Soil Fertility Properties, Leaf Nutrient Status and Yield Of Coconut and Intercrops as Influenced and Coconut Based Cropping System in Coastal Plain of Western India

An experiment was conducted during 2013 -2019 to study the impact of intergrated nutrient management through organic matter recycling (OMR) on the soil properties, leaf nutrient status and yield of coconut and its components crops at Regional Coconut Research Station (AICRP on Palms), Bhatye, Maharashtra, India. The experiment was laid out in 0.40 ha with four treatments namely T1, T2, T3 and T4. Results showed that, INM practices significantly improved the soil physico-chemical, biological properties and leaf nutrient status, whereas it was more prominent for the T1 treatment. The soil organic carbon content during post experimental period gradually increased in the organic recyclable treatment under cropping system (0.80 to 0.86%) compared to monocropping (0.60%). The recyclable biomass produced from the system varied between 9.0 - 18.0 t/ha/year and vermicompost produced was 4.8 to 10.2 t/ha/year by composting through earthworm. The nut yield (147.2 and 138.4 nuts/palm), copra output (25.75 and 23.06 kg/palm) and oil output (17.11 and 15.72 kg/palm) under treatment T1 and T2 were on par and differed significantly compared to monocrop. Bangladesh J. Bot. 50(4): 1067-1075, 2021 (December)

Early Diagenesis in the Hypoxic and Acidified Zone of the Northern Gulf of Mexico: Is Organic Matter Recycling in Sediments Disconnected From the Water Column?

Hypoxia and associated acidification are growing concerns for ecosystems and biogeochemical cycles in the coastal zone. The northern Gulf of Mexico (nGoM) has experienced large seasonal hypoxia for decades linked to the eutrophication of the continental shelf fueled by the Mississippi River nutrient discharge. Sediments play a key role in maintaining hypoxic and acidified bottom waters, but this role is still not completely understood. In the summer 2017, when the surface area of the hypoxic zone in the nGoM was the largest ever recorded, we investigated four stations on the continental shelf differentially influenced by river inputs of the Mississippi-Atchafalaya River System and seasonal hypoxia. We investigated diagenetic processes under normoxic, hypoxic, and nearly anoxic bottom waters by coupling amperometric, potentiometric, and voltammetric microprofiling with high-resolution diffusive equilibrium in thin-films (DET) profiles and porewater analyses. In addition, we used a time-series of bottom-water dissolved oxygen from May to November 2017, which indicated intense O2 consumption in bottom waters related to organic carbon recycling. At the sediment-water interface (SWI), we found that oxygen consumption linked to organic matter recycling was large with diffusive oxygen uptake (DOU) of 8 and 14 mmol m–2 d–1, except when the oxygen concentration was near anoxia (5 mmol m–2 d–1). Except at the station located near the Mississippi river outlet, the downcore pore water sulfate concentration decrease was limited, with little increase in alkalinity, dissolved inorganic carbon (DIC), ammonium, and phosphate suggesting that low oxygen conditions did not promote anoxic diagenesis as anticipated. We attributed the low anoxic diagenesis intensity to a limitation in organic substrate supply, possibly linked to the reduction of bioturbation during the hypoxic spring and summer.

Going Underground

Termites are important soil engineers, responsible for decomposing organic matter, recycling nutrients, and creating habitats for other organisms. But some species cause damage, including several genera that attack cacao trees. These include termites belonging to the genera Macrotermes, Nasutitermes, Microcerotermes, Ancistrotermes, and Coptotermes. Some are mound-builders, while others construct carton nests of faeces and wood on tree trunks, or small dome-shaped mounds on trees. Twenty years ago, the termite Macrotermes bellicosus was not thought to damage cacao, but today, it is considered a major pest of the crop, responsible for significant damage to seedlings and even mature trees. This chapter examines termite biology and looks at how they damage cacao trees and what can be done to manage the problem.

Ocean acidification reduces growth and grazing impact of Antarctic heterotrophic nanoflagellates

High-latitude oceans have been identified as particularly vulnerable to ocean acidification if anthropogenic CO2 emissions continue. Marine microbes are an essential part of the marine food web and are a critical link in biogeochemical processes in the ocean, such as the cycling of nutrients and carbon. Despite this, the response of Antarctic marine microbial communities to ocean acidification is poorly understood. We investigated the effect of increasing fCO2 on the growth of heterotrophic nanoflagellates (HNFs), nano- and picophytoplankton, and prokaryotes (heterotrophic Bacteria and Archaea) in a natural coastal Antarctic marine microbial community from Prydz Bay, East Antarctica. At CO2 levels ≥634 µatm, HNF abundance was reduced, coinciding with increased abundance of picophytoplankton and prokaryotes. This increase in picophytoplankton and prokaryote abundance was likely due to a reduction in top-down control of grazing HNFs. Nanophytoplankton abundance was elevated in the 634 µatm treatment, suggesting that moderate increases in CO2 may stimulate growth. The taxonomic and morphological differences in CO2 tolerance we observed are likely to favour dominance of microbial communities by prokaryotes, nanophytoplankton, and picophytoplankton. Such changes in predator–prey interactions with ocean acidification could have a significant effect on the food web and biogeochemistry in the Southern Ocean, intensifying organic-matter recycling in surface waters; reducing vertical carbon flux; and reducing the quality, quantity, and availability of food for higher trophic levels.

Ocean acidification reduces growth and grazing of Antarctic heterotrophic nanoflagellates

High-latitude oceans have been identified as particularly vulnerable to ocean acidification if anthropogenic CO2 emissions continue. Marine microbes are an essential part of the marine food web and are a critical link in biogeochemical processes in the ocean, such as the cycling of nutrients and carbon. Despite this, the response of Antarctic marine microbial communities to ocean acidification is poorly understood. We investigated the effect of increasing fCO2 on the growth of heterotrophic nanoflagellates (HNF), nano- and picophytoplankton, and prokaryotes in a natural coastal Antarctic marine microbial community from Prydz Bay, East Antarctica. At CO2 levels ≥ 634 μatm, HNF abundance was reduced, coinciding with significantly increased abundance of picophytoplankton and prokaryotes. This increase in picophytoplankton and prokaryote abundance was likely due to a reduction in top-down control of grazing HNF. Nanophytoplankton abundance was significantly elevated in the 634 and 953 μatm treatments, suggesting that moderate increases in CO2 may stimulate growth. Changes in predator-prey interactions with ocean acidification could have a significant effect on the food web and biogeochemistry in the Southern Ocean. Based on these results, it is likely that the phytoplankton community composition in these waters will shift to communities dominated by prokaryotes, nano- and picophytoplankton. This may intensify organic matter recycling in surface waters, leading to a decline in carbon flux, as well as a reducing the quality and quantity of food available to higher trophic organisms.

Recycling of domestic organic waste with the use of composting and vermicomposting

The increase of the world population associated to the concentration of this population in urbanized environments has caused the growth of the production of residues of organic solids, that in most of the times are discarded in inadequate places that can pollute the environment. Another factor that is also related to population growth is the demand for more food, mainly agricultural products, which need different inputs, such as fertilizers to increase productivity. Given this context, it is essential to use technologies that allow the recycling of nutrients from organic waste, which have the potential to condition soils and fertilize agricultural crops. This work has the objective of evaluating two already consolidated technologies for recycling solid organic waste, such as composting and vermicomposting, implanted in compact systems. Among these feasible systems were evaluated the humic compounds and the slurries generated, the parameters being evaluated the assimilable phosphorus (P), the active acidity, organic matter and the organic carbon. The results obtained indicate that the vermicompost presents a higher production of humic compound and less of slurry in relation to the composting process, and that the humic compound produced in the composting process and the slurry produced by the vermicompost process have higher P indices, organic and organic carbon, in relation to their corresponding, and the acidity index was practically the same for the slurries and humic compounds produced in both organic matter recycling processes.