Browsing by Author "Herath, H. M. I. K."

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Potential of potassium polyacrylate polymer and shrimp pond sludge for enhancing water retention capacity of sandy regosols
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Wijayasinghe, W. A. K. P.; Herath, H. M. I. K.
Water retention in soil is vital for the uninterrupted supply of essential nutrients to the plants. Materials that enhance moisture retention in soil are becoming scarce with the present climate change. Sandy regosols is a highly permeable soil type with less water retention capacity (WCR). This study attempts to evaluate the amendment of shrimp pond sludge (SPS) which is a waste material, and potassium polyacrylate which is a super absorbent polymer (SAP) on the water retention capacity of sandy regosols. The treatments were T1 – Control with no added amendments, T2 – Soil with SAP applied at the rate of 0.2 %, T3 – Soil with SAP applied at the rate of 0.4 %, T4 – Soil with SPS applied at the rate of 10 %, T5 – Soil with SPS applied at the rate of 20 %. All the treatments each with three replicates were arranged in a completely randomized design. The WRC was evaluated on a weight gain basis. A microbial growth assay was done to evaluate the effect of these amendments on soil microorganisms. Analysis of variance (ANOVA) was used to analyze the data using R statistical software (version 3.2.4). Initial analysis of soil indicated the organic matter content of this soil is as low as 0.3% which indicates an extremely poor contribution from organic matter content for its WRC and the Initial WRC was 28.9%. Significantly high WRC was shown in 0.4% of SAP amended soil throughout the experiment, while the lowest was shown in the control. The WRC of the treatment of SAP added at the rate of 0.4% soil has been increased to a level of 36.12% which was a 29% increment compared to the control. WRC of the shrimp pond sludge added treatment has been increased by 8% compared to control. There was no significant difference in the microbial population of SAP and SPS amended soils. The results indicate the potential of using SAP and SPS to enhance the water retention capacity in soil
Quantifying the environmental impact on coconut cultivation in the low country intermediate zone of Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Hansamali, H. M. T. N.; Herath, H. M. I. K.
Among the critical environmental impacts, the effect on climate change in terms of carbon dioxide emission and the impact on water resources in terms of net water recharge are of paramount importance. Environmental impact indicators provide information to comprehend the extent of the impact on the environment. Eco-verification of agricultural production using environmental indicators is important for understanding its sustainability and to claim premium prices for agricultural products. Among the plantation crops grown in Sri Lanka, coconut is the most widely grown crop with strong social, cultural, and economic ties to the Sri Lankan people. The present study attempts to quantify the environmental impact of coconut cultivations in the low country intermediate zone in Sri Lanka. The impact was objectively evaluated using Combined Environmental Impact Indicator (CEII) which consists of two indices, i.e. Carbon Sequestration Index (CSI) and Water Recharge Potential (WRP). CSI was calculated by determining the total carbon sequestration and dividing it by the total carbon emission by the plantation. Total carbon sequestration of coconut plantations in the intermediate zone was 26.39t C ha-1yr-1. Based on previous findings, the average total carbon emission of coconut plantations has been calculated to be 0.1176t C ha-1yr-1 in the intermediate zone. Therefore, the CSI was calculated as 224.24 and the scale score was 3 for CSI, which indicates a significant positive impact in terms of carbon sequestration. (CSI<0 scored as -2; significant negative impact, 0