Duraisamy Selvi

Phosphorus (P) is an essential macronutrient involved in energy metabolism, regulation of physiological processes, and biomass production in plants. P deficiency is a major constraint to plant growth, and its direct effects are often obscured in soil-based studies due to phosphorus fixation and microbial interactions. The Present study evaluated the varying inorganic phosphate (Pi) concentrations (0.001, 0.025, and 0.25 mM Pi) on morphology, dry matter allocation, gas exchange, PS II efficiency, and photosynthetic pigment composition on 21-day-old muskmelon (Cucumis melo L.) seedlings grown under hydroponic conditions. Adequate Pi (0.25 mM Pi) supply significantly enhanced the shoot growth, total dry weight, photosynthetic rate, stomatal conductance, and transpiration. These responses were closely associated with higher PS II efficiency, indicated by increased F_v/F_m and F_v/F_o ratios and photosynthetic pigments chlorophyll a, chlorophyll b, and carotenoid. Reduced Pi (0.001 mM Pi) limited the growth, gas exchange, PS II efficiency, and photosynthetic pigments, and while promoting root growth and increasing root-to-shoot ratio. The coordinated modulation of growth, physiological, and photochemical responses of muskmelon seedlings under controlled Pi supply demonstrates that phosphorus availability directly regulates photosynthetic functionality and biomass allocation.

Silicon (Si) deficiency limits plant growth, physiological efficiency, and yield in high-value crops such as Coriandrum sativum L. A field experiment was conducted on Si-deficient soil at TNAU Coconut Farm, Coimbatore, India, using coriander variety CO (CR) 4. Seven treatments in a randomized block design with three replications evaluated calcium silicate (CaSiO₃), and rice husk ash (RHA) at 225, and 275 kg Si ha^- 1, alone, and combined with Bacillus altitudinis SSB4, across growth, physiological, biochemical, antioxidant, and yield parameters. Si + SSB4 integration significantly improved plant height (up to 60.9% over control), leaf area index, SPAD index, and shoot and root dry matter production. Leaf Si content increased by 84.1-88.4% over absolute control, and 21.7-24.5% over RDF alone. Antioxidant enzymes (CAT, POD, and SOD), and biochemical attributes (total soluble sugars, total soluble protein, total phenols, and ascorbic acid) were markedly enhanced, with total soluble protein recording the highest increase (194.8% over absolute control). RHA-based treatments marginally but non-significantly outperformed CaSiO₃-based treatments. The highest leaf yield (5.46 t ha^- 1) was recorded with RDF + RHA at 275 kg Si ha^- 1 + SSB4 (53.8% over RDF), followed by RDF + CaSiO₃ at the same level (52.1%). Strong positive correlations (r = 0.863-0.990) among Si content, antioxidant enzymes, biochemical parameters, and yield confirmed a coordinated Si-mediated improvement. Integrated application of CaSiO₃ or RHA with B. altitudinis SSB4 synergistically enhanced growth, antioxidant defence, biochemical quality, and leaf yield of coriander in Si-deficient soils, supporting the adoption of combined chemical-biological Si management strategies.

The notable increase in chicken waste resulting from the rapid expansion of the chicken industry represents a major concern and danger to public health and the environment. Therefore, this varied waste stream in the chicken industry, including bedding materials, dung, feathers, and mortalities, requires efficient management techniques. Improper chicken waste disposal can lead to nutrient leakage and water and soil contamination, which can cause eutrophication and aid in spreading harmful bacteria such as Escherichia coli and Salmonella. Moreover, untreated waste exacerbates climate change by increasing greenhouse gas emissions. Thus, in response to these challenges, this review analyses many treatment techniques that might convert this complicated waste stream into a useful resource to support environmental sustainability in the chicken industry and enhance soil health. Furthermore, this study evaluates gasification, pyrolysis, anaerobic digestion, and composting as viable methods to reduce pollution from chicken waste while producing useful byproducts. Anaerobic digestion uses bacteria to produce biogas, a sustainable energy source; pyrolysis produces biochar and bio-oil; composting converts waste into fertilizer; gasification produces syngas for fertilizer production. However, choosing the most efficient treatment approach necessitates thoroughly assessing waste properties, intended end products, and economic factors. This review aims to expand the understanding of these treatment procedures and their related advantages to assist in developing sustainable and effective strategies for dealing with chicken waste. These strategies, which prioritize value development, environmental preservation, and public health, have the potential to pave the way for a more responsible and sustainable future for the chicken industry.

Alterations in land patterns in Kolli Hills(KH) of the Eastern Ghats, Tamil Nadu, transitioning from native ecosystems to various land uses, have notably diminished soil carbon concentrations. To measure this reduction, the Carbon Management Index (CMI) was evaluated across key land-use categories, including Agricultural System (AS), Horticultural System (HS), Plantation System (PS), Thorn Forest (TF), Deciduous Forest (DF), and Evergreen Forest (EF). The analysis focused on Total Organic Carbon (TOC), Total Carbon (TC), Total Inorganic Carbon (TIC), and carbon pools with varying degrees of lability, including less labile carbon (LLC), labile carbon (LC), very labile carbon (VLC), and non-labile carbon (NLC). The findings indicated that EF's carbon pools were markedly higher (p < 0.05) than AS and HS. The contribution of LC, VLC, LLC, and NLC to TOC was highest in EF and DF, while it was lowest in AS and HS. The TOC at 15 cm depth was highest in the surface soils of EF (106.17 g kg-1), with a gradual decline in concentration with increasing depth. This highlights carbon pool degradation from land-use change, quantified by the CMI. When EF was used as the reference ecosystem, the CMI was higher in DF (51.93) and TF (45.69) at a 30 cm depth, while AS (10.75) and HS (12.46) showed a much lower CMI. These findings highlight the need to implement effective carbon management strategies in KH to restore soil vitality and safeguard biodiversity.

Rice husk ash (RHA) contains appreciable amounts of exchangeable cations and plant nutrients which can be used as liming material for acid soil reclamation. Hence, the present study was carried out to assess the potential of rice husk ash for soil acidity reclamation and its effect on related soil properties. RHA was collected from a modern rice mill and its physical and chemical properties were assessed. The results confirmed the alkaline nature of RHA with a pH of 8.30 at 1:10 RHA-to-water suspension. An incubation experiment was conducted with five levels of RHA viz., 10, 20, 30, 40 and 50 t ha-1; compared with the treatments without liming material and the lime application as per lime requirement. Soil sampling was performed at 15, 30, 45 and 60 days after incubation (DAI) and analysed. The results indicated that the application of RHA 50 t ha-1, 40 t ha-1,30 t ha-1 and lime (100% lime) were comparable in enhancing the soil pH, effective cation exchange capacity and percent base saturation and reduced the total acidity and exchangeable Al. With all levels of RHA and lime application, favourable effects on soil properties related to acidic soil reclamation were observed over time. Exchangeable Ca and Mg were the highest in the 100% lime requirement, followed by RHA at 50 t ha-1. Exchangeable K and Na were the highest in rice husk ash at 50 t ha-1. The results emanated from this study ensured the potential of rice husk ash as a source of lime for acidic soils reclamation.

Bioavailability of zinc was impacted by soil properties, externally applied sources, time, and various fractions of zinc. An experiment was conducted to investigate the bioavailable and other zinc fractions in calcareous soil and the efficiency of organic and inorganic sources on bioavailability with the presence and absence of zinc solubilizing bacteria (ZSB). The sequential extraction procedure followed at every interval of the incubation period for all forms of zinc was studied. Externally added inorganic sources significantly affected all fractions of zinc compared to untreated soils. Among them, ZnSO4 influences all forms of zinc, mainly Ws+Ex (water soluble+exchangeable) and carbonate-bound zinc, whereas Zn-EDTA maintains a high status of bioavailable zinc throughout the experimental period. On the 60th day of incubation, Zn-EDTA and ZnSO4 applied to soil maintained bioavailable zinc content of 3.71 and 2.94 times higher than that of control. Irrespective of sources, the available zinc of Zn fertilizers applied to soils was reduced with an increase in incubation days. Organic and microbial addition effects solely or combined increase the soil zinc content significantly in both fertilized and unfertilized soils. Among two different organic sources, the zinc solubility performance of farmyard manure was higher than that of vermicompost. In untreated soil, residual and carbonate-bound fractions contribute a major portion towards total zinc based on quantity. The bioavailable fraction mainly the Ws+Ex and organically bound fractions were markedly influenced in all treatments.