The cadmium (Cd) uptake and accumulation in the cereal crops like wheat and rice are a serious concern in recent years. Application of various organic amendments in Cd-contaminated soil is an effective technique in management of crop growth and health as organic amendments not only promote plant’s growth but also check Cd translocation in plants. For this purpose, 3 organic amendments (wheat straw biochar (WSB), cotton stick biochar (CSB), and compost comp) were applied @ 0.5% (under randomized complete block design with 4 replicates) in sewage water fed Cd-contaminated soil for effective locking of Cd in soil being cultivated with wheat and rice. The experiment was completed in almost 1 year (December 2014 to November 2015). Our results revealed that all amendments can enhance plant growth and physiology and decrease soil bioavailable Cd contents, but WSB was most prominent among 3 applied. Our results conclude that WSB can enhance straw yield (29.20 and 26.78% for wheat and rice) and grain yield (22.69% and 26.70%) and boast all physiological attributes (chlorophyll contents, stomatal/substomatal conductance, photosynthetic and transpiration rate). Application of WSB decreased post-harvest bioavailable soil Cd contents after wheat and rice crops to 56.37, 48.99% and 7.63, 26.78% in 0–15-cm and 15–30-cm soil depths, respectively. The WSB also decreased Cd translocation in grain, thus helping in decreasing the health risk index (HRI) associated with Cd-contaminated grain consumptions. For economics, amendment application in wheat crops increases its cost, so the benefit–cost ratio was observed to be less than 1. But for upcoming cropping seasons, residues of amendments will still be actively influencing plant growth and yield, so we expect a net higher benefit–cost ratio proving long-lasting use of amendments (especially WSB) a net beneficial approach.

Natural ecology has been affected by the cosmetic inclined towards urbanization and industrialization. Water and land resources are the major entities to be affected by this revolution. These resources are not only shrinking but also deteriorating due to a variety of anthropogenic activities. Land degradation possesses a severe threat to sustainable agriculture and food security as it affects 1 to 6 billion hectares of arable land worldwide. Soil salinization, organic and inorganic pollution, soil erosion, waterlogging and poor nutrition are major causes of soil degradation. Ecological remediation and management of land resources is the primary concern all over the world in general and specific for the developing countries. There are many options which are available for remediation of marginal and intensively degraded soils. These include different organic and inorganic compounds which have their residual effects in soils and plants. The microbial association is an alternative concept to economize ecofriendly remediation of marginally degraded soils. Like halophytic plant growth-promoting bacteria (PGPR), which help the plants, withstand salinity as it boosts plant nutrient uptake via the production of plant hormones. Similarly, using bacterial consortium to degrade soil organic pollutants and decrease concentrations of inorganic metal has huge economic and ecological benefits. Plant-fungal association (mycorrhizae) is reported to have a significant role in better management of degraded soil by enhancing nutrient and water uptake as well as protecting the plant from root pathogens. Screening of objective specific microorganisms for the management of degraded soil is very important to the discipline of sustainable agriculture. Therefore this chapter is an effort to comprehensively explain all aspects associated with microbial assisted ecology reclamation and restoration of degraded soils with historic literature, recent advances, and possible future prospects.

Plant growth and development are constantly influenced by environmental conditions such as biotic and abiotic stresses. These stresses are the factors that decide the yield and growth of the crops resulting in food shortage and compromise food security of the world. Drought is one of the factor that limits yield and growth of plants by decreasing cell elongation and expansion, root ramification, and decreased chlorophyll in plants. The effects of stress can be seen at plant physiological, molecular, and biochemical levels such as growth inhibition, organic solutes accumulation, variation in phytohormones excretion, and changes in gene expression of plants facing drought stress. To cope with drought, plant tend to control water loss via closing stomata and bringing morphological and physiological adaptation. Major alteration brought by plants are increased root growth, decreased stem and leaf expansion, stress protein production, and antioxidants production to quench reactive oxygen species (ROS). Balanced nutrient provision, exogenous application of organic and inorganic amendments, symbiotic plant microbe associations, microbial consortia and metabolites application are assisting approaches to get sustainable production from plant facing drought. Genetic engineering for drought tolerance is another approach to cope with ever-lasting drought impacts. This chapter is and effort to summarize impacts of drought on plants and how plants act to mitigate this stress.

The contamination of cadmium (Cd) in the agricultural lands due to the irrigation of untreated wastewater and raw city effluents has become a serious issue with further increment being done by other anthropogenic activities. This practice has become a serious health hazard for humans as cereal crops like rice (Oryza sativa L.) can accumulate significant Cd and become unsafe to consume. Application of organic amendments like biochar has significant reported effects on Cd immobilization and mitigation of Cd toxicity in plants. Modifications in biochar have become well-practiced to enhance its efficacy, especially in alkaline soils. The objective of our study was to test the Cd stress mitigation in rice mediated by the acid-treated biochar. Acid Treated rice husk biochar (RHB) was prepared by treating RHB with three acids (HCl, HNO3, H3PO4), each applied at 2 levels (2.5 N and 5 N). Acid-treated biochars were applied at 2% making a total of 8 treatments including 2 controls (contaminated/spiked and non-contaminated). Rice growth, paddy yield, and Cd accumulation proved the efficacy of 5 N H3PO4treatment of RHB as the most efficient treatment. Compared to contaminated control, 5 N H3PO4-RHB application has shown the most significant increment in rice growth (plant height 48.8%, spike length 36.4%, root length 58.8%, root dry weight 234%, straw yield 132.9%, paddy yield 61.7% increase compared to contaminated control). The 5 N H3PO4-RHB also decreased bioavailable Cd in soil by 87%, and its accumulation in shoot and paddy by 83.4% and 95.7%, respectively compared to contaminated control. The HCl treatment has shown some toxicity, which might be due to excess of chloride.

The inadequacy of fresh water availability in the agricultural sector has become a severe problem. Coupled with prevailing drought conditions, unavailability of plant essential nutrients has accelerated the food security threat significantly. However, unchecked loading of cadmium (Cd) into the environment due to the extensive use of adulterated fertilizers, sewage, and waste water, and dumping of industrial waste into agri-lands has made the plight of agricultural commodities more critical. Among different heavy metals, Cd is the most toxic, due to its high solubility and mobility in soil-plant systems. It inhibits plant growth and development through several mechanisms. Cd competes with plant essential nutrients (PENs) for uptake and translocation, and adversely affects plants' water status. Cadmium toxicity disturbs plant metabolism because of the restricted uptake and translocation of mineral nutrients. This chapter will discuss, in detail, the effects of Cd toxicity on nutrient uptake by roots and their onward translocation to aerial plant parts. Moreover, this chapter will also discuss possible strategies to offset the harm of Cd toxicity with the use of organic and inorganic amendments, incorporation of plant growth regulators, and the addition of microbial inoculums.

Cadmium (Cd) toxicity is one of the most devastating threats in the agricultural field. It is an alarming risk for human health and environment sustainability, being highly mobile and ecotoxic even at low concentration. Escalated industrialization and intensive agricultural practices have liberated large amounts of Cd into agricultural lands. However, the use of inorganic amendments for Cd immobilization and/or insolubilization is a benign, realistic, and economically feasible approach. Various inorganic amendments, depending upon their composition, play an important role for Cd decontamination by accelerating the precipitation, ion exchange, and immobilization processes. Latest research shows that use of Cd immobilizers binds Cd into the soil medium by surface adsorption, chelation, and precipitation, and is important for safe food production from low- to medium-Cd-contaminated soil. However, researchers are ambiguous about the stability and persistence of these complexes, precipitates, and chelates in the soil environment. Similarly, use of Cd mobilizers such as sulfur and ammonium reduce the soil pH and, thus, accelerates Cd availability to hyperaccumulators. Hyperaccumulators collect the bulk of Cd concentration into their various tissues that can be used for oil formation and is an efficient strategy for Cd decontamination. Besides, use of nutrient-based amendments such as phosphate and silicon-based fertilizers are attracting more concern of farmers, due to the high-fertility status of soil along with remediation purposes. Given the previously described sanctions, economically feasibility of inorganic amendments is well documented for Cd decontamination in agricultural soils. This chapter covers all aspects of Cd contamination of soils and its negative impacts on plant growth and human health. Moreover, this chapter also explains the use of inorganic amendments, their mechanism, and efficacy for Cd decontamination.

The successful phytoextraction of potentially toxic elements (PTEs) from polluted soils can be achieved by growing non-food and industrial crops. Tobacco (Nicotiana tabacum L.) is one of the main industrial crops and is widely grown in many countries. Tobacco can uptake high concentrations of PTEs especially in aboveground biomass without suffering from toxicity. This review highlighted the potential of tobacco for the phytoextraction of heavy metals and tolerance mechanisms under metal stress. Different management practices have been discussed which can enhance the potential of this plant for metal extraction. Finally, suitable options for the management/disposal of biomass enriched in excess metal have been elaborated to prevent secondary pollution.

Cadmium (Cd) toxicity is a major threat for food security all over the world. High mobility, persistent bio-availability, and unavoidable toxicity risks, even at low concentrations, have highlighted Cd as one of the most dangerous heavy metals (HMs). However, use of Solanum nigrum (S. nigrum) for phyto-management of Cd-contaminated soil is well documented. This chapter will explain the negative impacts of Cd toxicity and the role of S. nigrum in phyto-management of Cd-contaminated soils. S. nigrum, commonly known as black nightshade, is a perennial weed with a fast-growing nature and high biomass production, and bulk Cd accumulation in its various tissues characterizes it as a Cd hyperaccumulator plant. S. nigrum possesses some unique characteristics, such as release of organic acids, activation of natural resistance-associated macrophage proteins (NRAMPs), and use of the antioxidant defense mechanism for phyto-management of Cd. Therefore, S. nigrum restricts Cd entry into the food chain by binding Cd into its nonactive parts, coupled with Cd complexation and/or stabilization into the rhizosphere with the release of root exudates. However, use of some additional strategies, such as farming practices, growth activators, soil amendments, and transgenic aid accelerates the S. nigrum-based Cd phyto-management technique significantly. At the moment, long-term field trials are required for testing the effectiveness and economic viability of this proximal technique for decontamination of Cd-contaminated soils on a sustainable basis.

Biochar is considered a promising amendment for the reduction of metal concentration in plants; however, the effects of biochar in terms of dose and feedstock on metal uptake by plants remain widely unclear. In the current study, three individual biochars were prepared at 450 °C from different feedstocks (wheat straw, sukh chain (Pongamia pinnata), and cotton sticks). The main aim was to evaluate their ability to remediate cadmium (Cd)-spiked soil in terms of growth response and Cd uptake by wheat (Triticum aestivum) tissues. Biochars were separately applied at 0, 1, and 2% (w/w) in Cd-spiked soil and wheat was grown until maturity in pots and then morphological and physiological parameters and Cd concentrations in grains, roots, and shoots were determined. The post-harvest soil was analyzed for extractable Cd concentrations. Plants grown in Cd-spiked soil treated with biochars had higher seed germination, lengths of roots, shoots, and spikes, grains per spike and leaf relative water contents, chlorophyll contents, and dry weight of roots, shoots, and grains as compared to the untreated control. Biochar treatments significantly decreased the Cd concentrations in shoots, roots, and grains as well as total Cd uptake by grains. Soil extractable Cd concentrations were significantly decreased with biochar treatments. The application of 2.0% wheat straw biochar was the most efficient treatment in increasing grain yield and decreasing Cd in grains as well as soil extractable Cd than the other two biochars and doses applied.

Accessibility of good-quality food on a sustainable basis has become a global life-threatening problem. Nanotechnology is an emerging strategy designed to eliminate the awful effects of food shortage, heavy metal contamination, and other abiotic stresses. Iron oxide nanoparticles play a proficient role in increasing the growth, development, and enhancement of the stress tolerance of plants and the provision of nutrients. It has also been revealed that iron oxide nanoparticles have a high sorbent affinity toward hazardous contaminants such as arsenic. Because iron oxide nanoparticles seem to have revolutionized the world by providing proximal food, efficient ways to combat diseases, and proficient methods to resolve environmental concerns, it is necessary to study the behavior, response, and ultimate fate of these iron oxide nanoparticles. This chapter focuses on the advances and future perspectives of iron oxide nanoparticles in agricultural development. By thoroughly studying every aspect of iron oxide nanoparticles, we should be able to decide the most appropriate use of these nanoparticles in our daily lives. Thus this chapter will broaden the reader's vision regarding the background of iron oxide nanoparticles, their composition and characterization, application method, plant uptake, absorbance affinity of contaminants, transfer and accumulation mechanism in plants, and positive and harmful impacts on plant growth. It should be realized that the use of iron oxide nanoparticles is no doubt a proximal approach in the agricultural sector but it is also important to consider the negative impacts of keeping this development and progress on a sustainable track.

Rare earth oxide nanoparticles (REONPs) have a high privilege in agriculture due to their unique properties as compared to their bulk counterparts. The most important REONPs include scandium, cerium, and other lanthanides, which are frequently used as fertilizer additives in many countries. Several approaches are being adopted for the commercial synthesis of REONPs. The available literature presents contradictory reviews about their beneficial effects on living organisms. Beneficial or harmful effects on plant growth are mainly dependent on the concentration of REONPs and species of plant. Bioavailability and mobility of REONPs in soil is a pH-dependent process and is also affected by their interaction with anionic ligands because of the higher oxidation state of REONPs. Plants can uptake REONPs from the soil and distribute them to aerial parts including edible organs. Accumulation of REONPs within various plant parts exhibits the potential to initiate seed emergence, escalate root and shoot growth, enhance plant growth by increasing the availability of mineral nutrients, stimulate photosynthetic processes, support plants to cope with environmental stresses by acting as a scavenger of free radicles including oxygen species, start oxidase activity, initiate antioxidant systems, and modify the enzyme activation process. Along with all these blessings there are still controversies regarding their effects on plants. This chapter is helpful for answering all ambiguous questions related to the unique characteristics of REONPs, their uptake mechanism, their interaction with soil organic and inorganic components, and their impacts on plant growth. This discussion also elucidates the phytotoxicity of REONPs in plants and their potential to accumulate in plants. This discussion helps to explore new horizons for the beneficial use of REONPs to maximize plant growth and yield on a sustainable basis along with the quality of the produce.

A field study was performed to determine the efficiency of diammonium phosphate (DAP) applied alone or combined with biochar, lignite, and farmyard manure (FYM) on growth and cadmium (Cd) accumulation in wheat and rice. Before crop sowing, different treatments were applied in the field such as a control (T 1 ), DAP alone (0.1%, T 2 ), DAP + lignite (0.05% each, T 3 ), DAP + FYM (0.05% each, T 4 ), and DAP + biochar (0.05% each, T 5 ). Afterwards, the wheat seeds were sown in the soil. At wheat postharvest, rice was sown without any further treatment. Raw effluent was applied as an irrigation source during the whole growth period of both crops since it is the common practice of the farmers of study area. It was revealed that the use of amendments enhanced the yield and photosynthesis but lowered the Cd contents in straw as well as grains of both crops. In both crops, the highest yield of straw and grain was found in DAP + FYM whereas the lowest Cd concentration was found in DAP alone. The ammonium bicarbonate-DTPA extractable Cd of post wheat and post rice soils were decreased while the soil pH and immobilization index were increased in all treatments as compared with the control. The present field study highlighted that the DAP + FYM can be effective in increasing yield with decreased Cd concentrations in crop grains.

Cadmium (Cd) stress is a serious concern in agricultural soils worldwide whereas little is known about the impact of farmyard manure (FYM) alone or combined with limestone, lignite and biochar on Cd concentrations in plants. Wheat was grown in Cd-contaminated field amended with control (T1), FYM @ 0.1% (T2), FYM + limestone @ 0.05% each (T3), FYM + lignite @ 0.05% each (T4), FYM + biochar @ 0.05% each (T5) and subsequent rice was grown without additional use of amendments. Soil application of amendments increased straw and grain yield and thousand grain weight being maximum in FYM + limestone treatment. Wheat and rice straw yield increased by 19% and 10% in T3 than control respectively. Photosynthetic pigments increased with the supply of amendments than control. Amendments decreased Cd concentration, total Cd uptake in straw and grains and Cd harvest index of both crops and the maximum reduction in these parameters was recorded with where FYM + limestone (T3). Cd concentration in wheat and rice straw decreased by 78.5% and 65% in T3 than control, respectively. The highest benefit to cost ratio was obtained in FYM + limestone (T3). Ammonium bicarbonate - diethylenetriamine penta acetic acid (AB-DTPA) extractable Cd of the post-harvest soil reduced whereas Cd immobilization index and soil pH increased with the supply of all treatments than control being maximum in T3. The present study revealed that field management with FYM + limestone increased plant yield and reduced Cd concentrations in grains.

Cadmium (Cd) uptake and accumulation in crop plants, especially in wheat (Triticum aestivum) and rice (Oryza sativa) is one of the main concerns for food security worldwide. A field experiment was done to investigate the effects of limestone, lignite, and biochar on growth, physiology and Cd uptake in wheat and rice under rotation irrigated with raw effluents. Initially, each treatment was applied alone at 0.1% and combined at 0.05% each and wheat was grown in the field and then, after wheat harvesting, rice was grown in the same field without additional application of amendments. Results showed that the amendments applied increased the grain and straw yields as well as gas exchange attributes compared to the control. In both crops, highest Cd concentrations in straw and grains and total uptake were observed in control treatments while lowest Cd concentrations was observed in limestone + biochar treatment. No Cd concentrations were detected in wheat grains with the application of amendments except limestone (0.1%). The lowest Cd harvest index was observed in limestone + biochar and lignite + biochar treatments for wheat and rice respectively. Application of amendments decreased the AB-DTPA extractable Cd in the soil while increasing the Cd immobilization index after each crop harvest. The benefit-cost ratio and Cd contents in plants revealed that limestone + biochar treatment might be an effective amendment for increasing plant growth with lower Cd concentrations.

Cadmium (Cd) accumulation in agricultural soils is one of the major threats to food security. The application of inorganic amendments such as mono-ammonium phosphate (MAP), gypsum and elemental sulfur (S) could alleviate the negative effects of Cd in crops. However, their long-term residual effects on decreasing Cd uptake in latter crops remain unclear. A field that had previously been applied with treatments including control and 0.2, 0.4 and 0.8% by weight of each MAP, gypsum and S, and grown with wheat and rice and thereafter wheat in the rotation was selected for this study. Wheat (Triticum aestivum L.) was grown in the same field as the third crop without further application of amendments to evaluate the residual effects of the amendments on Cd uptake by wheat. Plants were harvested at maturity and grain, and straw yield along with Cd concentration in soil, straw, and grains was determined. The addition of MAP and gypsum significantly increased wheat growth and yield and decreased Cd accumulation in straw and grains compared to control while the reverse was found in S application. Both MAP and gypsum decreased AB-DTPA extractable Cd in soil while S increased the bioavailable Cd in soil. Both MAP and gypsum increased the Cd immobilization in the soil and S decreased Cd immobilization in a dose-additive manner. We conclude that MAP and gypsum had a significant residual effect on decreasing Cd uptake in wheat. The cost-benefit ratio revealed that gypsum is an effective amendment for decreasing Cd concentration in plants.

Cadmium (Cd) is a biologically non-essential heavy metal while the cultivation of Cd-tolerant varieties/hybrids (V) seems the most promising strategy for remediation of Cd-contaminated soils. For this, 24-day-old seedlings of seven maize hybrids, DKC 65-25, DKC 61-25, DKC 919, 23-T-16, 32-B-33, 31-P-41, and Syn hybrid, were grown in hydroponic conditions for 21 additional days in various Cd concentrations (0, 5, 10, and 15 μM). Effects of variety, Cd, and their interaction were highly significant (p ≤ 0.05) for studied plant agronomic and physiological traits except the V × Cd interaction for leaf chlorophyll content, root-shoot length, and root dry weight. The Cd accumulation in root and shoot increased gradually with increasing Cd treatments while copper (Cu), zinc (Zn), and manganese (Mn) uptake was decreased in all hybrids. The reduction in root and shoot biomass and Cd uptake was lower in 32-B-33 and 23-T-16 compared to other hybrids. The highest accumulation of Cu, Zn, and Mn was observed in 32-B-33, DK C65-25, and 31-P-41, respectively. The differential uptake and accumulation of Cd by maize hybrids may be useful in selection and breeding for Cd-tolerant genotypes.