Effect of biochar,clay substrate and manure application on water availability and tree-seedling performance in a sandy soil

In order to develop a method for extensive pomiculture on marginal soils in semiarid Brazil, a field experiment was conducted to study the impacts of the soil conditioners biochar, clay substrate and goat manure on soil physical parameters of a sandy soil and on seedling performance of Spondias tuberosa Arruda. Manure significantly increased total porosity, soil water content and reduced bulk density of the sandy soil. Water content at field capacity (θ_fc) and at permanent wilting point (θ_pwp) were increased due to manure application. Neither biochar nor clay substrate had a significant impact on the soil physical parameters. Biochar combined with clay substrate led to lower soil water content and significantly reduced the period of retaining atmospheric water. Due to a strong correlation (R² = 0.75) between θ_fc and θ_pwp, the available water capacity within all treatments remained unchanged. Amelioration and initial nutrient supplies had no effect on seedling survival and stem growth of S. tuberosa during the 23-month experiment. This underlines the nondomesticated character of the available plant material of S. tuberosa. The independence of the seedling performance of soil management makes S. tuberosa an interesting species for low-input orchards and for reforestation within the Caatinga.     

The effect of weight loss on protein profiles of gastrocnemius muscle in rabbits: a study using 1D electrophoresis and peptide mass fingerprinting

The study of physiological changes occurring during selection contributes to an improved understanding of relationships leading to efficiencies in animal production. To investigate the effects of food restriction in gastrocnemius muscle protein expression, 20% weight reduction was induced in New Zealand White (meat producing) and wild rabbits, using one‐dimensional gel electrophoresis and peptide mass fingerprinting. Lower expression levels of myosin heavy chains were found in the Wild Rabbits Restricted Group, while myosin light chain and α‐crystallin proteins were not detected in restricted groups. Glyceraldeyde‐3‐phosphate dehydrogenase and glycogen phosphorylase expression levels were similar for all experimental groups. Phosphopyruvate hydratase β was not detected in the wild rabbit restricted diet group. Pyruvate kinase levels were 50% lower in the New Zealand Restricted group. LIM protein detection was absent in the control New Zealand group. Results also show relevance of actin in preserving muscle structure in depressed food availability, the sensitivity of both myosin light chain and α‐crystallin protein to restricted feed and the role of PK in the resistance of New Zealand rabbits to food restriction.     

Electron paramagnetic resonance and ultraviolet-visible spectroscopic evidence for copper porphyrin in actinomycete melanins

The coordination chemistry of iron (III) (Fe³⁺) and copper (II) (Cu²⁺) in melanins synthesized by seven actinomycetes isolated from Brazilian latosol soils under savanna (cerrado) vegetation was investigated using electron paramagnetic resonance (EPR) and ultraviolet-visible (UV-Vis) spectroscopy. The EPR spectra indicated the presence of Cu²⁺ ions bound to oxygenated and nitrogenous functional groups, and rhombic coordinated Fe³⁺ ions. In some of the actinomycete melanins the EPR hyperfine splitting of Cu⁺² ion complexes was well resolved, and indicated four magnetically equivalent nitrogen atoms in a plane. This result suggested the presence of Cu⁺² porphyrin complexes, which was confirmed by Soret bands in the 400-nm region of the UV-Vis spectra. The concentration of Mn in actinomycete melanins, determined by inductively coupled plasma atomic emission spectroscopy, was lower than those of Cu and Fe. Received: 9 April 1997     

A consortium of fungal isolates and biochar improved the phytoremediation potential of Jacaranda mimosifolia D. Don and reduced copper,manganese, and zinc leaching

Journal of Soils and Sediments - A consortium of fungal isolates may improve phytoremediation by stimulating root growth whereas biochar reduces metal leaching in contaminated soils. We combined...     

Enhancement of the rootability of a structurally fragile tropical soil using gypsum and leguminous residues to increase the yield of maize

In humid tropical areas, a combination of factors related to soil conditions for root development contribute to decreased nutrient use efficiency. Our aim was to evaluate the combined effects of the application of gypsum and mulch from leguminous trees on rootability of root zone soil, root growth, phosphorus recovery efficiency and maize yield in a sandy loam soil prone to hardsetting. The experiment involved a randomized block design with four replications and six treatments: no residue or gypsum (control, C); leguminous residues (L); leguminous residues and 6 t/ha of gypsum (LG6); urea and 6 t/ha of gypsum (UG6); leguminous residues, urea and 6 t/ha of gypsum (LUG6); and leguminous residues, urea and 12 t/ha of gypsum (LUG12). Application of gypsum plus leguminous residues enhanced soil rootability, when applied to a tropical Arenic Hapludult, through the combined effects of increased porosity and decreased penetration resistance. These improvements facilitated root growth in deeper soil layers and greater nutrient uptake. Application of leguminous residues increased the input and retention of calcium in deeper layers. The use of large amounts of gypsum with leguminous residue, despite a significant increase in phosphorus uptake, did not result in a proportional increase in maize yield. Given the small differences in calcium content between the 6 and 12 t/ha gypsum treatments, applying a low dose of gypsum combined with leguminous residue, rather than administering a single large gypsum dose, is recommended for tropical sandy loam soils with low cation retention capacities.     

早期产蛋鸡的饲养管理

当前来航鸡不断改良正在满足市场的需要 ,当新的遗传品系出现后 ,诸如钙和磷的配比等问题就需要重新评比 ,本文主要介绍当前商品产蛋鸡钙磷的代谢以及骨、蛋壳对钙磷的需要等问题。1　营养的效果由于软蛋、产蛋量下降以及较高的死亡率而导致产蛋总量的下降对养鸡户来说是非常重要的。有几个营养因素影响笼养蛋鸡的疲劳和蛋壳质量 ,虽说钙、磷是主要因素 ,其他的如 VD3、氧化物以及电解质的平衡也应考虑 (表 1 )。表 1　影响蛋壳质量的几个因素因　　素影响蛋壳的质量日粮高钙 +大颗粒的钙源 +夜间饲喂大颗粒的钙源 +电解质中钠离子和氯离子…     

钙和磷与早熟商品蛋鸡骨和蛋壳质量的关系

来杭型蛋鸡在不断地得到遗传改良以满足市场需求。新母鸡的成熟周龄在稳定步降，而产蛋量和蛋重则在不断增加。所以，营养管理也需要加以改变才能适应新品系遗传潜力的需要，在采用新型遗传系时，需要经常对钙、磷等的管理事项进行检查。