我国部分造林树种的生态值

研究了17个树种的地理生态值、温度生态值、雨量生态值和干燥生态值。在此基础上、又研究了它们的综合生态值,并进行了聚类分析。结果表明,17个树种可分为7类:樟子松和南亚松是一类,其生态值最低,对环境要求最为严格。白榆是一类,生态值最高,其生态幅度宽,适应性广;胡杨、梭梭是一类,是一组生态幅度宽的旱生树种;其它树种生态值中等。     

高寒草原放牧绵羊瘤胃液酸度、温度和游离氨浓度的动态变化

通过瘤胃瘘管采样测定了高寒草原放牧条件下绵羊瘤胃液ｐＨ、温度、游离氨浓度的变化动态，结果表明绵羊瘤胃液ｐＨ值、温度和游离氨浓度平均值在８：００时分别为６．７４、３９．０℃、１３．５８ｍｇ／１００ｍＬ，变化范围分别为５．４０～７．２７、３６．７～３９．７℃、４．６３～４１．０６ｍｇ／１００ｍＬ；在２０：００时分别为５．５７、３９．５℃、１０．９１ｍｇ／１００ｍＬ，变化范围分别为５．２３～７．７７、３８．０～４０．３℃、５．６６～１９．６４ｍｇ／１００ｍＬ。游离氨浓度日内变幅（４．６２～１０．８１）低于日间（８：００时５．６６～１９．６４，２０：００时１１．３２～４１．０６），波动较为强烈。温度和游离氨浓度的高峰值与ｐＨ值的低峰值对应出现。     

氮肥和高温对早稻淦鑫203产量、SPAD值及可溶性糖含量的影响

为探究氮肥和幼穗分化后期高温对水稻产量的综合影响,以杂交稻淦鑫203为材料,设置2个氮肥水平,于水稻幼穗分化后期37 °C高温处理4d,研究氮肥和穗分化后期高温对早稻产量、SPAD值及可溶性糖含量的影响.结果表明,高氮或是常氮下,与适温相比,高温降低了淦鑫203的结实率、单茎产量、SPAD值和可溶性糖含量.高温或适温下,与常氮相比,高氮增加了结实率、单茎产量和可溶性糖含量.高温高氮的结实率、单茎产量和单株产量高于高温常氮,说明适当增施氮肥可缓解高温的减产作用.     

小麦面筋物理品质性状的双列分析

对沉淀值,比沉淀值两个面筋物理品质性状利用Hayman方法进行的分析表明,两性状低值表现部分显性,高值与隐性效应相联系。加性方差和显性方差分量均达显著,基因的加性效应比显性效应更重要。     

上海和韩国粳稻品种米质特性比较

利用6个上海粳稻品种和9个韩国粳稻品种进行了品质特性比较分析。结果表明,上海和韩国品种间的粒宽、长宽比、穗着粒密度、直链淀粉含量、蛋白质含量和碱消值均呈显著的差异,上海水稻品种比韩国水稻品种粒型较细长,穗着粒密度高,直链淀粉含量、蛋白质含量和碱消值高,但食味值和淀粉谱特性则相反,韩国水稻品种的食味值和淀粉谱特性中的最高粘度值、最终粘度值和下降粘度值显著高于上海水稻品种。水稻品质特性间相关分析结果表明,食味值与直链淀粉含量,蛋白质含量和穗着粒密度呈极显著负相关,而与最高粘度值和下降粘度值呈显著的正相关。直链淀粉含量和蛋白质含量与最高粘度值、最低粘度值和最终粘度值均呈极显著的负相关。由此认为,通过育种手段降低直链淀粉含量和蛋白质含量,改进穗型和粒型结构,并在栽培措施上降低氮肥施用量是提高上海水稻品质的有效途径。     

种猪遗传育种分析系统的设计

利用数据库技术和面向对象程序设计方法（OOPM），结合对种猪遗传育种工程中的最优选配问题，设计出种公猪、种母猪及后裔数据库等，在此基础上计算遗传力、重复力以及育种值，建立了种猪遗传育种分析系统，提高了种猪生产的品质和效率。     

泥鳅网箱高效养殖技术

农户可利用河道．湖泊、水库等大水面．避开主航道，水深2-4米．水底平坦．污泥少．水体pH值为7．0-8．5，溶解氧在4．8毫克，升以上．硝酸态氮和亚硝酸态氮的含量分别不高于20×10^-6和0．1×10^-6浓度。一般库湾、湖汊、河道、外荡或面积较大的池塘都可设置养鳅的网箱。[第一段]     

6.9%威霸水乳剂防除大豆田稗草效果

1　试验材料与方法试验于2004年设在黑龙江省二九一农场试验站和原种场 10 号地,土壤类型均为潜育化草甸黑土。试验站土壤有机质含量 3.48%,pH值 8.1,速效氮93.1mg/kg,速效磷 19.1mg/kg,速效钾103.8mg/kg,前茬玉米,春耙茬整地,原垄种大豆;每公顷施肥200kg,氮、磷、钾比例为 1∶     

Effect of increasing levels of nitrogen on yield of tea in different agro-ecological conditions of Pakistan

Field experiment was conducted on mature tea bushes of Qi-Men variety at two different altitudes from sea level i.e. at National Tea Research Institute Shinkiari （1000 m） and on farmer＇s field in Konsh valley at village Battal （1500 m）. Different levels of nitrogen with constant dose of phosphorus and potassium were applied to observe the optimal dose of nutrients for highest yield under local edaphic conditions. The experiment was repeated for three consecutive years. The highest yield of fresh tea leaves were obtained by the application of 420 kg ha^-1 N followed by the application of 360 kg ha^-1 N at 1000 masl. The highest dose of nitrogen also reduced significantly the soil pH in the upper （0-15cm） layer depth during 1998 and 1999. During the year 2000, the reduction in soil pH was observed by the application of highest dose of nitrogen but was non-significant at 5% level. The lower soil depth （15-30 cm） showed the reduction in pH with the highest dose of nitrogen during the experimental year but was statistically non significant. At the higher altitude of 1500 masl the highest yield of fresh tea leaves was obtained by the application of 420 kg ha^-1 during the experimental years but the increase was significant during the year 1999 and 2000. The yield of the fresh tea leaves was positively correlated with the amount of nitrogen application at both the altitudes. The increasing amount of nitrogen decreased the soil pH at both the depths of 0-15cm and 15-30cm. Unlike the lower altitude （1000 m） there was no any significant reduction in the soil pH during 1998 and 1999. A significant reduction in soil pH was found in the year 2000.