Biplov Oli

Phosphorus (P) is essential for crop production, yet its use still follows a largely linear pathway: phosphate rock is mined, applied to agricultural land, transferred through food and waste systems, and often lost to rivers, lakes, and coastal waters. This review examines how P supply vulnerability, agricultural surpluses and deficits, legacy soil P, eutrophication, climate-sensitive transport, and recovery technologies are connected across food and water systems. A structured narrative review was conducted using Web of Science, Scopus, Google Scholar, and relevant institutional sources. The searches focused on phosphorus fertilizer, legacy P, eutrophication, runoff, wastewater recovery, circular economy, and governance. English-language peer-reviewed studies and high-authority reports, mainly published between 1995 and 2026, were screened for relevance, methodological clarity, and quantitative evidence. A total of 191 records were identified, 115 full texts were assessed, and 101 sources were included. Evidence was grouped into four areas: mineral supply and trade, soil and aquatic P accumulation, recovery from waste streams, and policy. The review shows that concentrated reserves can increase supply risk, but do not alone indicate imminent scarcity. Costs, ore quality, trade, demand, recycling, and technological change also influence P security. Legacy P may support crop uptake while continuing to impair water quality. Recovery technologies such as struvite production and sludge-ash processing offer useful pathways, but their adoption depends on economics, contaminants, regulation, and logistics. Effective P stewardship therefore requires region-specific strategies that reduce losses, improve access and efficiency, manage legacy P, and support practical recovery.

Soil degradation, nutrient depletion, and persistent weed pressure represent critical challenges in the adoption of sustainable agriculture practices in subtropical organic farming systems. Reliance on conventional inputs threatens long-term soil health and ecosystem resilience, highlighting the need for regenerative alternatives. Cover crops are widely recognized as multifunctional agroecological tools with the capacity to enhance nutrient cycling, perform weed suppression, and improve soil organic matter. To evaluate their effectiveness in South Florida's subtropical climate and organic raised bed systems, a field experiment was conducted as a Randomized Block Design (RBD) at the Florida International University Organic Garden during the 2024 summer season. The six cover crops species that were tested include green gram (Vigna radiata), hibiscus (Hibiscus sabdariffa), sorghum (Sorghum bicolor), soybean (Glycine max), sunn hemp (Crotalaria juncea), and pearl millet (Pennisetum glaucum). Data collected includes plant establishment, biomass accumulation, weed suppression, soil physiochemical properties, and plant nutrient composition. Sorghum and sunn hemp produced the highest fresh and dry biomass, with sorghum achieving the most effective weed suppression with the lowest weed biomass and weed population. Sunn hemp contributed to enhanced nitrogen content in plant tissues, while hibiscus promoted the highest soil P and N concentrations. Pearl millet exhibited the highest total carbon and organic matter content, indicating potential for enhancing soil carbon content and soil fertility. Results show that each cover crop species can provide a specialized or generalized ecosystem service depending on management goals.

For the quantitative evaluation of the efficacy of Nitrogen through different plant nutrient sources in the growth and yield of radish, the field experiment was conducted from March 2020 to June 2020 in an Inceptisol with sandy loam soil of the research field of G. P. Koirala College of Agriculture and Research Centre, Gothgaun, Morang, Nepal. The experiment was carried out in a Randomized Complete Block Design with eight treatments (Biogas Byproduct, Poultry Manure, Goat Manure, Farmyard Manure, Vermicompost, Packaged Organic Manure, Recommended Dose of Chemical Fertilizer, and Control) and four replications. Forty Day (released in 1994 AD) variety of radish was used as a test crop. The recommended 100 kg N per hectare was supplied from each treatment, calculated based on the nitrogen content of each nutrient source. Results showed that there was a significant difference in almost all studied parameters from all treatments over control (P≤ 0.05). The highest total fresh biomass yield (123.415 Mt/ha) and highest delta fresh shoot yield (22.806 Mt/ha) were recorded from the application of a recommended dose of fertilizer, and the highest delta fresh root yield (30.127 Mt/ha) was obtained from the application of FYM. The experiment suggests that the application of FYM significantly increased root yield and was positively correlated with other parameters, which might be a good alternative for chemical fertilizers. Int. J. Appl. Sci. Biotechnol. Vol 9(3): 203-212.