不同硼效率棉花品种果胶与不同形态硼含量的差异

溶液培养条件下研究硼(B)对不同B效率棉花品种水溶性果胶、原果胶及水溶性B、酸溶性B含量的影响.结果表明,供B充足时,B低效棉花品种各部位果胶含量均大于高效品种,不同形态B含量也有同样的规律.缺B时,高效品种各部位果胶含量一般高于低效品种.严重缺B使2个棉花品种不同形态B含量均显著降低,水溶性B变化比酸溶性B更明显,低效品种各部位酸溶性B及上部幼叶水溶性B含量降低幅度均大于高效品种,下部老叶和根中水溶性B降低幅度小于高效品种.缺B还使2个品种上部幼叶与下部老叶水溶性B含量比值增加,高效品种增加幅度大于低效品种,该比值在品种间的差异明显大于水溶性B和酸溶性B含量的差异,可以更好地反映不同品种的B效率.     

不同硼效率棉花品种根系参数和伤流液组分的差异

溶液培养条件下研究硼对不同硼效率棉花品种根系参数、伤流量及伤流液组分的影响。结果表明,缺硼抑制棉花根系生长,根重、根体积、根长、活跃吸收面积、总吸收面积、活跃吸收面积占总吸收面积的比例以及伤流量均显著降低,高效品种降低幅度比低效品种小;缺硼还使高效品种根系比表面积升高,而低效品种无显著变化。缺硼显著影响不同棉花品种伤流液各组分含量,与低效品种相比,高效品种伤流液中有较多的NO3-、K+、无机磷、可溶性糖和游离氨基酸。说明缺硼条件下高效品种根系比低效品种具有更强的吸收、代谢活力,可能是其硼效率较高的主要原因之一。     

Growth of Brazilian Cotton Cultivars in Response to Soil Applied Boron

ABSTRACT

The growth of cotton (Gossypium hirsutum L.) was evaluated in a 6 × 5 factorial experiment with 6 boron (B) levels (0.0, 0.5, 1.0, 1.5, 2.0, and 3.0 mg dm^?3), 5 cultivars (‘CNPA 8H’, ‘BRS Aroeira’, ‘BRS Antares’, ‘BRS Sucupira’, ‘BRS Ipe’), and 3 replications. As B increased in the soil, leaf B concentrations increased linearly in ‘BRS Aroeira’ and ‘CNPA 8H’, and quadratically in ‘BRS Ipe’ and ‘BRS Sucupira’. The concentrations of B in the leaves and in the soil increased with the B increasing in the soil. The agronomic characteristics evaluated showed ‘BRS Aroeira’ and ‘BRS Sucupira’ responding more and BRS responding less to the B doses applied. The variation in the effFiciency of B utilization was: ‘BRS Aroeira’ > ‘CNPA 8H’ = ‘BRS Antares’ > ‘BRS Sucupira’ > ‘BRS Ipe’. Cultivar ‘BRS Aroeira’ had the greatest potential to respond positively to the addition of B to the soil.     

Phosphorus and Micronutrient Nutrition of Chickpea Genotypes in a Multi-Nutrient-Deficient Typic Ustochrept

ABSTRACT

The chickpea breeding program in India has not yet considered the genotypic variation in phosphorus (P) efficiency, despite the fact that the largest proportion of chickpea-growing soils are P deficient. Since general P application to chickpea is at sub-optimum levels, efficient P-utilizing genotypes will perform better than others under P-deficient conditions. High levels of P application may induce zinc (Zn) deficiency in plants grown on Zn-deficient soils. Twenty chickpea genotypes were evaluated for their P efficiency at varied levels of added P, and the effect of P levels on Zn, iron (Fe), copper (Cu), and manganese (Mn) nutrition was studied in pot-culture experiments. Three criteria were used for evaluating P efficiency; shoot dry-matter yield without P, P-uptake efficiency (PUPE), and P-utilization efficiency (PUSE). Under P-deficiency conditions (control), the genotypes BG-256, HK-94-134, Phule-G-5, and Vikash produced the highest shoot biomass. However, genotypes that were found to be superior in the absence of P did not perform in a similar way under optimum P supply. Root dry weight showed a highly significant correlation with P uptake at all P levels. In the case of PUPE, genotypes KPG-59 and Pusa-209 were found to be superior to others. With increasing P levels, PUSE declined in all the genotypes. Increasing P up to 13.5 mg kg^?1 soil increased Zn concentration, while further increase led to decreased concentration. Genotypes KPG-59, BG-256, RSG-888, and JG-315 showed Zn concentrations below the critical limit of 20 μg Zn g^?1 dry weight (DW) at the high level of P application (27.0 mg kg^?1). Iron concentration decreased with increasing P levels. Up to 13.5 mg kg^?1 P application, Cu concentration increased and thereafter decreased. Manganese concentration gradually increased with the increasing P levels studied. Based on three criteria, BG-256 can be recommended for use in P-deficient conditions and can be good germplasm source material for chickpea-breeding programs for evolving P-efficient genotypes. Results also suggest that when selecting P-efficient genotypes of chickpea, it is essential to apply deficient micronutrients.     

Boron Requirement of Irrigated Cotton in a Typic Haplocambid for Optimum Productivity and Seed Composition

Boron (B) deficiency hampers cotton (Gossypium hirsutum L.) growth and productivity globally, especially in calcareous soils. The crop is known as a heavy feeder of B; however, its reported plant analysis diagnostic norms for B-deficiency diagnosis vary drastically. In a 2-year field experiment on a B-deficient [hydrochloric acid (HCl)–extractable 0.47 mg B kg^?1], calcareous, Typic Haplocambid, we studied the impact of soil-applied B on cotton (cv. CIM-473) growth, productivity, plant tissue B concentration, and seed oil composition. Boron was applied at 0.0, 1.0, 1.5, 2.0, 2.5, and 3.0 kg B ha^?1, as borax (Na₂B₄O₇·10H₂O), in a randomized complete block design with four replications, along with recommended rates of nitrogen (N), phosphorus (P), potassium (K), and zinc (Zn). Boron use improved crop growth, decreased fruit shedding, and increased boll weight, leading to seed cotton yield increases up to 14.7% (P < 0.05). Improved B nutrition of plants also enhanced seed oil content (P < 0.05) and increased seed protein content (P < 0.05). Fiber quality was not affected. Fertilizer B use was highly cost-effective, with a value–cost ratio of 12.3:1 at 1 kg B ha^?1. Fertilizer B requirement for near-maximum (95% of maximum) seed cotton yield was 1.1 kg B ha^?1 and HCl-extractable soil B requirement for was 0.52 kg ha^?1. Leaf tissue B requirement varied with leaf age as well as with plant age. In 30-day plants (i.e., at squaring), B-deficiency diagnosis critical level was 45.0 mg kg^?1 in recently matured leaves and 38.0 mg kg^?1 in youngest open leaves; at 60 days old (i.e., at flowering), critical concentration was 55.0 mg kg^?1 in mature leaves and 43.0 mg kg^?1 in youngest leaves. With advancement in plant age critical B concentration decreased in both leaf tissues; that is, in 90-day-old plants (i.e., at boll formation) it was 43.0 mg kg^?1 in mature leaves and 35.0 mg kg^?1 in the youngest leaves. As critical concentration range was narrower in youngest leaves (i.e., 35–43 mg kg^?1) compared with mature leaves (i.e., 43–55 mg kg^?1), B concentration in youngest leaves is considered a better indicator for deficiency diagnosis.     

Phosphorus Stress-Induced Differential Growth,and Phosphorus Acquisition and Use Efficiency by Spring Wheat Cultivars

ABSTRACT

Phosphorus (P) is a finite, non-renewable, and natural resource and a vital major nutrient for plant metabolic and developmental processes. However, adverse soil biogeochemical characteristics of alkaline-calcareous soils (especially Aridisols) and highly weathered acid soils (i.e., Ultisols and Oxisols) render orthophosphate (Pi) as the least available major nutrient due to P complexation, sorption, and/or fixation. In such soil environments, plant bioavailable P is only a small fraction of total soil P, seriously limiting crop growth and production. Different plant species, and even cultivars of the same species, may display a suite of growth responses that enable them to solubilize and scavenge soil P either by enhancing external Pi acquisition or reprioritizing internal Pi use under P-stress soil environments. This paper reports relative growth responses, P acquisition and P-use efficiency characteristics by 14 cultivars of spring wheat (Triticum aestivum L.) grown in solution culture with high/low P supply induced by applying soluble NH₄H₂PO₄, sparingly soluble rock phosphate, and Ca₃(PO₄)₂. The wheat cultivars exhibited considerable genetic diversity in biomass accumulation, P concentrations, P contents, factor (PSF) and P efficiency characteristics [i.e., P utilization efficiency (PUE), P efficiency (PE), and PE ratio (PER)]. Plant growth and PE parameters were significantly correlated, while P uptake was linearly related with biomass increase and solution pH decrease. The wheat cultivars with high PUE, PER and P uptake, and low PSF, and plant P concentration were more efficient in utilizing P and, hence, more tolerant under P-stress environment. Biomass and P contents of “P efficient/low-P tolerant” wheat cultivars were superior to “P inefficient/low-P sensitive” cultivars at all P-stress levels. Hence, “P efficient/low-P tolerant” cultivars are the most desirable wheat genotypes for P-stress environments because they are able to scavenge more P from sparingly soluble P sources or soil-bound P forms.     

Transformations and Availability of Iron to Wheat as Influenced by Phosphorus and Manganese Fertilization in a Typic Haplustept Soil

An investigation was conducted using Typic Haplustept, sandy loam soil, to investigate the interactive effects of phosphorus (P) and manganese (Mn) fertilization on native iron (Fe) pools in soil and their availability to wheat (cv. PBW-343) crop. Phosphorus fertilization moved Fe from residual mineral fraction of Fe to manganese oxides (MnOX), organic matter (OM), amorphous (AMPOX), and crystalline (CRYOX) Fe and Al oxide fractions. However, Mn application decreased specifically adsorbed (SAD)–Fe and CRYOX–Fe but increased OM–Fe and mineral fraction of Fe. Available Fe in soil decreased as Olsen P and P:Mn ratio increased in the soil. Higher Olsen P (>60 mg P kg^?1soil) reduced mean Fe uptake by shoot. P content and P:Mn ratio in soil as well as in root and shoot were inversely related to Fe concentration in both the plant parts. The role of soil Fe associated with oxides and organic matter was found most notable in Fe nutrition of wheat.     

干旱区春小麦产量对沟垄参数和灌水技术的响应

为了提高干旱区春小麦垄作沟灌的灌水质量,建立灌水技术参数优化模型,本试验研究了垄沟参数（垄坡、垄宽、沟深、沟宽）、灌水技术参数（沟长、沟坡、入沟流量）之间的组合对垄作沟灌小麦的生长指标、产量及水分利用效率的影响。结果表明:在其他参数不变的情况下,垄宽与小麦株高呈负增长的变化趋势;沟长50 m、垄宽40 cm、入沟流量1.0 L/s、田面坡度1/500的参数组合的小麦在整个生育期内的总光合势最高,为0.018 （m²·d）/m²,在其他参数不变的情况下,随着垄宽的增大,小麦在整个生育期的总光合势降低,沟长与小麦的总光合势呈负相关的关系;沟长50 m、垄宽40 cm、入沟流量1.5 L/s、田面坡度1/1 000的参数组合的小麦产量最高,为9 142.87 kg/hm²,同时水分利用效率亦最高为29.18 kg/（hm²·mm）,为试验区提出适宜的春小麦高产栽培管理技术。     

Effect of long‐term fertilization and manuring on potassium release properties in a Typic Ustochrept

A long‐term fertilizer experiment, over 27 years, studied the effect of mineral fertilizers and organic manures on potassium (K) balances and K release properties in maize‐wheat‐cowpea (fodder) cropping system on a Typic Ustochrept. The treatments consisted of control, 100% nitrogen (100% N), 100% nitrogen and phosphorus (100% NP), 50% nitrogen, phosphorus, and potassium (50% NPK), 100% nitrogen, phosphorus, and potassium (100% NPK), 150% nitrogen, phosphorus, and potassium (150% NPK), and 100% NPK+farmyard manure (100% NPK+FYM). Nutrients N, P, and K in 100% NPK treatment were applied at N: 120 kg ha^—1, P: 26 kg ha^—1, and K: 33 kg ha^—1 each to maize and wheat crops and N: 20 kg ha^—1, P: 17 kg ha^—1, and K: 17 kg ha^—1 to cowpea (fodder). In all the fertilizer and manure treatments removal of K in the crop exceeded K additions and the total soil K balance was negative. The neutral 1 N ammonium acetate‐extractable K in the surface soil (0—15 cm) ranged from 0.19 to 0.39 cmol kg^—1 in various treatments after 27 crop cycles. The highest and lowest values were obtained in 100% NPK+FYM and 100% NP treatments, respectively. Non‐exchangeable K was also depleted more in the treatments without K fertilization (control, 100% N, and 100% NP). Parabolic diffusion equation could describe the reaction rates in CaCl₂ solutions. Release rate constants (b) of non‐exchangeable K for different depth of soil profile showed the variations among the treatments indicating that long‐term cropping with different rates of fertilizers and manures influenced the rate of K release from non‐exchangeable fraction of soil. The b values were lowest in 100% NP and highest in 100% NPK+FYM treatment in the surface soil. In the sub‐surface soil layers (15—30 and 30—45 cm) also the higher release rates were obtained in the treatments supplied with K than without K fertilization indicating that the sub‐soils were also stressed for K in these treatments.     

Differential Growth Response of Wheat Genotypes to Ammonium Phosphate and Rock Phosphate Phosphorus Sources

ABSTRACT

A solution culture experiment was conducted to determine the response of 15 wheat genotypes for growth, phosphorus (P) uptake, and P utilization efficiency, and their adaptability to P stress conditions using adequate [250 μM P in nutrient solution as ammonium phosphate (NH₄H₂PO₄)] and stress (powdered rock phosphate suspended in nutrient solution) P supply levels. Shoot dry matter (SDM) and total plant DM (shoot + root) and P uptake were generally higher for most genotypes in adequate P than stress P level treatment, but the opposite was true for root dry matter (RDM), root: shoot ratio (RSR), and root P uptake. Relative reduction in SDM due to P deficiency stress ranged from none to 54%. Genotypes Kohinoor 83, PB 85, Parvaz 94 and 4770 did not respond to P deficiency stress for SDM production, while genotypes FSD 83, Chakwal 86, Pasban 90, 4072, 4943, 5039, 6529-11, and 6544-6 were highly responsive to P application for SDM. Shoot P uptake in genotypes at adequate P level was about 3-times higher than those genotypes grown at stress P level. Differences in P concentration of shoot ranged between 2.00 to 3.06 mg P g^?1 in stress P level treatment, and had a significant positive correlation with P harvest index (PHI) (r = 0.558?, P < 0.05) and root efficiency ratio (RER) (r = 0.611?, P < 0.05) and negative correlation with P efficiency ratio (PER) (r = ?0.909??, P < 0.01). A significantly positive correlation of P utilization index (PUI) and SDM (r = 0.784??, P < 0.01) and non-significant negative correlation (r = ?0.483) of PUI with P concentration in shoot implies that wheat genotypes with higher PUI may be selected for P deficient milieu. Genotypes with higher PUI (>0.8 g mg^?1 P) in rook phosphate treatment were Inqlab-91, Pak-81, Lu 26s, Parvaz 94, 4072, 4770, 4943, and 5039. There was no interrelationship observed between shoot P uptake and P efficiency in stress P level treatment. However, highly significant and positive correlation (r = 0.720??, P < 0.01) between PHI and RER suggested that shoot P uptake depended upon root efficiency and it increased with the increase in P uptake per unit RDM. Consequently, this resulted in increased SDM which is evident from the significant positive correlation (r = 0.833??, P < 0.01) between SDM and shoot P uptake. In summary, the findings suggest that PUI and RER may be used for selecting P efficient wheat genotypes (e.g., 4072, 4770, 4943, Pak 81, and Inqlab 91) for dry matter production and P use.     

Response of Wheat Cultivars to Nitrogen and Sulfur for Crop Yield,Nitrogen Use Efficiency,and Protein Quality in the Semiarid Region

ABSTRACT

The effects of nitrogen (N at 0, 100 and 180 kg N ha-1) and sulfur (S at 0, 20, 40 and 60 kg S ha-1) on crop yield, nutrient uptake, nitrogen use efficiency (NUE), and amino acid composition of two bread wheat cultivars, ‘Shehan’ and ‘Enkoy,’ grown in Andisols and Cambisols in randomized blocks with three replications were evaluated. Both cultivars responded significantly (P < 0.05) to N and S applications and S application with N improved the NUE by 28%. The yield increase for the two cultivars by N and S application ranged between 0.8 to 2.4 Mg ha^?1. The N concentration increased significantly from N0 to N2 in both cultivars. Sulfur fertilization increased the concentration of cysteine and methionine by 27% and 14%, respectively, as compared to N alone. The grain yield, NUE, N, and S uptake, and the S-amino acid concentration of ‘Enkoy’ were significantly higher than ‘Shehan’ cultivar.     

Internal and External Phosphorus Requirements for Optimum Grain Yield are Associated with P-utilization Efficiency of Wheat Cultivars

ABSTRACT

Considerable variation exists among wheat cultivars for phosphorus (P) acquisition and utilization to produce higher yields. We investigated critical P requirements for optimum grain yield of two wheat cultivars contrasting in P-use efficiency, i.e., NIA-Sunder (P-efficient) and NIA-Saarang (P-inefficient). Grain yield, P accumulation, and other P-efficiency relations of both cultivars increased with progressive addition of P, but at variable rates. NIA-Sunder exhibited higher grain yield, grain P concentration, harvest index, and P-use efficiency at all P levels as compared to NIA-Saarang. Internal P requirement for achieving 95% relative grain yield in NIA-Sunder and NIA-Saarang was obtained when P concentration in their grains was 4.07 and 3.48 mg g^?1 recorded at external P levels of 57.2 and 78.1 mg kg^?1 soil, respectively. Overall, NIA-Sunder accumulated 15% more grain P and required 27% less external P for attaining 95% relative yield than P-inefficient cultivar. Results suggested that internal and external P requirements aiming at optimum grain yield are associated with genotypic variations in wheat cultivars for P-utilization efficiency.     

Variation in Selenium Tolerance,Accumulation, and Growth Parameters of Different Wheat Cultivars

In a greenhouse experiment, wheat cultivars PDW 291, PBW 550, and TL 2908 were grown in alkaline sandy-loam soil treated with sodium selenate at 0, 2, and 4 mg selenium (Se) kg^?1 soil. Selenate-treated wheat plants accumulated greater Se in roots, stems, leaves, and grains and showed growth retardation, snow-white chlorosis, decreased shoot length and chlorophyll, and reduced leaf area and produced less number of grains as compared to control plants. Maximum reduction in these parameters was observed in selenate-treated TL 2908 plants and most of the plants died before maturity with almost no grain formation with 4 mg Se kg^?1 soil. Selenium accumulation resulted in decreased reducing sugar, starch, and protein contents in grains whereas total free amino acids increased significantly in all the three cultivars. Selenium accumulation in wheat showed metabolic disturbances and its accumulation in grains was beyond toxic levels, thus making it unfit for consumption.     

2个小麦品种水分利用效率的差异及其与深层水分利用的关系

研究旨在探究不同小麦品种对深层土壤水分利用差异及其对产量、水分利用效率的影响。试验于2017—2019年在陕西长武进行,试验为品种、播量双因子试验,品种为主处理(A为长旱58,B为长航1号),播量为副处理(10:播量150 kg/hm~2,12:播量180 kg/hm~2),分析不同处理对冬小麦各生育期土壤水分消耗及其产量和水分利用效率的影响。结果表明:在不同的试验年,与长旱58相比,长航1号对土壤水分的消耗均显著增加。与此同时,相比长旱58,长航1号的小麦穗粒数、收获指数、产量及水分利用效率均显著提高。说明长航1号较长旱58增加了对土壤水分的消耗,尤其增加了对深层土壤水分的消耗,从而影响小麦穗粒数和收获指数,最终获得了较高的产量及水分利用效率。     

Zinc Deficiency in Selected Cultivars of Wheat and Barley as Tested in Solution Culture

Abstract

The relative zinc (Zn) efficiencies of 33 wheat and 3 barley cultivars were determined by growing them in chelate‐buffered culture solutions. Zn efficiency, determined by growth in a Zn‐deficient solution relative to that in a medium containing an adequate concentration of Zn, was found to vary between 10% and 63% among the cultivars tested. Out of the 36 cultivars tested, 12 proved to be Zn efficient, 10 were Zn inefficient, and the remaining 14 varieties were classed as intermediate. The most Zn‐efficient cultivars included Bakhtawar, Gatcher S61, Wilgoyne, and Madrigal, and the most Zn inefficient included Durati, Songlen, Excalibur, and Chakwal‐86. Zn‐efficient cultivars accumulated greater amounts of Zn in their shoots than inefficient cultivars, but the correlation between shoot Zn and shoot dry matter production was poor. All the cultivars accumulated higher concentrations of iron (Fe), copper (Cu), manganese (Mn), and phosphorus (P) at deficient levels of Zn, compared with adequate Zn concentrations. The Zn‐inefficient cultivars accumulated higher concentrations of these other elements compared to efficient cultivars.     

Evaluation of Growth Responses in Wheat as Affected by the Application of Zinc and Boron to a Soil Deficient in Available Zinc and Boron

A soil–pot culture experiment was conducted to study the individual and interactive effects of zinc (0, 5, and 10 mg kg^?1 soil) and boron (0, 0.75, and 1.5 mg kg^?1 soil) on growth, enzymatic activity, nutrient uptake, seed reserve content, and yield in wheat (var. HD2285) in a soil deficient in available zinc and hot water–extractable boron. Although the application of zinc and boron alone significantly increased the plant height, grain yield, total dry-matter yield, tissue zinc, and boron content in maize, maximum increase was obtained with the combined application of zinc and boron. The activities of enzymes peroxidase and starch phosphorylase decreased as compared to untreated control but the activity of carbonic anhydrase increased. Protein, starch, and phytate content of grains also increased with the application of the micronutrients. Moreover, in the absence of zinc, application of boron decreased the starch content of grains.     

Meta-analysis of Winter Wheat Response to Chloride Fertilization in Kansas

Cereal grain yield response to chloride (Cl) fertilization has been reported in most of the Great Plains. The objective of this study was to use meta-analytic methods to summarize and provide quantitative estimates of the effects of soil and fertilizer Cl on wheat (Triticum aestivum L.) response including grain yield and flag leaf Cl tissue level. Meta-analysis evaluated the effect of soil and fertilizer Cl application from different studies on a common scale of effect size. Chloride tissue concentration using the flag leaf correlated well with fertilizer plus soil Cl at a depth of 0–60 cm. However, our analysis indicates possible luxury uptake of Cl in relation to grain yield, with a possible upper limit in plant uptake with soil Cl levels around 68 kg Cl ha^–1. Application of Cl fertilizer generated average wheat yield increases of approximately 8%.     

Phosphorus Response of Oryza sativa,O. glaberrima,and Hybrid Rice Cultivars on an Ultisol

Phosphorus (P) deficiency is a major constraint to upland rice production on Ultisols in the humid zone of West Africa. Integrated use of P-efficient cultivars and P nutrition is needed for enhanced sustainable productivity on these soils. This article reports on the P responsiveness of interspecific rice hybrids (crosses from Oryza sativa and O. glaberrima) along with O. sativa and O. glaberrima cultivars grown on an acidic Ultisol, low in available P. The cultivars differed in yield and P-uptake response to fresh and residual P. Two interspecific cultivars gave a linear response to P and produced the greatest grain yield under direct and residual P. The O. glaberrima cultivar CG 14 did not respond to the applied P, whereas the O. sativa cultivar was moderate in its performance. Our results show that the interspecific rice cultivars have the potential to adapt and perform well on acidic upland soils.     

Relationship between Nitrogen Use Efficiency and Response Index in Winter Wheat

Although nitrogen use efficiency (NUE) of small grains is well documented at 33% worldwide, there has been little research relating NUE to yield factors. This study examined the relationship between NUE and the response index at harvest (RI_HARVEST) of winter wheat (Triticum aestivum L.). Yield data from a long-term fertility study established at Lahoma, Oklahoma in 1971 was used to explore the relationship. In this report, six nitrogen (N) rates at non-limiting levels of P and K were evaluated. Regression analysis showed a positive relationship between NUE and RI_HARVEST for all years across all N rates (r² = 0.37). But this relationship was improved (r² = 0.45) when both RI_NDVI and RI_HARVEST were included in the model. The linear relationship between NUE and RI_HARVEST was significantly improved, when yield data and corresponding NUE were separated according to the annually applied fixed N rate. As the N rate increased the resulting slope of the relationship between NUE and RI was reduced. These analyses also demonstrate that temporal variability in NUE exists and that NUE can be predicted.     

Response of Wheat Plants to Zinc,Iron, and Manganese Applications and Uptake and Concentration of Zinc,Iron, and Manganese in Wheat Grains

This experiment was conducted at Zahak Agricultural Research Station in the Sistan region in southeast Iran. A factorial design with three replications was used to determine the effects of zinc (Zn), iron (Fe), and manganese (Mn) applications on wheat yield, Zn, Fe, and Mn uptakes and concentrations in grains. Four levels of Zn [soil applications of 0, 40, and 80 kg ha^?1 and foliar application of 0.5% zinc sulfate (ZnSO₄) solution], two levels of iron sulfate (FeSO₄; 0 and 1%) as foliar application, and two levels of Mn (0 and 0.5%) also as foliar application were used in this study. Results showed that the interactive effects of Zn and Mn were significant on the number of grains in each spike. The highest number of grains resulted from the application of 80 kg ZnSO₄ ha^?1 and foliar Mn. The interactive effects of Zn and Fe were significant on weight of 1000 grains. The highest weight of 1000 grains resulted from application of 80 kg Zn and foliar Fe. Application of 80 kg ZnSO₄ ha^?1 alone and 80 kg ZnSO₄ ha^?1 with foliar application of Mn significantly increased grain yield in 2003. The 2‐year results showed that foliar application of Zn increased Zn concentration and Fe concentration in grains 99% and 8%, respectively. Foliar application of Fe resulted in a 21% increase in Fe concentration and a 13% increase in Zn concentration in grains. The foliar application of Mn resulted in a 7% increased in Mn concentration in grains.