The World Health Organization (WHO) states that in developing nations, there are three million cases of agrochemical poisoning. The prolonged intensive and indiscriminate use of agrochemicals adversely affected the soil biodiversity, agricultural sustainability, and food safety, bringing in long-term harmful effects on nutritional security, human and animal health. Most of the agrochemicals negatively affect soil microbial functions and biochemical processes. The alteration in diversity and composition of the beneficial microbial community can be unfavorable to plant growth and development either by reducing nutrient availability or by increasing disease incidence. Currently, there is a need for qualitative, innovative, and demand-driven research in soil science, especially in developing countries for facilitating of high-quality eco-friendly research by creating a conducive and trustworthy work atmosphere, thereby rewarding productivity and merits. Hence, we reviewed (1) the impact of various agrochemicals on the soil microbial diversity and environment; (2) the importance of smallholder farmers for sustainable crop protection and enhancement solutions, and (3) management strategies that serve the scientific community, policymakers, and land managers in integrating soil enhancement and sustainability practices in smallholder farming households. The current review provides an improved understanding of agricultural soil management for food and nutritional security.
The fate, properties and determination of microplastics (MPs) and nanoplastics (NPs) in soil are poorly known. In fact, most of the 300 million tons of plastics produced each year ends up in the environment and the soil acts as a log-term sink for these plastic debris. Therefore, the aim of this review is to discuss MP and NP pollution in soil as well as highlighting the knowledge gaps that are mainly related to the complexity of the soil ecosystem. The fate of MPs and NPs in soil is strongly determined by physical properties of plastics, whereas negligible effect is exerted by their chemical structures. The degradative processes of plastic, termed ageing, besides generating micro-and nano-size debris, can induce marked changes in their chemical and physical properties with relevant effects on their reactivity. Further, these processes could cause the release of toxic oligomeric and monomeric constituents from plastics, as well as toxic additives, which may enter in the food chain, representing a possible hazard to human health and potentially affecting the fauna and flora in the environment. In relation to their persistence in soil, the list of soil-inhabiting, plastic-eating bacteria, fungi and insect is increasing daily. One of the main ecological functions attributable to MPs is related to their function as vectors for microorganisms through the soil. However, the main ecological effect of NPs (limited to the fraction size < than 50 nm) is their capacity to pass through the membrane of both prokaryotic and eukaryotic cells. Soil biota, particularly earthworms and collembola, can be both MPs and NPs carriers through soil profile. The use of molecular techniques, especially omics approaches, can gain insights into the effects of MPs and NPs on composition and activity of microbial communities inhabiting the soil and into those living on MPs surface and in the gut of the soil plastic-ingesting fauna.
A majority of biochemical reactions are often catalysed by different types of enzymes. Adsorption of the enzyme is an imperative phenomenon, which protects it from physical or chemical degradation resulting in enzyme reserve in soil. This article summarizes some of the key results from previous studies and provides information about how enzymes are adsorbed on the surface of the soil solid phase and how different factors affect enzymatic activity in soil. Many studies have been done separately on the soil enzymatic activity and adsorption of enzymes on solid surfaces. However, only a few studies discuss enzyme adsorption on soil perspective; hence, we attempted to facilitate the process of enzyme adsorption specifically on soil surfaces. This review is remarkably unmatched, as we have thoroughly reviewed the relevant publications related to protein adsorption and enzymatic activity. Also, the article focuses on two important aspects, adsorption of enzymes and factors limiting the activity of adsorbed enzyme, together in one paper. The first part of this review comprehensively lays emphasis on different interactions between enzymes and the soil solid phase and the kinetics of enzyme adsorption. In the second part, we encircle various factors affecting the enzymatic activity of the adsorbed enzyme in soil.
Over centuries and even today, traditional farming practices are well performed without any ecological degradation. However, management practice such as conservative tillage combined with nutrient and residue could increase the crop production as well as soil fertility. A three-year replicated study was conducted to assess the effects of agronomic modification of traditional farming practices on productivity and sustainability of rice (wet season)–rice (dry season) system (RRS). The replacement of farmers practice (T2) with conservation effective tillage (no-till (NT)) and integrated nutrient management (INM) practice along with 30% residue retention (T5) enhanced the straw, root and biomass yield of both wet season rice (WR), dry season rice (DR) and system as a whole over T2. Treatment T5 recorded significantly lower soil bulk density (ρb) and higher pH than the T2 after three years of the experiment. Further, treatment T5 increased total soil organic carbon (2.8%), total soil organic carbon stock (2.8%), carbon sequestration rate (336.5 kg ha−1 year−1), cumulative carbon stock (142.9%) and carbon retention efficiency (141.0%) over T2 of 0–20 cm depth after three year. The soil microbial biomass carbon concentration was significantly the highest under T5. Similarly, the dehydrogenase activity was the maximum under T5. Adoption of conservation tillage and nutrient management practice involving NT and INM along with residue retention can enhance the system productivity, and C and N sequestration in paddy soils is thereby contributing to the sustainability of the RRS.