Processes that influence dissolved organic matter in the soil: a review

Abstract

In tropical regions, climate conditions favor fast decomposition of soil organic matter (SOM), releasing into the soil organic composts in solid, liquid, and gaseous forms with variable compositions. Dissolved organic matter (DOM), a complex mixture of thousands of organic compounds, is only a small fraction of the decomposition products; however, it is highly mobile and reactive to the soil. Therefore, DOM play a key role in soil aggregation (formation of organometallic complexes), energy source for microorganisms, as well as C storage, cycling, and provision of plant-available nutrients. DOM multifunctionality to sustain soil functions and important ecosystem services have raised global scientific interest in studies on DOM fractions. However, previous studies were conducted predominantly under temperate soil conditions in natural ecosystems. Therefore, there is paucity of information on tropical soil conditions under agricultural systems, where DOM turnover is intensified by management practices. This review synthesized information in the literature to identify and discuss the main sources, transformations, and future of DOM in soils. We also discussed the importance of this fraction in C cycling and other soil properties and processes, emphasizing agricultural systems in tropical soils. Gaps and opportunities were identified to guide future studies on DOM in tropical soils.

The Effects of Combining Farm Yard Manure, Starter Nitrogen, Phosphorus and Zinc on Growth and Yield of Green Grams

“…The significant increase in green gram plant height and number of leaves by zinc + manure treatment can be attributed to the combined effects of organic matter and zinc on the soil environment, nutrient availability and resulting uptake efficiency. Manure is important in modification of soil physical, chemical and biological properties leading to improved moisture holding capacity, nutrient holding capacity, soil temperature regulation, improved germination and root penetration [2,4,5,6,9,36]. Improvement of all this factors ensures adequate nutrient availability for plant uptake leading to improved crop growth [5,36].…”

“…Manure is important in modification of soil physical, chemical and biological properties leading to improved moisture holding capacity, nutrient holding capacity, soil temperature regulation, improved germination and root penetration [2,4,5,6,9,36]. Improvement of all this factors ensures adequate nutrient availability for plant uptake leading to improved crop growth [5,36]. Zinc on the other hand plays an important role in plant protein synthesis by nitrogen uptake; photosynthesis by carbon anhydrase activity and synthesis of chlorophyll; resistance against abiotic and biotic stresses such as oxidative damage resistance and pathogens among others [22,37].…”

Genetic and Metabolic Diversity of Soil Microbiome in Response to Exogenous Organic Matter Amendments

“…SOM consists of all organic substances originating from living organisms in different phases of decomposition. The sources of organic matter in soil are mainly the dead parts of plants and animals, microorganisms and metabolites produced during their growth and decomposition, as well as humic compounds [1]. Microorganisms play a crucial role in the decomposition of organic matter and the global cycle of elements, and they are involved in the breakdown of complex organic compounds into compounds, which are simple and more easily absorbed by plants.…”

Solid Waste: Its Implication for Health and Risk of Vector Borne Diseases

“…In tropical regions, climate conditions favour fast decomposition of soil organic matter (SOM), releasing into the soil organic composts in solid, liquid, and gaseous forms with variable compositions. Dissolved organic matter (DOM), a complex mixture of thousands of organic compounds, is only a small fraction of the decomposition products; however, it is highly mobile and reactive to the soil [8]. The group at risk from the unhygienic disposal of solid waste include the population in areas where there is no proper waste disposal method, especially the waste workers and workers in facilities producing toxic, and infectious material [5].…”