摘要：Improvement in food security and environmental preservation should be the major concern of innovators of farming system. Huge global population with high consumption of food, water, and other agricultural products are putting pressure on agricultural sector, and thus has replaced traditional practices of agriculture with advanced technologies. Conventional agriculture focuses on advancing the agriculture technologies for increasing the potential yield of crop. Conventional agriculture cannot fulfill the needs of 7 billion human populations without destroying the integrity of soil environment. Consequently, loss of carbon from soil as soil carbon (C) is a major constituent of global carbon cycle and its management can affect atmospheric carbon dioxide concentration. Soil carbon has also been recognized as carbon sink for sequestering the atmospheric CO2. Carbon dioxide is main emitter among the greenhouse gases by agriculture in the global food web. Soils of the arable land are mainly depleted of the soil organic carbon (SOC) and the threshold level of SOC is 1.5-2% at root zone. For sustainable agricultural productivity and stable environment, it is necessary to build up the soil carbon contents by increasing carbon inputs, or decreasing decomposition of organic matter in soil. While, soil carbon can also be improved by adapting the conservation agriculture practices like no tillage, intensifying crop rotation and by optimizing the agronomic practices like fertilizer, pesticides and irrigation etc. Therefore, conservation agriculture could also play major role in reducing C emission from the agricultural sector. This paper represents the status and relationship of C contents in soil and atmosphere and elaborates the effect of climatic factor, burning of crop residues, biofertilizer and microbial activity on soil organic carbon. The review also focuses on issues related to low soil C contents and how to conserve the soil carbon through conservation agriculture practices.
关键词：Soil carbon;conservation agriculture;fertilizer;tillage;biofertilizer;microbial activity;greenhouse gases;cropping system
