Comparison of biomass production, tree allometry and nutrient use efficiency of multipurpose trees grown in woodlot and silvopastoral experiments in Kerala, India

In woodlot and silvopasture experiments involving a total of three age-sequences, the rates of biomass accumulation and nutrient accumulation by multipurpose trees were evaluated. The woodlot experiment included nine multipurpose trees (Acacia auriculiformis, Ailanthus triphysa, Artocarpus heterophyllus, Artocarpus hirsutus, Casuarina equisetifolia, Emblica officinalis, Leucaena leucocephala cv. K8, Paraserianthes falcataria and Pterocarpus marsupium) and the silvopastoral experiment involved a subset of four trees (Acacia auriculiformis, Ailanthus triphysa, Casuarina equisetifolia and Leucaena leucocephala cv. K8). Both plantings were maintained at Thiruvazhamkunnu, Kerala, India. Trees in the woodlot experiment were felled (partially) at 8.8 years of age and that of the silvopastoral experiment both at 5 years and 7 years of age. Rate of biomass accumulation and nutrient accumulation was highest for Acacia and the least for Leucaena. Allometric relationships linking above ground biomass with DBH and/or total height gave reasonable predictions. A comparison between species and among tissue types within species indicated that nutrient use efficiency for N, P and K varied widely. Implications for nutrient export from the site through whole tree harvesting systems involving fast growing multipurpose tree species are discussed

Climate Dynamics over Kerala, India: Insight from a Century-long Temperature and Rainfall Data Analysis

Historical climate data analysis is of great significance in climate change adaptation and mitigation planning at global as well as regional levels. This article attempted to study the long-term trends of temperature and rainfall across the districts in Kerala, India. CRU monthly time series data of rainfall and temperature data spanning from 1901-2022 were used for the analysis. Mann-Kendall test and Sen’s Slop estimator were applied to detect the presence and magnitude of the trend, and Pettitt’s homogeneity test was used to find the climate change point in temperature time series data. The analysis found a significant and positive temperature trend across all districts in Kerala, with temperature increases ranging from 0.0086°C/year to 0.0102°C/year. In terms of rainfall trends, June and January experienced a significant decrease, while July and September saw a significant increase over the years. The year 1976 was identified as the point of climate change. It was observed that there was an increase in the southwest and Northeast monsoons in the post-period, with higher variability in the latter. Winter rainfall notably decreased during the post-period. The variability in climate parameters identified in this study could impact crop cycles and agricultural productivity, requiring further investigation at a micro-level for effective adaptation and mitigation strategies for the state

Fenóis derivados da lignina, carboidratos e aminoaçúcares em serapilheira e solos cultivados com eucalipto e pastagem

O cultivo de espécies florestais como o eucalipto em solos ocupados por pastagens pode levar a alterações no processo de decomposição de resíduos vegetais e na formação da matéria orgânica do solo (MOS), principalmente por alterar a contribuição de diferentes compostos orgânicos e modificar a atividade e a diversidade microbiana. Neste sentido, o presente estudo teve o objetivo de avaliar alterações causadas pelo cultivo do eucalipto em compostos orgânicos, tais como: fenóis derivados de lignina, carboidratos e aminoaçúcares, visando identificar o estádio de decomposição e a contribuição de compostos de origem microbiana para a MOS em solos do litoral Norte do Espírito Santo em comparação àqueles de pastagem. Os resultados indicaram menor aporte de carboidratos e teor de lignina similar na serapilheira de eucalipto em comparação àqueles da pastagem. Os fenóis derivados de lignina, que se caracterizaram pela presença de compostos do grupo cinamil (ácidos ferúlico e p-coumárico) em maior teor, refletiram em maior acúmulo destes compostos e carboidratos totais no solo de pastagem, embora os teores totais de lignina, COT, NT e aminoaçúcares tenham sido semelhantes entre os cultivos. Nos solos cultivados com eucalipto obteve-se maior contribuição de componentes de origem vegetal (menor relação H/P) para a MOS que aqueles de origem microbiana em comparação aos solos sob pastagem. O teor de determinados aminoaçúcares, como a glucosamina, nos solos indicou que os fungos são mais abundantes que bactérias e actinomicetos, especialmente no solo de pastagem