期为结荚期和开花期。     

Restoration of a small‐scale forest wetland in a Belgian nature reserve: a discussion of factors determining wetland vegetation establishment

• 1. The main aim of this restoration attempt within a nature reserve was to recreate sustainable conditions for wetland species, particularly aquatic plants.
• 2. In the process of restoration, two phases of activity were distinguished: a pre‐restoration phase, during which information on land‐use history and past vegetation was collected and used to establish clear restoration goals; and a restoration phase for stimulating germination and establishment of target species originating from the soil seed bank and species pool.
• 3. Within the first year of the study, pond digging allowed the establishment of extremely rare native species that react positively to mudflat creation and standing water availability. The results of this experiment indicate that pond digging can be a very suitable technique for re‐establishing aquatic and wetland vegetation, providing that the site is well chosen.
• 4. An essential prerequisite for successful restoration is a study of the past vegetation of the target site and its surroundings. This work illustrates the importance of past vegetation in affecting current restoration success and provides an example of how restoration projects benefit from knowledge and understanding of both historical and present conditions.

Copyright © 2004 John Wiley & Sons, Ltd.     

VAM Fungi Spore Populations in Different Farming Situations and Their Effect on Productivity and Nutrient Dynamics in Maize and Soybean in Himalayan Acid Alfisol

To assess the effect of five vesicular arbuscular mycorrhizae (VAM) isolates of Glomus mosseae screened out from different farming situations, two pot experiments were conducted on maize and soybean in a phosphorus (P)–deficient Himalayan acid Alfisol. There was variation in VAM spore populations of Glomus mosseae isolates screened out from maize harvested fields, soybean fields, vegetable fields, tea orchard, and citrus orchard. Glomus mosseae isolate from vegetable-based cropping system exhibited maximum root colonization at flowering in maize (32%) and soybean (28%), followed by Glomus mosseae isolate from soybean fields, and exhibited the lowest in Glomus mosseae isolate from tea farm. Glomus mosseae isolate from vegetable-dominated fields was at par with Glomus mosseae isolate from soybean-based cropping system, again resulting in significantly high root biomass, nitrogen (N)–P–potassium (K) uptake, and grain and straw productivity both in maize and soybean crops besides the greatest Rhizobium root nodule biomass in soybean. There was a considerable reduction in soil fertility with respect to NPK status over initial status in pot soils inoculated with Glomus mosseae isolate from vegetable-dominated ecosystem, thereby indicating greater nutrient dynamics by this efficient VAM strain in the plant–soil system and greater productivity in a P-deficient acidic Alfisol. Overall, VAM isolates from different cropping systems and farming situations with variable size and composition of VAM mycoflora resulted in differential effects on growth, productivity, and nutrient dynamics in field crops. Overall, Glomus mosseae isolates from vegetable and soybean fields proved to be superiormost in terms of root colonization, growth, and crop productivity as well as nutrient dynamics in above study. Thus, isolation, identification, and selection of efficient VAM strains may prove as a boon in low-input intensive agriculture in P-deficient Himalayan acidic Alfisol.     

3种兽药及其主要代谢产物在猪粪中的排泄规律

以磺胺二甲嘧啶、金霉素和泰乐菌素为研究对象,探讨在饲粮中添加兽药后,猪粪中3种兽药原形及其主要代谢产物的排泄规律。试验选取60头33k左右的长大二元杂交母猪,在饲粮中加入200mg／kg的磺胺二甲嘧啶、75mg／kg的金霉素和100mg／kg的泰乐菌素,分用药期和休药期收集猪粪检测其中的兽药原形及其代谢产物残留。结果表明,7d用药期内猪粪中磺胺二甲嘧啶及其主要代谢产物对位氨基乙酰化磺胺二甲嘧啶的平均残留分别为59．50,15．98μg／g;金霉素及其代谢产物4位差向异构金霉素平均残留分别为239．92,217．79μg／g;泰乐菌素A及其代谢产物泰乐菌素D的平均残留分别为10．50,65．99／μg／g。进入休药期后,猪粪中兽药原型及其代谢产物残留下降很快,到休药期结束时,相应试验组的猪粪中已检测不出金霉素及其代谢产物残留,但仍可检出磺胺二甲嘧啶及其代谢产物和泰乐菌素A及其代谢产物。由此可知,兽药的体内代谢产物在兽药的排泄中占重要比例,提示除兽药原形外还应重视其代谢产物进入环境后的生态毒理学效应。     

Evaluating candidate wetlands for the assisted colonization of the western swamp turtle Pseudemydura umbrina in a changing climate: Macro-invertebrate food resources and turtle diet

1. The natural habitat of the western swamp turtle (Pseudemydura umbrina Siebenrock, 1901) – the ephemeral, winter wet swamps north of Perth, Australia – is in danger owing to climate change and habitat fragmentation. The decline in rainfall in this area over the last five decades is predicted to continue, shortening the annual activity period for the turtles and potentially shifting their optimal climate zone to the south.
2. Assisted colonization to wetlands in the cooler far south west of the state is one management response. As a contribution to such a measure, the diversity and abundance of food resources and consumption by turtles were evaluated at two potential and one existing colonization site.
3. Thirty-five captive-bred juvenile P. umbrina were temporarily released into three sites: Moore River Nature Reserve north of Perth (into which the species had already been successfully translocated) and Meerup and East Augusta in the cooler far south of Western Australia.
4. Food resources were assessed using sweep nets to sample invertebrates on two occasions at each wetland. Separate samples were collected for biomass determination and for assessing invertebrate diversity. Feeding by turtles was assessed by stomach flushing.
5. Neither biomass nor biodiversity differed significantly between the southern sites and the reference site north of Perth. Stomach contents varied greatly, from 0 to 62 animals per turtle. The main prey items were beetles, ostracods, isopods and tadpoles.
6. Each candidate wetland provided adequate food resources, indicating that assisted colonization to the cooler south coast of Western Australia has the potential to become a reasonable conservation tool to ensure the long-term survival of P. umbrina.

     

Earthworm community development in soils of a reclaimed steelworks

Long-term studies are essential to learn earthworm community development and soil formation post reclamation. Investigations were undertaken at a former steelworks site at Hallside, near Glasgow, UK, reclaimed in the 1990s using a mixture of colliery spoil and sewage sludge. The site was largely planted for production of short rotation coppice willow (Salix spp.). Earthworm inoculation formed a part of the restoration process. Minimal monitoring occurred in the interim, but some records of earthworm sampling existed in 2000 and 2005. This study focused on monitoring earthworms and soil properties across the site, drawing comparisons with adjacent unspoiled soil. Results showed that after 22 years, a species-rich community of earthworms (n=16) colonized the site, with endogeic Aporrectodea caliginosa being dominant by number and anecic A. longa by mass. Across the site, earthworm community density and biomass were 208 individuals m^-2 and 71 g m^-2, respectively. The Shannon diversity index for earthworms was 1.89, with an evenness of 0.68. The sewage sludge increased the soil organic matter, but the stone content of the colliery spoil prevented digging in some locations. Soil chemistry had no negative effect on earthworms, but the compacted substrate did hinder water infiltration. Earthworms colonized the reclaimed site from adjacent areas, and community structure and density below well-drained, scrub-free willow, birch, and grassland were not significantly different (P>0.05) from those of the adjacent unspoiled areas. The results show that the historical earthworm inoculation was unnecessary and badly timed. Future reclamations of similar sites can learn from this investigation.