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Global climate change associated with increasing temperature and unreliable rainfall events will have consequences for crop production. Therefore, strategizing crop management gained the attention of crop scientists to curtail the adverse impacts of climate change on crop production. However, the projected effects of climate change on wheat may vary in different cropping systems as wheat production is reported to be significantly impacted by future climate change in major cropping systems worldwide. In the present study, ten experiments were conducted under irrigated (2007–2013) and rainfed (2010–2014) cropping systems of Pakistan to quantify the interactive impacts of future climate change (CO2, temperature, and rainfall) on wheat phenology, grain yield, crop evapotranspiration (ETc), and water use efficiency (WUE) using the DSSAT-CERES-Wheat. The DSSAT-CERES-Wheat was executed using 17 Global Climate Models (GCMs) and four Representative Concentration Pathways (RCPs; 2.6, 4.5, 6.0, and 8.5) to forecast the climate projections for 2030, 2050, and 2090. The average temperature at both sites will increase by 1.3, 1.9, 1.9, and 2.9 ℃ under RCP 2.6, 4.5, 6.0, and 8.5. The simulated output varies among GCMs, RCPs, CO2 concentration, and future periods. A general reduction in wheat phenology, grain yield, ETc, and WUE was anticipated. However, higher CO2 concentration and early maturity improved the WUE of wheat under irrigated and rainfed conditions. Nevertheless, this gain in WUE was at the cost of a relatively higher yield loss. Wheat yield is expected to decline by 2–19% and 9–30% under irrigated and rainfed conditions, respectively by aggregating the simulated future climate change impacts across GCMs and RCPs. Adaptation strategies to mitigate the climate change impacts on wheat production in irrigated and rainfed areas will be required. Our findings will serve as a foundation for designing future climate change adaptation strategies to sustain wheat production in Pakistan's irrigated and rainfed cropping systems.

Crop production is highly sensitive to climate. It is affected by long-term trends in average rainfall and temperature, inter-annual climate variability, shocks during specific phenological stages and extreme weather events. As climate changes, crop production strategies must change too. Field trials were conducted at Nuclear Institute for Agriculture and Biology, Faisalabad-Pakistan, on wheat to assess nutrient and water productivity in irrigated semiarid conditions of Faisalabad. The treatments were six dates of sowing (DOS) (20th October, 30th October, 10th November, 20th November, 30th November and 10th December) with five nitrogen levels (N-levels), i.e., (0, 60, 120, 180 and 240 kg ha−1). CSM-CERES wheat model under the umbrella of DSSAT (4.6) was used to assess the impact of changing climate on wheat production. Model was then evaluated on the basis of data collected during field experiments. Model’s performance was evaluated by computing different statistical variables (d, R2). Intergovernmental Panel on Climate Change’s (IPCC), Representative Concentration Pathways (RCPs) were used to assess the climatic changes in the near, the middle and at the last of the century (2030, 2050 and 2090). Data collected during field experiment showed that biological and grain yields were increased up to 10th November DOS and then a decreasing trend was started up to 10th December DOS. A statistically significant (p ≤ 0.05) interaction was observed between DOS and N-levels. DOS and N-levels interactive affect showed significantly higher biological and grain yields at 180 and 240 kg N ha−1, respectively, when crop was sown on 10th November, while significantly lower yield at 0 kg N ha−1 with sowing date 20th October. The model results indicated that N-levels have not much significant effect on wheat yield under changing climate scenarios RCPs. But the changes in DOS showed significant results under these RCPs in irrigated conditions. The DOS 30th November with 180 kg N ha−1 will performs better in 2030, 2050 and 2090 than other DOS as predicted by the model. Model predicts the lowest yields in the early date of sowing, i.e., 30th October, 10th November, etc. But in later DOS model showed significantly higher yields for 2030, 2050 and 2090.

Simulation models are widely used for making decision support especially under sub-optimal climatic conditions for yield improvement. The impact of uncertain weather conditions on cotton production can be explored with the aid of such models. Cotton, being the queen of fibers, enjoys itself a predominant position amongst all other cash crops and has the potential to narrow the gap between production and consumption of fiber and edible oil. The goal of the study was to evaluate the performance of Cropping System Model CROPGRO-Cotton for examining temporal variation in cultivars and to determine the potential impact of planting dates. The model was calibrated using a diverse range of field observation for phenology, growth and seed cotton yield (SCY) and its components of 20-April planting date, genetic coefficients were estimated using Generalized Likelihood Uncertainty Estimation (GLUE) and sensitivity analysis sub modules in CSM-DSSAT. Calibrated and evaluated results were reasonably good for phenology, growth, boll weight, SCY and yield attributes with good statistics. Simulation and observed data revealed the decreasing trend with delayed planting for all cultivars. Phenological phases were predicted well with high d-index (>0.94 and >0.85), and the dynamics of time series for LAI and biomass were predicted also well (d > 0.96 and >0.98), respectively during model evaluation for all planting dates and cultivars. Seed cotton yield was simulated with lower RMSE (137–382) at final picking, while dynamics of time series for SCY were predicted reasonably well with high values of d-index (0.95–0.99) for all cultivars during model evaluation. Planting date analyses of the years (1980–2013) agreed with observed SCY trend, showed decrease of 27% for delayed planting from 20-April to 21-June while first too early planting (10-March) had also faced 8% reduction for all cultivars. Cultivars [MNH-886, NIAB-9811 (NIAB-Kiran) and NIAB-112] outperformed with higher SCY predominantly due to longer appropriate growing season by utilizing optimal weather conditions, attained optimum growth at all key phenological phases. Cultivar NIAB-112 performed well being a short duration and attained high SCY for late planting (1-June) as well during the growing years. Cotton cultivars planting during 1-April–10-May can be suggested for the farmer’s field to avoid weather stress and to improve utilization of resources for sustainable cotton production in the region. Result demonstrated the model potential for decision support for cotton management practices in the region, including identifying optimum planting dates for cotton production.

Wheat production under rainfed conditions is restrained by water scarcity, elevated temperatures, and lower nutrient uptake due to possible drought. The complex genotype, management, and environment (G × M × E) interactions can obstruct the selection of suitable high yielding wheat cultivars and nitrogen (N) management practices prerequisite to ensure food security and environmental sustainability in arid regions. The agronomic traits, water use efficiency (WUE), and N use efficiencies were evaluated under favorable and unfavorable weather conditions to explore the impacts of G × M × E on wheat growth and productivity. The multi-N rate (0, 70, 140, 210, and 280 kg N ha−1) field experiment was conducted under two weather conditions (favorable and unfavorable) using three wheat cultivars (AUR-809, CHK-50, and FSD-2008) in the Pothowar region of Pakistan. The experiments were laid out in randomized complete block design (RCBD), with split plot arrangements having cultivars in the main plot and N levels in the subplot. The results revealed a significant decrease in aboveground biomass, grain yield, crop N-uptake, WUE, and N use efficiency (NUE) by 15%, 22%, 21%, 18%, and 8%, respectively in the unfavorable growing season (2014–2015) as compared to favorable growing season (2013–2014) as a consequence of less rainfall and heat stress during the vegetative and reproductive growth phases, respectively. FSD-2008 showed a significantly higher aboveground biomass, grain yield, crop N-uptake, WUE, and NUE as compared to other wheat cultivars in both years. Besides, N140 appeared as the most suitable dose for wheat cultivars during the favorable growing season. However, any further increase in N application rates beyond N140 showed a non-significant effect on yield and yield components. Conversely, the wheat yield increased significantly up to 74% from N0 to N70 during the unfavorable growing season, and there was no substantial difference between N70–N280. The findings provide opportunities for maximizing yield while avoiding excessive N loss by selecting suitable cultivars and N application rates for rainfed areas of Pothowar Plateau by using meteorological forecasting, amount of summer rainfall, and initial soil moisture content.

Soil management through the cultivation of salt-tolerant plants is a practical approach to combat soil salinization. In this study, salt tolerance of 35 barley (Hordeum vulgare L.) genotype...

In the Indo-Gangetic plains of south Asia, conventional tillage (CT) and removal of crop residues have been the major cause of declining soil fertility. While zero tillage (ZT) farming combined with retention of crop residues as surface mulch are well known to improve soil quality and crop productivity in different climatic zones, only limited knowledge exists on the performance ZT technology in the Indo-Gangetic plains. A field study was conducted under subtropical arid climate to elucidate short-term effects of different tillage, residue mulch and N fertilizer regimes on the productivity of irrigated maize grown for five cropping seasons. Treatments included CT and ZT; each with mulch (M + ) or without mulch (M − ), and with N (N + ) or without N (N − ). Fate of the fertilizer-N applied to the 5th maize crop was also investigated using 15 N tracer. After five cropping seasons, soil organic C (SOC) in the arable soil layer was higher under ZT compared to CT (29% increase), under M + compared to M − (16% increase) and under N + compared to N − (13% increase). Highest SOC was recorded under ZT-M + -N + treatment (19.1 Mg ha −1 ) and the lowest under CT-M − -N − (10.7 Mg ha −1 ). Nitrogen application increased the grain yield; the increase was higher under ZT than under CT in three cropping seasons. Mulch application reduced the grain yield in four cropping seasons. During all growing seasons, the grain as well as total biomass yields were highest under ZT-M − -N + . Recovery of the fertilizer-N in soil (0–100 cm depth) ranged from 28 to 39% of the applied with lowest recorded under ZT-M − . The fertilizer-N recovery in plant was highest (40%) under ZT-M − , whereas the total fertilizer N recovery in the soil-plant system was not influenced by tillage or mulch regimes. Plant-N derived from soil (Ndfs) was higher under ZT compared to CT (47% increase), and under M + compared to M − (15% increase); the highest Ndfs was recorded under ZT-M − (31–68% increase). While mulch had no effect on the added-nitrogen-interaction, the latter was significantly higher under CT compared to ZT (65% increase). Results suggested that as compared to other tillage/mulch regimes, ZT without mulch produced similar or higher grain yield and showed highest fertilizer-N use efficiency in continuous maize cropping system under subtropical conditions prevailing in the Central Punjab, Pakistan.

Future climate projections and impact assessments are critical in evaluating the potential impacts of climate change and climate variability on crop production. Climate change impact assessment in combination with crop, climate models under different climate change scenarios is uncertain and it is challenging to select an appropriate climate scenario. This study quantifies the uncertainty associated with projected climate change impacts on cotton yield in Punjab, Pakistan using 29 general circulation models (GCMs) under high and moderate representative concentration pathway (RCP) scenarios (4.5 and 8.5) at near-term (2010–2039) and mid-century (2040–2069) time spans. Cropping System Model (CSM) CROPGRO-Cotton (DSSAT v 4.6) was calibrated and evaluated with field experiment data collected under arid/semi-arid climatic conditions. Enormous variation was observed in GCMs climatic variables, which were therefore classified into different categories. According to mean ensemble of 29 GCMs, there is a projected increase in seasonal average temperature 1.52 °C and 2.60 °C in RCP 4.5 and 1.57 °C and 3.37 °C in RCP 8.5 scenario as compared to the seasonal baseline (31.48 °C) in near-term (2010–2039) and mid-century (2040–2069), respectively. Maximum consensus by GCMs revealed the increase in temperature of 1.2–1.8 °C and 2.2 to 3.1 °C in RCP 4.5 scenario while 1.4–2.2 °C and 3.0–3.9 °C increase is expected under RCP 8.5 for near term and mid-century time periods, respectively. Similarly, rainfall changes are expected −8% to 15% and −5 to 17% in RCP 4.5 scenario while −8 to 22% and −2 to 20% change is expected under RCP 8.5 scenario in near term and mid-century time periods, respectively. Seed cotton yield (SCY) are projected to decrease by 8% on average by 2039 and 20% by 2069under the RCP 4.5 scenario relative to the baseline (1980–2010). Mean seed cotton yield is projected to decrease by 12% and 30% on average under the RCP 8.5 scenario. Uncertainties were observed in GCMs projections and RCPs due to variations in climatic variables projections. GCMs, GFDL-ESM2M (45% and 35%), GFDL-ESM2G (28% and 43%) and MIROC-ESM (39% and 70%) predicted the higher mean SCY reduction ensemble of cultivars than others under emission scenario of 4.5 in near term and mid-century, respectively. Lower SCY reduction was revealed in CCSM4, HADGEM2-CC, HADGEM2-ES, INMCM4 and CNRM-CM5 due to mild behavior of climatic variables especially temperature under RCP 4.5 in the near-term and mid-century. High reduction in mean SCY (16%–19%) is expected in CMCC-CMS, IPSL-CM5B-LR, GISS-E2-H, GFDL-ESM2M and GFDL-ESM2G under the RCP 8.5 scenario. However, under the same scenario, mean SCY increases by 1% in HADGEM2-ES and by 4% in HADGEM2-CC relative to the baseline yield (4147 kg ha−1). GFDL-ESM2M and GFDL-ESM2G are hot and dry while HADGEM2-ES and HADGEM2-CC are hot but wet, resulting in less cotton yield loss. MIROC-ESM and GFDL-ESM2G projected a severe reduction in mean SCY (70% and 69%) due to a steep increase in maximum and minimum temperature (6.97 °C and 4.38 °C, 4.91 °C and 3.70 °C), respectively and sever reduction in rainfall by mid-century and may call worse case scenarios. Climate models like, CCSM4, HadGEM2-CC, HadGEM2-ES, INMCM4, CanESM2, CNRM-CM5, ACCESS1-0, BNU-ESM and MIROC5 are found less uncertain and showed stable behavior. Therefore, these models can be used for climate change impact assessment for other crops in the region. Adaptation management options like five weeks early sowing than current (10-May), increasing nitrogen fertilization (30%), higher planting density (18% for spreading and 30% for erect type cultivars) and 17% enhanced genetic potential of cultivars would compensate the negative impacts of climate change on cotton crop. This study provide valuable understandings and direction for cotton management options under climate change scenarios. This multi-model and multi-scenario analysis provides a first overview of projected changes in temperature and precipitation, cotton yield and potential management options under changing climate scenarios in arid to semi-arid climatic conditions of Punjab-Pakistan.

Cadmium (Cd) contamination of farmland soils is a widespread problem around the globe, and rice (Oryza sativa L.) tends to accumulate more Cd and is considered as one of the major sources of Cd intake in humans, especially consuming rice-derived products. The current study investigated the effects of foliar applied aspartic acid (Asp) on growth parameters, biomass, chlorophyll concentration, gas exchange characteristics, Cd uptake, and antioxidative capacity in the shoots and roots of rice seedlings exposed to Cd stress. For this, 30-day-old rice nursery was transferred in the soil with aged Cd contamination (2.86 mg kg−1). After 2 weeks of growth, different concentrations (0, 10, 15, and 20 mg L−1) of Asp were foliar applied four times with a 7-day interval, and the crop was harvested after 10 weeks of transplanting. Foliar applied Asp increased the plant height, shoot and root dry weight, chlorophyll concentration, and gas exchange parameters, while it reduced the Cd concentrations in both shoots and roots as well as shoot to root Cd translocation factor compared to the control. Foliar application of Asp reduced the malondialdehyde content and electrolyte leakage in rice parts compared to the control in a dose-additive manner. The activities of key antioxidant enzymes increased while peroxidase activity decreased by exogenous Asp. The increase in plant weight and photosynthesis might be due to lower Cd concentrations in plants which may reduce the oxidative stress and also help the plants to minimize direct damage caused by Cd to the photosynthetic organs.

Sowing methods and harvesting times are the important management considerations for getting the optimum yield and quality of fodder crops. This study, investigated the influence of sowing methods and harvesting times on the growth, yield and quality of sweet sorghum. Chinese sweet sorghum was grown by broadcast method, 30 cm apart lines and 45 cm apart lines and harvested after 60, 75 and 90 days after sowing, respectively. All the tested sowing patterns and harvesting times considerably affected the growth, yield and quality of sweet sorghum. However, sowing in 30 cm apart rows produced maximum leaves per plant (13.09), fresh forage yield (38.1 t ha-1), dry matter yield (4.85 t ha-1), crude proteins (8.9%), ash contents (11%) and sugar contents (12.8%), respectively. Similarly, harvesting after 90 days of sowing gave highest leaves per plant (14.72), fresh forage yield (45.1 t ha-1), dry matter yield (5.60 t ha-1), ash contents (12.2%) and sugar contents (14.1%), respectively. These results suggested that sowing in 30 cm apart lines and harvesting after 90 days of sowing improved the growth, yield and quality of sweet sorghum under the semiarid region of Faisalabad.

Contamination of soils with heavy metals (HMs) is an important issue due to the contamination of agricultural crops, which are further transferred into the food chain. Phytoremediation is an emerging method of remediating metal-contaminated soils. Sunflower has been widely adopted for phytomanagement of HM-contaminated soils owing to its high biomass production and capacity for metal accumulation. Sunflowers can tolerate the toxic effects of certain HMs through different mechanisms, such as enhancements in antioxidant enzyme activities, deposition in nonactive parts of the plant, and stimulation of osmolytes. Stress caused by HMs affected negatively the seed germination, nutritional status, photosynthesis, and growth of sunflower. However, the responses of sunflowers to this stress vary with cultivar/variety, soil type, metal type, dose, and duration of metal exposure. This review critically summarizes the effects of HMs in sunflowers and examines field-relevant approaches to improve the phytoextr...

Cadmium (Cd) level is continuously increasing in agricultural soils mainly through anthropogenic activities. Cadmium is one of the most phytotoxic metals in soils. The present study investigates the possible role of exogenously applied glycinebetaine (GB) in alleviating Cd toxicity in cotton (Gossypium hirsutum L.) plants in a hydroponic system. Three concentrations of Cd (0, 1.0, and 5.0 μM) were tested with and without foliar application of GB (1.0 mM). Cadmium toxicity caused a significant decrease in plant height, root length, number of leaves per plant, fresh and dry weights of leaf, stem and root and intensively increased Cd concentration in different plant parts. Cadmium toxicity also decreased photosynthetic pigments and gas exchange characteristics in leaves. Superoxide dismutase (SOD), guaiacol peroxidase (POD), catalases (CAT) and ascorbate (APX) activities increased under lower Cd stress (1.0 μM) while decreased under higher Cd stress (5.0 μM). Cadmium toxicity increased the concentration of reactive oxygen species (ROS) as indicated by the increased production of malondialdehyde (MDA), hydgrogen peroxide (H2O2) and electrolyte leakage in both leaves and roots. Application of GB decreased Cd concentration in different plant parts, alleviated Cd-induced inhibition in plant growth and biomass and led to a significant increase in photosynthetic pigments, protein contents and antioxidant enzymes. Glycinebetaine application alleviated the oxidative damage as evidenced by the decreased production of electrolyte leakage, H2O2 and MDA contents. These results revealed that GB might alleviate Cd toxicity in cotton plants through lowering Cd concentrations and regulating Cd induced oxidative stress in different plant parts possibly by increasing the performance of the antioxidant enzymatic system.

A crop modeling approach can be used to assess various crop management options and water productivity to improve crop production for different environments. The goal of this study was to determine optimum planting dates and nitrogen management options using a systems analysis approach based on the Cropping System Model (CSM) CERES-Wheat of DSSAT v 4.6. Wheat experiments were conducted from 2007 to 2013 under semi-arid conditions at the experimental fields of the Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan. The CSM-CERES-Wheat model was calibrated for wheat (Triticum aestivum L.) cultivar Sehar-2006 from a 3-year field experiment data on flowering day, maturity day, canopy cover, grain yield, biomass, grain nitrogen content, and nitrogen harvest index. After calibration, the CSM-CERES-Wheat model produced satisfactory simulations for wheat phenology and crop growth parameters. The model was then evaluated using six years of independent datasets for both irrigated and rainfed conditions. The evaluation showed that the model performed well as indicated by the accurate simulation of wheat phenology [the normalized root mean square error (NRMSE) = 3%] and crop growth parameters such as crop cover (NRMSE = 7%–13%), biomass (NRMSE = 17%), and grain yield (NRMSE = 9%) against measured data. The model's performance was less satisfactory for biomass production under high soil moisture or rainfed conditions. Focusing on differences in temperature and rainfall patterns during the potential growing season, the model was used to estimate the optimum planting dates and in-season nitrogen management options using 39 years (1974–2013) of historical weather data for short-term adaptation against climate variability. The scenario simulations for planting dates showed that growing wheat under rainfed conditions at the study region is not a viable option. However, based on the simulation results, we concluded that early planting from November 1st to 10th for irrigated conditions with applications of 150 kg N ha−1 in three equal splits with the first at sowing and the rest two splits during vegetative growth phase could result in higher crop yield and water use efficiency. This study showed that the model can be a promising tool for providing crop management recommendations under high-temperature conditions found in the semi-arid conditions.

Tannery wastewater mainly comes from leather industries. It has high organic load, high salinity, and many other pollutants, including chromium (Cr). Tannery wastewater is generally used for crop irrigation in some areas of Pakistan and worldwide, due to the low availability of good quality of irrigation water. As tannery wastewater has many nutrients in it, its lower concentration benefits the plant growth, but at a higher concentration, it damages the plants. Chromium in tannery wastewater accumulates in plants, and causes stress at physiological and biochemical levels. In recent times, the role of micronutrient-amino acid chelated compounds has been found to be helpful in reducing abiotic stress in plants. In our present study, we used lysine chelated zinc (Zn-lys) as foliar application on maize (Zea mays L.), growing in different concentrations of tannery wastewater. Zinc (Zn) is required by plants for growth, and lysine is an essential amino acid. Maize plants were grown in tannery wastewater in four concentrations (0, 25%, 50%, and 100%) and Zn-lys was applied as a foliar spray in three concentrations (0 mM, 12.5 mM, and 25 mM) during plant growth. Plants were cautiously harvested right after 6 weeks of treatment. Foliar spray of Zn-lys on maize increased the biomass and improved the plant growth. Photosynthetic pigments such as total chlorophyll, chlorophyll a, chlorophyll b and contents of carotenoids also increased with Zn-lys application. In contrast to control plants, the hydrogen peroxide (H2O2) contents were increased up to 12%, 50%, and 68% in leaves, as well as 16%, 51% and 89% in roots at 25%, 50%, and 100% tannery water application, respectively, without Zn-lys treatments. Zn-lys significantly reduced the damages caused by oxidative stress in maize plant by decreasing the overproduction of H2O2 and malondialdehyde (MDA) in maize that were produced, due to the application of high amount of tannery wastewater alone. The total free amino acids and soluble protein decreased by 10%, 31% and 64% and 18%, 61% and 122% at 25%, 50% and 100% tannery water treatment. Zn-lys application increased the amino acids production and antioxidant activities in maize plants. Zn contents increased, and Cr contents decreased, in different parts of plants with Zn-lys application. Overall, a high concentration of tannery wastewater adversely affected the plant growth, but the supplementation of Zn-lys assertively affected the plant growth and enhanced the nutritional quality, by enhancing Zn and decreasing Cr levels in plants simultaneously irrigated with tannery wastewater.

Cotton (Gossypium hirsutum L.) is a well-known and economically most beneficial crop worldwide while nickel (Ni) toxicity is a widespread problem in crops grown on Ni-contaminated soils. We investigated the response of silicon (Si) in cotton under Ni stress with respect to growth, biomass, gas exchange attributes, enzymatic activities, and Ni uptake and accumulation. For this, plants were grown in hydroponics for 12 weeks with three levels of Ni (0, 50, and 100 µM) in the presence or absence of 1 mM Si. Results showed that Ni significantly reduced the plant growth, biomass, gas exchange attributes, and pigment contents while Si application mitigated these adverse effects under Ni stress. Nickel stress significantly decreased antioxidant enzymes’ activities while increased malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EC) in leaves and roots. The application of Si enhanced the activities of antioxidant enzymes and reduced MDA, H2O2, and EC in plants. Nickel application significa...

Performance of B. napus in phytoextraction—an in situ environment friendly technique for the cleanup of contaminated soils—was evaluated through its response to cadmium (Cd) toxicity in combination with a chelator ethylenediamminetetraacetic acid (EDTA) while growing hydroponically in greenhouse conditions under three levels of Cd (0, 10, and 50 µM) and two levels of EDTA (0 and 2.5 mM). Cadmium presence decreased plant growth, biomass and chlorophyll concentrations, while the application of EDTA enhanced plant growth by reducing Cd-induced effects in Cd-stressed plants. Addition of EDTA improved the net photosynthetic and gas exchange capacity of plants under Cd stress. Presence of Cd at 10 and 50 μM significantly increased electrolyte leakage, the production of hydrogen peroxidase (H2O2) and malondialdehyde (MDA) resulting into a significant reduction in the activities of catalase, guaiacol peroxidase, ascorbate peroxidase and superoxide dismutase in Cd-stressed plants. Application of EDTA at the rate of 2.5 mM alone and with combination of Cd increased the antioxidant enzymes activities and reduced the electrolyte leakage and production of H2O2 and MDA. The B. napus actively accumulated Cd when applied with EDTA in roots, stems and leaves viz. 2817, 2207 and 1238 mg kg−1 DW, respectively, at higher Cd level (50 μM) followed by lower level of Cd (10 μM) viz. 1704, 1366 and 763 mg kg−1 DW, respectively. Results showed that this technique could be useful for the remediation of heavy metal-contaminated agricultural and industrial soils.

Contamination of soils with cadmium (Cd) is a serious problem worldwide. Rice (Oryza sativa L.) is reported to accumulate relatively higher Cd contents in consumable parts and is considered a main source of Cd toxicity to humans from rice-derived products. The aim of this pot trial was to investigate the effect of foliar-applied iron (Fe) complexed with lysine on growth, photosynthesis, Cd concentration in plants, oxidative stress, and activities of antioxidants of rice in soil contaminated with Cd. Rice seedlings (30-day-old) were transferred to the soil, and after 2 weeks, different concentrations of Fe-lysine (0, 1.5, 3.0, 4.5, 6.0, and 7.5 mg L−1) were applied as a foliar spray once in a week for 4 weeks and plant samples were taken after 10 weeks of growth in the soil under ambient conditions. Foliar supply of Fe-lysine complex significantly enhanced the plant height, dry weights of plants, concentration of chlorophyll, and gas exchange attributes in Cd-stressed rice. Fe-lysine decreased the Cd concentrations in plants while increasing the Fe concentrations in rice seedlings being maximum with Fe-lysine of 6.0 mg L−1. Electrolyte leakage decreased while activities of key antioxidant enzymes increased with Fe-lysine compared to the control. According to the present results, Fe-lysine complex can effectively be used to reduce Cd concentrations in rice and probably in other crop species.

The use of chromium (Cr)-contaminated tannery wastewater for irrigation is a common practice, especially in developing countries like Pakistan. This practice is due to the shortage of good quality irrigation water for crop growth as well as the issue of tannery wastewater disposal. The current study was done to evaluate the effect of citric acid (CA) (0, 1.0, and 2.0 mM) on the growth and Cr uptake by spinach irrigated with different mixtures of tap water and tannery wastewater (100:0, 50:50, and 0:100 tap water to wastewater ratio). Plants were grown for 8 weeks under ambient conditions. Results showed that 50:50% tap water and wastewater increased plant height, dry weights of shoots and roots, total chlorophyll contents, and gas exchange attributes than the plants treated with only tap water or only wastewater. Increasing wastewater ratio increased electrolyte leakage (EL) in plants and enhanced the leaf key antioxidant enzyme activities as well as increased Cr contents. Foliar application of CA increased the plant dry weights, photosynthesis, and enzyme activities, whereas reduced the EL and Cr concentrations in plants than respective treatments without CA application. It can be concluded that 50:50 tap water and wastewater irrigation along with foliar CA application might be an effective strategy for increasing vegetable growth with reduced metal concentrations.

Phytoextraction is an eco-friendly and cost-effective technique for removal of toxins, especially heavy metals and metalloids from contaminated soils by the roots of high biomass producing plant species with subsequent transport to aerial parts. Lower metal bioavailability often limits the phytoextraction. Organic chelators can help to improve this biological technique by increasing metal solubility. The aim of the present study was to investigate the possibility of improving the phytoextraction of Cd by the application of citric acid. For this purpose, plants were grown in hydroponics under controlled conditions. Results indicated that Cd supply significantly decreased the plant growth, biomass, pigments, photosynthetic characteristics and protein contents which were accompanied by a significant increase in Cd concentration, hydrogen peroxide (H₂O₂), electrolyte leakage, malondialdehyde (MDA) accumulation and decrease in antioxidant capacity. The effects were dose dependent with obvious effects at higher Cd concentration. Application of CA significantly enhanced Cd uptake and its accumulation in plant roots, stems and leaves. Citric acid alleviated Cd toxicity by increasing plant biomass and photosynthetic and growth parameters alone and in combination with Cd and by reducing oxidative stress as observed by reduction in MDA and H₂O₂ production and decreased electrolyte leakage induced by Cd stress. Application of CA also enhanced the antioxidant enzymes activity alone and under Cd stress. Thus, the data indicate that exogenous CA application can increase Cd uptake and minimize Cd stress in plants and may be beneficial in accelerating the phytoextraction of Cd through hyper-accumulating plants such as Brassica napus L.

Heavy metals are among the major environmental pollutants and the accumulation of these metals in soils is of great concern in agricultural production due to the toxic effects on crop growth and food quality. Phytoremediation is a promising technique which is being considered as an alternative and low-cost technology for the remediation of metal-contaminated soils. Solanum nigrum is widely studied for the remediation of heavy metal-contaminated soils owing to its ability for metal uptake and tolerance. S. nigrum can tolerate excess amount of certain metals through different mechanism including enhancing the activities of antioxidant enzymes and metal deposition in non-active parts of the plant. An overview of heavy metal uptake and tolerance in S. nigrum is given. Both endophytic and soil microorganisms can play a role in enhancing metal tolerance in S. nigrum. Additionally, optimization of soil management practices and exogenous application of amendments can also be used to enhance metal uptake and tolerance in this plant. The main objective of the present review is to highlight and discuss the recent progresses in using S. nigrum for remediation of metal contaminated soils.

Presence of heavy metals in agricultural soils is of major environmental concern and a great threat to life on the earth. A number of human health risks are associated with heavy metals regarding their entry into food chain. Various physical, chemical and biological techniques are being used to remove heavy metals and metalloids from soils. Among them, phytoremediation is a good strategy to harvest heavy metals from soils and have been proven as an effective and economical technique. In present review, we discussed various sources and harmful effects of some important heavy metals and metalloids, traditional phytoremediation strategies, mechanisms involved in phytoremediation of these metals, limitations and some recent advances in phytoremediation approaches. Since traditional phytoremediation approach poses some limitations regarding their applications at large scale, so there is a dire need to modify this strategy using modern chemical, biological and genetic engineering tools. In view of above, the present manuscript brings both traditional and advanced phytoremediation techniques together in order to compare, understand and apply these strategies effectively to exclude heavy metals from soil keeping in view the economics and effectiveness of phytoremediation strategies.

Using an alkaline calcareous soil, experiments were conducted to elucidate the effects of nitrification inhibitor dicyandiamide (DCD) on the fate of 15N-labelled urea applied to cotton, maize, and wheat under greenhouse conditions. Combined effects of DCD and two levels of wheat straw (applied to cotton) and of fertilizer application method (conventional broadcast vs. point injection in maize and wheat) on the recovery of the fertilizer N were also studied. High soil temperatures prevailed under cotton and maize, whereas the soil temperature was relatively moderate during the wheat growing season. The fertilizer N loss under cotton was lowest (44% of the applied) when urea was applied alone; the loss increased due to DCD (54%) or wheat straw (50–54%) and was highest (63–64%) when DCD and wheat straw were applied together. Under maize also, DCD increased the loss of the fertilizer N applied by the conventional method (51% without DCD vs. 66% with DCD) or by point injection (26% without DCD vs. 42% with DCD). With the conventional method under wheat, DCD had no effect on the fertilizer N loss (34–37% of the applied). The fertilizer N loss under wheat was least (16%) when urea solution was point-injected but increased (24–26%) due to DCD or/and when pH of the urea solution was reduced to 2. Besides, DCD significantly reduced the fertilizer N uptake and increased the fertilizer N immobilization in soil under cotton and maize. However, DCD applied in combination with a higher level of wheat straw significantly increased the cotton dry matter and N yields due to increased N availability from sources other than the fertilizer. The results suggested that the use of DCD may not be beneficial in alkaline calcareous soils and that point injection of urea solution without any amendment is more effective in conserving the fertilizer N as compared to the conventional broadcast method.

Organic city wastes are recycled to prepare composts with improved physical properties and enriched with nutrientsfor their better utilization. Combined application of composts along with inorganic fertilizers may sustain cropproductivity and soil fertility. Present study was conducted to assess the impact of 3 city waste composts (2 nonenrichedand 1 enriched with 25% N requirement of crop) on the economical utilization of urea in wheat. Generally,fertilizer application along with compost increased the yield, N and P uptake by wheat compared to the fertilizeralone. Performance of the treatments was found in the order: NEC (nitrogen enriched compost) + fertilizer > nonenrichedcompost + fertilizer > fertilizer. The NEC along with lower fertilizer-N rate (75 mg kg-1 soil) was found atpar with that of the highest fertilizer rate (175 mg N kg-1 soil) alone. The results showed that the use of NEC (200mg kg-1 soil) for wheat production could be a useful tool to improve the efficiency of commercial N-fertilizer.

Silicon (Si) is as an important fertilizer element, which has been found effective in enhancing plant tolerance to variety of biotic and a-biotic stresses. This study investigates the Si potential to alleviate zinc (Zn) toxicity stress in cotton (Gossypium hirsutum L.). Cotton plants were grown in hydroponics and exposed to different Zn concentration, 0, 25, and 50 μM, alone and/or in combination with 1 mM Si. Incremental Zn concentration in growth media instigated the cellular oxidative damage that was evident from elevated levels of hydrogen peroxide (H2O2), electrolyte leakage, and malondialdehyde (MDA) and consequently inhibited cotton growth, biomass, chlorophyll pigments, and photosynthetic process. Application of Si significantly suppressed Zn accumulation in various plant parts, i.e., roots, stems, and leaves and thus promoted biomass, photosynthetic, growth parameters, and antioxidant enzymes activity of Zn-stressed as well unstressed plants. In addition, Si reduced the MDA and H2O2 production and electrolyte leakage suggesting its role in protecting cotton plants from Zn toxicity-induced oxidative damage. Thus, the study indicated that exogenous Si application could improve growth and development of cotton crop experiencing Zn toxicity stress by limiting Zn bioavailability and oxidative damage.