现代集约化肉羊业主要关键技术研究与应用

专门化肉用种羊选定、引进后，通过适应性研究，在较大规模养羊业生产实践中。对现代集约化肉羊业的主要关键技术进行研究、完善和创新，组装集成并应用于生产。技术研究应用结果既为市场提供了大批专门化肉用种羊和优质安全的杂种肉羊，取得了高水平的研究成果及显著的经济效益和社会效益．又为我国目前正在迅速发展的集约化肉羊业提供了可靠的技术支持和理想的生产模式：从适宜的专门化肉羊品种到运用高效母羊快速扩繁技术．建立和完善有效的肉羊杂交利用体系，普遍应用种羊鲜、冻精生产大批肉用杂种羔羊，种植高产优质饲草及其科学加工调制和利用．建立严格兽医防疫制度．实行放牧 补饲或全舍饲的精细管理和集约化育肥，至生产优质、安全、标准肉羊，获得显著的经济效益和社会效益。     

邓州市耕地有效态硫元素丰缺状况分析、产生原因及应变对策

该文通过对邓州市2006~2007连续两年所分析的4700个土样有效硫（S）化验结果整理分析发现，邓州市目前近30%耕地中有效态硫含量对禾谷类作物而言是缺乏的，有近60%的耕地中有效态硫含量对于种植十字花科、百合科、豆科等需硫较多的作物来说，属于潜在缺硫耕地；同时从施肥结构、种植结构变化详细分析了其产生的原因，并依据硫在植物体内移动状况、硫肥性状等因素提出相应对策。     

紫色土光谱特征及其碱解氮的预测研究

文章分析探索了应用可见近红外光谱技术快速、高效、便捷测定土壤营养参数的可能性。采集蓬莱镇组紫色土样本，比对分析了不同肥力水平、土壤厚度和土壤粒径条件下采集土壤光谱对可见近红外光谱特征的影响，筛选出不同厚度、粒径土壤条件下的碱解氮含量预测模型。研究结果表明，土壤样本厚度为30mm时具有最大的光谱反射率，建立的氮含量预测模型效果最佳，校正集和验证集的相关系数分别为0.84和0.83，均方根误差分别为1.79和1.87。土样粒径在0.25-0.85mm时氮含量的预测效果最佳，校正集和验证集的相关系数均超过0.8，且均方根误差较小；但当土样粒径<0.25mm时，氮含量预测模型效果明显下降。采用20目（<0.85mm）过筛、30mm厚度土壤样本采集可见近红外光谱和偏最小二乘法（PLS）模型预测，可以实现对蓬莱镇组紫色土碱解氮含量的较好光谱预测。     

不同有机肥用量对黄瓜生长及养分吸收的影响

在温室基质栽培条件下,研究了配施等量化肥时不同用量有机肥对黄瓜生长及养分吸收的影响。试验采用有机肥系烘干鸡粪,所有供试肥料均以底肥形式一次施入。研究结果表明,高量有机肥处理(有机肥50,100 kg/m3)严重抑制了黄瓜定植初期的生长,黄瓜前期产量也明显低于不施或低量有机肥处理。随着施肥量的增加,黄瓜氮、磷、钾养分吸收量均显著增加。黄瓜定植后74 d,所有处理基质的速效氮养分均已处于极低的水平,黄瓜普遍出现缺肥症状。试验初步证明了长季节栽培条件下一次施用高量有机肥难以及时提供足量的速效氮源,无法满足蔬菜养分需求。     

黄土高原半干旱区退耕还林对土壤微量元素的影响

为了探明黄土高原半干旱区退耕还林对土壤微量元素(Cu、Zn、Mn、Mo、Fe)含量的影响及其与影响因子间的关系,以甘肃省关川河流域退耕还林地和农地为研究对象,使用有效性评价、通径分析等方法研究土壤微量元素与土壤环境变量间的关系。结果表明:退耕后土壤微量元素含量随土层深度增加而减少,在表层土壤中呈一定的富集现象。退耕地Cu、Mn、Mo的有效性指数高于Zn、Fe,侧柏林地有效性综合指数高于云杉林地。偏相关分析显示,退耕还林区土壤微量元素有效态含量的主要影响因素为土壤有机质、全钾、全氮与土壤含水率;回归分析显示,土壤环境因子可解释38.1%~73.8%有关土壤微量元素含量的变异;通径分析表明,土壤全钾对土壤微量元素的直接作用最大,土壤全氮对微量元素的间接作用最大;决策分析表明,土壤全钾与土壤有机质是退耕还林区微量元素含量的决策变量,而土壤含水率是土壤微量元素的限制变量。     

Distribution of Arbuscular Mycorrhizal Fungi in Upland Field Soil of Japan 1. Relationship Between Spore Density and The Soilenvironmental Factor

Abstract

To Quantify The Effects of Arbuscular Mycorrhizal Fungi (Am Fungi) On The Growth of Upland Field Crops Cultivated in Japan, We Analyzed Soil Samples From 124 Sites in 18 Japanese Prefectures For Available P Content, Ph and Am Fungal Spore Density. The Am Fungal Spore Density in The 124 Soil Samples Was 1.7 Per G Dw On The Average, and Lower Than 1.0 Per G Dry Soil (Dw) in About Half of The Soil Samples. The Maximum Spore Density Was 20.6 Spores Per G Dw. The Density of Am Fungal Spore Did Not Vary Significantly With The Sampling Site and The Kind of Cultivated Crop in The Sampling Field. The Ph of The Soil With A High Spore Density Ranged From 6 To 8, and in The Soil Samples With A Ph Lower Than 6 and Higher Than 8, TheSpore Density Was Lower Than 5 Spores Per G Dw. Thus, in The Acid Or Alkaline Soil, The Sporogenesis of Am Fungi Is Suppressed. Because Available P Content Was Consistently Low in The Soil Samples With A High Spore Density, P Content Was Considered To Correlate With The Am Fungal Spore Density. Therefore, Crop Cultivation With Limited P Fertilizer Application and Reduced Available P Content May Be Important To increase Am Fungal Spore Density in Upland Field Soil.     

新型豆粕氨基酸营养价值的评定

用FOSS2300瑞士全自动凯氏定氮仪和德国氨基酸分析仪测定新型豆粕的粗蛋白质为453.092g/kg,18种氨基酸含量为327.65 g/kg,占粗蛋白质含量的72.31%,氨基酸的总消化率为79.31%。生长畜禽所需的10种必需氨基酸含量达163.36 g/kg,占18种氨基酸总量的49.86%,以70日龄未取盲肠公鸡测定其消化率为74%~90%。以蛋鸡和肉仔鸡理想蛋白质为模型计算平衡性指数,表明新型豆粕为家禽的良好蛋白源。     

The pH change in rhizosphere ofPinus koraiensis seedlings as affected by different nitrogen sources and its effect on phosphorus availability

Root mat method described by Kuchenbuch and Jungk was used to study the rhizosphere processes. The experiment was carried out on two years oldPinus koraiensis seedlings. Soil samples collected from the upper 20-cm soil layer in Changbai Mountain were treated with three different forms of nitrogen fertilizers: NO₃ ⁻−N, NH₄ ⁺−N and NH₄NO₃. The results showed that the soil pH and available P near the roots were all lower than in the bulk soil in control treatment. NH₄ ⁺−N application greatly decreased the soil pH near the roots compared to the control treatment and promoted the absorption of phosphorus, which led to a more remarkable depletion region of available P. On the contrary, the rhizosphere soil pH was higher than in the bulk soil in treatments with NO₃ ⁻−N and retarded the P absorption, which led to a nearly equal available P contents to the bulk soil. In treatment with NH₄NO₃, the rhizosphere soil pH was only a little lower than that in the control treatment and its effects on P absorption is mediate between the treatments with NH₄ ⁺−N and NO₃ ⁻−N. Foundation item: This paper was supported by National Natural Science Foundation of China (Grant No. 30170167). Biography: Chen Yong-liang (1969-), male, Ph. Doctor, lecture of Northeast Forestry University, Harbin 150040, Post-doctor in Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P.R. China. E-mail: ylchin@sohu.com Responsible editor: Seng Funan     

Soil phosphorus fractions and their availability over natural succession from clear-cut of a mixed broadleaved and Korean pine forest in northeast China

To assess phosphorus (P) status of forest soil under naturally restored vegetation,P fractions in the 10-cm soil layer were quantified at different successional stages on the clear-cut site of mixed broadleaved and Korean pine forest.Four communities of shrub,softwood broad-leaved forest,softwood and hardwood broad-leaved forest,and hardwood broad-leaved forest represented different succes-sional stages.A soil sample from a primary broad-leaved and Korean pine stand was the control.A sequential P frac-tionation scheme extracted empirically defined pools of P and path analysis used to partition the direct and indirect contribution of soil P fractions to available P.The results show that available P increased significantly with long-term succession,while both sodium bicarbonate-extractable P(NaHCO3-P) and sodium hydroxide-extractable P (NaOH-P) fractions were reduced in early successional stages and increased in late stages.Compared to the primary forest,concentrations of P fractions in the four stages signifi-cantly decreased except for HCl-P,indicating that soil P supplements over the long-term did not return to primary forest levels.The results of related analysis also showed that NaHCO3-Pi levels were significantly related to avail-able phosphorus.According to the path analysis coeffi-cient,NaHCO3-Pi exhibited the highest effect on available P among eight P fractions;the indirect effects of other P fractions via NaHCO3-Pi were larger than those with other P fractions.Overall,this study suggests that soil P bioavail-ability gradually improved during natural vegetation res-toration on clear-cut sites mainly through the increase of NaHCO3-P,where phosphorous is immediately available,and subsequently available phosphorus NaOH-P.     

Dynamics of phosphatase activities in a cork oak litter (Quercus suber L.) following sewage sludge application

As part of a study of the processes involved in litter biodegradation following sewage sludge (SS) addition, the variations over 14 months of phosphatase activities in a cork oak litter (Quercus suber L.) were investigated. A field experimental design was carried out using the litter-bag method on both a fertilized plot receiving SS applications (twice ) and a control plot. Acid (APH) and alkaline (BPH) phosphatases were measured, along with several biotic and abiotic variables potentially involved in the regulation of these enzymes. These included moisture, temperature, pH, water-extractable inorganic P (P_W), culturable heterotrophic bacteria and fungi. Sludge addition had significant effects on all the variables measured. Indeed, sludge increased significantly BPH activities, available P_W, microbial densities (i.e. bacteria and fungi) and pH in the fertilized plot. In contrast, APH activities decreased significantly following sludge addition. As a consequence, the BPH/APH ratio increased markedly and immediately in the fertilized plot, but only after the 1st amendment. Following the 1st preconditioning SS amendment, the 2nd fertilization had fewer effects on biological variables, because of summer dryness. The different properties examined varied significantly with incubation time, and most were significantly related to the seasonal patterns of litter moisture in this Mediterranean forest ecosystem. Hence, sewage sludge application modified the intensity of microbial responses to environmental factors, but biological patterns regulating P turn-over were maintained.