ABSTRACT The objectives of the present study are to determine the cycle and budget of nitrogen in larviculture ponds of the swimming crab Portunus rrituberculatus and to evaluate their impact on water quality and survival rate. Field surveys were carried out at the Hiroshima Prefecture Fish Farming Center from 1990 to 1993. Among nitrogenous compounds. concentrations of NH -N and particulate or...

The level of nitrogen leaching from organic compared to conventional farming was evaluated by using a systems modelling approach. Two different methods were used for estimating and evaluating nitrate leaching. A simple function was used in which nitrate leaching is dependent on percolation, soil clay content, average nitrogen input and crop sequence. A nitrogen balance model was used to estimat...

Pyrolysis oil, a complex mixture of several organic compounds, produced during flash pyrolysis of organic lignocellulosic material was evaluated for its suitability as alternative carbon source for fungal growth and fermentation processes. Therefore several fungi from all phyla were screened for their tolerance toward pyrolysis oil. Additionally Aspergillus oryzae and Rhizopus delemar, both est...

ABSTRACT- Energy use patterns and the contribution of energy input vary among farming systems. The optimal use of improved farm machinery coupled with the optimal use of other recommended sources permit an increase in paddy yield up to potential levels. In order to determine the effect of production systems on energy use efficiency focusing on mechanization for paddy production in Khuzestan pro...

This paper considers the potential problems that may militate against the adoption of organic poultry production in Nigeria. Factors identified include: higher risk of diseases like coccidiosis and Newcastle disease, disease prevention and control / herd health management, disease containment in times of outbreak, land acquisition (land tenure system), market economies / cost-benefit ratio, pas...

We determined the net rate of biogenic silica (bSiO2) production and estimated the diatom contribution to new production and organic matter export in the Costa Rica Dome during summer 2010. The shallow thermocline significantly reduces bSiO2 dissolution rates below the mixed layer, leading to significant enhancement of bSiO2 relative to organic matter (silicate-pump condition). This may explain...

The long-term burial of organic carbon in sediments results in the net accumulation of oxygen in the atmosphere, thereby mediating the redox state of the Earth's biosphere and atmosphere. Sediment microbial activity plays a major role in determining whether particulate organic carbon is recycled or buried. A diverse consortium of microorganisms that hydrolyze, ferment, and terminally oxidize or...