Improvement of Physical and Biological Quality of Soil in a Sugarcane Plantation through the Management of Organic Matter Input

Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicator. This research aimed to study the effect of the addition of various quality and quantity of organic matter on soil biology （earthworms） and physical quality （aggregate stability, macroporosity and infiltration rate）. There were i 5 treatment combinations tested. The first factor is the type of organic matter： （1） cattle manure （CM）, （2） filter cake （FC）, （3） sugarcane trash （ST）, （4） a mixture ofCM ＋ FC and （5） a mixture of CM ＋ ST. The second factor is the application dose of organic matter, which consists of three levels-5, l0 and 15 Mg/ha. The treatments were arranged in a factorial randomized block design with three replicates and one control treatment （without organic matter input）. The result of this research showed that the highest population density of earthworms was found in the treatment of ST （78 individuals/m2） and a mixture of CM ＋ ST （84 individuals/m2）. The type of organic matter with C/N ratio ranged from 15.5 to 34.7 and cellulose content in 33.3%-40.1% gave better growth of earthworm. The effect of increase in earthworm growth on soil physical improvement is more apparent in the treatment of mixture of low quality and high quality organic matter. The increase of earthworm density and biomass enhanced soil macroporosity （from r = 0.683 to r = 0.606） and infiltration rate （from r = 0.669 to r = 0.756）. The results of this study suggest a mixture of CM ＋ ST or ST alone as organic matters, which is recommended to improve soil physical and biological quality of sugarcane land, with the dose application ranged from 10 Mg/ha to 15 Mg/ha.

Assessment of Soil Quality Using Microarthropod Communities Under Different Land System： A Case Study in the Mid-Hills of Central Nepal

The study aimed to evaluate soil quality using microarthopods density, diversity and soil biological quality index （QBS-ar） under different land use systems and elevation gradients. A secondary aim was to determine the relationship among soil biological and physiochemical indicators. Three groups of soil microarthropods were recognized viz. （1） Collembola （38%） （2） Acarina （33%） and （3） other microarthropods （29%）. ANOVA indicated that total microarthropods densities differed significantly with land use and elevation. Population density of Acarina and other mieroarthropods were weakly significant different according to land use, while Collembola and Acarina densities showed highly significant difference with elevation. Total microarthropods, Acarina and Collembola densities were positively significantly correlated with soil organic carbon （SOC） and moisture but negatively correlated with bulk density, pH and temperature of the soil. SOC and soil moisture appeared to be good indicators of soil quality as reflected by the higher density and diversity of soil total microarthropods, Collembola, Acarina and other microarthropods group. The use of microarthropods for soil quality assessment could be effective and relatively inexpensive tool; however, further research is required to evaluate the impact of agricultural practices and elevation gradient on soil microarthropods density, diversity and species composition for the sustainable management of agro ecosystems.

Research of Primary Agricultural Mechanization in Developing Countries

For providing a correct and reasonable strategy to develop agricultural mechanization in developing countries, this paper took China as the representative to analyze the poor agricultural equipment service condition. It also put forward the ecology and social crisis brought out by the long-term and large-scale primary mechanization. According to the characteristics of national condition, this paper brought forward several certain policies and solutions, such as compelling to shorten the continuance cycle of traditional primary stage, seeking for new economic growth poles of high-added-value agricultural production by fully using the abundant labor force, etc. It is a feasible technical program to develop harmonious agricultural modernization in developing countries