Effect of Different Factors on the Soil Quality of Typic Ustipsamments of State Kerala, in India

Aims: Assessment of soil quality of selected panchayaths of sandy plains (Typic Ustipsamments ) of Kerala based on various soil attributes and to work out soil quality index (SQI).

Study Design: A study was conducted in the selected panchayaths of sandy plains of Kerala (AEU 3) and 100 representative georeferenced surface soil samples were collected from various land uses. These soil samples were characterized for important physical, chemical, and biological properties.

Place and Duration of Study: Onattukara Regional Agricultural Research Station, Kayamkulam between April 2021 and May 2022.

Methodology: Hundred geo-referenced surface soil samples were collected from various land uses of selected panchayaths of sandy plains of Kerala and characterized for various physical (texture, bulk density, particle density, porosity, aggregate analysis, soil moisture, and WHC), chemical (pH, EC, organic carbon and available macro and micronutrients and biological attributes (acid phosphatase and dehydrogenase activity). Principal component analysis was used to set up the minimum data set of the indicators to compute the soil quality index. Seven principal components were extracted from which nine indicators that highly influenced the soil quality were identified. Scores and weights were assigned to each indicator, and they were aggregated to compute the soil quality index. The relative soil quality index of the soils was also found.

Results: Increased soil acidity and low levels of nutrients like nitrogen, potassium, magnesium, sulfur, and boron were noticed in these soils. The available P content of the soil was high. Mg, S, and B were deficient in 100 percent of the samples, whereas, Fe and Mn remained sufficient. Ca, Zn, and Cu exhibited 72.9, 24.3, and 21.7 percent deficiency, respectively. The majority of the soils belonged to medium soil quality (78.6 percent), followed by poor (12.8 percent) and good (8.6 percent) quality.

Conclusion: The majority of soils of selected panchayaths of sandy plains of Kerala fell into the medium soil quality class. However, there are several soil fertility issues in these soils. Hence site-specific and crop-specific management strategies have to be followed for the profitable cultivation of the crops and soil test-based fertilizer application has to be followed. It is mandatory to maintain the fertility of the soil for the sustainability of the environment.