Effect of preceding crops and their residues on availability of zinc in a calcareous Zn-deficient soil

Limited information is available on the effect of preceding crop on phytoavailability of zinc (Zn) in soil. This pot experiment examined the effect of four preceding crops including clover, sunflower, safflower, and sorghum residues on shoot and grain Zn uptake by two wheat genotypes differing in Zn-deficiency tolerance Back Cross and Kavir in a calcareous Zn-deficient soil. Incorporation of all preceding crop residues into the soil significantly increased organic matter (OM) content, dissolved organic C (DOC), and diethylene triamine pentaacetic acid (DTPA) extractable Zn concentration in the soil. Residues of safflower and clover had the greatest effect on increasing DOC. Shoot and grain Zn concentrations were increased by incorporating all pre-crop residues into the soil although this increase was greater at safflower and clover treatments. Incorporation of sorghum residues into the soil had a negative effect on shoot and grain dry matter yield of wheat. Incorporation of safflower and clover residues into the soil increased Zn uptake by wheat shoot and grain. There was a positive significant correlation between shoot and grain Zn concentration with DOC in soil solution. It shows that DOC, produced from decomposition of crop residues, has facilitated Zn uptake by roots of wheat plants and particularly its transfer to grains.     

Zinc fractions in soil and uptake by wheat as affected by different preceding crops

Zinc (Zn) deficiency is widespread in alkaline and calcareous soils. Limited information is available on the effect of preceding crops on the distribution of Zn in soil solid phase. This field study was conducted to investigate the changes in Zn chemical forms in soil solid phase as affected by four preceding crops [Sunflower (Heilianthus annuus L. cv. Allstar), Sorghum (Sorghum bicolor L. cv. Speed Feed), Clover (Trifolium pratense L.) and Safflower (Carthamus tinctorius L. cv. Koseh-e-Isfahan)] in a calcareous soil. A control treatment with no preceding crop (fallow) was also used. Our results showed that the preceding crops increased Zn concentration in exchangeable fraction (EXCH-Zn), the organically bound zinc form (ORG-Zn) and zinc bound to iron and manganese oxides (FeMnOX-Zn) while decreased carbonates bound-zinc (CAR-Zn) and residual zinc forms (RES-Zn). However, the changes in Zn fractions were dependent on the preceding crop type. The EXCH-Zn and ORG-Zn pools can be considered labile pools that play significant roles in supplying Zn for plants. Among the preceding crops used in this experiment, clover (Clo) had the highest effect on transforming CAR-Zn form to EXCH-Zn and ORG-Zn labile forms and thus resulted in the highest Zn accumulation in tissues of the target wheat (Triticumaestivum L. cv. Back Cross). Although the changes in chemical forms of Zn in the soil solid phase are complex and dependent on various factors, our findings showed that the preceding crops significantly increased the concentration of Zn in exchangeable and organic matter pools and in turn resulted in higher uptake of Zn by the target wheat.     

The effectiveness of seed priming with synthetic zinc-amino acid chelates in comparison with soil-applied ZnSO4 in improving yield and zinc availability of wheat grain

The effect of soil applied zinc (Zn) sulfate and seed priming with Zn-glutamine [Zn(Gln)₂], Zn-glycine [Zn(Gly)₂], Zn-arginine [Zn(Arg)₂], and Zn-histidine [Zn(His)₂] on yield and grain nutritional quality of two bread (Triticum aestivum L. cvs. Back Cross and Kavir) and a durum wheat genotype (Triticum durum L. cv. Durum) was investigated. Seed priming with [Zn(Gly)₂] and [Zn(Gln)₂] increased grain yield of wheat over soil applied Zn-sulfate treatment by 46 and 14%, respectively. Seed priming with [Zn(Gln)₂], [Zn(Arg)₂], and [Zn(His)₂] significantly increased grain protein content of wheat in comparison with control treatment. Seed priming with [Zn(Arg)₂] and [Zn(His)₂] resulted in higher Zn and Fe accumulation in wheat grain as compared with the other Zn treatments. Priming seeds with [Zn(Arg)₂] reduced phytic acid to Zn molar ratio of wheat grain. Seed priming with [Zn(Arg)₂] and [Zn(His)₂] might be used as an alternative approach for soil application of Zn-sulfate to overcome Zn deficiency in calcareous soils.     

The role of root plasma membrane ATPase and rhizosphere acidification in zinc uptake by two different Zn-deficiency-tolerant wheat cultivars in response to zinc and histidine availability

ABSTRACT

We investigated the effect of histidine (His) and Zn deficiency on H⁺-ATPase activity and H⁺ release from wheat roots. Two bread wheat (Triticum aestivum L. cvs. Kavir and Back Cross Roshan) were grown in a nutrient solution for four weeks before being transferred to treatment solutions consisting of two concentrations of His (0 and 50 µM) and two concentrations of Zn (0 and 10 μM). The Zn-only and the Zn+His treatments were observed to release more H⁺ in the root media than did the control ones, with the highest achieved under the Zn+His treatment which was roughly 2.1 times higher than that under the control conditions. The H⁺ release from wheat roots increased slightly but significantly in the presence of only His when compared with the control solutions. The hydrolytic and transport activities of H⁺-ATPase were affected by both Zn deficiency and His supply. In both cultivars, application of Zn and His resulted in a higher hydrolytic activity of H⁺-ATPase when compared with the control solutions. The highest hydrolytic activity of H⁺-ATPase in the root plasma membrane vesicles was achieved with the Zn+His treatment. The ‘Back Cross Roshan’ exhibited a higher (PM) H⁺-ATPase activity and H⁺ pumping than did ‘Kavir’.     

Agronomic and economic efficiency of ground tire rubber and rubber ash used as zinc fertilizer sources for wheat

The aim of this 2-year field experiment was to investigate agronomic and economic efficiency of ground tire rubber and rubber ash as zinc (Zn) sources for wheat (Triticum aestivum L. cvs. Kavir and Back Cross) compared with a commercial zinc sulfate (ZnSO₄). A similar rate of Zn was used by soil incorporation of 40 kg/ha ZnSO₄, 200 kg/ha waste tire rubber ash, and 1000 kg/ha ground rubber. A no Zn added treatment was also considered as control. All Zn fertilizers significantly increased grain yield of wheat over the control, although effectiveness of rubber ash was greater than the other Zn sources. Wheat plants treated with rubber ash accumulated higher Zn in their grains compared with those treated with ground rubber and ZnSO₄. Tire rubber ash had the highest agronomic and economic efficiency and contained low levels of cadmium (Cd) and lead (Pb). Therefore, it can be used as an economic substitution for commercial ZnSO₄.     

Zinc Efficiency of Wheat Cultivars Grown on a Saline Calcareous Soil

Abstract

Zinc (Zn) deficiency is a yield limiting constraint for wheat production in central Iran. A field experiment was conducted for two consecutive years (1999/2000 and 2000/2001) to study Zn use efficiency of five wheat cultivars. Two Zn rates were used, i.e., 0 and 40 kg Zn ha^?1 applied as zinc sulfate. Significant variation was found among wheat cultivars in relation to grain yield, straw yield, Zn use efficiency and yield components. Based on grain yield and Zn use efficiency across two years, cultivar Cross was most efficient and Dur-3 was most inefficient for Zn use efficiency. Cultivars Kavir, Falat, and Rushan were intermediate in Zn use efficiency. Zinc concentration and uptake were higher in the zinc efficient cultivar Cross, while these values were lowest in the Zn inefficient cultivar Dur-3.     

Population dynamics of amoebae in soils suppressive and non-suppressive to wheat take-all

Populations of soil amoebae were estimated throughout two wheat crops and a fallow from wheat rotations suppressive and non-suppressive to take-all. The suppressive pasture-pasture-wheat plot showed higher rhizosphere populations of mycophagous amoebae and higher associations of mycophagous and other amoebae with wheat roots throughout the crop period than the non-suppressive continuous-wheat plot. Populations of mycophagous amoebae were positively and significantly (P = 0.05) correlated with populations of the take-all fungus in both soils, and with soil moisture in the non-suppressive soil. The possible role of mycophagous amoebae in the wheat rhizosphere in suppressive soil is discussed.     

Zinc nutrition effect on the tolerance of wheat genotypes to Fusarium root-rot disease in a solution culture experiment

Abstract

Zinc (Zn) nutrition and plant genotype are two factors that may affect the tolerance of wheat to root-rot diseases. The aim of the present study was to determine the effect of Zn on shoot yield, root permeability and infection by Fusarium solani in six wheat genotypes with different Zn efficiency. A greenhouse (solution culture) experiment was carried out in which five bread wheat genotypes (Triticum aestivum L. cvs Rushan, Kavir, Cross, Pishtaz and Falat) and one durum wheat genotype (Triticum durum L. cv. Yav79), which are common in Zn-deficient soils of Iran and were exposed to two levels of Zn (0 and 1?μmol?L^–1?Zn?kg^?1, as ZnSO₄.7H₂O) and two F. solani infection levels (0 and 10⁶?spore?mL^?1). Zinc deficiency significantly decreased shoot dry matter in five of the genotypes (Yav79, Kavir, Rushan, Cross and Falat), but had no effect on shoot growth in Pishtaz. Infection with F. solani significantly decreased the shoot dry matter in Yav79, but did not affect the shoot dry weight of the other wheat genotypes. Root membrane permeability was lower in the Zn treatments than in the Zn-free treatments. Zinc deficiency caused a decrease in root reactive sulfhydryl (SH) groups, particularly in the Cross genotype. Root sulfhydryl groups decreased with Fusarium infection. Zinc application sharply increased the Zn content and decreased the Mn content of the shoots. Application of Zn had a positive effect on the tolerance of wheat to F. solani root rot. The relationship between Zn nutrition and disease tolerance suggests that Zn deficiency should be treated before evaluating the cost-effectiveness of fungicides. No correlation was found between the Zn efficiency of the wheat genotypes and Fusarium root-rot disease severity in this solution culture experiment.     

Responses of Wheat Genotypes to Zinc Fertilization Under Saline Soil Conditions

ABSTRACT

A greenhouse experiment with four bread wheat [Triticum aestivum L.] genotypes, ‘Rushan,’ ‘Kavir,’ ‘Cross,’ and ‘Falat,’ and a durum wheat [Triticum durum L.] genotype, ‘Dur-3,’ at two zinc (Zn) rates (0 and 15 mg Zn kg^?1 dry soil) and four salinity levels (0, 60, 120, and 180 mM NaCl) was conducted. After 45 d of growth, the shoots were harvested, and Zn, iron (Fe), potassium (K), sodium (Na), and cadmium (Cd) concentrations were determined. In the absence of added Zn, visual Zn deficiency symptoms were observed to be more severe in ‘Dur-3’ and ‘Kavir’ than in other genotypes. The effect of Zn deficiency on shoot dry matter was similar to its effect on visual deficiency symptoms, such that shoot growth was most depressed in ‘Kavir’ and ‘Dur-3.’ At the 180 mM treatment, Zn fertilization had no effect on shoot dry matter of genotypes. Genotypes with high Zn efficiency had greater shoot Zn content than genotypes with low Zn efficiency. In the absence of added Zn, the Dur-3, and ‘Cross’ genotypes had the highest and lowest Cd concentrations, respectively. Application of Zn had a positive effect on salt tolerance of plants.     

Effects of soil mesofauna and farming management on decomposition of clover litter: a microcosm experiment

The effects of soil mesofauna and different farming systems on decomposition of clover (Trifolium repens) litter were investigated in a laboratory experiment. Microcosms were incubated for 16 weeks with fine and coarse litterbags in soils from three types of management systems: fallow, integrated farming and organic farming, the latter two cropped with wheat. The effects were studied by analysing litter mass loss, C and N content, DOC, nitrate and pH in soil leachate, and CO₂ production, as well as mesofauna. Mesofauna significantly accelerated mass loss and C and N release from clover litter in all three soils. With mesofauna access, at the end of the experiment average clover mass loss was almost twice as high and clover C and N content were 60% lower than without mesofauna. Farming systems influenced the decomposition through affecting both element turnover and mesofauna. Although in the first weeks less N was leached from organic farming than from integrated farming soil, cumulative N leaching did not differ between these soils. However, more than 20% less N was leached from the fallow soil than from the field soils. CO₂ production was highest in fallow soil. Here, mesofauna had no effect on this variable. In soil with integrated farming, mesofauna reduced cumulative CO₂ production by 10% whereas in soil from organic farming it increased CO₂ production by 20%. Our data suggest that differences in C and N turnover in different management systems are strongly mediated by soil mesofauna.     

Zinc and amino acids on wheat-soybean intercropping under no-till management

Abstract

Foliar fertilization with micronutrients and amino acids (AAs) has been used to increase the grain yield and quality of different crops. The aim of the present study was to evaluate the effects of Zn and AAs foliar application on physiological parameters, nutritional status, yield components and grain yield of wheat-soybean intercropping under a no-till management. We used a randomized block experimental design consisting of eight treatments and four replicates. The treatments were five Zn rates (0, 1, 2, 4 and 8?kg ha^?1) and 2?L ha^?1 of AAs and three additional treatments: a control (without the Zn or AA application), 2?kg ha^?1 Zn and 2?kg ha^?1 Zn + 1?L AA. The treatments were applied by spraying during the final elongation stage and at the beginning of pre-earing for the wheat and in growth stage V6 for the soybean for two crop years in a Typic Oxisol (860?g kg^?1 clay). Zinc foliar fertilization increased the wheat grain Zn concentrations. The Zn rates and AA foliar fertilization in soil with did not affect the physiological parameters, nutrient status or yield components. The AA application at the different concentrations tested changed the soybean grain yield and the leaf N concentration. The results suggest that Zn and amino acids application increases the grains Zn concentration in the wheat, being an important strategy to agronomic biofortification.     

Changes in Grain Production,Mechanisms for Sale of Grain and Possible Effects on Grain Quality in Lithuania in the Period 1990-1999

The main objective was to compare the response of grain yield to fertiliser N in a winter wheat-white clover intercropping system with the response in wheat alone. Clover was undersown in spring barley and remained established in two consecutive crops of wheat in two field experiments. Clover reduced grain yield in the first crop of wheat and increased it in the second. There was more inorganic N in the soil and a higher concentration of N in the grains in the intercropping system. The grain and N yield response to fertiliser N was equal or less with intercropped than with wheat alone. The reduction of clover biomass with a herbicide increased grain yield of the first crop of wheat without reducing the clover biomass or the positive residual effect in the second wheat crop. It was concluded that in order to produce large grain yields, competition from clover needs to be kept small when wheat is at the tillering stage.     

长期施用磷肥对冬小麦根际磷、锌有效性及其作物磷锌营养的影响

以中国农业大学昌平试验站长期定位试验为基础,研究了长期施用磷肥对冬小麦根际磷锌有效性及其对作物磷锌营养的影响。结果表明,长期施用磷肥[P2O5,135.kg/(hm2.a)]导致土壤有效磷含量逐年提高;对根际和非根际土壤有效锌含量没有显著影响,但是根际土壤有效锌含量显著高于非根际土壤;长期施用磷肥冬小麦抽穗期植株锌含量显著低于不施磷处理;无论拔节期和抽穗期,植株含磷量和植株磷锌比(P/Zn)都随着施磷量的增加而显著增加。长期施用磷肥处理(P1和P2)在显著提高了冬小麦子粒含磷量的同时,显著降低了其含锌量;冬小麦子粒磷锌比(P/Zn)随着施磷量的增加也显著增加,子粒含磷量与含锌量呈极显著的负线性相关关系。     

Zinc in wheat grain as affected by nitrogen fertilization and available soil zinc

Greenhouse and field experiments were conducted to determine the influence of nitrogen (N) fertilization and DTPA‐extractable soil zinc (Zn) on Zn concentration in wheat (Triticum aestivum L., cv. Pioneer 2375) grain. Application of zinc sulfate (ZnSO₄) in the range of 0 to 8 mg Zn kg^‐1 increased linearly DTPA‐extractable Zn in an incubated calcareous soil from 0.3 to 5.0 mg kg^‐1. Application of these rates of ZnSO₄ to the same soil under greenhouse conditions increased Zn concentration of wheat grain from 26 to 101 mg kg^‐1. The influence of 134 kg urea‐N ha^‐1 on Zn concentration in wheat grain at eight field sites, with DTPA‐extractable soil Zn levels ranging from 0.3 to 4.9 mg kg^‐1, was studied. Nitrogen fertilizer increased wheat‐grain yields in four of the eight experiments but had little effect on grain‐Zn concentration. Grain‐Zn concentration ranged from 31 to 45 mg kg^‐1 in N‐fertilized plots at the various sites and was related (r=0.74*) to DTPA‐extractable soil Zn.     

Effect of zinc application methods on apparent utilization efficiency of zinc and potassium fertilizers under rice-wheat rotation

Apparent utilization of zinc (Zn) and potassium (K) fertilizers was examined in rice (Oryza sativa L.)-wheat (Triticum aestivum L.) using combinations of no K; soil applied K levels and no Zn; soil and foliar applied Zn. Application of 33.2 kg K ha^?1 in rice and 24.9 kg K ha^?1 in wheat along with foliar spray of 2 kg Zn ha^?1 at 30 and 60 days gave the highest mean grain yields. Foliar application of zinc increased Zn concentration in flag leaves, grain, and straw of rice and wheat and K concentration in flag leaves of rice and straw of wheat significantly. Potassium application increased Zn concentration in rice grain and straw and K concentration in wheat straw significantly. Zinc and K increased the uptake of each other in grain; straw and total uptake by both crops significantly. Zinc fertilizer enhanced the utilization of soil K. Potassium fertilizer enhanced the utilization of applied Zn.     

Diversity and vertical distribution of indigenous arbuscular mycorrhizal fungi under two soybean rotational systems

To evaluate the importance of arbuscular mycorrhizal fungi (AMF) to crop production, it is imperative to move beyond the plow layer to include the full soil profile impacted by plant roots. To illustrate this, we investigated the vertical distribution of AMF biomass and community structure within the top 100 cm of soil in soybean (Glycine max (L.) Merr., cv: Enrei) rotational systems cropped to wheat (Triticuma estivum L. cv: Bandowase) or left fallow using fatty acid methyl ester (FAME) biomarkers and molecular analysis, respectively. AMF biomass, as measured by concentration of C16:1cis11, declined during fallow and with increasing soil depth. Greater than 50 % of the stored AMF biomass was found at depths below 35 cm. Phylogenetic analysis revealed 16 AMF phylotypes, including nine Glomus, two Gigaspora, two Scutellospora, and one each of Diversispora, Paraglomus, and an unknown glomeromycete, at different sampling depths in this study. Cluster analysis based on the number and abundance of each AMF phylotype formed two distinct clusters separating wheat from fallow rotations. There was no distinct relationship with soil depth beyond clustering AMF communities above and below 20 cm under wheat. Redundancy analysis (RDA) and hierarchical cluster analysis demonstrated that AMF communities by soil depth within each rotation were not significantly different. However, AMF communities were clearly influenced by crop rotation, where the distribution of specific AMF phylotypes responded to the presence of the wheat crop.     

Green manuring with clover and ryegrass catch crops undersown in spring wheat: effects on soil structure

Abstract. The objective of the present study was to investigate the potential of undersown catch crops to counteract soil degradation after autumn ploughing. Italian ryegrass (Lolium multiflorum Lam.) and white clover (Trifolium repens L.) were undersown in spring wheat on a loam soil in southern Norway, allowed to grow as cover crops after grain harvest and ploughed in to 20 cm depth as green manure in late October. Ryegrass prevented a collapse of the ridged plough furrow profile during winter, which occurred on grain monoculture and white-clover plots. Also, it tended to improve the water stability of aggregates, aggregate size distribution, bulk density, and pore volume in soil sampled in May. The preservation of the plough furrow profile was mainly attributed to enmeshment by an extensive system of fine roots and less to rhizosphere and microbial effects on aggregate stability. The results showed that ryegrass catch crops may give rapid structure improvements that are likely to contribute appreciably to easier seedbed preparation and less soil degradation in arable farming systems, even if the soil is ploughed in autumn.     

Zinc Deficiency in Rainfed Wheat in Pakistan: Magnitude,Spatial Variability,Management, and Plant Analysis Diagnostic Norms

Abstract

Zinc (Zn) deficiency is a widespread micronutrient disorder in crops grown in calcareous soils; therefore, we conducted a nutrient indexing of farmer‐grown rainfed wheat (Triticum aestivum, cv. Pak‐81) in 1.82 Mha Potohar plateau of Pakistan by sampling up to 30 cm tall whole shoots and associated soils. The crop was Zn deficient in more than 80% of the sampled fields, and a good agreement existed between plant Zn concentration and surface soil AB‐DTPA Zn content (r=0.52; p≤0.01). Contour maps of the sampled areas, prepared by geostatistical analysis techniques and computer graphics, delineated areas of Zn deficiency and, thus, would help focus future research and development. In two field experiments on rainfed wheat grown in alkaline Zn‐deficient Typic Haplustalfs (AB‐DTPA Zn, 0.49–0.52 mg kg^?1), soil‐applied Zn increased grain yield up to 12% over control. Fertilizer requirement for near‐maximum wheat grain yield was 2.0 kg Zn ha^?1, with a VCR of 4∶1. Zinc content in mature grain was a good indicator of soil Zn availability status, and plant tissue critical Zn concentration ranges appear to be 16–20 mg kg^?1 in young whole shoots, 12–16 mg kg^?1 in flag leaves, and 20–24 mg Zn kg^?1 in mature grains.     

Effects of ZnSO4 and Zn‐EDTA applied by broadcasting or by banding on soil Zn fractions and Zn uptake by wheat (Triticum aestivum L.) under greenhouse conditions

Zinc biofortification of staple food crops is essential for alleviating worldwide human malnutrition. Agronomic interventions to promote this should include fertilizer selection and management. A chelated Zn source, Zn‐EDTA, and an inorganic Zn source, ZnSO₄ × 7 H₂O, were applied either by banding or by broadcasting in soil, and Zn fractions in soil and Zn uptake by wheat were determined in a pot experiment. Compared to ZnSO₄ × 7 H₂O, Zn‐EDTA produced higher Zn concentration in grain regardless of application method and even at a lower application rate. Residual Zn fraction was the largest Zn fraction with both ZnSO₄ and Zn‐EDTA amendment. ZnSO₄ banded in soil caused Zn fractions to be restricted to the Zn‐amended soil band and resulted in lower grain Zn concentrations than did broadcast ZnSO₄. Planting wheat slowed Zn fixation by promoting the maintenance of a high concentration of Zn fraction loosely bound to organic matter (LOM‐Zn) in soil. Zn‐EDTA was a better Zn source for Zn biofortification of wheat than was ZnSO₄.     

Effect of zinc application methods on apparent utilization efficiency of zinc and phosphorus fertilizers under basmati rice–wheat rotation

To examine the effect of zinc (Zn) application method on the utilization of phosphorus (P) from applied P fertilizer, a field experiment was conducted on basmati rice–wheat rotation with combinations of Zn levels (0, soil application of 2.5 kg Zn ha ^{– 1} and two foliar applications of 2.0 kg Zn ha ^–1) and P levels (0, soil application of 8.7, 17.5 and 26.2 kg P ha ^–1). The highest pooled grain yields of basmati rice and wheat were obtained with soil application of 17.5 kg P ha ^–1 and foliar applications of 2 kg Zn ha ^–1. Foliar applications of Zn increased the P concentration in grain and straw and the total P uptake by basmati rice and the P concentration in flag leaves of wheat significantly, while soil or foliar application of Zn increased the total P uptake of wheat. Phosphorus application increased the Zn concentration in flag leaves, grain and straw of basmati rice and in grain and straw of wheat and the total Zn uptake of both crops. Phosphorus levels up to 17.5 kg P ha ^–1 increased utilization efficiency of soil or foliar application of Zn. Zinc application increased the P utilization efficiency of basmati rice and wheat up to 17.5 kg P ha ^–1 level; foliar Zn application was more effective in a wheat crop than a rice crop.