Supplying Zinc Salt Tablets Increased Zinc Concentration and Yield of Coffee Trees

In Brazil there are two usual forms of supplying zinc (Zn) to coffee plants, in the soil with macronutrient fertilizers or by means of foliar sprayings. Both have limitations that compromise the Zn availability to the plant. This study examined the plant responses to the foliar sprays with ZnSO₄ and insertion of Zn salt tablets, made with a mix of Zn sources, into the orthotropic branches of Coffea arabica L. Zinc supplied by foliar sprays or tablets inserted into the trunk both increased leaf Zn content, although the tablets provided more consistent Zn supply. Coffee production was higher with Zn treatments, regardless of the method of supply. The supply of Zn by the insertion of tablets into coffee tree trunks thus proved to be a promising way to supply Zn.     

Photosynthesis,Chlorophylls, and SPAD Readings in Coffee Leaves in Relation to Nitrogen Supply

The export of nitrogen (N) from senescent plant parts is important for the efficient use of this macronutrient. The objective of this study was to establish correlations among the photosynthetic pigment content, total N, and the photosynthetic variables with the SPAD‐502 readings in Coffea arabica leaves. Correlations were established among the chlorophyll content, N content, and chlorophyll a and b with SPAD‐502 readings taken on coffee leaves at different months. The results show that all variables decreased with time. However, correlation increased linearly with N doses. Total chlorophyll presented a direct linear correlation with readings of the portable chlorophyll meter. The SPAD readings have shown to be a good tool to diagnose the integrity of the photosynthetic system in coffee leaves. Thus, the portable chlorophyll SPAD‐502 instrument can be used to evaluate the N status and can also help to evaluate the photosynthetic process in coffee plants.     

Zinc Tolerance in Wheat Cultivars as Affected by Varying Levels of Phosphorus

Abstract

The effect of zinc–phosphorus (Zn‐P) interaction on Zn efficiency of six wheat cultivars was studied. The higher dry matter yields were observed when Zn was applied at 5 µg g^?1 soil than with no Zn application. Phosphorus applications also increased dry matter yield up to the application of 25 µg P g^?1 soil. The dry matter yield was significantly lower at the P rate of 250 µg g^?1 soil. At the Zn‐deficient level, the Zn‐efficient cultivars had higher Zn concentrations in the shoots. Zinc concentrations in all cultivars increased when the P level in the soil was increased from 0 to 25 µg P g^?1 soil except for the cv. Durati, in which Zn concentrations decreased with increases in P levels. However, when Zn×P interactions were investigated, it was observed that at a Zn‐deficient level, Zn concentrations in the plant shoot decreased with each higher level of P, and more severe Zn deficiency was observed at P level of 250 µg g^?1 soil.     

Changes of Nutritional Status during a Phenological Cycle of Coffee under High Nitrogen Supply by Fertigation

High-technology coffee cultivation systems involving fertigation commonly apply high rates of nitrogen (N). However, there is little information on the plants' uptake of N under these conditions. The objective of this study was to evaluate the changes in the nutritional status of coffee plants during a phenological cycle in response to N applied by fertigation. The study was conducted with 7-year-old trees of Coffea arabica L., under pivot irrigation and fertigation, with five N rates (0, 200, 400, 600, and 800 kg ha^?1) applied on the plants. The changes in nutritional status were monitored during the phenological cycle, and the yield was measured at the end of the cycle. The N concentration increased with the N rates and varied with the phenological period, with the greatest concentration occurring during anthesis, the same as for the sulfur level. However, N rate did not affect the concentrations of other nutrients. The greatest concentrations of phosphorus, calcium, and magnesium were obtained in the final fructification phases and for potassium in the initial phases. Micronutrient concentrations were greater in the vegetative phases and anthesis but were reduced in the fruit- formation phase and increased again when the berries started to mature. The maximum yield, considering a relative production of 90%, was obtained with application of 415 kg ha^?1 of N. Leaf concentrations of N were directly related to the N rates, showing that the nutritional status of coffee plants can be evaluated in the ripening phase to adjust the fertilization parameters for the next year.     

Soil Zinc Transformations as Affected by Applied Zinc and Organic Materials

Information on soil zinc (Zn) distribution is essential for understanding its chemical reactions and bioavailability. An experiment was conducted to evaluate the effect of wheat straw, cow manure, and vermicompost applied with Zn rates on Zn distribution in a calcareous soil. A sequential extraction scheme was used to fractionate Zn into soluble and exchangeable, bound to carbonate, organically bound, bound to manganese (Mn) oxide, bound to amorphous iron (Fe) oxide, bound to crystalline Fe oxide, and residual forms. In untreated soil, Zn was mainly in the residual fraction. Increasing rates of applied Zn increased all forms of Zn. Carbonate and residual forms showed the greatest increase. Organic materials application increased all fractions, except Mn-oxide form, and this increase was more pronounced for the organically bound form. Concentration of soluble, exchangeable, and organically bound forms was greatest in cow manure–amended samples as compared to other organic materials, suggesting that cow manure contained more bioavailable Zn than other organic materials.     

Synthetic Zeolite A as Zinc and Manganese Fertilizer in Calcareous Soil

The Leccino olive cultivar was grown in pots contained calcareous rendzina soil amended with NPK fertilizer (control treatment) or with further addition of Zeolite A (ZA) containing either zinc (Zn²⁺) or manganese (Mn²⁺) (Zn-ZA and Mn-ZA). After one year, vegetative growth and root morphological parameters were measured and elemental analysis was performed on the root, stem, and leaves. Compared to other treatments, the Zn-ZA fertilizer enhanced Zn concentration and total quantity in the root, stem, and leaves, as well as the root diameter. The root volume was greater using Zn-ZA treatment than control treatment. The total quantity of Mn in root and the root length were enhanced when using Mn-ZA compared to control or Zn-ZA treatment. According to the results of this study, it appears that zeolites containing Zn provide favorable conditions for Zn uptake in calcareous soils, while both Zn and Mn zeolites have a positive impact on olive root morphology.     

Phosphorus Uptake by Young Citrus Trees in Low-P Soil Depends on Rootstock Varieties and Nutrient Management

Because low-phosphorus (P) availability limits citrus growth, rootstocks with a relatively high capacity for P uptake are desirable. An experiment was conducted with trees on Cleopatra mandarin (CM) and Rangpur lime (RL). Treatments consisted of P rates (20, 40, and 80 mg kg^?1 of soil) applied in soil layers of 0–0.30 m and/or 0.31–0.60 m, besides an unfertilized control. The P fertilization increased root and shoot growth, and P nutrition was improved as indicated by greater leaf P concentration, P uptake, and P root uptake efficiency (PUE). The P applied in both soil layers improved shoot growth, P uptake, and PUE. Trees on RL took up 23–126% more P and had root systems with greater growth and PUE compared to those on CM. Thus, P uptake by citrus trees in low-P soils can be improved by augmenting the depth of fertilizer application and the use of more adapted rootstocks.     

丛枝菌根真菌对紫花苜蓿吸收土壤中镉和锌的影响

采用温室盆栽试验方法,研究了镉（Cd）、锌（Zn）污染土壤中,8种不同丛枝菌根真菌（AMF）Glomus lamellosum（G.la）、Acaulospora mellea（A.m）、Glomus mosseae（G.m）、Glomus intraradices（G.i）、Glomus etunicatum（G.e）、Glomus constrictum（G.c）、Diversispora spurcum（D.s）、Glomus aggregatum（G.a）对紫花苜蓿（Medicagosativa L.）吸收Cd、Zn的影响。结果表明,Cd、Zn污染下AMF仍然明显侵染紫花苜蓿,并促进紫花苜蓿对Cd、Zn的吸收积累,但不同AMF影响的效应和植株不同部位对重金属的吸收积累规律存在差异。AMF处理下紫花苜蓿根部Cd、Zn含量和积累量明显增加,但地上部Cd、Zn的含量则降低,地上部Zn的积累量也减小,这表明AMF处理减弱了Cd、Zn由根部向地上部的运移,减轻了植物地上部毒害。接种AMF条件下,植株尤其是根部生物量增加是Cd、Zn在其体内含量和积累量增加的重要因素,不同种类AMF促进植株生物量增加的幅度不同,导致植株对Cd、Zn的积累和抗性存在差异。     

Nutrients,Free Amino Acids,and Sugar Contents in Narcissus Roots Affected by N,P, K Deficiency during Winter

Non-rooted bulbs of Narcissus L. cv. “Garden Giant” were planted on October 25, 1993 and cultivated under N, P, or K deficiency or in complete medium (control). The roots emerged on November 5 and were sampled on March 7, 1994. The X-ray microanalyzer images showed the distribution of N, P, K, Ca, Mg, S, and Cl in a control root. The distribution of Cl was similar to that of K and also a similar distribution was found between Ca and S. There were significant differences in the concentration of N, P, K, Ca, Mg among treatments. Interaction among nutrient levels was observed. Control roots accumulated a large amount of nitrogen (84 mg g DW^-1) which was partitioned almost equally between the 80% ethanol soluble and insoluble fractions. N-deficient roots in the -N treatment, on the other hand, accumulated only about 12 mg g DW^-1 nitrogen, mostly in the insoluble fraction (83% of total N). Total amino acid contents responded to N, P, or K deficiency. Glutamine was a major free amino acid in control roots (17 mg N g DW^-1) and K-deficient roots (29 mg N g DW^-1), while arginine seemed to be the predominant amide in P-deficient roots. Content of total soluble sugars in the control, -P and -K treatments that was 49, 46, and 49 mg g DW^-1, respectively, was lower than in the -N treatment (137 mg g DW^-1). Mono- and disaccharides; fructose, glucose, and sucrose, were found in narcissus roots.     

Zinc Application Enhances Biological Yield and Alters Nutrient Uptake by Cotton (Gossypium hirsutum L.)

Zinc (Zn) deficiency is often associated with calcareous soils throughout the world, whereas application of Zn not only enhances biological yield but exhibits significant interactions with nutrients. Hence, a two-year field experiment was performed in 2004 and 2005 to assess the crop Zn requirements as well as nutrient interactions in cotton. The present study followed a randomized complete block design with five Zn levels: 0.0, 5.0, 7.5, 10.0, and 12.5 kg Zn as ZnSO₄.7H₂O. The biological yield of cotton increased progressively with increasing Zn rates. In general, cotton yield was higher in 2005 over 2004. Interestingly, Zn fertilization resulted in increased accumulation of nitrogen (N), potassium (K), boron (B), and Zn, whereas decreased the phosphorus (P), calcium (Ca), magnesium (Mg), iron (Fe), copper (Cu), and manganese (Mn) (p ≤ 0.05) uptake by cotton. The enhanced macronutrients accumulation in cotton by Zn application improved the cotton yield. In conclusion, biological yield and nutrient composition of the cotton plant are greatly influenced by Zn supply under irrigated environments.     

Yield,Nutrient Uptake,and Quality of Stevia as Affected by Organic Sources of Nutrient

A field experiment was conducted during 2008 and 2009 at the Council of Scientific and Industrial Research-Institute of Himalayan Bioresource Technology, Palampur, India, to study the effect of organic sources of nutrient on yield, nutrient uptake, fertility status of soil, and quality of stevia crop in the western Himalayan region. The experiment comprised eight different combinations of organic manure [farmyard manure (FYM), vermicompost (VC), and apple pomace manure (AP)]. Total leaf dry biomass increased by 149% over the control with application of VC 1.5 t ha^?1 + AP 5 t ha^?1. Application of organic manures enhanced organic carbon and available nutrient status of soil more than the control. Nitrogen (N) and phosphorus (P) content in stem were significantly affected by the application of organic manures over the control. Stevia plants supplied with FYM 10 t ha^?1 + AP 2.5 t ha^?1 recorded more total glycoside than other treatments. Stevioside yield (kg ha^?1) was greater with application of FYM 10 t ha^?1 + AP 2.5 t ha^?1.     

Diagnosis and Recommendation Integrated System Norms,Sufficiency Range,and Nutritional Evaluation of Arabian Coffee in Two Sampling Periods

ABSTRACT

The objective of this work was to establish and compare Diagnosis and Recommendation Integrated System (DRIS) norms with the sufficiency range approach, and apply these methods on nutritional diagnosis of Arabian coffee, in field samples collected in summer and winter in Southern Brazil. DRIS norms and sufficiency range were established in groves with average biennial yield equal or above 3000 kg ha^{? 1}. The “t” test was used to verify the differences between the sufficiency range and the DRIS norms. The foliar concentrations of nitrogen (N), phosphorus (P), and sulfur (S) were higher in summer, and iron (Fe), and manganese (Mn) in winter. The reference values should be specific for the period of the year. There were differences in the foliar nutritional diagnosis, between the DRIS method and the sufficiency range approach. In samples during the summer analyzed with DRIS, copper (Cu), S, potassium (K), and zinc (Zn) were considered more limited nutrients and Mn, S, K, and calcium (Ca) when the sufficiency range was used.     

Root Growth,Nutrient Uptake,and Nutrient-Use Efficiency by Roots of Tropical Legume Cover Crops as Influenced by Phosphorus Fertilization

Roots are important organs that supply water and nutrients to growing plants. Data related to root growth and nutrient uptake by tropical legume cover crops are limited. The objective of this study was to evaluate root growth of tropical legume cover crops and nutrient uptake and use efficiency under different phosphorus (P) levels. The P levels used were 0 (low), 100 (medium), and 200 (high) mg kg^?1 of soil, and five cover crops were evaluated. Root dry weight, maximum root length, and specific root length were significantly influenced by P and cover crop treatments. Maximum values of these root growth parameters were achieved with the addition of 100 mg P kg^?1 soil. The P?×?cover crops interactions for all the macro- and micronutrients, except manganese (Mn), were significant, indicating variation in uptake pattern of these nutrients by cover crops with the variation in P rates. Overall, uptake pattern of macronutrients was in the order of nitrogen (N) > calcium (Ca) > potassium (K) > magnesium (Mg) > P and micronutrient uptake pattern was in the order of iron (Fe) > Mn > zinc (Zn) > copper (Cu). Cover crops which produced maximum root dry weight also accumulated greater amount of nutrients, including N, compared to cover crops, which produced lower root dry weight. Greater uptake of N compared to other nutrients by cover crops indicated that use of cover crops in the cropping systems could reduce loss of nitrate (NO₃ ^?) from soil–plant systems. Increase in root length and root dry weight with the addition of P can improve nutrient uptake from the soil and lessen loss of macro- and micronutrients from the soil–plant systems.     

深松对玉米产量和养分吸收的影响

为了研究深松对我国玉米主产区产量、养分吸收利用以及土壤养分分布的影响,于2011—2014年在我国东北、华北以及西北地区的9个试验站进行深松改土与常规旋耕对比的联网试验。结果表明,相比于传统耕作,3个区域深松均表现出了增产趋势,产量增加的中值为5.8%,其中,东北和西北区域的增产幅度高于华北区域,而东北区域秋季深松增产的变异低于春季深松。相比于常规旋耕,深松对玉米植株地上部氮和磷的吸收有显著的促进作用,在东北、西北和华北区域深松处理的地上部吸氮量和吸磷量均有所增加,中值分别为24%,5%和10%以及17%,8%和19%。深松处理增加了东北和西北区域土壤表层(0—15cm)和亚表层(15—25cm)的有效磷含量,而在华北区域没有趋势性变化。     

Light Intensity Effects on Growth and Micronutrient Uptake by Tropical Legume Cover Crops

ABSTRACT

Cover crops are important components of a sustainable crop-production system in plantation crops such as cacao (theobroma cacao), coffee (Coffee arabica), oil palm (Elaeis Spp.), and banana (Musa Spp.). Optimal growth of cover crops in plantation agriculture is determined by adaptability of crop species, light intensity reaching their leaf canopies, and their nutrient-use efficiencies, including those of micronutrients. An experiment was conducted in a climatically controlled growth chamber to evaluate the influence of levels of light intensity on growth and micronutrient [boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn)] uptake parameters in legume cover crops. Two photosynthetic photon flux density (PPFD, 200 and 400 μmol m^?2 s^?1) light treatments were imposed on nine legume species (joint vetch (Aeschynomene americana), sunhemp (Crotalaria juncea L.), Crotalaria rchroleuca, showy crotalaria (crotalaria spectabilis), hairy indigo (Indigofera hirsute L.), lab-lab (Lablab purpureus), sesbania (Sesbania microcarpa), Brazilian stylo (Stylosanthes guianensis), and cowpea (Vigna unguiculata)). Overall, light intensity significantly affected growth, micronutrient uptake, and use-efficiency ratios; with few exceptions, interactions between cover crop species and PPFD were also significant. Such PPFD × crop species interactions show that the cover crops used in this study differed in growth and nutrient-uptake parameters under the conditions imposed. Sunhemp, cowpea, sesbania, and lab-lab species were superior in producing shoot dry weight and in nutrient accumulation compared with other species at lower as well as at higher PPFD levels. Interspecific differences in nutrient influx and transport were observed. Influx and transport of micronutrients was in the order Mn > B > Fe > Zn > Cu. Overall, growth, nutrient uptake, and use-efficiency ratios were higher at higher PPFD than at lower PPFD. Results of this study indicate that the use of proper crop species at adequate light intensities is an important component of successful cultivation of cover crops in plantation agriculture.     

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.     

Interaction of Iron with Copper,Zinc, and Manganese in Wheat as Affected by Iron and Manganese in a Calcareous Soil

Iron (Fe) availability is low in calcareous soils of southern Iran. The chelate Fe-ethylenediamine di (o-hydroxy-phenylacetic acid) (Fe-EDDHA), has been used as an effective source of Fe in correcting Fe deficiency in such soils. In some cases, however, its application might cause nutritional disorder due to the antagonistic effect of Fe with other cationic micronutrients, in particular with manganese (Mn). A greenhouse experiment was conducted to evaluate the influence of soil and foliar applications of Fe and soil application of manganese (Mn) on dry matter yield (DMY) and the uptake of cationic micronutrients in wheat (Triticum aestivum L. var. Ghods) in a calcareous soil. Results showed that neither soil application of Fe-EDDHA nor foliar application of Fe sulfate had a significant effect on wheat DMY. In general, Fe application increased Fe uptake but decreased that of Mn, zinc (Zn), and copper (Cu). Application of Mn increased only Mn uptake and had no significant effect on the uptake of the other cationic micronutrients. Iron treatments considerably increased the ratio of Fe to Mn, Zn, Cu, and (Mn + Zn + Cu). Failure to observe an increase in wheat DMY following Fe application is attributed to the antagonistic effect of Fe with Mn, Zn, and Cu and hence, imbalance in Fe to (Mn + Zn + Cu) ratio. Due to the nutritional disorder and imbalance, it appears that neither soil application of Fe-EDDHA nor foliar application of Fe-sulfate is appropriate in correcting Fe deficiency in wheat grown on calcareous soils. Hence, growing Fe-efficient wheat cultivars should be considered as an appropriate practice for Fe chlorosis-prone calcareous soils of southern Iran.     

Influence of Ammonium and Nitrate Nutrition on Plant Growth and Zinc Accumulation by Indian Mustard

ABSTRACT

The source of nitrogen (N) used in soil fertility practices affects plant growth, nutrient absorption, and the availability of nutrients. Consequently, the potential of plants to extract zinc (Zn) from soils may be increased by controlling the ratio of NH₄ ⁺ to NO₃ ^? to maximize growth and Zn accumulation. The objectives of this research were to determine the effects of Zn supply and different molar ratios of NH₄ ⁺ to NO₃ ^? on growth and Zn accumulation in Indian mustard (Brassica juncea Czern.). In a factorial experiment with solution culture, Indian mustard (accession 182921) was supplied with two concentrations of Zn (0.05 and 4.0 mg L^?1) in combination with six N treatments with different molar percentage ratios of NH₄ ⁺ to NO₃ ^? (0:100, 10:90, 20:80, 30:70, 40:60, and 50:50) for three weeks. Zinc supplied at 0.05 mg Zn L^?1 represented a common concentration of Zn in solution culture, whereas 4.0 mg Zn L^?1 was excessive for plant nutrition. If the supply of Zn in solution was excessive, plants developed symptoms of foliar chlorosis, which became severe if plants were supplied with 80% of N as NO₃ ^?. Supplying high proportions of NO₃ ^? in the nutrient medium stimulated Zn accumulation, whereas increasing proportions of NH₄ ⁺ (up to 50% of the total N) enhanced shoot growth. The pH of nutrient solutions generally decreased with increasing proportion of NH₄ ⁺ in solutions and with increased Zn supply. The Zn phytoextraction potential of Indian mustard was maximized, at about 15 mg Zn plant^?1, if plants received 10% of the total N as NH₄ ⁺ and 90% as NO₃ ^?.     

Morphological Changes in Leaves of Mexican Lime Affected by Iron Chlorosis

Iron (Fe) chlorosis reduces the concentration of photosynthetic pigments, photosynthates, and crop yield. The effect of Fe chlorosis on leaf composition and cell structure was evaluated in Mexican lime (Citrus aurantifolia) with different degrees of Fe chlorosis. Iron chlorosis significantly reduced concentrations of chlorophylls a, b, and a + b, and caused thickening of leaves, due to the increase in palisade and spongy parenchyma cells. The chloroplasts of the chlorotic and albino leaves showed a disorganized ultrastructure; they had an elongated shape with disarrayed thylakoids, underdeveloped grana, scarce starch granules, and hole-like folds in the thylakoid membranes. The accumulation of calcium oxalate crystals in the upper and lower sides of the epidermis, crystal length, and total crystal content increased with Fe chlorosis severity. The green leaves, in contrast, had chloroplasts with typical ultrastructure. The degree of Fe chlorosis in the leaves significantly affected the concentrations of potassium (K); Fe, manganese (Mn), Fe²⁺, and the phosphorus (P)/Fe and K/calcium (Ca) ratios.     

Root exudation of sugars,amino acids,and organic acids by maize as affected by nitrogen,phosphorus, potassium,and iron deficiency

Root exudates play a major role in the mobilization of sparingly soluble nutrients in the rhizosphere. Since the amount and composition of major metabolites in root exudates from one plant species have not yet been systematically compared under different nutrient deficiencies, relations between exudation patterns and the type of nutrient being deficient remain poorly understood. Comparing root exudates from axenically grown maize plants exposed to N, K, P, or Fe deficiency showed a higher release of glutamate, glucose, ribitol, and citrate from Fe‐deficient plants, while P deficiency stimulated the release of γ‐aminobutyric acid and carbohydrates. Potassium‐starved plants released less sugars, in particular glycerol, ribitol, fructose, and maltose, while under N deficiency lower amounts of amino acids were found in root exudates. Principal‐component analysis revealed a clear separation in the variation of the root‐exudate composition between Fe or P deficiency versus N or K deficiency in the first principal component, which explained 46% of the variation in the data. In addition, a negative correlation was found between the amounts of sugars, organic and amino acids released under deficiency of a certain nutrient and the diffusion coefficient of the respective nutrient in soils. We thus hypothesize that the release of dominant root exudates such as sugars, amino acids, and organic acids by roots may reflect an ancient strategy to cope with limiting nutrient supply.