Soil organic carbon maintenance

Non-isotopic and 13C Isotopic Approaches to Calculate Soil Organic Carbon Maintenance Requirement... 

SOC NHC NHCa NHC m "initial socM Soil organic carbon Non-harvested crop residues Amount of non-harvested carbon applied Non-harvested carbon maintenance requirement Soil organic carbon at the beginning of the experiment Soil organic carbon contained in soil at the end of the Experiment... 

Declining amounts of arable land, increasing world populations, and increasing costs of fertilizer and food and energy needs will make it increasingly difficult to maintain our soil resources. A key component for sustaining soil productivity is the maintenance of soil organic carbon (SOC). SOC maintenance requires the amount of carbon added to the system to equal the amount of relic carbon mineralized... 

Liming an acidic lake is similar to the process many people use to maintain a pH balance in their soil for lawn maintenance. Plants have an optimum pH range in which they strive. Acidic conditions often develop in soils for several reasons. Rain tends to leach away basic ions, weak organic acids develop from the carbon dioxide produced by decaying organic matter, and strong acids, such as nitric acid, can form when ammonium fertilizers oxidize. To neutralize these acids, different forms of lime such as quicklime, CaO, and slaked lime, Ca(OH)2, are used to neutralize the acid and increase the pH of the soil. Table 13.9 shows how much fertilizer is wasted when applied to... 

The characteristics and merits of organic materials that are commonly used as humus sources in agriculture are discussed below. These include crop residues that never leave the soil, portions of plants that are removed and returned, outside carbon sources, and crops that are incorporated into soil for soil improvement. These humus sources are not of equal value per unit of carbon, and maximum benefits are realized only by varying the methods of use to fit the individual soil and cropping system. These benefits may include not only the maintenance or build-up of soil organic matter but also better tilth, increased water use efficiency, improved nutrient status of the soil, increased buffer and exchange capacity, and erosion control. 

---