Kiran Reddy, V Govardhan and K L Sharma
Posters: Agrotechnol
This study was conducted with an objective to identify the key indicators of soil quality and to study Soil Quality Indices (SQI) under different moisture regimes in NSLBC (LBC) of Nalgonda district of Andhra Pradesh. Soils are degrading due to several physical, chemical and biological constraints. Appropriate soil moisture regimes may help to check further soil degradation. This study was conducted in 2011 with six different soil moisture regimes of command and adjacent upland areas: command area-head reach, middle reach, tailend and upland area - having assured irrigation, protective irrigation and rainfed. Sixty soil samples, ten each from each moisture regime were collected from six different moisture regimes and were analyzed for physical, chemical and biological parameters. A standard methodology using principal component analysis (PCA) and linear scoring technique (LST) was adopted to identify the key indicators and for computation of soil quality indices. Among six moisture regimes, the soil quality index (SQI) ranged from 0.848 to0.945. The highest SQI was obtained in assured irrigation (0.945) followed by tail end (0.927) = protective irrigation (0.927), rainfed (0.897), head reach (0.889) while the lowest was under middle reach (0.848). The key indicators, which contributed considerably towards SQI, were bulk density, water holding capacity, organic carbon, dehydrogenase activity, available N, available Mn, ESP, available P, available K, pH and exchangeable Mg. On and average, the order of relative contribution of these indicators towards SQI was: bulk density (31.46%) > water holding capacity (24.96%) > available N (8.87%) > organic carbon (7.33%) > dehydrogenase activity (7.14%) > available Mn (6.98%) > pH (4.91%) > K (3.73%) > available P (3.60%) > exchangeable Mg (1.70) > ESP (1.03%).