Soil degradation due to heavy metal accumulation under long term fertilization of paddy (Oryza sativa L.)

Long term fertility experiment (LTFE) under double rice cropping system was investigated in Tamil Nadu Rice Research Institute, Aduthurai, India with two varieties (ADT 43 and ADT 45) in two seasons (Kharif and Rabi) under six fertilizer treatments to study the heavy metal accumulation in soil and its impact on paddy. There was a significant variation in physico-chemical properties of soil due to different fertilizer treatments. The surface soil (0-15cm soil depth) in all the treatments showed relatively higher heavy metal accumulation than subsurface. In thelong run, there was a build up in the total heavy metal content in soil and it was found to be relatively high in phosphatic fertilizer applied treatments than others. Total Cd and Pb was found high, but the availability was below detectable limit indicated that Cd and Pb were found in unavailable forms, while Cu and Zn were slightly in mobile forms which had been translocated into grain and straw of paddy. The DTPA (Diphenyl Triamine Penta Aceticacid) extractable Cd and Pb in the soil was low, but there was heavy increase in Cu and Zn comparing with initial period. The rate of increase in Cd and Pb content was lower in N alone and control plots. This might be due to the long term application of phosphotic and zinc sulphate fertilizers. Cd and Pb were evenly distributed at low concentrations in grain and straw under various treatments. In case of Cu and Zn, it was relatively higher in grains and paddy strawamong various fertilizer treatments. There was no significant difference among the varietal (seasons) treatments for the accumulation of heavy metals in grain and straw

Utilization of flower waste for the removal of chromium from tannery effluent

In this work we used flower waste biomass as a biosorbent to remove Cr from tannery effluent through column experiments. The sorption capacities of biosorbent (Fine, coarse and rough grades) were also evaluated by employing chemical pretreatments viz., sodium hydroxide, acetic acid, glutaraldehyde and hydrogen peroxide. The order of percentage removal of Cr using the above pretreatments was: 10% hydrogen peroxide < Raw powdered-FWB < 2% Gluteraldehyde < 10% Acetic acid < 0.1N sodium hydroxide. Among the different grades of biosorbents used, fine grade adsorbed more Cr (70 %) than that of coarse (64%) and rough (62 %) sorbents. The removal percentage of Cr from tannery was analyzed by using Atomic Absorption Spectroscopy, the functional groups which are responsible for adsorption was examined by Fourier Transform- Infrared Spectroscopy and the amorphous behaviour of FWB facilitating metal biosorption was indicated by the X-ray diffractogram. This study showed that pretreated flower waste biomass is a potential sorbent of Cr, which could be successfully used to reduce the Cr content in tannery effluent

Evaluation of localization of lead and nickel in plant cells of Amaranthus sp. and Brassica sp. absorbed from mine spoil waste

A detailed survey was undertaken in the sewage water contaminated areas of Coimbatore to select the natural hyper accumulators to rehabilitate the contaminated mine spoils. From this experiment the Pb and Ni accumulators, Amaranthus sp. and Brassica sp. were selected for further studies towards remediating the metal contaminated mine spoils. Microtomy of root, stem and leaf of Amaranthus sp. and Brassica sp. showed that the colour development in the plant species is evidence for accumulation of metals in different parts of plants and also tolerance mechanism employed by plant species under metal stress condition. The accumulation of heavy metals from soil to plant did not follow any particular pattern and varied with respect to metals, species and plant parts. However, the maximum Pb localization took place in root portion than in aerial parts. But the Ni accumulation was almost equal or higher in aerial parts (leaf and stem) compared to roots. This study revealed that the Amaranthus sp and Brassica sp stored lead and nickel in roots, leaves and stems. The roots showed more localization of metals followed by leaves and stems

Nutrient nexus: Linking soil, plants, animals and humans

The complex interrelationships between soil, plants, animals, and humans form the nutrient nexus, where the health and well-being of each component are intricately linked. This article comprehensively explores the dynamics of nutrients through this continuum, emphasizing the vital role of nutrient management in ensuring food security, sustainable agriculture, and a balanced ecosystem. It delves into the importance of nutrients at various levels, investigating case studies that illustrate the correlation between soil nutrient availability, plant uptake, animal nutrition, and human health. The article also examines government initiatives, nutrient management practices, and strategies like dietary diversification, biofortification, food fortification, and supplementation to combat nutrient deficiencies. The integration of traditional knowledge with modern scientific advancements advocates for a holistic approach to nutrient management, considering local resources, cultural practices, and environmental conditions. Ultimately, the article highlights the necessity of efficient nutrient management not only for ensuring food security but also for preserving the delicate balance of our planet's ecosystems for future generations

Sustainable maize production through organic amendments: Evaluating growth performance and environmental impact

The current study investigates the impact of organic and inorganic fertilizers on maize (Zea mays L.) growth and greenhouse gas (GHG) emissions. Organic amendments such as farmyard manure (FYM) and composted press mud, as well as inorganic fertilizers, were applied across various treatments to evaluate their effects on plant height, leaf production, chlorophyll content (SPAD values), leaf area index (LAI) and GHG emissions and carbon dioxide (CO?). The experiment was conducted for one crop season (September to December 2023) using a Factorial Randomized Block Design (FRBD) in Tamil Nadu, with static chamber methods employed to measure GHG emissions. The results demonstrated that treatments involving organic inputs significantly enhanced maize growth compared to inorganic fertilizers. N9 (T3 + 5 t Composted Pressmud) consistently recorded the highest plant height, leaf count and LAI, while the control (T1) had the lowest values. Organic amendments also showed reduced GHG emissions under rain-saturated conditions, although methane emissions were higher due to the anaerobic decomposition of organic matter. The study concludes that integrating organic fertilizers improves soil health and crop productivity while reducing GHG emissions, but careful management is needed to mitigate methane emissions in wet conditions. These findings support the adoption of organic inputs as part of sustainable agricultural practices to enhance productivity and environmental outcomes

Unveiling the rhizosphere microbial community of castor plant (Ricinus communis L.) grown in textile effluent contaminated ecosystem and assessing its phylogenetic traits for plant growth promotion

Various factors influence the microbial community in the plant rhizosphere, including the variety, activity, and population structure. Plant species and soil type are critical determinants of the composition and diversity of the microbial communities linked to plant roots. Understanding these interactions is crucial for enhancing plant development and soil vitality, especially under adverse conditions such as salt-affected soils. This study evaluated the structure and composition of rhizosphere microbial communities in response to castor plant (Ricinus communis L.), a crop known for its resilience to various soil conditions. The bacterial community in the castor rhizosphere was examined by 16S rDNA sequencing in conjunction with an assessment of various plant growth-promoting (PGP) characteristics of the isolated bacterial strains. These findings indicated that the rhizosphere bacterial community was primarily comprised of Bacillus species, which are essential plant growth-promoting rhizobacteria (PGPR). These bacteria exhibit considerable potential to augment nutrient absorption, strengthen stress resilience, and promot overall plant vitality. Their supremacy underscores their adaptability and functional significance in castor root systems, particularly under diverse soil conditions. This study elucidates the microbial dynamics of the castor rhizosphere, highlighting the crucial role of Bacillus species in enhancing plant growth and soil fertility. These findings indicate that Bacillus-dominated microbial communities can be efficiently utilized for sustainable agriculture and soil remediation initiatives

Cassava intercropping systems for enhanced land productivity and farmer livelihoods: A review

Cassava is a tropical root vegetable from the Euphorbiaceae family, commonly cultivated for its starchy roots. It serves as a significant source of carbohydrates and calories, especially in Africa, where it contributes to more than 65 % of the global cassava production. Due to its long growth duration, broad spacing requirements, and slow early–stage development, this crop presents an opportunity for interplanting with short–duration species, thereby enhancing resource utilisation, land–use efficiency and overall biological productivity. Cassava–based intercropping is widely practised in tropical regions with moderate to high humidity. Intercropping offers several advantages, including enhanced pest control, improved soil health and more effective weed management. Growing cassava alongside short–term crops, such as maize or legumes, can enhance resource utilisation, increase yields and improve the efficiency of land use. The Land Equivalent Ratio (LER) assesses the biological efficiency and economic benefits of intercropping systems about monocultures. Cassava–maize intercropping is an extensively utilized and efficient system, as the crops exhibit complementary growth habits and resource needs. Growing cassava with legumes like cowpea, groundnut and soybean can boost soil fertility via nitrogen fixation, improve weed management and raise total productivity per land area. Intercropping can also reduce the risks associated with monoculture and offer additional sources of income for small landholders. 

Predictive soil mapping using random forest models: Applications in pH and soil organic matter assessment

Digital Soil Mapping (DSM) presents a highly scalable and efficient alternative to traditional soil analysis, which is typically limited by its labor-intensive processes, time constraints and low spatial resolution. By utilizing advanced computational techniques such as machine learning and remote sensing, DSM overcomes these limitations and improves the accuracy, efficiency and scalability of soil property assessments. This study, conducted across Tamil Nadu, India, applied DSM and Random Forest (RF) models to predict 2 key soil properties: pH and Soil Organic Matter (SOM). We employed Conditioned Latin Hypercube Sampling (cLHS) for optimized sampling point selection and utilized the Boruta algorithm to identify the most relevant covariates for accurate modeling. The RF models were fine-tuned using a comprehensive grid search, with the optimal configuration spanning from 500 to 2000 trees (ntree) and mtry from 1 to 11. The best-performing model was found with 2000 trees and mtry set to 1 yielding superior prediction for SOM and pH with Root Mean Square Error (RMSE) values of 0.71 and 0.60 respectively, showcasing a high level of predictive accuracy. Our findings emphasize the critical role that remote sensing indices play in predicting SOM, while pH was influenced by both terrain features and remote sensing data. In comparison to previous studies, this research offers novel improvements in both sampling optimization and model configuration, leading to enhanced predictive performance. These results hold significant potential for sustainable land-use planning, agricultural productivity and environmental management

Assessment of long-term Site-Specific Nutrient Management (SSNM) on soil organic carbon dynamics and sequestration in a rice-rice cropping system

This study examined the long-term effects of the Site-Specific Nutrient Management Integrated Plant Nutrient System (SSNM-IPNS) on carbon sequestration, stock, loss and mineralization in soil within a 26-year-old ricerice cropping system at wetland of Tamil Nadu Agricultural University, Coimbatore. The research focused on the impact of integrated organic and inorganic nutrient application on carbon fractions compared to conventional fertilization methods under wetland ecosystems. Results indicated that the SSNM-IPNS approach significantly enhances soil total organic carbon (TOC), with levels reaching 1.56% compared to just 0.78% in control treatments. Furthermore, labile carbon fractions such as permanganate-oxidizable carbon (POx-C), microbial biomass carbon (MBC), water-soluble carbon (WSC), and particulate organic carbon (POC) were found to be greater in the SSNM-IPNS management. Increased rates of carbon mineralization and basal respiration also reflected a more active and efficient microbial community in these soils. Soil microbial indices, including the microbial quotient (qMic) and the metabolic quotient (qCO2), further emphasized the benefits of the SSNM-IPNS approach in enhancing soil health. Overall, the findings demonstrate that SSNM -IPNS significantly improves carbon sequestration, nutrient cycling, and soil fertility, promoting sustainable agricultural practices vital for long-term productivity in intensive cropping systems. This research underscores the importance of adopting innovative nutrient management practices for sustainable agriculture