高产稳产优质耐旱型水稻新品种金穗1号选育 及旱直播栽培技术

金穗1号是以花培品种“早花2号”为亲本,与优良性状互补的品种杂交配组育成的水稻新品种。既保持了水稻品种高产稳产抗性强品质优的特点,而且抗旱性突出,适合旱直播栽培。冀东旱直播高产栽培的关键在于早播,充分利用当地的气候条件。     

添加甲酸+甲醛对草木樨青贮品质的影响

在刚收获及收获后经过8和30 h晾晒的初花期草木樨青贮料中,加入甲酸 甲醛进行青贮.结果表明,草木樨低水分(DM为44.98%)青贮可以使青贮料的氨态氮含量降低,并保存更多的干物质、粗蛋白质和可溶性糖.甲酸 甲醛青贮能明显改善草木樨青贮料的发酵品质,即降低青贮料的氨态氮含量和保存更多的可溶性糖和粗蛋白质.晾晒8 h组添加甲酸(2.0 ml/kg) 甲醛(2.0 g/kg)的效果最好;而晾晒30 h组添加甲酸(3.0 ml/kg) 甲醛(1.0g/kg)的效果最好.     

猪粪干、湿法厌氧发酵过程中碳、氮的流失

试验以新鲜猪粪为发酵原料,研究湿法和干法两种不同厌氧发酵过程的碳、氮排放量。湿发酵和干发酵组发酵料液的总固体(TS)含量分别为8%和20%,发酵液pH为6.8~7.4,发酵温度为35℃,体积为1.2 L,周期为21 d。试验期间每天测产气量,每4天取发酵样,测其全氮含量和TS降解率。结果表明,湿法和干法发酵组的CH4总产气量分别为9114 mL和12537 mL;CO2的总产气量分别为251.90 mmol和343.67 mmol;TS降解率分别为52.5%和29%。湿发酵的碳流失率和全氮流失率极显著高于干发酵(P<0.05)。     

短穗兔耳草的克隆生长特征

以调查统计的方法研究了高寒草甸匍匐茎植物短穗兔耳草Lagotis brachystachya无性系的生长特征、形态特征以及能量分配规律,研究结果表明:匍匐茎只有1条的短穗兔耳草最多,占60．47％,匍匐茎有4条的短穗兔耳草只占6．98％。在牧草生长盛期,短穗兔耳草无性系的基株高度4．03 cm,根长为9．11 cm,叶数为7．98;分株高度0．85 cm,根长2．73 cm,叶数为3．08;匍匐茎的茎生叶数为12．54,长度为15.14 cm,匍匐茎比节间重为2．18 mg／cm,粗度为0．97 mm,不同构件的干质量呈现出基株>匍匐茎>分株>茎生叶的规律。随着匍匐茎数目的增多,短穗兔耳萆无性系的基株根长逐渐增加,用于克隆繁殖的能量投资也有增加的趋势,其他参数都没有明显的变化规律。     

东祁连山不同退化程度高寒草甸土壤有机质含量及其与主要养分的关系

对东祁连山金强河河谷轻度、中度、重度退化高寒草甸土壤有机质含量变化及其与土壤全磷、全氮、速效磷、速效氮含量之间的关系进行了研究。结果表明：随着退化程度的加重,020 cm层土壤有机质、全氮和速效磷含量均不断下降,全磷含量呈现出先降后升但总体呈下降的趋势,但速效氮含量则不断上升,各养分的变化差异均达到极显著水平(P<0.01)。在划分的轻度退化草地土壤中,有机质含量分别与全磷、全氮、速效磷、速效氮含量之间均不存在显著的相关关系(P>0.05),另外所划分的中度退化和重度退化草地也同样如此。但是通过把3个不同程度退化草地结合起来作为整体进行综合分析,结果表明,除了全磷,土壤有机质含量分别与全氮、速效氮、速效磷含量三者之间存在极显著的相关关系(P<0.01)。在较大尺度上,有机质可以作为土壤营养状况的主要判断指标。在研究高寒草地土壤养分状况及其综合评价中,要特别注意其时空异质性,要重视尺度问题。     

Soil physical fertility, soil structure and rooting conditions after ploughing organically managed grass/clover swards

Effective management of soil structure and organic matter are essential in organic cropping to ensure good rooting conditions and to optimize the production of mineralized N and thus minimize greenhouse gas emissions. We investigated how mid‐winter or early spring ploughing and three grazing duration treatments prior to ploughing influenced soil structure, soil organic matter and plant root growth under the first spring barley crop after a grass–clover ley. The experiment was carried out over two seasons. We also studied the soil under first‐year oats in a long‐term rotations experiment where 2 or 3 years of arable crops followed 3 or 4 years of grass. Pore size distribution and pore continuity, bulk density, particulate (light fraction) organic matter, readily oxidizable organic matter (ROM), aggregate size distribution and root length densities were measured. Macroporosity appeared to be the best indicator of soil physical fertility; it was sensitive to changes in soil structure arising from compaction and root growth. This, along with visual examination, revealed the loosening resulting from ploughing. The generally favourable macroporosity amongst small, stable aggregates reduced the likelihood of development of anaerobism. Macroporosity and aggregate size can be estimated from visual examination of the soil, a method that offers the advantage of being quick and of sampling a large volume. The content of ROM was high 6.1–6.4 g 100 g^?1 whole soil. However, particulates formed only a small fraction (6–9%) of the ROM. Despite the favourable ROM and structure, the soil was susceptible to compaction damage during seedbed preparation in wet soil after ploughing which reduced grain yield in some plots. Grazing by sheep before ploughing and date of ploughing had minor effects on soil quality. Grazing for 2 months prior to ploughing increased root length density in the upper topsoil in the following arable crop, possibly because of the higher quality of the animal and grass–clover residues. Conservation of soil quality was related more to secondary tillage and sowing operations after ploughing than to duration and timing of grazing.     

Chemical composition and in sacco dry matter degradability of residue and by-products of palm fruit processing in the rumen of steers

The nutritive value of residue (palm calyx leaves (PCL)) and by-products (palm press fiber (PPF) and palm oil sludge (POS)) of palm fruit processing were studied through analysis of their chemical components and degradability of their dry matter (DM) in the rumen of steers. Chemical analysis showed that the materials have similar organic matter components (mean = 95.2%), while crude protein (CP, g/100 g) and metabolisable energy (ME, MJ/kg DM) were highest in POS (10.02 and 9.43), followed by PPF (7.02 and 8.61) and least in PCL (5.42 and 8.04). An opposite trend of CP and ME was noticed in NDF and ADF contents, being 61.53 and 49.11% in PCL, 44.84 and 32.08% in PPF and 25.35 and 20.29% in POS. Mineral contents showed that PPF and POS had the lowest and highest concentration, respectively, of Mg (0.07 vs. 0.11%), Cu (58.5 vs. 143.9 mg/kg) and Fe (1374.5 vs. 4086.0 mg/kg). Dry matter degradation characteristics and effective degradability varied significantly ( P  < 0.05) and were consistently highest in POS and least in PCL. Results have generally shown that the residue and by-products could be ranked for their potential feeding value as POS > PPF > PCL. It is concluded that POS and PPF can be harnessed directly as feed resources for ruminant animals, while PCL will require some treatments to enhance its nutritive value in ruminants.     

Chloroacetic acids—Degradation intermediates of organic matter in forest soil

Chloroacetic acids (CAA), especially trichloroacetic acid (TCA), were considered phytotoxic secondary air pollutants of anthropogenic origin affecting conifers and were therefore intensively studied. However, another source of CAA has been then found: a forest soil in which humic substances are degraded by microbial processes to CAA and chloroform. This new aspect—formation of CAA in the soil—means that CAA are continuously produced and also biodegraded by other microorganisms in the soil and contribute thereby to the degradation of soil organic matter (SOM). Here we show for the first time the formation of dichloroacetic acid (DCA) and TCA in the forest soil by chlorination of SOM using ³⁶Cl labeled chloride. We suggest that CAA are both formed and biodegraded in the forest soil and thus represent intermediates in one of the processes of SOM decay.     

浅谈锯材干燥产生干裂问题

本文阐述了锯材在干燥过程中出现的干裂问题及产生的原因和防止办法。