Influence of soil phosphorus status,texture, pH and metal content on the efficacy of amendments to pig slurry in reducing phosphorus losses

Cost‐effective strategies for using chemically amended organic fertilizers need to be developed to minimize nutrient losses in surface and groundwater. Coupling specific soil physical and chemical characteristics with amendment type could increase their effectiveness. This study investigated how water‐extractable phosphorus (P) was affected by chemical amendments added to pig slurry and how this effect varied with soil properties. A 3‐month incubation study was conducted on 18 different mineral soils, stored at 10 °C and 75% humidity and treated with unamended and amended slurry which was incorporated at a rate equivalent to 19 kg total P (TP )/ha. The amendments examined were commercial‐grade liquid alum, applied at a rate of 0.88:1 [Al:TP ], and commercial‐grade liquid poly‐aluminium chloride (PAC ), applied at a rate of 0.72:1 [Al:TP ]. These amendments were previously identified by the authors as being effective in reducing incidental losses of P. The efficacy of the amendments varied with the soil test P, the degree of P saturation (DPS ) and the Mehlich aluminium, iron and calcium, but not soil texture. Chemical amendments were most effective in soils with DPS over approximately 20%. Due to their high cost, the incorporation of amendments into existing management practices can only be justified as part of a holistic management plan where soils have high DPS .     

恩肥对平菇菌丝生长,产量及品质的影响

本文报道了恩肥的施用浓度、施用时期对平菇菌丝生长、产量和品质的影响。试验结果表明,施用恩肥可促进平菇菌丝生长和子实体发育,有利于提高产量及改善品质。用肥量为每1000ml PDA或每公斤干培养料0.2～0.3ml时,菌丝生长速度显著加快,长满袋的时间可缩短4～5d,子实体产量可提高45.7％～55.9％,蛋白质、必需氨基酸和非必需氨基酸分别增加25.8％、14.94％和11.32％。在不同施肥时期中,又以现蕾期喷施效果最佳。     

弓形虫P30基因及其功能

弓形虫 P30基因所编码的蛋白为弓形虫主要表面抗原 SAG1 ,其约占速殖子总蛋白量的 5 %,SAG1对虫体侵入宿主细胞及其毒力具重要性 ,并有高度免疫原性和免疫保护性 ,被用于弓形虫疫苗的研制和弓形虫感染的分子诊断     

通过农杆菌介导法将口蹄疫结构蛋白全长基因P1导入大豆的研究

本研究以大豆体细胞胚为受体。用农杆菌介导法将口蹄疫病毒结构蛋白全长基因P1导入大豆基因组中．获得了抗性植株。经GUS染色、PCR及PCR-southern杂交等分子检测。证明目的基因已导入并整合到大豆基因组中。为利用大豆作为生物反应器生产口蹄疫新型口服疫苗奠定了基础。     

以CP23重组蛋白为抗原建立检测微小隐孢子虫抗体间接ELISA方法的研究

摘要：以在E.coli高效表达的微小隐孢子虫子孢子表面抗原CP23为抗原，以辣根过氧化物酶(HRP)标记的山羊抗鼠IgG为二抗，建立了检测微小隐孢子虫抗体的间接ELISA方法。经检测筛选出最佳反应条件为1μg／孔纯化的E.coli表达的CP23抗原包被酶标板，用10％免血清进行封闭，以正常E.coli裂解上清液稀释待检血清。实验表明应用CP23重组蛋白作为诊断C.parvum抗原具有特异性高、抗原易纯化和成本低等特点。     

夏大豆亩产262.1kg生理指标研究

研究了夏大豆中油－８９Ｄ亩产２６２．１ｋｇ各项生理指标：叶面积系数，开花期、结荚期、鼓粒期分别为３．９８、５．８０、４．９１；总光合势１８．２万ｍ＾２·日，平均净光合生产率４．８１ｇ／ｍ＾２·日，氮磷总积累量分别为２２．２８ｋｇ和３．１３ｋｇ，每生产１００ｋｇ籽粒需吸收氮８．５０ｋｇ，磷１．１９ｋｇ，总干物质积累８７６．４７ｋｇ，粒茎比０．５１，经济系数０．３０。     

糙皮侧耳和佛罗里达侧耳菌丝原生质体的形成与再生

本文报道了使用蜗牛酶和纤维素酶从糙皮侧耳和佛罗里达侧耳双核菌丝体中,成功地分离了高产量的原生质体。菌丝体培养时间,混合酶液 pH 值,一定浓度的酶液用量,酶解温度和时间与原生质体形成相关。原生质体的两种再生型被观察到,并计算了再生频率,糙皮侧耳为2.5%.佛罗里达侧耳为2.3%。     

Epidemiology of beet necrotic yellow vein virus in sugar beet at different initial inoculum levels in the presence or absence of irrigation

A field experiment was set up in 1988 to study the development of rhizomania disease of sugar beet at different inoculum levels of beet necrotic yellow vein virus (BNYVV) in soil. Five, tenfold different, inoculum levels were created by addition of the approximate amounts of 0, 0.5, 5, 50 and 500 kg infested soil per ha (the latter corresponding to 0.01% v/v calculated to the tillage layer). A drip irrigation treatment was applied to study the influence of soil moisture on disease. Susceptible sugar beet, cv. Regina, was grown for three consecutive years.In the first year, root symptoms were not observed, but BNYVV-infected plants were detected by ELISA in low numbers at all inoculum levels at harvest. After late drilling in 1989, high numbers of infected plants, up to 90–100% in plots with the highest inoculum level, were detected already in June. Root symptoms were also observed from June onwards. In both these years disease incidence increased in time and was significantly influenced by the initial inoculum level. In the third year, the whole field was heavily diseased, and only for the non-irrigated plots incidence differed for different initial inoculum levels. The expression of symptoms by BNYVV-infected plants was influenced by initial inoculum level, thus by the amount and timing of primary infection.Root weight at harvest was not affected, but sugar content decreased with increasing inoculum level already in 1988, leading to a reduction in sugar yield of 10% at the highest inoculum level. In 1989, both root weight and sugar content decreased progressively with increasing inoculum level, resulting in sugar yield reductions of 11–66% (down to approximately 3000 kg ha^–1) for low to high inoculum levels compared to the control. As the control plots became contaminated, all yields were low in 1990, still showing a decrease with increasing inoculum level in the non-irrigated plots, but an overall mean sugar yield of 3323 kg ha^–1 for the irrigated ones.Sodium and -amino nitrogen content of the root, additional quality parameters determining extractability of sucrose, showed an increase and decrease, respectively, with increasing initial inoculum level already in the first year. The relative differences in contents compared to those from the control were largest for Na content. A significant negative correlation was found between Na (mmol kg^–1 root) and sugar content (% of fresh weight); linear for 1988, exponential for 1989 and 1990.In spring 1989, the infestation of individual plots was assessed using a quantitative bioassay estimating most probable numbers (MPNs) of infective units of BNYVV per 100 g dry soil. The relationship between the MPns determined and root weight, sugar content and sugar yield at harvest could be described by Gompertz curves. The increase in disease incidence with increasing MPN in 1989 was adequately fitted with a logistic equation.