Agroforestry is a sustainable land use system with a promising potential to sequester atmospheric carbon into soil. This system of land use distinguishes itself from the other systems, such as sole crop cultivation and afforestation on croplands only through its potential to sequester higher amounts of carbon (in the above- and belowground tree biomass) than the aforementioned two systems. According to Kyoto protocol, agroforestry is recognized as an afforestation activity that, in addition to sequestering carbon dioxide (CO) to soil, conserves biodiversity, protects cropland, works as a windbreak, and provides food and feed to human and livestock, pollen for honey bees, wood for fuel, and timber for shelters construction. Agroforestry is more attractive as a land use practice for the farming community worldwide instead of cropland and forestland management systems. This practice is a win-win situation for the farming community and for the environmental sustainability. This review presents agroforestry potential to counter the increasing concentration of atmospheric CO by sequestering it in above- and belowground biomass. The role of agroforestry in climate change mitigation worldwide might be recognized to its full potential by overcoming various financial, technical, and institutional barriers. Carbon sequestration in soil by various agricultural systems can be simulated by various models but literature lacks reports on validated models to quantify the agroforestry potential for carbon sequestration.
The current study evaluated the effect of groundwater and wastewater irrigation on lead (Pb) accumulation in soil and vegetables, and its associated health implications. A pot experiment was conducted in which spinach (Spinacia oleracea), radish (Raphanus sativus), and cauliflower (Brassica oleracea) were irrigated with groundwater and wastewaters containing varying concentrations of Pb. Lead contents were measured in wastewaters, soils and root and shoot of vegetables. We also measured health risk index (HRI) associated with the use of vegetables irrigated by wastewaters. Results revealed that Pb contents in groundwater and wastewater samples (range: 0.18-0.31 mg/L) were below the permissible limits (0.5 mg/L) set by the Food and Agriculture Organization (FAO). Application of Pb-containing groundwater and wastewater increased Pb concentration in soil and vegetables. Lead concentrations in all soils ranged from 10 to 31 mg/kg and were below the permissible limits of 300 mg/kg set by the European Union. Significant Pb enrichment was observed in the soils whereby all types of vegetables were grown and assessed for Pb risk. Our data showed that Pb contents, in all three vegetables (21-28 mg/kg DW), were higher than the permissible Pb limit of FAO (5 mg/kg Dry Weight (DW)). The HRI values were > 1.0 for radish and cauliflower. It is proposed that Vehari city wastewater/groundwater must be treated prior to its use for irrigation to avoid vegetable contamination by Pb, and as such for reducing Pb-induced human health risk.
Arsenic (As) is a toxic metalloid. Serious concerns have been raised in literature owing to its potential toxicity towards living beings. The metalloid causes various water- and food-borne diseases. Among food crops, rice contains the highest concentrations of As. Consuming As-contaminated rice results in serious health issues. Arsenic concentration in rice is governed by various factors in the rhizosphere such as availability and concentration of various mineral nutrients (iron, phosphate, sulfur and silicon) in soil solution, soil oxidation/reduction status, inter-conversion between organic and inorganic As compounds. Agronomic and civil engineering methods can be adopted to decrease As accumulation in rice. Agronomic methods such as improving soil porosity/aeration by irrigation management or creating the conditions favorable for As-precipitate formation, and decreasing As uptake and translocation by adding a inorganic nutrients that compete with As are easy and cost effective techniques at field scale. This review focuses on the factors regulating and competing As in soil-plant system and As accumulation in rice grains. Therefore, it is suggested that judicious use of water, management of soil, antagonistic effects of various inorganic plant-nutrients to As should be considered in rice cultivated areas to mitigate the building up of As in human food chain and with minimum negative impact to the environment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.