Effects tillage system, fertilization and crop protection practices on Literature review

Effects tillage system, fertilization and crop protection practices on soil quality parameters - Literature review Example It participates in the C, N, P and S transformations and plays a significant task in the decomposition of xenobiotic organic compounds and the formation of the soil structure. Microbial biomass, C and N and their ratios to the total and light fraction C and N and pools in soils of the organic systems are higher in organic systems than in conventional systems due to the enhanced decomposition of the easily available pool of soil organic matter (SOM) with increasing microbial biomass levels. The higher levels of light fraction organic matter in organically managed soils are from plant residues and manure. The higher microbial biomass in organically managed soils indicates higher quality soil organic matter responsible to nutrient mineralization and short term storage of potentially leachable nutrients indicating comparative advantage of organically managed systems over conventional ones. ... Microbial biomass specific respiration gives the status of the substrate quality and availability in the soil (Insam et al., 1996). Microbial biomass is also used to check the improvement of degraded soils over time and serves as an early indicator of changes in the total organic matter in the soil. Long term cultivation leads to decreased levels of microbial biomass due to dwindled levels of microbial activity and soil organic C pools (Kocyigit, 2008). Higher levels of microbial biomass decrease specific respiration of micro organism, which shows that micro organisms living in low quality soils respond by increasing their specific respiration. 1.1.2 Soil Basal Respiration (SBR) Soil basal respiration is the constant rate of respiration in the soil caused by changes in organic matter levels. The rate of basal respiration in the soil indicates the amount and quality of the carbon source. Basal respiration can be used to analyze the potential of the soil biota to decompose both indigen ous and antropogenically introduced (Bloem et al., 2006). Soil respiration is a key process for carbon flux to the atmosphere. Soil water content, o2 concentration and the bioavailability of carbon are the main factors that regulate soil respiration (Bloem et al., 2006). Soil basal respiration indicates the level of microbial activity in the soil and is positively correlated with biomass activity. It involves the aerobic and anaerobic energy yielding processes where the reduced organic and inorganic compounds are utilized by microbial cells and serve as primary electron donors and oxidized compounds serve as terminal electron acceptors (Bloem et al., 2006). Processes in the soil such as fermentation and abiotic processes release co2. Water is