Effects of Application of Boron on Growth,Yields, and Quality of Red Bayberry

ABSTRACT

Three field experiments at three sites in east Zhejiang Province were conducted to determine the influence of applications of boron (B) on growth, yield, and quality of the red bayberry trees (Myrica rubra Sieb. et Zuca) with a manure species of “Buqizhong” in Linhai city. Ground B application or foliar B spraying significantly improved length and incidence rates of spring and summer shoots and increased fruit set rates, which resulted in the increases in fruit yield (13.7–17.5% for ground B application or 13.2–27.3% for foliar B spraying) and in improvement of fruit quality. The optimum yields were recorded with the treatments of ground B application of 40 g tree^?1 of borax or foliar B spraying of 2.0 g L^?1 of borax. Spring shoot incidents for the treatment of ground application of 50 g borax tree^?1 every year during the experiment (4B₅₀) were significantly higher than that for the treatment of ground application of 50 g borax tree^?1 only in the first year of the experiment (B₅₀), but the yield difference between them was not significant at P = 0.05. The increased yield effect of ground B application could last for 3 years. Boron application of red bayberry trees can be carried out by foliar-spraying 2.0 g borax L^?1 every year or ground application of 50 g borax tree^?1 every 3 years. The results of this study showed that application B could significantly improve the growth and increased fruit yield and quality of the red bayberry trees not exhibiting any vegetative symptoms of B deficiency.     

Effects of Boron and Paclobutrazol on Growth,Fruit Set,Nutrient Uptake,and Alternate Bearing of Muye Red Bayberry

Alternate bearing, resulting mainly from boron (B) deficiency, and excessive fruits in the alternate years of red bayberry trees are the most important limiting factors for production. This investigation was conducted on 18-year-old Muye red bayberry trees (Myrica rubra Sieb. et Zuca) in a commercial red bayberry orchard located in Laxi County, Zhejiang Province in 2006–2007.The results indicated that foliar application of paclobutrazol (PB) significantly increased the vegetative growth parameters (i.e., spring shoot incident and spring shoot length). Spring shoot incidents and spring shoot lengths of red bayberry were increased with increasing PB concentrations, but the optimum fruit yield and quality were obtained from foliar-applied PB at 100–200 mg L^?1 at full bloom. Foliar application of PB increased the contents of N and K in the leaves with increases of PB concentrations up to 300–600 mg L^?1. Fruit quality of red bayberry trees treated with PB or and boron fertilizer (BF) was improved at full bloom. Foliar application of PB reduced the percentage of fruit set by 62.1% in the year after treatment with PB but increased the yield by 49.0% the following year. Foliar application of PB at 100–300 mg L^?1 gave the most significant improvement in fruit quality: increase in fruit weight, soluble solid content, and the ratio of soluble solids (SS)?/?total acidity (TA) and decrease in total acidity. Foliar application of BF slightly reduced the fruit yields in the current year but significantly increased those the following year. Combined application of BF and PB or application of PB alone markedly reduced the fruit yields in 2006 by 40.5% and 43.8%, respectively, but markedly increased those by 44.6% and 17.8% in 2007, respectively. The effects of alleviating alternate bearing of red bayberry for different treatments followed the order of combined application of FB + PB > PB > BF > control. It is suggested that PB and BF can be used to alleviate alternate bearing.     

Fruit yield and quality characteristics of “Shahmiveh” pear cultivar grafted on six rootstocks

The growth, yield and fruit quality of 7-year-old trees of “Sahahmiveh” pear grafted on six rootstocks, including four quinces (QA, QB, QC, and PQBA29) and an Iranian native pear “Konjoni,” and a wild-type European pear (Pyrus communis L.), were evaluated in a completely randomized design trial with three replications at the Agricultural Research Center of Kabutarabad, Isfahan, Iran in 2 years (2013 and 2014). Yield and fruit weight of all rootstocks were markedly enhanced in the second year of the experiment. Considering both fruit yield and quality, “Sahahmiveh” scions on PQBA29 had the most suitable performance in both years. “Sahahmiveh”-PQBA29 combination exhibited the largest leaf dimensions (5.03?cm width and 7.27?cm length), fruit size values (6.3?cm width and 9.3?cm length), fruit weight (205?g per fruit) the highest yield (41.3?kg per tree), and acceptable fruit internal quality (0.4% titratable acidity and 17.4°brix total soluble solid) in 2014. The highest yield followed by QA (39.6?kg per tree) without significant differences compared to PQBA29. However, “Sahahmiveh”-QA fruit weight (189?g per fruit) and width (5.9?cm) values were markedly less than that of “Sahahmiveh”-PQBA29 in 2014. In conclusion, “Shahmiveh” pear cultivar grafted on PQBA29 exhibited more suitable fruit yield and quality values compared to the other rootstocks and, thus, would be the best rootstock for “Sahahmiveh” pear in Isfahan.     

Effect of foliar boron application on boron,chlorophyll, phenol,sugars and hormones concentration of olive (Olea europaea L.) buds,leaves, and fruits

The objective of this study is to investigate the effect of different time and rates of boron (B) foliar application on olive (Olea europaea L.) tree's tissue boron concentration, total phenol, chlorophyll, total soluble sugars, and endogenous hormones. A field experiment was conducted during two successive seasons 2010/2011 and 2011/2012 using 20 years old olive trees cv. Frantoio. The trees are grown in sandy soil planted at 5 × 5 m apart under drip irrigation system at the Nuclear Research Center Experimental Farm, Inshas, El-Qaliubiya Governorate, Egypt. Boron was applied foliarly as boric acid at the following rates (0.0, 100, 200, 300, 400, 500 mg L^?1) at flower initiation and after 1 and 2 months from flower initiation. Results showed that boron was significantly effective in increasing leaf, bud, and fruit boron concentration. Total phenol concentration in leaves and buds were significantly highest in the control treatment, significantly decreased as the boron application rate increased. Total chlorophyll, chlorophyll a and b, and total soluble sugars significantly increased as the boron application rate increased and the highest increase was achieved at 200 mg L^?1 boron concentration rate. Leaf and bud endogenous indole acetic acid (IAA) and abscisic acid (ABA) were highest in the control treatment; they decreased as the boron application rate increased. However, gibberellic acid (GA₃) increased in response to boron treatments compared with the control. The maximum increase was observed at 200 mg L^?1 boron rate. We concluded that boron is mobile in olive tree as reproductive organs accumulated more boron than vegetative organs. There is evidence that boron is involved in reduction of phenols, increase in fruit set, and in sugar transport. A balance in endogenous hormones (IAA, GA, ABA) concentrations in olive tree has induced the maximum fruit set and yield.     

Alleviation of alternate bearing phenomenon in mango (Mangifera indica L.) trees using boron and nitrogen fertilization

Abstract

This investigation was conducted during two successive seasons (2014/2015) and (2015/2016) using 15?years old productive mango (Mangifera indica) trees cv. Zebda. The trees were grown at AlMalak Valley Farm, El-Sharkeya Governorate- Egypt (30–51° North; 32–53° East). Trees were planted 8?×?8 meter within and between rows in sandy soil under drip irrigation system using the Nile water. The objective of this study is to alleviate alternate bearing in cv. Zebda using mineral nutrients (nitrogen in the on year and boron in the off year). Treatments included three concentrations of nitrogen (1000, 1250, 1500?g/tree/year) and three concentrations of boron (0.0, 250, 500?mg L^?1). Nitrogen was applied to the soil as ammonium sulfate and boron was applied as foliar spray of boric acid. The extra amount of nitrogen fertilizer (250 and 500?g N/tree) was applied at three installments in (May, June and July). Treatment was arranged in a factorial Completely Randomized Block Design with three replicates for each treatment. Results show that the on-year nitrogen fertilization significantly increased mango tree vegetative growth (number of shoot/branch, shoot length, shoot thickness, number of leaves/meter and leaf area) and yield. The average yield in the on year is 85.5?kg/tree at 1250?g N/tree but 67.4?Kilogram/tree at 1000?g N/tree (the control treatment). While in the off year boron foliar application resulted in a significant increase in flowering, initial fruit set, final fruit set and fruit yield. The average yield in the off year is 47?kg/tree at 250?mg L^?1 boron but 9?kg/tree at 0.0?mg L^?1 boron rate (the control treatment).The interaction treatment of 250?mg L^?1 boron + 1500?g nitrogen/tree is the best treatment as it resulted in the highest values for all the tested parameters. The average yield of this treatment is 53.5?kg/tree. This treatment helps alleviate alternate bearing phenomenon by 41% and obtain the highest economic yield in the off-year, i.e. increased yield by 5.9 fold.     

Treatment of Pistachio Trees with Zinc and Copper in Time of Swollen Bud in Two Consecutive Years

This study was done to investigate the effects of foliar sprays of zinc (Zn) and copper (Cu) on fruit set, yield, yield components, vegetative growth, and leaf nutrient concentrations of pistachio trees (cv. Owhadi), over two consecutive seasons 2010 (ON) and 2011 (OFF). Tests were done at a commercial orchard in the region of Rafsanjan in Iran. Tests were designed as a 3 × 2 factorial experiment in a randomized complete block with four replications. Treatments tested in the study were three concentration levels of zinc sulfate (0, 1000, and 2000 mg L^?1) and two concentration levels of copper sulfate (0 and 200 mg L^?1). Results showed that Zn foliar application increased first fruit set, final fruit set, fresh yield, and dry yield. Nut weight was increased by Zn spray by 3 and 4% at the second and third levels of Zn, respectively, compared with the control. However, Cu application increased splitting and vegetative growth. Vegetative growth in the OFF year was greater than that of the ON year. Phosphorus, sodium, and Cu concentrations in leaf were greater in the ON year than in the OFF year, but concentrations of Zn and potassium in leaf were lower in the ON year than they were in the OFF year. These results show that Zn and Cu applications can affect growth and yield of pistachio, especially when the plant is grown in calcareous soils. However, the alternate bearing pattern had a significant effect on vegetative growth and some leaf nutrient concentrations.     

BORON APPLICATION ON A CHESTNUT ORCHARD: EFFECT ON YIELD AND QUALITY OF NUTS

Although boron (B) deficiency in chestnuts (Castanea sativa Mill.) has been identified in Portugal and B fertilization was carried out in some orchards, the post-treatment evaluations have not been made to date. So the objective of this trial was to confirm the B deficiency and to quantify the effect of B applications to the soil on nut yield and quality. In October 2006, a fertilizer trial was established in a 15 year-old orchard in a very acid soil derived from siliceous schists. Soil liming and a basal fertilization were carried out in 16 trees and two levels of sodium tetraborate (Granubor, 14.6% B) were applied to eight trees: control (B0) and 100 g of Granubor per tree (B1). In the beginning of September chestnut leaves were collected from five trees and analyzed for macro- and micronutrients. Nut productivity was measured per tree and some nut quality parameters were evaluated, including the chemical composition of the kernel (soluble sugars, starch, total fiber, crude protein, and crude fat) in 2007, and dry matter, nut caliber, and fruit damage in 2007 and 2008. Boron fertilization of chestnuts significantly increased nut production: 75% in the first year (8 kg and 14 kg per tree, respectively, in the B0 and B1) and, in the second year, was over four times higher (4 kg and 17 kg per tree, respectively, in the B0 and B1). No significant differences were found in dry matter, nut caliber, nut damage and chemical composition of the kernel in the first year, but in the second year lower fruit damage by chestnut tortrix (P<0.0089) was observed. Foliar analyses exhibit relatively low B concentrations in the control trees (average value of 8 mg kg^?1) in both years, while in the fertilized trees the foliar B concentration were in average 61 mg kg^?1 in the first year, and 34 mg kg^?1 in the second year. The large drop in the foliar B concentration in the second year suggests the need to monitoring the nutrient status of chestnut orchards or more frequent of B application than usual practice.     

Foliar feeding of boron improves the productivity of cotton cultivars with enhanced boll retention percentage

Abstract

Cotton (Gossypium hirsutum L.) is of prime importance because of its quality fiber and edible oil production. Boron (B) is among essential micronutrients for plant growth; it aids in the transfer of sugars and nutrients from leaves to fruit that are involved directly or indirectly in many plant functions. Cotton growth, yield and quality are strongly affected with boron application. A two-year study was conducted to evaluate the impact of foliar applied B (0, 2, 4, 6, 8 and 10?g of B L^?1 of water) on the performance of cotton cultivars (FH-113, MNH-786 and CIM-496). The results indicated that growth, yield and quality traits of cotton were significantly influenced by different levels of foliar applied boron as well as cultivars of cotton. Among cotton cultivars, the yield and quality parameters were superior in cultivar “FH-113.” Foliar application of boron at 6?g L^?1 of water improved leaf area index and leaf area duration and eventually improved the number of bolls per plant, boll retention percentage, average boll weight, lint yield, ginning out turn, fiber length and uniformity ratio of cotton. Foliar application of B at 6?g per liter of water, showed promising results by improving growth and quality parameters and is recommend to enhance the economical yield production of cotton cultivar “FH-113” with improved quality.     

Effect of Boron Application on Yield,Quality, and Nutritional Status of Peach Cultivar Andross

During the cultivation period of 2005–2007, a project was carried out in the region of Eirinoupolis, prefecture of Imathia, Macedonia, northern Greece. The study investigated the application of boron (B) timing (flowering, fruit set, fruit growth) and method (soil and foliage) on the vegetative growth, fruit yield and quality, and nutritional status of the cling-stone peach variety Andross. The cultivar was grafted onto an 8-year-old rootstock GF 677. The results showed that the greatest marketable yield (135 kg tree^–1) was achieved in peach trees where B was applied on soil during the flowering stage in combination with a balanced nitrogen–phosphorus–potassium (NPK) basal application. Boron concentration in fruits of that treatment was increased in both cultivation years compared to most of the applied treatments. Foliar application of B at flowering, fruit set, and fruit growth, primarily in combination with foliar calcium (Ca) application, showed fruits to be less affected by cracking and Monilinia over all treatments. However, foliar application of Ca did not significantly promote leaf or fruit Ca concentration.     

Influence of Mineral Fertilizer,Farmyard Manure,Natural Zeolite,and their Mixture on Fruit Quality and Leaf Micronutrient Levels of Apple Trees

Adequate soil conditions and fertilization as a cultural practice are the basis of fruit crops production. This study was conducted in 2011 and 2012 to determine impact of soil application of complex nitrogen, phosphorus, and potassium (NPK) mineral fertilizer alone and its mixture with cattle manure (M) and natural zeolite (A) on yield, fruit physico-chemical traits and leaf micronutrient amounts at 120 days after full bloom (DAFB) in “Idared” and “Melrose apples grown on heavy and acidic soil under Serbian conditions. Results showed that NPK increased yield in “Idared” and both NPK+A and NPK+M in “Melrose.” Fertilizer applications were not influenced by fruit physico-chemical attributes, but differences between cultivars were significant. Fertilizers induced changes of leaf micronutrients amount, but effect was not consistent. In “Idared,” NPK+A and NPK+M mixtures improved amounts of the most micronutrients, whereas in “Melrose,” NPK and mixture NPK+A+M increased leaf micronutrients in more cases. According to deviation from optimum percentage (DOP and ΣDOP indexes), excessive leaf iron (Fe) and zinc (Zn) was found and deficiency of manganese (Mn), copper (Cu), and boron (B). “Melrose” exhibited much better balanced nutritional values for nutrients as compared to “Idared,” whereas NPK+M in “Idared” and NPK alone in “Melrose” promoted better balanced nutritional values. Since the impact of nutrients on the studied features is not consistent, more research will need to be conducted to investigate the long-term effect of NPK alone or in mixture with natural zeolite and manure fertilization on apples.     

Citrus leaf nutrient status: A critical evaluation of guidelines for optimal yield in Israel

Maintaining orchards with trees at optimal leaf nutrient concentrations is one of the key issues for maximizing yield. Experiments for evaluating and updating guidelines are very rare since they require several years of field experiments with mature fruit‐bearing trees. In the present paper, we first evaluated the Israeli guidelines for citrus by comparing them to the Israeli orchard leaf mineral status using a 10‐year leaf‐mineral database (results of 20 244 leaf analyses from commercial orchards all over Israel). Then, we created an updated guideline using a second database (the Israeli National Wastewater Effluent Irrigation Surveys database; INWEIS). This database summarizes yield and leaf mineral concentrations of commercial orchards from all over Israel. The data were collected from 122 orchards: 39 orchards of “Oroblanco” Pomelit (Citrus grandis), 33 orchards of “Michal” mandarin (C. reticulata), 30 orchards of “Star Ruby” grapefruit (C. paradise), and 20 orchards of “Shamouti” oranges (C. sinensis) over a 7‐year period. Based on the first database, there was a disagreement between recommendations and the leaf nutrient status (e.g., the Israeli Ministry of Agriculture recommendations were higher than orchard median values), which indicated that the growers and/or the recommendations need to be corrected. Based on the INWEIS database, a new guideline was set. It was found that the optimal leaf nutrient concentrations for grapefruit trees are 1.7% to 2.1% dry weight (DW) for N, 0.08% to 0.010% DW for P, 0.37% to 0.48% DW for K, and 0.33% to 0.45% DW for Mg. For orange trees, the optimal leaf nutrient concentrations are 1.9% to 2.3% DW for N, 0.11% to 0.14% DW for P, 0.80% to 1.00% DW for K, and 0.19% to 0.26% DW for Mg. For mandarin trees, the optimal leaf nutrient concentrations are 2.0% to 2.4% DW for N, 0.09% to 0.12% DW for P, 0.55% to 0.69% DW for K, and 0.19% to 0.26% DW for Mg. Maintaining leaf nutrient concentrations within these ranges will support maximal yields of 110 to 120 t ha^–1 for grapefruit, 65 to 70 t ha^–1 for orange, and 60 to 70 t ha^–1 for mandarin cultivars.     

The effects of autumn foliar applications of boron and urea on flower quality,yield, boron and nitrogen reserves of apricot

In order to determine the effects of autumn foliar application of boron (B) and/or urea on abortive flower ratio, yield, fruit weight, total soluble solid (TSS) and B and nitrogen (N) contents of reserves of non-irrigated apricot trees, field experiments were carried out between 2009 and 2012 in Malatya province of Turkey. The application of B and/or urea stimulated perfect flower development, B and N accumulation and resulted in significant yield increase. Boron, urea and B+urea applications increased fruit yield by 33.1%, 26.1% and 26.9%, decreased abortive flower ratio by 34.6%, 27.1% and 35.9% compared to the control, respectively. In addition, B and N contents of wood, bark and buds of apricot trees were significantly increased by B and/or urea treatments. It was also observed that B and N contents were the highest in bud compared to wood and bark in all treatments. The highest B (16.53 ppm) and N (1.56%) contents were determined to buds in B+urea treatment. The results of this study suggest that autumn foliar B and/or urea application have the potential to decrease abortive flower ratio and increase the yield and B and N contents of reserves of apricot trees under non-irrigated conditions.     

“Egusi” melon seed yield,proximate content and soil nutrient changes with poultry manure fertilization

Abstract

“Egusi” melon (Colocynthis citrullus L.) is a seed vegetable whose yield is limited by nutrient supply. Two field experiments were conducted with “Egusi” melon at the Crops Research Farm of the Federal University of Agriculture, Abeokuta, Nigeria, to evaluate response of poultry manure (PM) rate on seed yield, seed proximate content, and changes in soil nutrients. The study was conducted from May to August 2013 and repeated same period in 2014 using PM at: 0, 2, 4, 6, 8, and 10 t ha^?1. With the first planting, seed yields of 458 and 452?kg?ha^?1 from applications of 6 and 8 t ha^?1 PM were similar with the highest of 522?kg?ha^?1 from application of 10 t ha^?1 PM. The second planting, with residual fertilizer effect had a higher seed yield of 242?kg?ha^?1 from application of 10 t ha^?1 PM. Number of seeds per fruit was higher; 183 seeds per fruit in the first planting and 163 seeds per fruit in the second planting, from plants treated with 10 t ha^?1 PM. Shelling percent was comparable in both experiments. It was 19.5% with application of 10 t ha^?1 PM and 33.4% with the unfertilized plants for the first planting but was 28.0% with application of 10 t ha^?1 PM and 31.3% with the unfertilized plants for the second planting. Seed crude protein, crude fiber and ash contents were enhanced with application of 10 t ha^?1 PM. Soil pH in the first planting was reduced from initial 6.8 to 6.6 with the unfertilized plants and to 6.7 with applications of 2 and 10 t ha^?1 PM, but increased to 7.1 with application of 6 t ha^?1 PM. In the second planting, it was reduced to 5.0 with applications of 0, 2 and 4 t ha^?1 PM but to 5.3, 5.1, and 5.2 with applications of 6, 8, and 10 t ha^?1 PM, respectively. The initial total N of 0.14% was reduced to 0.12% with applications of 6 and 8 t ha^?1 PM but to 0.11% with the other treatments in the first planting; but reduced to 0.08% with applications of 2 and 4 t ha^?1 PM and to 0.06 and 0.09% with applications of 8 and 10 t ha^?1 PM, respectively, in the second planting. Available P in the first planting was reduced from an initial 17.62?mg kg^?1 to 4.32?mg kg^?1with the control treatment and to 6.74 and 5.83?mg kg^?1 with applications of 2 and 4 t ha^?1 PM, respectively, but to 8.32 and 8.24 with applications of 8 and 10 t ha^?1 PM, respectively. In the second planting, it was reduced to 1.92?mg kg^?1with the control treatment and to 2.53 and 1.81?mg kg^?1 with applications of 2 and 4 t ha^?1 PM, respectively but to 1.90 and 1.56 with applications of 8 and 10 t ha^?1 PM, respectively. Application of 10 t ha^?1 PM supplying 19?kg N, 0.5?kg P and 27?kg K per ha was adequate for enhanced seed yield and proximate contents of “Egusi” melon.     

Potassium and Boron Nutrition Enhance Fruit Quality in Midwest Fresh Market Tomatoes

The tomato fresh fruit market has rigorous quality standards that can be challenging to meet, particularly under highly variable climatic conditions. Information is required about the influence of nutritional regime on tomato fruit and the interaction of potassium (K) and boron (B) in particular. A field experiment was conducted in 2002 and 2003 to evaluate the effects of K and B on yield and quality of fresh market tomatoes cv. ‘Mountain Spring’ at a southwest Michigan site with well‐drained soil (Alfisol Hapludalf, Oakville fine sand). Treatments applied during fruit development included three fertigation regimes (1N:0.8K, 1N:1.7K, and 1N:2.5K) in the presence and absence of a weekly foliar spray of B (300 mg?L^?1 B). Increasing K concentration in the fertilizer increased K content in leaf tissue, but in some cases reduced tissue calcium (Ca) and B. Fruit quality was influenced by nutrition, as the greatest rate of K was associated with increased crack susceptibility as indicated by a fruit bioassay and a 14% increase in incidence of the defect “shoulder check” in field‐grown fruit compared to less rates of K nutrition. Boron foliar spray increased tomato marketable yield and fruit quality, reducing shoulder check incidence by 50% compared to zero‐B‐treated plants in 2003. Because of yield and quality improvements, B was a cost‐effective treatment as shown by partial budget analysis, whereas increasing K nutrition did not provide consistent economic benefits. Moderate K rates were associated with the greatest marketable yield, and the 1N:1.7K plus foliar B nutrient regime produced the greatest quality fruit. Overall data were consistent with the need to carefully evaluate K and B nutrition in tomatoes, in the context of soil type, yield potential, fruit quality, and nutrition regime.     

‘Schattenmorelle’ Tart Cherry Response to Boron Fertilization

ABSTRACT

The objective of the experiment was to examine the effects of soil and foliar applications of boron (B) on tart cherry (Prunus cerasus L.) tree vigor, yield, and fruit quality. The study was conducted during 2003–2004 on mature ‘Schattenmorelle’ tart cherry trees grown at a commercial orchard in central Poland on coarse-textured soil with low B content. Trees were supplied with B as foliar sprays or via soil application. Foliar B sprays were performed: (1) in the spring, at the white bud stage, when 5%–10% of flowers were at full bloom, and 5 d after petal fall, at a rate of 0.2 kg B ha^?1 per each spray treatment; and (2) in the fall, approximately six weeks before the natural leaf fall, at a rate of 0.8 kg B ha^?1. Soil B application was made at the bud-break stage at a rate of 2 kg ha^?1. Trees untreated with B served as a control. Spring and fall B sprays increased flower B concentrations, but had no effect on summer leaf B status. Leaf B concentrations of trees with B supplied to the soil were higher than those of the control trees. However, soil B application had no influence on flower B level. Vigor and yield of tart cherry trees were not influenced by B fertilization. Also, mean fruit weight and titratable acidity of fruit did not differ among treatments. Fruit of trees with B supplied to the soil had higher soluble solids concentration (SSC) than those of the control plants. In conclusion, high yield of tart cherry can be obtained on soils with water-soluble B concentrations as low as 0.32 mg kg^?1. It is also postulated that at low soil-B availability, under conditions of low-light intensity during fruit ripening, soil-B application increases SSC in tart cherry fruit.     

STUDIES ON DIFFERENTIAL RESPONSE OF SPRING CANOLA CULTIVARS TO BORON TOXICITY

Although many states recommend boron (B) fertilizer for many field crops, information about B toxicity of canola is lacking. This experiment was carried out at Central Anatolia, Turkey from 2002 to 2003, to determine genotypic range in B efficiency of eight spring canola cultivars, to identify the B-inefficient cultivars and to identify specific responses. The cultivars were grown under B moderate deficiency (extractable B 0.56 mg kg^?1) and toxic B applied (15 kg B ha^?1) conditions. According to the results, seed yield varied significantly among the cultivars and B application decreased the seed yield by 31% on average. Also, toxic B application reduced protein and oil contents similar to seed yield, and increased leaf B concentration in all varieties. This study has shown that leaf B concentration has increased considerably when B is applied to Pactol and Star cultivars, but seed yield of +B and ?B has not shown significantly a change. It is possible to say that Star and Pactol—which have not been affected by the toxic B application—are genotypes that are tolerant to B toxicity and may be cultivated at B toxic lands.     

BORON AND LIME EFFECTS ON YIELD AND DEFICIENCY SYMPTOMS OF RICE GROWN IN GREENHOUSE ON ACID TYPIC GLOSSAQUALF*

ABSTRACT

No boron (B) deficiencies have been reported for rice (Oryza sativa L.) grown in the United States and, when occurring elsewhere, reports often lack details of deficiency symptoms and leaf-B critical values. An experiment was conducted to determine the effect of B and lime on yield, pollen viability, and to determine diagnostic symptoms of B deficiency in rice. Rice cv. “Bengal” was grown in the greenhouse on a soil acquired from a rice farm from SW Louisiana in the United States, a Caddo silt loam (Caddo sl) (Typic Glossaqualf, fine-silty, siliceous, thermic), treated with 0.44?mg?B?kg^?1 (+B) or no B (?B). Split plots were limed at rates of (i) none; (ii) 224?mg?kg^?1 CaO+40.3?mg?kg^?1 MgO; and (iii) 673?mg?kg^?1 CaO+121?mg?kg^?1 MgO. Rice was also grown in ?B and +B potting media and in ?B sand culture using nutrient solution identical to that used in other studies of ours. Rough-rice yields from the +B Caddo sl treatment was 11% higher than from the ?B treatment (29.3 vs. 26.3?g?pot^?1; P=0.02). The yield increase was likely due to fewer damaged pollen (8%) found from the +B than the ?B treatment (17%; P=0.014). Leaf-B at tillering was 11.3?mg?kg^?1 for the B-treated rice and 7.1?mg?kg^?1 from the ?B treatment. Liming did not significantly affect leaf B or yields. Boron deficiency symptoms were found only in the ?B sand-culture where yields were 1.1?g?pot^?1, 96% less than that from the +B Caddo sl. Symptoms were like those found in our earlier hydroponic studies with twisted and whitish leaf tips starting at tillering and 1-cm white bands across the width of leaves. Maturity was delayed about four weeks. Boron deficiency from the Caddo sl and sand treatments occurred with leaf B≤7?mg?kg^?1 and with a Caddo sl soil B of 0.18?mg?hws (hot-water soluble) B?kg^?1. Given that no B deficiency symptoms were found in rice experiencing moderate yield loss grown on the rice soil, one must rely on soil and plant analyses to help detect likely candidates for moderate B deficiency.     

Nitrogen nutrition diagnosis for olive trees grown in super-intensive cropping systems

Abstract

The results of a 4-year experiment combining irrigation, N, and K showed that to maintain productivity and tree growth it is necessary to attain a higher leaf N status than current diagnosis standards. To sustain high oil yield and quality and to avoid excessive vigor, a critical N concentration was established for olive trees of 1.94% for leaves sampled in July. A negative relationship was obtained between N leaf concentration and some quality parameters. Above 1.94% N, total phenolic content and oxidative stability fell below 220?mg kg^?1 and 10?hr, respectively. In addition, above this N leaf concentration other factors including the alternate bearing index (ABI) and vegetative growth distorted productive and qualitative responses. Moreover, the differential productive response of trees related to alternate fruit bearing status implies that the interpretation of leaf nitrogen content can be more accurate when ABI suggests an ON tree status.     

SEASONAL CHANGES IN LEAF NITROGEN OF OLIVE TREES GROWN UNDER DIFFERENT IRRIGATION REGIMES AND CROP LEVEL

An experiment was conducted over 12 months using field-grown olive trees (Olea europaea) to assess the combined effect of soil water availability and fruit number on seasonal changes in leaf nitrogen (N) concentration. Three irrigation regimes were established and three trees per irrigation treatment were thinned to reduce their yield to about half that of unthinned trees. The N concentration of fully-expanded leaves from either the current-year growth or one-year old part of fruiting shoots was determined every two months. Nitrogen concentration was higher in current-year leaves than in one-year old ones at most sampling dates. Maximum values of leaf N were measured in spring, minimum values in August. Leaf N concentrations were positively correlated with leaf water potential during fruit development. This relationship was weak at the onset of rapid oil accumulation in August and became more evident at harvest. There was no correlation between leaf N and crop level.