贵州林木良种生产与推广使用策略初探

文中就目前我省林木良种生产及使用情况,分析阐述了贵州省林木良种推广使用的主要问题,对如何加大我省林木良种生产和推广使用力度提出意见和相关策略。     

Estimating the production and mortality of fine roots in a Japanese cedar (Cryptomeria japonica D. Don) plantation using a minirhizotron technique

Fine roots are a key component of forested ecosystems, but available information is still limited. This study examined the production and mortality of fine roots less than 1 mm in diameter in a Japanese cedar (Cryptomeria japonica D. Don) plantation located on the Kanto Plain in central Japan. We used a minirhizotron technique in combination with soil coring, and collected data for 1 year (May 2002–May 2003). Fine root production and mortality were determined from changes in the lengths of individual fine roots on minirhizotron tubes. Both fine root production and mortality rates were greater in the upper soil than in lower soil levels. Both rates were seasonal, with higher values in summer than in winter; this trend was more pronounced in upper soil levels. These results suggest that environmental conditions, such as temperature or soil properties, affect the production and mortality rates of fine roots. Fine root production and mortality occurred simultaneously, and their rates were similar, which may have led to unclear seasonal changes in fine root standing crop estimates. Soil coring indicated that the fine root biomass of this stand was about 120 g m⁻², of which 40% was from Japanese cedar. The estimated rates of dry matter production and mortality of total fine roots, including understory plants, were both approximately 300 g m⁻² year⁻¹.     

广州地区草本花卉生产选种及栽培要点

结合广州地区气候特点,经过作者多年草花栽培经验,总结出草本花卉在本地区周年生产的品种及栽培要点。     

哈萨克斯坦小麦产业发展与挑战

我国小麦产需平衡有余,但专用优质小麦供给不足。小麦生产成本与日俱增,加之品质劣势,进口需求激增。小麦是哈萨克斯坦最主要的农作物,独立初期,由于技术落后、体制与政策等没有理顺,致使其农业陷入衰退期,小麦产业也进入困难期。经过哈国多年的调整和努力,小麦的种植、消费和出口逐渐恢复。长期以来,哈萨克斯坦小麦生产一直处于广种薄收、粗放经营和靠天吃饭的状态,播种面积大,产量增长较快,但单产水平却比较低。通过对哈国的农业环境、小麦产业发展、小麦育种栽培技术和品质分析,认识哈国小麦产业发展的特点和问题,提出中哈国两国小麦合作的前景。     

不同类型复合酸化剂在断奶仔猪饲料中的应用研究

将72头断奶1周的杜×长×大仔猪(35日龄)随机分成3组,包括1个对照组和2个试验组。各组的基础日粮相同,对照组为不添加酸化剂的基础日粮,试验1、2组分别添加0.15%普通复合酸化剂和0.15%缓释复合酸化剂,进行28 d的饲养试验。结果表明,添加0.15%缓释复合酸化剂可显著提高仔猪的日增重,降低料肉比、腹泻率和死亡率。     

泰妙菌素完全抗原制备及鉴定

为建立泰妙菌素(Tiamulin,TML)完全抗原制备方法,分别用混合酸酐法(Mixed anhydride,MA)和N,N-羰基二咪唑法(1,1′-Carbonyldiimidazole,CDI)将半抗原泰妙菌素偶联至载体牛血清白蛋白(Bovine serum albumen,BSA),以制备泰妙菌素完全抗原。对2种方法制备的抗原进行紫外扫描鉴定和SDS-PAGE凝胶电泳鉴定,根据SDS-PAGE凝胶电泳图估算出完全抗原的偶联比。结果均显示抗原偶联成功,估算出的偶联比分别约为1∶23.6和1∶8.1,说明,混合酸酐法制备泰妙菌素完全抗原时偶联率更高。     

普通荞麦自交不亲和两系互交制种技术研究

用自交不亲和性制种,实现普通荞麦杂种优势利用;创新杂交制种生产技术,提高效率,降低生产成本.将育成的近交系亲本矮B系与矮C系等量、混合种植,借助虫媒、风媒授粉,进行杂交制种.成熟后混合收获、脱粒,用机械将矮BF1（正交F1代）与矮CF1（反交F1代）分开,分别用于生产.制种田没有固定的父本,所收获种子95％是杂交种.正交F1代超亲优势为26.1％,反交F1代超亲优势为30.2％,平均优势为38.4％;试验表明,另一组合矮A系与恢3系所配杂交种比对照增产25.64％～44.87％,被审定为‘榆荞4号’品种.制种田省去了父本和按行比种植的工序,不仅提高了制种产量,降低了生产成本,而且制种效果好,在荞麦杂种优势利用上,是一种新的杂交种生产技术,可用于大规模生产杂交种.     

Constraints and possibilities for developing aquaculture

World aquaculture production in 1990 reached some 15 million tonnes, and predictions indicate that future production will reach 19.6 million tonnes by 2000, 37.5 million tonnes by 2010, and 62.4 million tonnes by 2025. Meanwhile, world fisheries production from capture will remain stable at about 100 million tonnes. Thus, all future increase in seafood supplies will have to come from aquaculture.Possibilities for development of aquaculture exist in a number of areas around the world. Technology and natural conditions determine the choice of sites and species to be produced, but current research indicates that a number of new species will be added to the present aquaculture production in the coming years. However, well-known species such as carp, tilapia, trout, salmon, turbot, halibut, cod, and sturgeon will be the most important in the immediate future. Among the crustaceans, shrimp will continue to be an important item, as will various kinds of gastropods and bivalves.Regions with a particular suitability for development of aquaculture include Africa, Asia, and Latin America. Freshwater aquaculture may also be developed on a larger scale in the former Eastern European countries, including the former Soviet Union, but here (and in Africa), political and economic constraints will slow down development for the next decade. A major constraint for development of aquaculture in Africa is the lack of infrastructure, as well as political problems, slow or deficient bureaucracies, and to some extent pollution. In Eastern Europe, development will be hindered by the lack of capital, and uncertainty about the political and economic development. Eastern Europe also has a major environmental problem, which may limit growth within this field. In Asia, space and availability of suitable sites are becoming a problem, as are pollution, diseases, and in some cases overproduction.A general constraint to global development of aquaculture may be price fluctuations, which affect the investment willingness of interested investors. This question must be seen in connection with the economics of operation. As new species are being launched, there is usually a short period of high profits, followed by a period of price reductions, and the collapse of several operators. After such turbulence, serious operators with proper management survive, and go on to operate a reasonably profitable business. The mechanism seems to be true for all new business areas, and does create a problem for sustained investor interest in aquaculture development.     

小麦专用涂层缓释一次肥在冬小麦生产上的应用效果

为了明确小麦专用涂层缓释一次肥在冬小麦生产上的应用效果,分别在中水肥和中低水肥2种肥力的地块上,以施用普通化肥（尿素和磷酸二铵）为对照,研究了底施小麦专用涂层缓释一次肥对小麦长势、产量和经济效益的影响。结果表明：施用小麦专用涂层缓释一次肥的小麦长势良好,秸秆粗壮,抗倒伏;中后期无需追肥也能满足小麦整个生育期的养分需求,省时省工;产量性状得到显著改善,籽粒产量和外观品质明显提高,增收节支合计收益高达2300元／hm2以上。小麦专用涂层缓释一次肥在小麦生产上有较好的应用效果和应用前景,可在生产上广泛推广应用。     

微生物肥料对不同节肥水平下烤烟生长与产质的影响

通过大田随机区组试验研究了10%、20%、30%节肥水平下两种微生物肥料对烤烟生长及产质的影响。结果表明:(1)在团棵期和旺长期,烤烟的农艺性状随着减肥量的增加而降低,在30%节肥水平时,降低较为明显,对烤烟生长的影响较大。到成熟期,金农肥中肥各节肥水平对烤烟的农艺性状均有不同程度的提升,德根贝在10%节肥水平时,烤烟的农艺性状有提升,在20%和30%节肥水平时分别降低10.4%、4.9%。(2)烤烟在3种节肥水平下其经济性状与对照均无显著差异,但不同节肥水平之间存在差异。两种微生物肥料均在20%节肥水平时,烤烟经济性状表现最好。金农肥中肥效果较为明显,显著提高了烤烟上等烟比例、中上等烟比例及均价,且烤烟产值比对照、10%节肥水平、30%节肥水平分别增加12.5%、34.5%、28.2%。