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Nitrogen (N), the building block of plant proteins and enzymes, is an essential macronutrient for plant functions. A field experiment was conducted to investigate the impact of different N application rates (28, 57, 85, 114, 142, 171, and 200 kg ha−1 ) on the performance of spring wheat (cv. Ujala-2016) during the 2017–2018 and 2018– 2019 growing seasons. A control without N application was kept for comparison. Two years mean data showed optimum seed yield (5,461.3 kg ha−1 ) for N-application at 142 kg ha−1 whereas application of lower and higher rates of N did not result in significant and economically higher seed yield. A higher seed yield was obtained in the 2017–2018 (5,595 kg ha−1 ) than in the 2018–2019 (5,328 kg ha−1 ) growing seasons under an N application of 142 kg ha−1. It was attributed to the greater number of growing degree days in the first (1,942.35°C days) than in the second year (1,813.75°C). Higher rates of N (171 and 200 kg ha−1 ) than 142 kg ha−1 produced more number of tillers (i.e., 948,300 and 666,650 ha−1, respectively). However, this increase did not contribute in achieving higher yields. Application of 142, 171, and 200 kg ha−1 resulted in 14.15%, 15.0% and 15.35% grain protein concentrations in comparison to 13.15% with the application of 114 kg ha−1 . It is concluded that the application of N at 142 kg ha−1 could be beneficial for attaining higher grain yields and protein concentrations of wheat cultivar Ujala-2016. [ABSTRACT FROM AUTHOR]

The effect of nitrogen (N) forms on growth and accumulation of nickel (Ni), zinc (Zn), copper (Cu), and manganese (Mn) by wheat genotypes viz. Lasani‐2008 and Sahar‐2006 is investigated. Genotypes are grown in Ni‐contaminated soil with different N forms viz. urea, NH4–N, mixed N (NH4–NO3), and NO3–N. Lasani‐2008 produces maximum shoot dry weight (SDW) with NO3–N while Sahar‐2006 produces maximum SDW with NH4–N. Lasani‐2008 has higher SDW (24%), greenness index (7%), photosynthetic rate (18%), and transpiration rate (29%) compared to Sahar‐2006. This genotype accumulates more N with mixed N (NH4–NO3) and NH4–N and has 47% higher remediation factor. Lasani‐2008 contains 43% more Ni and maximum Zn in roots with NH4–N while minimum with NO3–N. Lasani‐2008 accumulates Ni and Zn more in shoots while Sahar‐2006 retains more Ni in roots. Sahar‐2006 contains 16% higher Mn in shoot compared to Lasani‐2008. Manganese is maximum with NO3–N followed by urea in roots. It is concluded that genotypes differ for Ni accumulation in response to N forms. Lasani‐2008 proves effective for remediation of Ni‐contaminated soils while Sahar‐2006 can be a good choice for restricting the entry of potentially toxic elements into food chain. [ABSTRACT FROM AUTHOR]

We investigated the role of ascorbic acid (AsA) to alleviate nickel (Ni) induced adverse effects on growth and concentration of Ni, copper (Cu), and manganese (Mn) in hydroponically grown wheat varieties viz. Galaxy, Punjab-2011, and FSD-08. Plants were exposed to five levels of Ni viz. 0, 5, 10, 15, and 20 mg L−1. After 1 week, AsA (1 mM) was sprayed onto the Ni-stressed plants. FSD-08 produced the maximum SDW with and without AsA compared to other varieties. FSD-08, Galaxy, and Punjab-2011 witnessed 2.61-, 2.83-, and 7.5-fold increases in SDW with AsA, respectively. Wheat plants contained the maximum Ni in shoots and roots with a Ni level of 20 mg L−1 irrespective of varieties. Nickel in shoots decreased with AsA witnessing 13, 12, and 10% decrease in FSD-08, Punjab-2011, and Galaxy, respectively. Nickel in roots of FSD-08 decreased by 18% while increased by 3.34-fold and 3.50-fold in Galaxy and Punjab-2011, respectively with AsA. Nickel decreased Cu in shoot and Mn in shoot and root while Cu in roots of all wheat varieties increased. It was concluded that AsA improved the growth of Ni-stressed and FSD-08 performed better by maintaining good growth and less Ni in shoots compared to other varieties. Exploiting plant internal mechanisms with foliar application of different organic substances have widely been investigated to decrease metal accumulation and their adverse effects on plants. However, the differential response of different varieties to metal accumulation in response to foliar application of ascorbic acid is not well documented. This study was conducted to investigate the effect of exogenous application of ascorbic acid on growth response, the concentration of Ni, Cu, and Mn in three wheat varieties. [ABSTRACT FROM AUTHOR]

Contamination of agricultural soils with lead (Pb) is a widespread problem which is mainly due to anthropogenic activities. The present study investigated the effect of organic and inorganic amendments on wheat growth and reducing Pb concentration in the plant. A greenhouse experiment was conducted on Pb spiked soil (500 mg kg of soil) with the application of farmyard manure, poultry manure, gypsum and di-ammonium phosphate (DAP). Plants were harvested after 120 days of growth and analyzed for Pb concentration in different plant parts. Under Pb stress, amendments significantly ( p < 0.05) increased grain yield and root dry weights compared to the control. Grain yield and dry weights of shoots and roots were maximum with DAP compared to the control and other amendments. Amendments increased transpiration rate, stomatal conductance, chlorophyll contents and photosynthetic rate. The lowest Pb concentration was found in DAP treated plants which were about 88%, 84%, and 85% lower in root, shoots and grains than control respectively. DAP fertilizer was the most effective in improving these parameters than control and other amendments and can be used to reduce Pb concentration in wheat and probably other crops. [ABSTRACT FROM AUTHOR]

The essentiality of phosphorus (P) as a macronutrient and that of zinc (Zn) as micronutrient for plants has been established long ago but their interactive effects on economic yield of crops are still controversial particularly in calcareous saline-sodic soils. Therefore, a pot experiment was conducted to evaluate the P-Zn interaction effects on wheat in saline-sodic soil. The treatments comprised of four levels of P (0, 25, 50 and 75 mg kg-1 soil) and three levels of Zn (0, 5 and 10 mg kg-1 soil) arranged in completely randomized design each with three replications. The results showed that total number of tillers, plant height, straw dry weight and 1000-grain weight was significantly (P ≤ 0.05) higher in saline-sodic control closely followed by applied P at 75 mg kg-1 soil + Zn at 5 mg kg-1 soil (P75Zn5). While maximum Zn concentration in wheat straw and grains was observed in P75Zn5. The maximum ammonium-bicarbonate-diethylene-triamine-penta-acetic acid (AB-DTPA) extractable P and Zn in post-experiment soil was recorded with P at 75 mg kg-1 soil + Zn at 10 mg kg-1 soil (P75Zn10). Thus, application of P at 75 mg kg-1 soil along with Zn 5 mg kg-1 soil was the appropriate combination of P and Zn for substantial increase in growth and yield of wheat in saline-sodic soil. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) toxicity is a widespread problem in crops grown on contaminated soils, and little information is available on the role of inorganic amendments in Cd immobilization, uptake, and tolerance in crops especially under filed conditions. The effect of three amendments, monoammonium phosphate (MAP), gypsum, and elemental sulfur (S), on Cd immobilization in soil and uptake in wheat and rice plants, under rotation, were investigated under field conditions receiving raw city effluent since >20 years and contaminated with Cd. Three levels of each treatment, 0.2, 0.4, and 0.8 % by weight, were applied at the start of the experiment, and wheat was sown in the field. After wheat harvesting, rice was sown in the same field without application of amendments. Both crops were harvested at physiological maturity, and data regarding grain yield, straw biomass, Cd concentrations, and uptake in grain and straw, and bioavailable Cd in soil and soil pH were recorded. Both MAP and gypsum application increased grain yield and biomass of wheat and rice, while S application did not increase the yield of both crops. MAP and gypsum amendments decreased gain and straw Cd concentrations and uptake in both crops, while S application increased Cd concentrations in these parts which were correlated with soil bioavailable Cd. We conclude that MAP and gypsum amendments could be used to decrease Cd uptake by plants receiving raw city effluents, and gypsum might be a better amendment for in situ immobilization of Cd due to its low cost and frequent availability. [ABSTRACT FROM AUTHOR]

Nickel (Ni) contamination in soil is a widespread problem in this era of industrial development. Plant cultivars respond differentially to Ni contamination in soil. In the present study, we have investigated the effect of different Ni levels to the growth and mineral status of two wheat cultivars (Sehar-2006 and LU-26). Five different levels of Ni as NiSO4 · 4 H2O (0, 30, 45, 60, and 75 mg kg−1) were applied to soil in the pots. LU-26 performed better compared to Sehar-2006 in terms of dry weight production and physiological parameters. LU-26 contained higher Ni in roots compared to Sehar-2006, but the Ni concentration in shoots of both the cultivars was similar. LU-26 translocated less Ni toward the shoot compared to Sehar-2006 indicating the exclusion of Ni from shoots and retaining it in roots by LU-26 as evident from bioconcentration and translocation factors. Contradictly, Sehar-2006 translocated more Ni from root to shoot indicating its tolerance to Ni. Ni increased manganese (Mn) in shoots of Sehar-2006 and LU-26 up to 60 and 30 mg kg−1, respectively. Ni decreased copper (Cu) and zinc (Zn) concentration in shoots of both cultivars, however Zn concentration in roots increased at all levels of Ni. LU-26 excluded Ni from shoots and Sehar-2006 accumulated Ni in shoots. The present study helps in understanding the process of metal uptake and distribution during the early growth stages of the plant and can signify overall potential of a crop for its exploitation on contaminated soils. [ABSTRACT FROM AUTHOR]

With more pressing demands for non-agricultural sectors, availability of good-quality water is falling short of the crop water requirement, particularly in arid and semi-arid regions of the world, like Pakistan. Studies were conducted at three sites following randomized complete block design (RCBD) with three replications. The treatments employed were: Tube well water (TW) alone; TW + Gypsum @ 50% soil gypsum requirement (TW + G50); TW-Canal water (CW) + G50; TW-CW + farm manure (FM) @ 25 Mg ha-1 (TW-CW + FM) before sowing wheat. After the harvest of wheat 2008-09, non-significant decrease in bulk density was recorded with applied treatments while infiltration rate remained unchanged. There was maximum and significant decrease in ECe and SAR with TW-CW + FM at all the three sites. Maximum decrease in ECe (72.65%) at 0-15 cm soil depth was at site 2, while maximum decrease in ECe (77.62%) at 15-30 cm soil depth was at site 1. Maximum percent decrease in SAR was 75.76% at 0-15 cm followed by 63.93% at15-30 cm at sites 2 and 3, respectively, with TW-CW + FM. Maximum wheat grain yields (3656, 3531 and 3826 kg ha-1) and straw yields (4826, 4624 and 4707 kg ha-1) were recorded at sites 1, 2 and 3, respectively, with TW-CW + FM. The net benefit was maximum with TW-CW + FM at all the three sites. [ABSTRACT FROM AUTHOR]

Once soil solution phosphorus (P) level optimum for plant growth is identified, P adsorption isotherms or their equations can further be used to estimate fertilizer P rates required to adjust this desired soil solution P level to obtain maximum yield. Surface soil samples were collected from a farmer's field area and research area. An adsorption study was conducted on Ustic Endoaquerts (S1 soil), Typic Calciargids (S2 soil), and Typic Torripsamments (S3 soil) to develop the Freundlich-type equations. Phosphorus adsorption data were obtained by equilibrating 10-g soil samples in 100 mL of 0.01 M calcium chloride (CaCl2) containing various amounts of monopotassium phosphate (KH2PO4). Values of 1/n (slope) ranged from 0.4827 to 0.6452 L kg-1. Based on 1/n values, it was inferred that each of the two S1 and S3 soils was homogeneous and S2 was not. The KF (mg P kg-1) values of S1, S2, and S3 soils were 92.45, 55.81, and 23.38, respectively. The highest amount of P (92.45 mg kg-1) was adsorbed at unit EPC in S1 soil, whereas the lowest amount (23.38 mg P kg-1) was adsorbed in S3 soil. Thereafter, 11 P fertilizer doses were calculated by these Freundlich-type equations to adjust different estimated soil solution P levels that were designated as treatments (0.05 to 0.90 mg L-1). Then field experiments on wheat (cv. Inqalab-91) were conducted according to a randomized complete block design (RCBD) on these soils to determine internal (plant tissue), external (soil solution), and fertilizer P requirements. Maximum wheat gain yield (Mg ha-1) was 6.82 with T5 (0.25 mg P L-1) on S1 soil, 5.96 with T5 (0.25 mg P L-1) on S2 soil, and 4.97 with T7 (0.40 mg P L-1) on S3 soil that was obtained by application of 196 kg P2O5 ha-1 on S1 soil, 142 kg P2O5 ha-1 on S2 soil, and 78 kg P2O5 ha-1 on S3 soil. Internal P concentration (%) associated with 95% of maximum wheat yield at booting stage was 0.32 in S1, 0.21 in S2, and 0.33 in S3 soil. In straw, it was 0.123% in S1, 0.080% in S2, and 0.108% in S3 soil. The internal P requirement of wheat grain was 0.39% in S1, 0.40% in S2, and 0.37% in S3 soil. External soil solution P requirement (ESPR) for 95% of maximum yield of wheat was 0.45 mg L-1 in S1 soil, 0.34 mg L-1 in S2 soil, and 0.44 mg L-1 in S3 soil. Quantity of P2O5 corresponding to ESPR values were 217 kg ha-1 on S1, 123 kg ha-1 on S2, and 60 kg ha-1 on S3 soil. Putting ESPR values in the respective Freundlich-type equation, P fertilizer rates (kg P2O5 ha-1) were estimated that were 282 on S1, 167 on S2, and 83 on S3 soil; Practically, 262, 156, and 78 kg P2O5 ha-1 was applied in the field to adjust soil solution P level (mg L-1) at 0.40 (T7), 0.30 (T6), and 0.40 (T7) in S1, S2, and S3 soil, respectively, that are somewhat less than determined ESPR values. Phosphorous doses applied to achieve a desired EPAS value or estimated from graphs against predicted ESPR values, or calculated from corresponding Freundlich-type equations using desired ESPR values are in close proximity to one another. Therefore, any of the techniques can be used interchangeably to estimate the P fertilizer requirement for optimum wheat yield. [ABSTRACT FROM AUTHOR]

The large genotypic variation for salt tolerance in rice and wheat is the driving force behind efforts to identify appropriate cultivars for salt-prone environments where large variations in salinity (electrical conductivity, EC) and sodicity (sodium adsorption ratio, SAR) levels exist. An evaluation of the commonly grown rice and wheat cultivars at different EC/SAR ratios may thus help in coping with the crop failures on salt-affected soils. Accordingly, we evaluated some salt-tolerant cultivars of rice and wheat for growth and yield at different soil salinity and sodicity levels in a sandy clay loam soil. Among the cultivars tested, rice 'SSRI-8' produced the highest productive tillers and paddy yield, and wheat cultivar 'SIS-32' produced the highest tillers and grain and straw yields. The high EC/SAR ratios proved more hazardous for rice than for wheat. Irrespective of the varieties tested, the highest levels of EC and SAR (T5 and T6) caused significant reduction in paddy yield, whereas at the lowest levels of EC and SAR (T1 and T2), paddy yield was not affected significantly when compared with the control. However, in case of wheat crop, all the levels [i.e., the lowest (T1 and T2), medium (T3 and T4), and the highest (T5 and T6) of EC and SAR tested] affected wheat yield adversely with significant differences. For both the crops, there were little or no differences in yield between the two ratios tested (i.e., 1:2 and 1:4) at all the levels of EC and SAR. [ABSTRACT FROM AUTHOR]

Abstract: A pot study was used to examine the effects of amendments such as EDTA and elemental sulfur on the growth potential, gas exchange features, uptake and mobilization of Pb by wheat (Triticum aestivum L.) in two texturally different contaminated soils at three levels of EDTA (2, 4, 8mmolkg−1 dry soil) and two levels of elemental sulfur (100, 200mmolkg−1 dry soil). EDTA resulted in more solubilization of Pb than elemental sulfur in both soils. Application of EDTA and elemental sulfur increased shoot dry matter in the loamy sand soil, whereas in the sandy clay loam soil EDTA treated plants produced lower shoot dry matter compared to that observed with elemental sulfur. Application of EDTA 10d prior to harvest increased the amount of Pb accumulated into wheat shoots with more Pb accumulated by plants from the loamy sand than from the sandy clay loam soil. However, evaluation of the relative extraction efficiency expressed as the percentage of solubilized Pb that is subsequently also effectively accumulated by the plant shoots reveals that the relatively low efficiency does not warrant the massive mobilization induced by the environmentally persistent EDTA chelator. More modest mobilization of Pb induced by elemental sulfur and the higher relative extraction of mobilized Pb therefore deserves further attention in future research. In particular, attention needs to be paid to determining soil types in which elemental sulfur can induce significant impact on soil pH and metal mobility after application of a practically realistic dosage. [Copyright &y& Elsevier]

Wheat (Triticum aestivum L.) cultivation in cadmium (Cd) polluted soil is a core concern to food quality and food security all over the world. Cadmium toxicity is mainly associated with a Cd influx from contaminated soils to human via grain consumption. Organic amendments are widely used for Cd immobilization and enhancement in plant growth, but the residual effects of these amendments are mostly unknown. The present study addressed the long-term effects of organic amendments in contaminated soils by evaluating their residual effects on 3rd crop (wheat) in the sequence. Initially six organic amendments viz. rice husk biochar (RHB), wheat-straw biochar (WSB), cotton-stick biochar (CSB), poultry manure (PM), press mud (PrMd) and farm manure (FM) were applied once at a rate of 2% in Cd (50 mg kg−1) contaminated soil with wheat-rice rotation. After the harvest of wheat and rice crops, wheat (Var. Galaxy) was again grown in the same pots. Results revealed that plants grown under Cd stress (without any amendment) contain more tissue (root, shoot and grain) and soil AB-DTPA extractable Cd. The soil amended with RHB has shown lowest AB-DTPA extractable Cd (69% lower than control). Similarly, RHB application has significantly reduced wheat root, shoot and grain Cd concentrations compared to control and other amendments. Results have confirmed the effectiveness of RHB residual contents as an active amendment for restriction of Cd in non-bioavailable pool of soil and better growth and yield of wheat. • Residual effects of rice husk biochar (RHB) and press mud (PrMd) were higher compared to other amendments. • The increase in wheat growth and yield was highest in residual RHB treatment. • Cd immobilization index was highest in RHB treatment. • The grain Cd was below threshold level in RHB treatment. [ABSTRACT FROM AUTHOR]