Organic Carbon and Biological Properties of Soils in Various Agro-Ecological Units of Kerala, India

A study was carried out in four agro-ecological units (AEUs), viz., southern laterites (AEU 8), south central laterites (AEU 9), north central laterites (AEU 10), and the northern laterites (AEU 11) of Kerala, with the objective of detailing the soil fertility status of the study area and unveiling the relationship between organic carbon (OC) and various biological properties of soils, like population of phosphorus solubilizers and acid phosphatase activity, by following one-way analysis of variance (ANOVA). The findings of the study revealed that the average values of OC among the four AEUs varied from 0.63 to 0.82%, and remarkably, 98% of the collected soils displayed OC content ranging from 0.5 to 1.5%. The mean values for the population of phosphorus solubilizers ranged from 3.12 to 3.34 log cfu g-1 soil. The acid phosphatase activity also varied across the study area, with mean values ranging from 24.84 to 30.70 µg p-nitrophenol produced g-1 soil h-1, and most of the collected soils showed activity between 25 and 50 µg p-nitrophenol produced g-1 soil h-1. Implementation of effective soil management practices, in accordance with soil test results, is imperative for the preservation and enhancement of organic carbon levels through the incorporation of organic matter, such as compost and cover crops, while minimizing the excessive use of chemical fertilizers. This approach not only augments organic carbon content but also enhances the biological properties of soils, thereby improving soil fertility and overall soil health.

Physico-chemical Characterization of Biochar from Different Biomass Materials

Aim: To conduct the physico-chemical analysis of biochar derived from various organic residues, an examination of the physical characteristics including bulk density, water retention capacity, and the chemical properties such as pH, electrical conductivity, cation exchange capacity, total organic carbon, as well as the concentration of macro and micro nutrients were evaluated.Study Design: Experiment was conducted in completely randomized design with 7 treatments and 3 replications.Place and Duration of Study: The investigation was conducted at Integrated Farming System Research, Karamana, Kerala Agricultural University during 2021-2023.Methods: Organic residues from different sources were converted into biochar utilizing a double barrel Biochar Kiln, and subsequently, the biochars were analyzed in a Soil and Plant Analysis laboratory to determine their physical and chemical properties.Result: Physio-chemical properties of biochar vary significantly with the choice of feedstock material. Banana pseudostem biochar reported the lowest bulk density (0.21 Mg m-3) and highest water holding capacity (327.74%). All the biochar produced were alkaline in nature, and they contained high cation exchange capacity ranging between 9.34 to 14.10cmol (+) kg-1. Macro and micro nutrient contents were comparatively higher in Limnocharis flava biochar and Banana pseudostem biochar.Conclusion: Organic residues can be successfully converted to biochar and results obtained show the suitability of application of produced biochar as a soil amendment.