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Enhancing Fruit Yield and Citrus Quality through Integrated Application of Organic Fertilizers and Zinc
Abstract
Maximization of citrus fruit yield and enhancing their quality are ambitious objectives for citrus growers and scientist across the globe. This study explores the synergistic potential of organic manures and zinc to achieve these objectives. This integrated approach represents a sustainable and environmentally friendly strategy for citrus cultivation. For this, a study was conducted with different treatments of zinc and farm yard manure. The trial was conducted using randomized complete block design with five repeats. Results showed that the highest fruit yield (58.23 kg plant-1), fruit weight (169.40 g fruit-1), fruit diameter (72.80 mm), juice content (46.64%), TSS (10.87 ˚Brix), citric acid (645.22 mg 100 mL-1), ascorbic acid (593.45 mg 100 mL-1), total sugar content (7.05%), Zn content in leaf (19.46 mg kg-1), photosynthetic rate (14.68 µmol m-2 s-1), transpiration rate (3.95 mmol m-2 s-1), WUE (3.72 µmol CO2 mmol-1 H2O), stomata conductance (0.465 mmol m-2 s-1) and total chlorophyll (4.41 mg g-1) were obtained by application of T8: (Zn @ 50 g plant-1 + FYM @ 25 kg plant-1 + PM @ 10 kg plant-1). On the basis of our results, it is concluded that integrated use of Zn coupled with organic manures was the most effective combination of fertilization for improving physiological functioning and ionic metabolism, yield contributing attributes and fruit quality of citrus.
Under the changing climatic conditions, one of the most pressing issues in wheat production is the improvement of the yield quality, the lack of which has a negative impact on animal and human health. More than 25% of the world’s population are affected by micronutrient deficiencies in food products, a problem which is known as hidden hunger. Thus, effective micronutrient management is crucial for improving both the quantity and quality of wheat production by increasing the plant’s ability to tolerate various environmental stresses and diseases. In this review, previous works were assessed to investigate the significance of micronutrient fertilizers and their interaction effects on the wheat grain yield and quality, including high-quality and nutritionally rich products. The application of micronutrients mixed with macronutrients significantly increases plant growth, physiological traits, yield components, the grain yield, and the quality traits. Among the types of applications, the foliar application of nutrients is very profitable due to its efficiency in terms of economics, ecology, and the qualitative and quantitative yield. In short, in-depth studies are needed to determine the best concentrations, forms, and times of application of micro-fertilizers to the wheat field and to mitigate the challenges of the increasing wheat demand due to steadily rising world population growth and reducing the rates of nutritional deficiency.
At a global scale, about three billion people have inadequate zinc (Zn) and iron (Fe) nutrition and 500,000 children lose their lives due to this. In recent years, the interest in adopting healthy diets drew increased attention to mineral nutrients, including Zn. Zn is an essential micronutrient for plant growth and development that is involved in several processes, like acting as a cofactor for hundreds of enzymes, chlorophyll biosynthesis, gene expression, signal transduction, and plant defense systems. Many agricultural soils are unable to supply the Zn needs of crop plants, making Zn deficiency a widespread nutritional disorder, particularly in calcareous (pH > 7) soils worldwide. Plant Zn efficiency involves Zn uptake, transport, and utilization; plants with high Zn efficiency display high yield and significant growth under low Zn supply and offer a promising and sustainable solution for the production of many crops, such as rice, beans, wheat, soybeans, and maize. The goal of this review is to report the current knowledge on key Zn efficiency traits including root system uptake, Zn transporters, and shoot Zn utilization. These mechanisms will be valuable for increasing the Zn efficiency of crops and food Zn contents to meet global needs for food production and nutrition in the 21st century. Furthermore, future research will address the target genes underlying Zn efficiency and the optimization of Zn efficiency phenotyping for the development of Zn-efficient crop varieties for more sustainable crop production under suboptimal Zn regimes, as well food security of the future.
Citrus (Citrus sinenesis L.) orchards in Swat were assessed for micronutrients (Zn, Cu, Fe, Mn, B) deficiency during 2006. Representative soil and leaf samples from 51 citrus orchards were collected and analyzed for micronutrients. The results on leaf analysis showed that Zn was deficient in 100%, Mn in 96%, B in 24% and Cu in 16% orchards. The soil analysis showed that Zn was deficient in 10-44%, Fe in 12-18%, and Mn in 4-14% orchards, whereas Cu and B were adequate in all 51 orchards. The soil pH of citrus orchards was between 7.5 and 8.5, and EC was below 4.0 dS m-1. These results suggested that the deficiency of Zn and Mn in citrus orchards of Swat were wide-spread but that of B and Cu were sparse. The soil and plant tests for diagnosing micronutrient deficiencies in citrus orchards were poorly correlated. However, the surface soil (0-15 cm) and cumulative micronutrients contents of the profile (0-45 cm) were strongly positively correlated. Thus, the surface soil analysis can be used to measure pattern in micronutrients fertility of the profile using the regression equations developed in this study. Further studies are needed to determine suitable dose of micronutrients application to citrus orchards in Swat in field experiments.
Maintaining health of citrus plants by nutrition management demands to deal citrus as a tree plant that has growth in shifts. There is a need to chalk out nutrition programme by keeping in mind growth as well as phonological cycles of the plant because every shift of growth in association with phonological and growth cycles needs special attention to decide fertilization programme. There is a need to develop well established production technology to increase the production of this crop substantially by using non-conventional approaches alone or in combination with conventional approaches. The use of multi-nutrient plant growth regulator formulation amended with appetizer is a new and innovative approach to develop a cost effective foliar spray "Micro Power" for improving citrus yield. Results from two demonstration trials revealed that NPK fertilizers (calculated on the basis of age and foliage on fruit trees rather than on the basis of area) application on drip line in combination with foliar spray was helpful to improve production of quality citrus (kinnow) fruits up to 63%. Moreover, this strategic management of nutrition was also helpful to identify appropriate time and growth stage for the application of fertilizer mix.
Citrus by its avid nutrient-absorbing capacity, is considered a highly nutrient-responsive perennial fruit crop. Differential efficacy of two conventional methods of fertilization (soil versus foliar application), although helped in improving the quality citrus, but of late, continuous fertilization, has failed to sustain the same yield expectancy on a long-term basis due to depletion of soil carbon stock and consequently emerged multiple nutrient deficiencies, irrespective of soil type. The menace of multiple nutrient deficiencies would be further triggered through increase in air temperature via changes in microbial communities and activities within the rhizosphere in the light of climate change. Such changes will dictate adversely on the orchard’s productive life in the long run.
The effects of mineral and organic fertilization on the contents of Fe, Cu, Zn, Mn, B and Mo in soil and in the soil solution as well as on availability of these elements for crops were investigated in the long-term field trial. The highest contents of Zn, Fe, Mn and Cu in soil and soil solution were observed in the treatment with the lowest pH (NPK). In this same combination the content of B and Mo was the lowest. The concentration of Zn, B and Fe in the soil solution significantly increased under farmyard manure application. Liming significantly decreased contents extractable by 1 mol/L HCl forms of Mn and Zn and significantly increase the content of Mo in the soil. Regardless of fertilization applied, microelement concentrations in the soil solution are sufficient for fulfilling nutritional needs of plants cultivated during the trial.
Fertilization is one of the most important cultural practices in date palm orchards. Spraying micro-nutrients has an important role in fruit set, fruit retention, development, improved total yield, and fruit characteristics. The present study was conducted during the two successive seasons, 2011 and 2012, in order to investigate the effect of bunches sprayed with boron and/or zinc on fruit set, yield, and fruit quality of 10-year-old "Mnifi" date palm. Bunches were pollinated by placing 10 "Meghal" fresh male strands among female clusters during both seasons. Nine spraying treatments were performed twice; 2 h before pollination and 4 weeks after pollination. Results of the two seasons indicated that application of 1500 ppm boron +300 ppm zinc (B1+Zn1) increased total yield/palm, fruit weight and volume, flesh weight, soluble solids content (SSC), and total and reducing sugars. Fruit set and titratable acidity were improved with spraying of 1500 ppm boron (B1). Fruit dimensions and moisture content increased with B1 treatment in the first season and B1+Zn1 treatment in the second season. Application of boric acid alone (1500 ppm) or combined with zinc sulphate (300 ppm) to get a positive effect on fruit set, total yield, and fruit quality of "Mnifi" date palm could be recommended.
The deficiency of mineral nutrients, particularly of boron (B) and zinc (Zn) in many citrus orchards of Pakistan affect yield and quality. Effect of foliar application of B and Zn on leaf mineral nutrients, growth, productivity, and quality of ‘Kinnow’ were studied. Trees were sprayed with 37 mM boric acid and 49 mM zinc sulfate either alone or in combination at fruit setting stage or fruit setting and pre-mature stages. Leaf phosphorus (P), potassium (K), B, and Zn were significantly increased with treatments. Lowest fruit drop and maximum fruit weight and number, highest level of ascorbic acid, and reducing sugars were recorded in the trees sprayed with combine application of B and Zn at fruit set stage. In conclusion, combined application of B and Zn at fruit setting stage can be used effectively to increase nutrient uptake, reduce fruit drop, and increase yield with better quality of ‘Kinnow’ mandarin fruit.
Average yields of our orchards (9 tones ha-1) are much less when compared with the world average of 25 tones ha-1, which is mainly blamed to imbalance fertilization. Technical Services Wing of Fauji Fertilizer Company is the pioneer one in fertilizer sector, which is providing macronutrients as well as micronutrients analysis and recommendations facilities to farming community throughout the country absolutely free of cost. During a period of seven months, 329 soil samples of various depths collected throughout Pakistan from citrus, mango, guava, banana and apple orchards were analyzed for available iron, copper, manganese, born and zinc status. The results reveal a wide spread deficiency of zinc, boron, followed by iron throughout the country while the deficiencies of copper and manganese have also been observed occasionally. Due to restricted mobility of iron, zinc and boron in plant tissues and keeping in view plant physiology, the authors are of the view that as orchard crops try to accumulate maximum amounts of essential nutrients before flower formation so micronutrients foliar sprays should be made preferably after fruit harvest and before flower formation in addition to recommended deficiency doses already applied through soil. To make up the deficiencies, various management strategies and future options have been discussed in detail in this paper.
Zinc (Zn) has emerged as the plant nutrient limiting rice growth in several parts of the world. About 50% of world soils are deficient in Zn and this is also true for India. An analysis of 0.233 million samples taken from different states showed that 47% of Indian soils are deficient in Zn. In India, Zn deficiency is widespread, especially in the rice–wheat cropping system belt of North India, which has high pH calcareous soils. Zinc is also now recognized as the fifth leading health risk factor is developing Asian countries, where rice is the staple food and Zn nutrition of humans and animals has recently received considerable attention. However, no reports are available on the effect of Zn fertilization on kernel quality of aromatic rices. The present study was therefore undertaken to study the effect of Zn fertilization on yield attributes, grain, and straw yield, Zn concentrations in grain and straw, Zn uptake, Zn use indices and kernel qualities of the aromatic rices. A field study at the Indian Agricultural Research Institute, New Delhi, India showed that Pusa Sugandh 4 (‘PS 4’) is a better than the earlier developed aromatic rice variety Pusa Basmati 1 (‘PB 1’) in terms of grain yield (4.08 tonnes ha), kernel quality, zinc (Zn) concentrations in grain and Zn uptake (1,396.9 g ha), recovery efficiency (5.2%), agronomic efficiency (122.7 kg grain increase kg Zn applied), partial factor productivity (1,064.7 kg grain kg Zn applied) and physiological efficiency (39,625 kg grain kg Zn uptake) of applied Zn. From the grain yield (4.64 tonnes ha) viewpoint an application of 5 kg Zn ha was found sufficient for the aromatic rices grown on ustochrepts of north Indian rice-wheat cropping system belt. Application of 7.5 kg Zn ha increased Zn concentrations in the grain (37.0 mg kg DM) and straw (117.3 mg kg DM) of aromatic rices studied and this is important from the human and animal nutrition viewpoint under Indian conditions.
One of the widest ranging abiotic stresses in world agriculture arises from low zinc (Zn) availability in calcareous soils, particularly in cereals. Cereal species greatly differ in their zinc effici ency (ZE), defined in this article as the ability of a plant to grow and yield well under Zn deficiency. ZE has been attributed mainly to the efficiency of acquisition of Zn under conditions of low soil Zn availability rather than to its utilization or (re)-translocation within a plant. A higher Zn acquisition efficiency, further, may be due to either or all of the following: an efficient ionic Zn uptake system, better root architecture, i.e. long and fine roots with architecture favouring exploitation of Zn from larger soil volume, higher synthesis and release of Zn-mobilizing phytosiderophore by the roots and uptake of Zn-phytosiderophore complex. Seed Zn content has also been suggested to affect ZE. This article attempts to examine critically the scanty and scattered reports available on the status of Zn deficiency globally; morphological, biochemical and physiological basis of regulation of ZE in cereals and approaches to improve ZE in terms of grain productivity and grain Zn vis-à-vis its bioavailability under conditions of poor Zn availability. A causal relationship between important Zn-containing enzymes, viz. carbonic anhydrase (CA), Cu/Zn-superoxide dismutase (SOD) activities and ZE is reported in wheat and other cereal species. Enhanced production and release of Fe-mobilizing phyto-metallophores known as phytosiderophores (PS), is another mechanism relevant for cereal species in adaptation to zinc deficiency.
Sub-optimum nutrition of zinc is globally one of the prime concerns of targeting sustainability in citrus production. Metabolically, Zn-deficiency induces many morphological, cytological and anatomical changes that lead to low flowering intensity and fruit set in addition to affecting the quality of citrus produced on sustained basis. Global occurrence of Zn-deficiency known by various names like rosette, little leaf, frenching, mottle leaf, etc., is basically characterized by interveinal chlorosis which may or may not be coupled with rosetting or smalling of leaves. Zinc deficiency is also suggested to appear due to competition from P, Fe, Mn, Ca and up to some extent K, besides a number of soil properties influencing the Zn-availability. Etiology of Zn-deficiency can now be precisely established using a variety of soil-plant diagnostics including the use of biochemical markers like peroxidase, carbonic anhydrase and nitrate reductase for more accurate diagnosis compared to leaf/soil analysis. Citrus decline is, though, considered to be a syndrome of many contributory factors. But, a number of postulated hypotheses have established a definite role of zinc nutrition, a causal factor to citrus decline/blight. These include: dysfunction of water translocation, increased resistance to water transport in the xylem, altered disturbance and redistribution of Zn–especially in bark–suggesting horizontal movement instead of vertical movement of Zn in the outer wood next to cambium with distinct seasonal cycles of accumulation pattern. However, recent evidences suggest that abnormal zinc metabolism develop before the real dysfunction of water translocation becomes apparent.
The principles, equipment and procedures for measuring leaf and canopy gas exchange have been described previously as has
chlorophyll fluorescence. Simultaneous measurement of the responses of leaf gas exchange and modulated chlorophyll fluorescence
to light and CO2 concentration now provide a means to determine a wide range of key biochemical and biophysical limitations on photo synthesis
in vivo. Here the mathematical frameworks and practical procedures for determining these parameters in vivo are consolidated. Leaf CO2 uptake (A) versus intercellular CO2 concentration (Ci) curves may now be routinely obtained from commercial gas exchange systems. The potential pitfalls, and means to avoid these,
are examined. Calculation of in vivo maximum rates of ribulose‐1,5‐bisphosphate (RuBP) carboxylase/oxygenase (Rubisco) carboxylation (Vc,max), electron transport driving regeneration of RuBP (Jmax), and triose‐phosphate utilization (VTPU) are explained; these three parameters are now widely assumed to represent the major limitations to light‐saturated photosynthesis.
Precision in determining these in intact leaves is improved by the simultaneous measurement of electron transport via modulated
chlorophyll fluorescence. The A/Ci response also provides a simple practical method for quantifying the limitation that stomata impose on CO2 assimilation. Determining the rate of photorespiratory release of oxygen (Rl) has previously only been possible by isotopic methods, now, by combining gas exchange and fluorescence measurements, Rl may be determined simply and routinely in the field. The physical diffusion of CO2 from the intercellular air space to the site of Rubisco in C3 leaves has long been suspected of being a limitation on photosynthesis, but it has commonly been ignored because of the lack
of a practical method for its determination. Again combining gas exchange and fluorescence provides a means to determine mesophyll
conductance. This method is described and provides insights into the magnitude and basis of this limitation.
This document is SL 204, a fact sheet of the Soil and Water Science Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First printed: January 2003. SL 204/SS423: Micronutrient Deficiencies in Citrus: Iron, Zinc, and Manganese (ufl.edu)
The spatial variability of micronutrients (Zn, Cu, Fe, Mn and B) in citrus orchards in Malakand Agency of Khyber Pakhtunkhwa Province during 2008 was assessed and mapped. Soil samples at 0-30 cm depth from 24 different spots at 6 m distance from one another were collected from a citrus orchard located in Warther area of Dargai Malakand Agency and were analysed for micronutrients. Geostatistical technique of semivariogram analysis was applied on data to determine spatial structure of micronutrients in soils. Soil test values at other locations were interpolated using geostatistical technique of kriging and detailed isarithmic maps. The results showed that Zn was low in none, marginal in 54.17 % and adequate in 45.83 % samples. Similarly, B was low in none, marginal in 83.33 % and adequate in 16.67 % samples. However, Cu, Fe and Mn were adequate in 100 % samples. Semivariogram analysis showed that Cu, Fe and B had strong, Zn had a moderate and Mn had a poor spatial structure described by linear model. Computer generated maps using kriging technique showed that almost all the maps had some spatial variation in different micronutrient contents in the field. These results suggested that the citrus orchard was not uniform in micronutrient contents and can be delineated into different categories for variable rate fertilizer management.
In this investigation, influence of foliar application of micronutrients (Zn, Cu and B) was studied on the improvement in photosynthetic and fruit yield attributes of citrus (Kinnow) plants. Experiments were conducted in two districts of Punjab (Sargodha and Toba Tek Singh), Pakistan varying in soil properties and agro-climatic conditions. Plants at both sites were subjected to foliar spray of three different levels (i.e. 0.1, 0.2 and 0.3%) of each Zn, Cu and B at three different fruit developmental stages while macronutrients (NPK) were applied at recommended rates as soil amendment. Micronutrients (Zn, Cu and B) application caused a significant improvement in net photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), Chlorophyll “a”, “b”, “total”, and caroteniods in both the citrus orchards. However, effect of micronutrients i.e. Zn, Cu and B was more pronounced at the levels of 0.3, 0.1 and 0.2%, respectively. These levels of nutrients were also effective in improving fruit yield with better fruit quality.
Citrus genus is the most important fruit tree crop in the world and lemon is the third most important Citrus species. Several studies highlighted lemon as an important health-promoting fruit rich in phenolic compounds as well as vitamins, minerals, dietary fiber, essential oils and carotenoids. Lemon fruit has a strong commercial value for the fresh products market and food industry. Moreover, lemon productive networks generate high amounts of wastes and by-products that constitute an important source of bioactive compounds with potential for animal feed, manufactured foods, and health care. This review focuses on the phytochemistry and the analytical aspects of lemon compounds as well as on the importance for food industry and the relevance of Citrus limon for nutrition and health, bringing an overview of what is published on the bioactive compounds of this fruit.
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