稀土元素在鲤鱼体内的蓄积和分布

试验研究了稀土元素在鲤鱼体内的蓄积和分布规律。结果表明:鲤鱼饲料中添加硝酸稀土,主要蓄积在心脏和肝胰脏中,蓄积最少的组织器官为脑和肌肉。100,200 mg/kg剂量组和对照组稀土元素在鲤鱼体各组织器官中的分布规律为试验前30 d,心脏和肝胰脏>骨骼>鳞>肌肉>脑;试验后30 d,心脏和肝胰脏>鳞>骨骼>肌肉>脑。而剂量较高的300,400 mg/kg组试验前期稀土元素在各组织器官的分布规律为心脏、肝胰脏>骨骼>鳞>肌肉>脑;试验后期的分布规律为心脏、肝胰脏>骨骼>鳞>脑>肌肉。     

夏大豆植株干物质积累数学模拟研究

对夏大豆濉科8号、中黄13两个品种从出苗至成熟共15次测定了植株质量,建立了数学模型。结果表明:植株、茎叶质量呈"慢—快—慢—降"的单峰变化趋势,而籽粒质量呈"慢—快—慢"的S形曲线变化趋势,单株粒重、百粒重则随生育时期呈直线增长趋势。y=ef(t)真实的反映了出苗、始花、终花至成熟期植株、茎叶质量变化。     

沼液营养液对快菜生长和生理特性的影响

以"四季快菜一号"为试材,以华南农业大学农化室叶菜A改良配方为对照(CK),设定沼液添加量为10%、20%、40%、60%、80%,研究了不同沼液添加量对快菜生长和生理特性的影响。结果表明:在营养液中添加一定量的沼液,能明显提高快菜植株的维生素C、可溶性糖、粗纤维和粗蛋白含量,并能提高蔬菜产量,沼液添加量为40%时效果最好,但对粗脂肪和叶绿素相对含量提高并不明显。     

Rice Growth and Nutrient Accumulation as Affected by Different Composts

Abstract

This study evaluated the effects of four different kinds of compost: pea–rice hull compost (PRC), cattle dung–tea compost (CTC), hog dung–rice hull compost (HDR), and hog dung–sawdust compost (HDS). These types of compost differ in nitrogen composition and in the dry matter yield and nutrient accumulation [nitrogen (N), phosphorus (P), potassium (K)], of rice plants. The rice (Oryza sativa L.) plants were planted in an Oxisol soil. Plants were cultivated in pots, which contained 3 kg of soil, mixed with the four different composts (PRC, 404 g; CTC, 395 g; HDR, and HDS, 450 g) and chemical fertilizer (CHEM) (N:P₂O₅:K₂O=120:96:72) The residual effect was studied after the crop was harvested. All treatments were replicated four times, with a randomized complete block design. The nutrient concentrations in the root, leaf sheath, leaf blade, stalk, and grain were analyzed at different growth stages. After the first crop, the dry matter yield and the amount of N, P, and K absorbed from the CTC or HDS treatments were higher than those of the other treatments, at the most active tillering stage. The growth and nutrient accumulation of rice plants given the PRC treatment were higher than those given the CHEM treatment at the heading stage or the HDR treatment at the maturity stage. In the second crop, the dry matter yield from the PRC, CTC, and HDR treatments was higher than from the other treatments. The nutrient accumulation of the rice plants was positively correlated with the dry matter yield. The residual effect of the HDS compost was the least among all four composts.     

Low-protein supplement increases protein retention and reduces the amounts of nitrogen and phosphorus wasted by rainbow trout fed on low-fat herring

The growth, food utilization and amounts of nitrogen and phosphorus lost into the water by rainbow trout (initial size 485 g) fed on low-fat Baltic herring and supplemented with a low-protein dry diet fed separately were studied in an 18-week net cage trial. Similarly to balancing protein and nonprotein energy in full diets, giving nonprotein energy in different feeds several hours apart improved the protein retention of low-fat herring to a level comparable to a commercially available dry diet control. The amounts of nitrogen and phosphorus lost into the water were also reduced to the same extent. The losses from the plain herring-feeding were twice as high. The improved protein retention and reduced nutrient losses were accompanied by 15–25% reductions in growth of the fish compared with the control dry diet. The growth of the fish fed on plain herring was 14% lower than the growth on the dry diet control.     

陆地棉与海岛棉干物质累积分配特性

供试的四个陆地棉品种地上部分干物质累积速度和数量，从现蕾至吐絮始终高于四个海岛棉品种；陆地与棉与海岛棉的所有品种干物质累积速率最快的时间均在初期至有效花期期间。但海岛棉干物质累积最大量到８月２５日止，陆地棉则持续到９月９日；不同时期干 物质分配率的特点是；苗期；叶〉茎，苗期：叶〉茎〉蕾，花苗期：叶〉茎〉铃〉蕾〉花；铃期；铃〉茎〉叶；株铃重累积的最快速率时间，陆地棉与海岛棉均在７月２６日至８月２５日     

猪苓菌丝液体培养及富锌研究

对猪苓（Polyporus umbellatus Fr.)菌丝进行了液体培养及富集锌研究。结果表明，在培养温度22℃，PH7．0，振荡速度150r/min。培养基中锌添加量为40mg/kg时，猪苓菌丝的生物转化量及菌丝体富锌率最高。     

Irrigation and Nutrient Effects on Growth and Water–Yield Relationship of Wheat (Triticum aestivum L.) in Central India

Increasing production of wheat from a limited water supply can result from efficient irrigation and nutrient management. A 3‐year field experiment was conducted at the Indian Institute of Soil Science, Bhopal, to study the growth, yield, seasonal evapotranspiration (ET) and water use efficiency (WUE), and the water–yield relationship of wheat in a soybean–wheat cropping system on vertisols. Three levels of irrigation, viz. I₀, no post‐sowing irrigation; I₁, two irrigations [crown root initiation (CRI) and flowering stage]; and I₂, three irrigations (CRI, maximum tillering and flowering stage) and three nutrient management treatments, viz. F₀, control (without fertilizer/manure); F₁, 100 % NPK (100–21.5–24.9 kg ha^?1); and F₂, 100 % NPK + farmyard manure (FYM‐10 t ha^?1) were tested in a split‐plot design with three replication. It has been established (through anova ) that the year effect was rather negligible and the interaction effects of irrigation and nutrient management on the growth parameters, ET, yield components, yield and WUE were significant. Plant height, progressive leaf area index, dry matter accumulation and crop growth rate were higher in I₂F₂, and I₂F₁ and I₁F₂ were statistically at par. The seasonal ET increased significantly with the increase in water supply in every nutrient treatment and it was highest in I₂F₂ and lowest in I₀F₀. The highest grain yield was obtained in I₂F₂; and a similar yield was recorded in I₃F₁ and I₂F₂. This shows a strong interaction effect between irrigation and nutrients. Yield components, viz. number of ears m^?2, number of grains ear^?1 and 1000‐grain weight were significant. The higher number of ears m^?2 containing greater number of grains with relatively heavier weights appeared to have contributed to the higher yield in I₁F₂, I₂F₁ and I₂F₂. The highest WUE obtained in I₀F₂ did not correspond to the highest yield and maximum ET, but a WUE of 10.43 kg ha^?1 mm^?1 in the I₂F₂ combination corresponded with the highest yield and the seasonal ET requirement was 391.8, which was 137 % greater than the water use at maximum WUE. The ET–grain yield relationship was linear, with a lowest regression slope (i.e. marginal WUE) and elasticity of water production (E_wp) in F₀ and a considerably higher slope and E_wp in F₁ and F₂. As the E_wp is positive and close to one in 100 % NPK treatment, the scope of improving WUE and yield with only inorganic fertilizer is very little, and relatively greater scope exists in the integrated management of organic manure and inorganic fertilizer. The results suggest that integrated nutrient management (100 % NPK + FYM) in conjunction with three irrigations maximized yield of wheat with concomitant improvement in ET and WUE under limited water availability.     

营养元素在红三叶叶片分解过程中的释放动态

在我国北亚热带高海拔地区应用分解网袋法，研究了红三叶叶片凋落物在分解过程中营养元素的释放特征。结果表明，在分解过程中，各类营养元素的含量和残留率的动态特征均有明显不同。根据这些特征，将其释放模式分为4类，即物理因子主导型、生物因子主导型、生物和物理双重因子主导型和化学因子主导型。     

中华鲟幼鲟饲料中适宜动植物蛋白比的研究

按单因子梯度设计的原理 ,以鱼粉和豆粕作为蛋白源 ,设计出5种不同蛋白质水平的饲料配方 ,通过5周饲养试验和2周消化试验 ,以研究中华鲟幼鲟饲料中适宜的动植物蛋白比。结果表明 ,中华鲟饲料中动植物蛋白比为1:1时 ,幼鲟的生长就能达到较好的效果 ;当动植物蛋白比达3:1时 ,既能发挥中华鲟生长迅速的潜力 ,又可获得良好的经济效益