Zinc fertilization approaches for agronomic biofortification and estimated human bioavailability of zinc in maize grain

Maize (Zea mays L.) is generally low in bioavailable zinc (Zn); however, agronomic biofortification can cure human Zn deficiency. In the present experiment, Zn was applied in pots as ZnSO₄ · 7H₂O to maize cultivar DK-6142 as foliar spray (0.5% w/v Zn sprayed 25 days after sowing and 0.25% w/v at tasseling), surface broadcasting (16 kg Zn ha^?1), subsurface banding (16 kg Zn ha^?1 at the depth of 15 cm), surface broadcasting + foliar and subsurface banding + foliar in comparison to an unfertilized control. As compared to control, all treatments significantly (P ≤ 0.05) increased growth, yield and nutritional attributes in maize. Grain Zn and protein concentrations were correlated and ranged from 22.3 to 41.9 mg kg^?1 and 9 to 12 %, respectively. Zinc fertilization also significantly reduced grain phytate and increased grain Zn concentration. Zinc fertilization, especially broadcasting and subsurface banding combined with foliar spray decreased grain [phytate]:[Zn] ratio to 28 and 21 and increased Zn bioavailability by trivariate model of Zn absorption to 2.04 to 2.40, respectively. Conclusively, broadcasting and subsurface banding combined with foliar spray is suitable for optimal maize yield and agronomic Zn biofortification of maize grain. This would also be helpful to optimize Zn and protein concentration in maize grain.     

Assessment of ZN Interaction with Nutrient Cations in Alkaline Soil and its Effect on Plant Growth

An experiment was conducted to assess the zinc (Zn) availability to wheat in alkaline soils during Rabi 2009–2010. Wheat seedlings in pots having 2 kg alkaline sandy soil per pot were treated with 5, 10 and 15 kg Zn ha^?1 as soil and with 0.5 and 1.0% zinc sulfate (ZnSO₄) as foliar application. Results showed that Zn increasing levels in soil helped in phosphorus uptake up to boot stage but its conversion to grain portion lacked in Zn treated plants. Potassium (K) uptake also increased up to 6.24% in boot stage with treatment of 10 kg Zn ha^?1 + 1.0% ZnSO₄ foliar spray. Zinc (Zn) concentration increased in plant tissues with the increasing level of Zn application but this disturbed the phosphorus (P)-Zn interaction and, thus, both of the nutrients were found in lesser quantities in grains compared to the control. Despite of the apparent sufficient Zn level in soil (1.95 mg kg^?1), improvement in growth and yield parameters with Zn application indicate that the soil was Zn deplete in terms of plant available Zn. The above findings suggest that the figure Zn sufficiency in alkaline soil (1.0 mg kg^?1) should be revised in accordance to the nature and type of soils. Furthermore, foliar application of Zn up to 1.0% progressively increased yield but not significantly; and it was recommended that higher concentrations might be used to confirm foliar application of Zn as a successful strategy for increasing plant zinc levels.     

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.     

Zinc Sulfate Foliar Application Effects on Some Physiological Characteristics and Phenolic and Essential Oil Contents of Lavandula stoechas L. Under Sodium Chloride (NaCl) Salinity Conditions

Lavandula stoechas L. plant is a perennial evergreen used as a fragrant ornamental and medicinal plant. In order to study the effect of foliar spray of zinc sulfate (ZnSO₄) (0, 1000, and 2000 mgL^?1) and sodium chloride (NaCl) salinity (0, 75, and 150 mM) on some physiological characteristics of Lavandula stoechas L. plants, a pot experiment was carried out at the Research Greenhouse of Azarbaijan Shahid Madani University, Iran. Physiological characteristics [root and leaf dry weights, total soluble solids (TSSs), total anthocyanins, chlorophyll b, Zn²⁺, potassium (K⁺) contents, and K⁺/Na⁺ ratio] were significantly affected by the interaction effects of ZnSO₄ foliar application and salinity levels. The highest root dry weight, chlorophyll b, anthocyanin, and Zn contents as well as TSS were found in the plants with NaCl₀ × ZnSO_{4 2000} mgL^?1. For Na⁺, the greatest value was recorded with NaCl ₁₅₀ × ZnSO₄₀. The highest K⁺/Na⁺ ratio was found in the control plants. Foliar application of ZnSO₄ promoted the total phenolic content, especially at 2000 mgL^–1. The highest amounts of flower dry weights were recorded at NaCl₀. Chlorophyll a, total flavonoids, stem dry weight, and essential oil content were affected with ZnSO₄ treatment and salinity levels. The highest values for the essential oil content, chlorophyll a content, and stem dry weight were attained by the nonsaline treatment. Both foliar application levels positively influenced the essential oil and flavonoid contents of the plants. The results reveal that zinc application had marked effects on the physiological characteristics of Lavandula stoechas L. plants growing under salinity stress conditions.     

Agronomic biofortification of chickpea with zinc and iron through application of zinc and urea

ABSTRACT

Zinc (Zn) and iron (Fe) deficiency-related health problems in humans may be solved by improving their concentration in edible grains. The study, conducted in 2015–16 and 2016–17, investigated the effects of soil and foliar application of Zn and foliar application of urea on grain Zn and Fe accumulation of chickpea grains. Soil application of ZnSO₄ @ 25 kg ha^?1 + foliar spray of ZnSO₄ @ 0.5% at flowering and pod formation stages resulted in the highest Zn (45.06 & 44.69 mg Zn kg^?1 grain in the first and second year of study) and Fe (59.74 & 62.88 mg Fe kg^?1 grain) content. Urea application @ 2% at flowering and pod formation stages also resulted in the highest grain Zn (41.12 & 40.26 mg Zn kg^?1 grain) and Fe (58.95 & 61.95 mg Fe kg^?1 grain) content. Grain yield and protein content were significantly increased over control with these treatments. As compared to the sole application of Zn, the combined use of Zn and urea improved the grain Zn and Fe contents. Zinc and urea can be applied to improve Zn and Fe content in chickpea grains and, therefore, can help in ameliorating malnutrition in burgeoning human population.     

Agronomic evaluation of mulching and iron nutrition on productivity,nutrient uptake,iron use efficiency and economics of aerobic rice-wheat cropping system

Field experiments were carried out during rainy (kharif) and winter (rabi) seasons (June–April) of 2008–2010 at Indian Agricultural Research Institute (IARI), New Delhi, to study the productivity, nutrients uptake, iron (Fe) use-efficiency and economics of aerobic rice-wheat cropping system as influenced by mulching and Fe nutrition. The highest yield attributes, grain and straw yields (5.41 tonnes ha^?1 and 6.56 tonnes ha^?1, respectively) and nutrient uptake in rice was recorded with transplanted and puddled rice (TPR) followed by aerobic rice with Sesbania aculeata mulch. However, residual effect of aerobic rice with wheat straw mulch was more pronounced on yield attributes, grain and straw yields (4.20 and 6.70 tonnes ha^?1, respectively) and nutrient uptake in succeeding wheat and remained at par with aerobic rice with Sesbania mulch. Application of iron sulfate (FeSO₄) at 50 kg ha^?1 + 2 foliar sprays of 2% FeSO₄ was found to be the best in terms of all the yield attributes, grain and straw yield (5.09 and 6.17 tonnes ha^?1, respectively) and nutrient uptake and remained at par with 3 foliar sprays of 2% FeSO₄. Although residual effect of iron application failed to increase the yield attributes, yield and nutrient uptake nitrogen, phosphorus and potassium (N, P, K) except Fe. The highest system productivity, nutrient uptake, gross returns, net returns, B: C ratio and lowest cost of cultivation were recorded with aerobic rice with wheat straw and Sesbania aculeata mulch. Application of FeSO₄ at 50 kg ha^?1 + two foliar sprays of 2% FeSO₄ was found better in respect of system productivity, nutrient uptake, gross returns, net returns, B:C ratio and cost of cultivation in aerobic rice-wheat cropping system. The Fe use efficiency values viz. partial factor productivity (kg grain kg^?1 Fe), agronomic efficiency (kg grain increased kg^?1 Fe applied), agrophysiological efficiency (kg grain kg^?1 Fe uptake), physiological efficiency (kg biomass kg^?1 Fe uptake), apparent recovery (%) utilization efficiency and harvest index (%) of applied Fe were significantly affected due to methods of rice production and various Fe nutrition treatments in aerobic rice and aerobic rice-wheat cropping system.     

Effects of zinc fertilizer amendments on yield and grain zinc concentration under controlled environment conditions

The application of zinc (Zn) fertilizer to lentil is an agronomic strategy that has the potential to improve yield and enhance grain Zn concentration. A pot study was conducted to determine if Zn fertilizer applied to three popular Saskatchewan lentil cultivars could increase yield and concentration of Zn in the grain. The effects of soil and foliar applied Zn forms, including ZnSO₄, Zn chelated with EDTA, Zn lignosulphonate, and a control were evaluated. Forms of Zn were not found to significantly increase yield (P = 0.828) or grain Zn concentration (P = 0.708) in any of the lentil cultivars tested. Fertilization with soil applied ZnSO₄ resulted in significantly (P < 0.0001) higher amounts of residual available Zn in the soil relative to other Zn treatments. Soil fertilized with ZnSO₄ had 1.13 mg kg^?1 diethylenetriaminepentaacetic acid (DTPA)-extractable Zn compared to 0.84 mg Zn kg^?1 and 0.77 mg Zn kg^?1 in the soil and foliar applied chelated Zn, respectively.     

MODULATION IN YIELD AND JUICE QUALITY CHARACTERISTICS OF CITRUS FRUIT FROM TREES SUPPLIED WITH ZINC AND POTASSIUM FOLIARLY

Citrus, especially K innow (Citrus deliciosa × Citrus nobilis), fruit yield and quality in Pakistan is not competitive with that of other countries which could be mainly attributed to the lack of good nutrient management for citrus orchards. The yield losses in this fruit crop occur mainly due to heavy fruit dropping. Experiments to overcome these problems were conducted at four different sites one each in Faisalabad, Toba Tek Singh, Jhang and Sargodha districts of Punjab, Pakistan. The soil and leaf chemical analysis showed severe deficiency of Zn and our pervious results have shown that soil amendment with potassium (K) at 75 K₂O kg ha^?1 improved the citrus fruit yield and quality at all selected sites. In the present experiments, effect of foliar application of Zn and K alone or in combination was studied on nutrient uptake, fruit yield, fruit dropping and juice quality. The fruit trees were pretreated with a selected K level of sulfate of potash (SOP) or muriate of potash (MOP), i.e., 75 kg K₂O ha^?1 along with recommended nitrogen (N) and phosphorus (P) doses. Zinc [Zn, 1% zinc sulfate (ZnSO₄) solution], K [1% potassium sulfate (K₂SO₄) solution] and Zn + K (solution containing 0.5% each of ZnSO₄ and K₂SO₄) were sprayed at the onset of spring and flush of leaves or flowers, fruit formation and at color initiation on fruit. Overall, application of Zn, K or Zn + K was effective in improving the nutrient uptake, yield and quality parameters of citrus fruit at all sites. Fruit dropping was also reduced by the foliar spray of Zn, K or Zn + K but the most promising results were recorded with foliar spray containing both Zn and K.     

Enhancing nutrient translocation,yields and water productivity of wheat under rice–wheat cropping system through zinc nutrition and residual effect of green manuring

Abstract

Efficient nutrient and water use are two important considerations to obtain good harvests of wheat. This necessitates the development of an effective nutrient management technique that not only increases yield, but simultaneously can save nutrient and water use. In this context, a field experiment was conducted at Indian Agricultural Research Institute, New Delhi, India to evaluate the residual effect of sesbania and rice bean (in-situ), subabul (ex-situ) green manuring and Zinc (Zn) fertilization, using chelated Zn-ethylenediaminetetraacetic acid (Zn-EDTA) on nutrient use, yields and water productivity of wheat under rice–wheat cropping system. Among residual effects of green manure crops and Zn fertilization, sesbania and foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 days after sowing (DAS) recorded significantly higher nutrient content and uptake and yields than other green manure crops and Zn treatments. Residual effect of sesbania saved about 46.5?×?10³ and 30.5?×?10³ L irrigation water per tonne of wheat over subabul and rice bean, respectively. Foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 DAS saved about 55.5?×?10³, 47?×?10³ and 13?×?10³ L irrigation water per tonne wheat over residual effect of 5?kg Zn ha^?1 through chelated Zn-EDTA as soil application, 2.5?kg Zn ha^?1 through chelated Zn-EDTA as soil application + 1 foliar spray of 0.5% chelated Zn-EDTA at flowering and foliar spray of 0.5% chelated Zn-EDTA at active tillering?+?flowering?+?grain filling, respectively. Correlation analysis showed positive correlation between Zn uptake and grain yield.     

Symbiotic parameters,growth, nutrient accumulation,productivity and profitability as influenced by integrated nutrient management in lentil (Lens culinaris)

Field experiments evaluated the effects of integrated nutrient management on symbiotic parameters, growth, nutrient accumulation, productivity and profitability of lentil (Lens culinaris Medikus). Application of recommended dose of nutrients (RDN, 12.5 kg N ha^?1 + 40 kg P₂O₅ ha^?1) + 25 kg ZnSO₄ ha^?1 + seed inoculation with biofertilizers [Rhizobium + phosphate solubilizing bacteria (PSB) + plant growth promoting rhizobacteria (PGPR)] + 1.0 g ammonium molybdate kg^?1 seed recorded the highest number & dry weight of nodules, leghaemoglobin content, root & shoot dry weight, plant height, number of pods plant^?1 and 100-seed weight. The next best treatment was RDN + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg^?1 seed. On the basis of mean of three-year data, the treatment of RDN + 25 kg ZnSO₄ ha^?1 + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg^?1 seed proved the best in realizing the highest grain yield (34.0%), gross returns (34.0%) and net returns (54.8% higher over control). Nitrogen, phosphorus and potassium in the grains and straw were significantly improved where RDN was applied in combination with seed inoculation, basal application of ZnSO₄ and seed treatment with 1 g ammonium molybdate than their single applications.     

IMPROVING SEED YIELD OF BLACK GRAM (VIGNA MUNGO L. VAR. DPU-88-31) THROUGH FOLIAR FERTILIZATION OF ZINC DURING THE REPRODUCTIVE PHASE

The response of zinc (Zn) deficiency on reproductive yield and recovery through foliar application of Zn was determined in black gram, an important edible legume in India. Results revealed that foliar spray of Zn [0.01 and 0.5% zinc sulfate (ZnSO₄)] improved not only the flowering, pollen producing capacity, pollen viability, stigma-receptivity and pollen-stigma interaction but also the yield parameters like number, size and weight of pods and seeds. Zinc deficiency induced changes in pollen grain structure, activity of esterase and poor stigmatic exudation leading to improper pollen-stigma interaction, which seem to be the main cause of poor fertility and decreased seed yield. Foliar application of 0.5% ZnSO₄ after bud formation was most beneficial not only for reproductive yield but also seed Zn content.     

Effect of different foliar zinc application at different growth stages on seed zinc concentration and its impact on seedling vigor in rice

This study evaluated how zinc (Zn) concentration of rice (Oryza sativa L.) seed may be increased and subsequent seedling growth improved by foliar Zn application. Eight foliar Zn treatments of 0.5% zinc sulfate (ZnSO₄?·?7H₂O) were applied to the rice plant at different growth stages. The resulting seeds were germinated to evaluate effects of seed Zn on seedling growth. Foliar Zn increased paddy Zn concentration only when applied after flowering, with larger increases when applications were repeated. The largest increases of up to ten-fold were in the husk, and smaller increases in brown rice Zn. In the first few days of germination, seedlings from seeds with 42 to 67?mg Zn?kg^?1 had longer roots and coleoptiles than those from seeds with 18?mg Zn?kg^?1, but this effect disappeared later. The benefit of high seed Zn in seedling growth is also indicated by a positive correlation between Zn concentration in germinating seeds and the combined roots and shoot dry weight (r?=?0.55, p?相似文献   

Summer green-manuring crops and zinc fertilization on productivity and economics of basmati rice (Oryza sativa L.)

Field experiments were conducted to study the effects of summer green-manuring crops and zinc (Zn) fertilization on the productivity and economics of Basmati rice. Sesbania aculeata summer green-manuring crop residue incorporation (SGMI) gave highest values of all the growth and yield attributes, grain and straw yield, viz. 3.58, 3.69 t ha^?1 and 16.14, 16.25 t ha^?1 of Basmati rice in 2008 and 2009. Among the Zn fertilization treatments, application of 2.0% Zn-enriched urea (ZEU) as ZnSO₄ · H₂O significantly influenced yield attributes and yield of Basmati rice during both years, and the increase in grain yield was 38.5 and 40.0% over absolute control (no N and no Zn) and 11.9 and 13.6% over control (only N) in both years of study. However, 2.0% ZEU (ZnO) was very close in terms of yield attributes and grain, straw yields of Basmati rice. As regards to the economics of Basmati rice, SGMI and 2.0% ZEU (ZnSO₄ · H₂O) Zn fertilization treatments gave the highest gross (SGMI, 85,985 and 91,582 INR ha^?1; 2.0% ZEU, 89,837 and 59,851 INR ha^?1) and net (SGMI, 56,997 and 61,445 INR ha^?1; 2.0% ZEU, 59,851 and 64,442 INR ha^?1) returns, respectively, compared with incorporation of the remaining summer green manuring residue and Zn fertilization treatments in 2008 and 2009. A significantly higher benefit:cost ratio was recorded with SGMI and 2.0% ZEU (ZnSO₄ · H₂O). Overall, Sesbania aculeata green manuring and 2.0% ZEU (ZnSO₄ · H₂O) are excellent sources of N and Zn for improved productivity of Basmati rice.     

The effect of ZnSO4 and KNO3 on quantitative and qualitative properties of Punica granatum L.

Abstract

We investigated the effect of foliar application of potassium nitrate (KNO₃) and zinc sulfate (ZnSO₄) on the fruit quality of pomegranate (Punica granatum L. cv. Malas-E–Torsh in Saveh). Potassium was applied as KNO₃ at concentrations of 0%, 0.25%, and 0.5% and zinc was applied as ZnSO₄ at concentrations of 0%, 0.5%, and 1% in a completely randomized block design. To determine the effect of the treatments on fruit quality, we measured fruit weight, peel thickness, aril diameter, phenol content of the juice, pH, total soluble solids (TSS), titratable acidity (TA), and antioxidant capacity. Foliar application of KNO₃ significantly increased fruit weight, 100 aril weight, peel weight, peel thickness, TTS, and antioxidant capacity. In contrast, pH, TA, TSS/TA, and phenol content of the juice were not influenced by foliar application of KNO₃. ZnSO₄ significantly increased fruit weight, aril diameter, and phenol content of the juice. KNO₃ 1% and ZnSO₄ 0.5% were identified as the most appropriate treatments in improving quality and quantity of pomegranate. The fatty acid profile of the pomegranate oil was primarily composed of punicic acid, linoleic acid, oleic acid, palmitic acid, and stearic acid.     

Effects of Organic and Inorganic Fertilizers on Soil and Plant Nutrients and Yields of Pearl Millet and Wheat under Semi-arid Inceptisols in India

A study was conducted to assess fertilizer effect on pearl millet–wheat yield and plant-soil nutrients with the following treatments: T₁, control; T₂, 100% nitrogen (N); T₃, 100% nitrogen and phosphorus (NP); T₄, 100% nitrogen, phosphorus and potassium (NPK); T₅, 100% NPK + zinc sulfate (ZnSO₄) at 25 kg ha^?1; T₆, 100% NPK + farmyard manure (FYM) at 10 t ha^?1; T₇, 100% NPK+ verimcompost (VC) at 2.5 tha^?1; T₈, 100% NPK + sulfur (S) at 25 kg ha^?1; T₉, FYM at 10 t ha^?1; T₁₀, VC at 2.5 t ha^?1; T₁₁, 100% NPK + FYM at 10 t ha^?1 + 25 kg S ha^?1 + ZnSO₄ at 25 kg ha^?1; and T₁₂, 150% NPK treatments. Treatments differed significantly in influencing soil-plant nutrients and grain and straw yields of both crops. Grain yield had significant correlation with soil-plant N, P, K, S, and zinc (Zn) nutrients. The study indicated superiority of T₁₁ for attaining maximum pearl millet grain yield (2885 kg ha^?1) and straw yield (7185 kg ha^?1); amounts of N (48.9 kg ha^?1), P (8.8 kg ha^?1), K (26.3 kg ha^?1), S (20.6 kg ha^?1), and Zn (0.09 kg ha^?1) taken up; and amounts of soil N (187.7 kg ha^?1), P (13.7 kg ha^?1), K (242.5 kg ha^?1), S (10.1 kg ha^?1), and Zn (0.70 kg ha^?1). It was superior for wheat with grain yield (5215 kg ha^?1) and straw yield (7220 kg ha^?1); amounts of N (120.7 kg ha^?1), P (13.8 kg ha^?1), K (30 kg ha^?1), S (14.6 kg ha^?1), and Zn (0.18 kg ha^?1) taken up; and maintaining soil N (185.7 kg ha^?1), P (14.5 kg ha^?1), K (250.5 kg ha^?1), S (10.6 kg ha^?1), and Zn (0.73 kg ha^?1). Based on the study, 100% NPK + FYM at 10 tha^?1 + Zn at 25 kg ha^?1 + S at 25 kg ha^?1 could be recommended for attaining maximum returns of pearl millet–wheat under semi-arid Inceptisols.     

ZINC-COATED UREA IMPROVES PRODUCTIVITY AND QUALITY OF BASMATI RICE (ORYZA SATIVA L.) UNDER ZINC STRESS CONDITION

A field study conducted for two years (2006 and 2007) at the Research Farm of the Indian Agricultural Research Institute, New Delhi, India showed that zinc (Zn) fertilization increased yield attributes, grain and straw yield, enhanced Zn concentrations and its uptake and improved kernel quality before and after cooking in basmati rice ‘Pusa Sugandh 5’. A 2% Zn-coating with zinc sulfate (ZnSO₄·7H₂O) was found to be the best but a 2% Zn-coating with zinc oxide (ZnO) was very close to it in terms of grain and straw yield and Zn concentrations in basmati rice grain and straw under Zn stress conditions. Partial factor productivity (PFP) of applied Zn varied from 984–3,387 kg grain kg Zn^?1, agronomic efficiency (AE) varied from 212–311 kg grain kg^?1 Zn (applied) and physiological efficiency (PE) of Zn varied from 6,384–17,077 kg grain kg^?1 Zn (absorbed). Thus, adequate Zn fertilization of basmati rice can lead to higher grain yield and Zn-denser grains with improved cooking quality in basmati rices under Zn stress soil conditions.     

Effect of split application of zinc on yield of rice (Oryza sativa L.) in an inceptisol

Abstract

Rice is mostly transplanted under puddled low land soil conditions in India, where Zinc (Zn) deficiency is a common problem. The objective of this study was to find out the efficacy of split application of Zn on growth and yield of rice in an inceptisol. The split application of Zn as ZnSO₄ · 7H₂O performed better than its single basal application, while the split application of Zn-EDTA did not show any significant difference on yield and yield components of rice over its single basal application. Zn-EDTA was found to be better for growth and yield of rice among the two sources of Zn. The soil application of Zn at 1.0 kg ha^?1 as Zn-EDTA (T₇) recorded highest grain yield of 5.42 t ha^?1, filled grain percentage of 90.2%, 1000-grain weight of 25.41 g and number of panicles m^?2 of 452. The Zn content of grain and straw were found to be maximum in the treatment T₇ i.e. 38.19 and 18.27 mg kg^?1, respectively. Linear regression studies indicated that grain yield of rice is significantly influenced by Zn content of grain, Zn content of straw and DTPA extractable Zn content of soil at the level of 95.96, 96.74 and 95.57%, respectively.     

Determination of Optimum Rate and Growth Stage for Foliar‐Applied Phosphorus in Corn

Abstract

Foliar applications of fertilizer phosphorus (P) could improve use efficiency by minimizing soil applications. Nine experiments were conducted in 2002 and 2003 to determine foliar P rates and appropriate growth stages for application. Treatments comprised of 10 factorial combinations of three foliar P application timings and four rates of foliar P. Foliar application times were V4 (collar of fourth leaf visible), V8 (collar of eighth leaf visible), and VT (last branch of the tassel completely visible but silks not yet emerged) corn growth stages. Foliar P rates were 0, 2, 4, and 8 kg ha^?1. Foliar P applied at the VT growth stage improved grain and forage P concentration, which was reflected in increased grain yield in some of the experiments. A foliar P rate of 8 kg ha^?1 improved yield to some extent and forage and grain P concentration more than the smaller rates. The results suggest that foliar P could be used as an efficient P‐management tool in corn when applied at the appropriate growth stage and rate.     

The effectiveness of seed priming and foliar application of zinc- amino acid chelates in comparison with zinc sulfate on yield and grain nutritional quality of common bean

Abstract

The efficacy of seed priming and foliar application of zinc-amino acid chelates including zinc-histidine [Zn(His)₂] and zinc-methionine [Zn(Met)₂] in comparison with zinc sulfate (ZnSO₄) on yield and grain nutritional quality of two common bean cultivars (Phaseolus vulgaris L., cvs Talash and Sadri) was investigated in a severely Zn-deficient calcareous soil (DTPA-Zn: 0.38?mg kg^?1 soil) in a pot experiment. Bean response to Zn application varied depending on the Zn fertilizer, application method and cultivar. In ‘Talash’, seed priming with [Zn(His)₂] and [Zn(Met)₂] led to 24.1 and 11.6% increase in the grain yield of bean in comparison with ZnSO₄ treatment, respectively. In both cultivars, foliar application of [Zn(His)₂] led to significant increase in the grain yield in comparison with ZnSO₄. The highest grain Zn concentration was obtained by seed priming with [Zn(Met)₂] in ‘Sadri’ and [Zn(His)₂] in ‘Talash’, respectively. For Zn-amino acid chelates, seed priming was more effective than foliar application in increasing grain yield and Zn concentration. Foliar application of [Zn(His)₂] and [Zn(Met)₂] in ‘Sadri’ and [Zn(Met)₂] in ‘Talash’ resulted in higher protein content in bean grain as compared with ZnSO₄. In both cultivars, foliar application of [Zn(Met)₂] was the more effective than seed priming to increase grain protein content. The highest water-soluble carbohydrates concentration of grain was obtained by seed priming with [Zn(Met)₂] and [Zn(His)₂] in ‘Sadri’ and ‘Talash’ cultivars, respectively. Therefore, seed priming with [Zn(His)₂] and ZnSO₄ in ‘Sadri’ and [Zn(Met)₂] in ‘Talash’ can effectively be used for improving yield of common bean in Zn-deficient calcareous soils.     

Zinc Application Effects on Yield and Seed Oil Content of Sunflower Grown on a Saline Calcareous Soil

ABSTRACT

Two field experiments (2000–2001 and 2001–2002) were conducted at two nearby fields in the Qanavat region of Qom province, central Iran, to investigate the effects of zinc (Zn) fertilization on production of sunflower. The experiment was conducted in a randomized complete block design with six treatments in three replicates. Treatments were: Zn₀ (non-Zn fertilized), Zn₁₀, Zn₂₀, Zn₃₀, and Zn₆₀ (soil application of 10, 20, 30, and 60 kg Zn ha^?1, respectively), and Zn_Spray (foliar spraying of 0.5 kg Zn ha^?1 using ZnSO₄). Seeds of sunflower (Helianthus annuus cv. ‘Record’) were planted on June 20, 2000 and June 15, 2001. At harvest, shoot and seed yields as well as concentration of Zn, iron (Fe), manganese (Mn), sodium (Na), and chloride (Cl) in leaves of sunflower were determined. Addition of 20 kg Zn ha^?1 significantly increased seed production and shoot dry-matter yield of sunflower, while other Zn treatments had no significant effect on shoot dry-matter yield, or decreased it. The thousand-seed weight was the yield component most affected by Zn fertilization, while plant height and head diameter did not change. The maximum content of seed oil was achieved under the Zn₁₀ treatment, then decreased at higher rates of soil-applied Zn such that oil content of seed under the Zn₃₀ and Zn₆₀, treatments was significantly lower than that of the control. Seed oil content was unaffected by foliar spraying of Zn. The concentration of Zn in sunflower leaves was increased with an increase in soil-added Zn of from 0 to 60 kg Zn ha^?1. The highest leaf concentrations of Zn (162 and 175 mg kg^?1 day matter (DM) in the first and second year, respectively) were achieved by foliar application of ZnSO₄. Leaf concentration of Fe was significantly increased in the Zn₂₀ treatment compared with the control but decreased at the higher rates of soil-added ZnSO₄. Soil addition of different levels of ZnSO₄ decreased concentration of Na and Cl in leaves. The lowest concentration of Na and Cl in leaves was observed under Zn₂₀. The results of this study suggest that soil application of a suitable amount of Zn has a positive effect on both quantitative and qualitative yield of sunflower in saline, calcareous soils.