Influence of Foliar and Ground Fertilization on Yield,Fruit Quality,and Soil,Leaf, and Fruit Mineral Nutrients in Apple

ABSTRACT

The effectiveness of nitrogen (N)+ zinc (Zn) soil and foliar fertilizer applications on growth, yield, and quality of apple (Malus domestic Borkh ‘Golden Delicious’) fruit was studied in the Zanjan province, Iran. There were eight treatments 1) control (no fertilizer), 2) soil applied N, 3) soil applied Zn, 4) soil applied N+Zn, 5) foliar applied N, 6) foliar applied Zn, 7) foliar applied N+Zn and 8) combined soil and foliar applied N+Zn. The N source was urea [CO(NH₂)₂, 46% N] applied at 276 N tree^{? 1} yr^?1 and the Zn source was zinc sulfate (ZnSO₄,7H₂0, 23% Zn) applied at 110 g Zn tree^{? 1} yr^{? 1}. The soil treatments of N and Zn, were applied every two weeks during June through August (total of 6 times/year) in a 1 m radius around the tree trunk (drip line of trees). The foliar solutions of N (10 g l^{? 1} urea) and Zn [8 g l^{? 1} zinc sulfate (ZnSO₄)] were sprayed at the rate of 10 L tree^{? 1} every two weeks at the same times as described for soil applications. The highest yield (49 kg tree^{? 1}), and the heaviest fruits (202 g) were obtained in the soil and foliar combination of N+Zn treatment. The lowest yield (35 kg tree^{? 1}), and the smallest fruits (175 g) were recorded in the control. Nitrogen, and to a lesser extent Zn, foliar application resulted in decreasing fruit quality (caused russeting, and lower soluble solid), but increasing N leaf and fruit concentrations (2.4% DW and 563 mg kg^{? 1}, respectively). There were significant differences among yield and leaf mineral nutrient concentration in different treatments. But there was no significant difference between fruit mineral nutrient concentration (except N). Ratio of N/calcium (Ca), potassium (K)/Ca, and [magnesium (Mg)+K]/Ca in fruits were found suitable for fruit quality prediction. Combining the zinc sulfate with urea in the foliar applications increased the concentration of Zn from 0.7 to 1.5 mg per kg of apple tissue. Leaf N concentration varied during growth season. Foliar applied nutrient can be more efficient than soil applied, but a combination of soil and foliar applications is recommended for apple tree nutrient management.     

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 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.     

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.     

YIELD AND YIELD COMPONENTS OF UPLAND RICE AS INFLUENCED BY NITROGEN SOURCES

Ammonium sulfate and urea are main sources of nitrogen (N) for annual crop production in developing countries. Two greenhouse experiments were conducted using ammonium sulfate and urea as N sources for upland rice grown on a Brazilian Oxisol. The N rates used were 0, 50, 100, 150, 3000, and 400 kg N kg^?1 of soil. Yield and yield components were significantly increased in a quadratic fashion with increasing N rate. Ammonium sulfate X urea interaction was significant for grain yield, shoot dry matter yield, panicle number, plant height and root dry weight, indicating a different response magnitude of these plant parameters to two sources of N. Based on regression equation, maximum grain yield was achieved with the application of 380 mg N kg^?1 by ammonium sulfate and 271 mg N kg^?1 by urea. Grain yield and yield components were reduced at higher rates of urea (>300 mg kg N) but these plant parameters’ responses to ammonium sulfate at higher rates was constant. In the intermediate N rate range (125 to 275 mg kg^?1), urea was slightly better compared to ammonium sulfate for grain yield. Grain yield was significantly related with plant height, shoot dry weight, panicle number, grain harvest index and root dry weight. Hence, improving these plant characteristics by using appropriate soil and plant management practices can improve upland rice yield.     

氮锌配施对不同玉米品种灌浆期生理特性和籽粒氮锌含量的影响

提高粮食作物中可食部分的锌生物有效性是解决人体缺锌的重要措施。为研究氮锌肥料施用对玉米籽粒锌营养的影响,本研究以郑单958和谷神玉66为试验材料,在大田条件下研究3个氮水平(90、180 和225 kg N·hm^-2)和2个喷锌处理(0和4.5 kg·hm^-2 ZnSO₄·7H₂O)下玉米籽粒产量和氮锌含量以及灌浆期叶片生理特性的变化。结果表明,吐丝后,与施氮量90 kg·hm^-2处理相比,施氮量180和225 kg·hm^-2处理提高了吐丝后穗位叶SPAD值及硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、碳酸酐酶(CA)、超氧化物歧化酶(SOD)活性和灌浆后期PSⅡ综合性能指数(PI),降低了丙二醛(MDA)含量。施锌能提高吐丝后穗位叶CA、SOD、过氧化物酶(POD)、过氧化氢酶(CAT)活性和灌浆后期SPAD值和PI,降低MDA含量。2个品种相比,谷神玉66灌浆后期穗位叶SPAD值、叶片初始荧光(F_o)和最大荧光(F_m)较高,而灌浆前期穗位叶PI和吐丝后NR、CA、SOD以及POD活性则以郑单958较高。施氮量为90 kg·hm^-2时,玉米籽粒产量平均为8.55 t·hm^-2,随着施氮量增加,玉米籽粒产量显著提高。籽粒中氮含量以施氮量180 kg·hm^-2时最高,为14.85 g·kg^-1。施氮量90和180 kg·hm^-2时,籽粒锌含量平均为27.2 mg·kg^-1,显著高于施氮量225 kg·hm^-2处理。与不施锌相比,喷锌后玉米籽粒产量未有显著变化,籽粒中氮、锌含量分别增加了11.7%和18.0%。郑单958籽粒产量较谷神玉66提高了3.8%,籽粒氮锌含量则分别减少了11.9%和5.3%。综合来看,施氮量为180 kg N·hm^-2时,与喷施ZnSO₄·7H₂O 4.5 kg·hm^-2 配合施用能够增强玉米灌浆期叶片SPAD和荧光特性,提高氮锌代谢关键酶活性,增强氧自由基清除系统酶活性,减弱膜脂过氧化作用的伤害,促进籽粒中氮、锌的吸收和累积。本研究结果可为玉米生产中优化锌生物强化措施提供理论依据。     

Comparison of ammonium sulfate and urea as nitrogen sources in rice production

Wetland rice agriculture is the major anthropogenic source of methane, an important greenhouse gas. Methane emissions are less when ammonium sulfate (AS) rather than urea is the nitrogen (N) source. However, an agronomic advantage of AS over urea has not been established. The objectives of this study were: (i) to compare the effectiveness of AS, urea, and urea plus elemental sulfur (S) as sources of N in flooded rice culture, (ii) to compare fertilizer recovery of each source of N from application at preflood (PF) and panicle initiation (PI), and (iii) to determine if there is a response to S by rice grown on a soil with a less than optimum level of available S. ‘Cypress’ rice was . drill‐seeded in a Crowley silt loam soil (fine, montmorillonitic, thermic Typic Albaqualf) of 7.25 to 10.75 mg S kg^‐1. Ammonium sulfate, urea, or urea plus S was applied in split applications of 101 kg N ha^‐l PF and 50 kg N ha^‐1 PI. Microplots with retainers and ¹⁵N‐labeled N were used. Unlabeled N was used in field plots. Microplots were harvested at 50% heading, while field plots were harvested at maturity. Dry matter and total N accumulation at 50% heading and at maturity were similar regardless of N source. Grain dry matter yields were 8.54, 8.47, and 8.79 Mg ha^‐1 for AS, urea, and urea plus S treatments, respectively. Greater N recovery was generally found from N application at PI than at PF, but this was not reflected by an increase in grain yield. No response to S was detected, although grain yields were slightly higher when S‐containing fertilizers were used. Ammonium sulfate and urea were equally effective for flooded rice production in Louisiana.     

Influence of Urea and Ammonium Sulfate on Soil Acidity Indices in Lowland Rice Production

Urea and ammonium sulfate are principal nitrogen (N) sources for crop production. Two field experiments were conducted during three consecutive years to evaluate influence of urea and ammonium sulfate application on grain yield, soil pH, calcium (Ca) saturation, magnesium (Mg) saturation, base saturation, aluminum (Al) saturation, and acidity (H + Al) saturation in lowland rice production. Grain yield was significantly influenced by urea as well as ammonium sulfate fertilization. Soil pH linearly decreased with the application of N by ammonium sulfate and urea fertilizers. However, the magnitude of the pH decrease was greater by ammonium sulfate than by urea. The Ca and Mg saturations were decreased at the greater N rates compared to low rates of N by both the fertilizer sources. The Al and acidity saturation increased with increasing N rates by both the fertilizer sources. However, these acidity indices were increased more with the application of ammonium sulfate compared with urea. Rice grain yield had negative associations with pH, Ca saturation, Mg saturation, and base saturation and positive associations with Al and acidity saturation. This indicates that rice plant is tolerant to soil acidity.     

Zinc bioavailability response curvature in wheat grains under incremental zinc applications

Zinc application is generally recommended to enrich wheat grains with Zn; however, its influence on Zn bioavailability to humans has not received appreciable attention from scientists. In this pot experiment, seven Zn rates (from 0 to 18 mg kg^?1 soil) were applied to two wheat cultivars (Shafaq-2006 and Auqab-2000). Application of Zn significantly increased grain yield, grain Zn concentration and estimated Zn bioavailability, and significantly decreased grain phytate concentration and [phytate]:[Zn] ratio in wheat grains. The response of grain yield to Zn application was quadratic, whereas maximum grain yield was estimated to be achieved at 10.8 mg Zn kg^?1 soil for Shafaq-2006 and 7.4 mg Zn kg^?1 soil for Auqab-2000. These estimated Zn rates were suitable for increasing grain Zn concentration and Zn bioavailability (>2.9 mg Zn in 300 g grains) to optimum levels required for better human nutrition. Conclusively, Zn fertilization for Zn biofortification may be practiced on the bases of response curve studies aimed at maximizing grain yield and optimum Zn bioavailability. Moreover, additive Zn application progressively reduced the grain Fe concentration and increased the grain [phytate]:[Fe] ratio. However, a medium Zn application rate increased grain Ca concentration and decreased the grain [phytate]:[Ca] ratio. Hence, rate of Zn application for mineral biofortification needs to be carefully selected.     

氮肥用量和喷施锌钾肥对小麦籽粒锌含量及生物有效性的影响

  【目的】  小麦籽粒锌(Zn)含量普遍较低,在没有外源锌施用措施下难以满足以小麦为主食人群健康所需。探索提升小麦籽粒Zn含量,尤其是其加工产品面粉Zn含量和Zn生物有效性的农艺措施,具有实际重要的意义。  【方法】  于2013、2014年分别在陕西杨凌示范区和三原试验站进行小麦田间试验,两地均为潜在缺锌石灰性土壤,DTPA-Zn含量分别为0.67、0.90 mg/kg,种植制度为小麦–玉米轮作。以氮肥用量为主处理,杨凌试验点为N 0 (N₀)、120 (N₁)和240 (N₂) kg/hm2;三原试验点为传统施氮量(N 150 kg/hm2,N_C)、减氮15% (N 127.5 kg/hm2,N_R1)和减氮30% (N 105 kg/hm2,N_R2)。喷施处理为副处理,两地均为灌浆前期喷施清水(CK)、0.5% K₂SO₄ (K)、0.3% ZnSO₄·7H₂O (Zn)和0.3% ZnSO₄·7H₂O+0.5% K₂SO₄ (Zn+K)。测定了小麦籽粒及其加工面粉Zn等矿质养分含量、Zn形态及锌生物有效性。  【结果】  杨凌试验点,中等施氮量N₁ (120 kg/hm2)处理显著增加了小麦籽粒全粒及面粉和麸皮Zn含量,分别较N₀提高了8.78%、13.2%和17.3%,而N₂ (240 kg/hm2)降低了全粒及其各组分Zn含量,N₁处理显著降低了各加工组分植酸含量;与Zn处理相比,Zn+K处理对小麦全粒Zn含量提升幅度两季平均达13.1%;在中等施氮量条件下,Zn+K处理与Zn处理相比显著增加了面粉Zn含量,特别是增加了可溶性Zn含量,还大幅度降低了全粒和面粉的植酸/Zn摩尔比;氮肥用量与喷肥处理对籽粒Zn形态和Zn生物有效性具有显著的交互作用。三原试验点,小麦全粒、面粉和麸皮Zn含量均在N_R1处理下达到最高;与Zn处理相比,Zn+K处理并未显著影响小麦籽粒及其加工组分Zn含量;施氮量与喷施锌钾肥处理的交互作用(N×Zn)对面粉Zn含量两季均有显著影响。  【结论】  在北方潜在缺锌石灰性土壤上,适宜的氮肥用量和叶面喷施锌肥均可显著提升小麦籽粒和面粉Zn含量,降低植酸/Zn摩尔比,提高锌的生物有效性,且氮肥用量与喷施锌肥对提升小麦锌含量有显著的交互作用。喷施效果以锌与钾肥配合总体好于单独喷施硫酸锌。综合两地两年试验结果,获得高锌小麦的适宜氮肥用量为120 kg/hm2左右,喷施效果以硫酸锌和硫酸钾配合喷施为好。