Tree Nitrogen Status and Leaf Canopy Position Influence Postharvest Nitrogen Accumulation and Efflux from Pear Leaves

`Cornice' pear trees (Pyrus communis L.) were fertilized with ammonium nitrate depleted in “N in Spring 1987 and 1988. In Aug., Oct., and Nov. 1988, midleaves on current season shoots were sampled at three positions from the periphery to the center of the canopy. Total N/cm' of leaf area remained almost constant through October, even though percent N concentration declined as specific leaf weight (SLW) increased. Furthermore, there was no substantial net change in either labeled or unlabeled N in either treatment until senescence began in October. Peripheral leaves contained higher levels of both reserve and newly acquired N than did less-exposed leaves. Despite large differences in N/cm2 for October samples, by November leaves from both high (HN) and low N (LN) trees exported similar percentages of their total N. The average N export to storage tissues irrespective of tree N status was 71%, 61%, and 52% for peripheral, medium, and interior leaves, respectively. The export of N was influenced more by the leaf position in the plant canopy than the nutritional status of the tree.EEA Alto ValleFil: Sanchez, Enrique Eduardo. Oregon State University. Department of Horticulture; Estados Unidos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Righetti, Timothy L. Oregon State University. Department of Horticulture; Estados Unido

Management of Nitrogen and Calcium in Pear Trees for Enhancement of Fruit Resistance to Postharvest Decay

Management of pear (Pyrus communis L.) trees for low N and high Ca content in the fruit reduced the severity of postharvest fungal decay. Application of N fertilizer 3 weeks before harvest supplied N for tree reserves and for flowers the following spring without increasing fruit N. Calcium chloride sprays during the growing season increased fruit Ca content. Nitrogen and Ca management appear to be additive factors in decay reduction. Fruit density and position in the tree canopy influenced their response to N fertilization. Nitrogen: Ca ratios were lower in fruit from the east quadrant and bottom third of trees and from the distal portion of branches. High fruit density was associated with low N: Ca ratios. Nutritional manipulations appear to be compatible with other methods of postharvest decay control.EEA Alto ValleFil: Sugar, David. Oregon State University. Southern Oregon Experiment Station; Estados UnidosFil: Righetti, Timothy L. Oregon State University. Department of Horticulture; Estados UnidosFil: Sanchez, Enrique Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Khemira, Habib. Oregon State University. Department of Horticulture; Estados Unido

Response of Highbush Blueberry to Nitrogen Fertilizer During Field Establishment, I: Accumulation and Allocation of Fertilizer Nitrogen and Biomass

The effects of nitrogen (N) fertilizer application on plant growth, N uptake, and biomass and N allocation in highbush blueberry (Vaccinium corymbosum L. 'Bluecrop') were determined during the first 2 years of field establishment. Plants were either grown without N fertilizer after planting (0N) or were fertilized with 50, 100, or 150 kg.ha⁻¹ of N (50N, 100N, 150N, respectively) per year using ¹⁵N-depleted ammonium sulfate the first year (2002) and non-labeled ammonium sulfate the second year (2003) and were destructively harvested on 11 dates from Mar. 2002 to Jan. 2004. Application of 50N produced the most growth and yield among the N fertilizer treatments, whereas application of 100N and 150N reduced total plant dry weight (DW) and relative uptake of N fertilizer and resulted in 17% to 55% plant mortality. By the end of the first growing season in Oct. 2002, plants fertilized with 50N, 100N, and 150N recovered 17%, 10%, and 3% of the total N applied, respectively. The top-to-root DW ratio was 1.2, 1.6, 2.1, and 1.5 for the 0N, 50N, 100N, and 150N treatments, respectively. By Feb. 2003, 0N plants gained 1.6 g/plant of N from soil and pre-plant N sources, whereas fertilized plants accumulated only 0.9 g/plant of N from these sources and took up an average of 1.4 g/plant of N from the fertilizer. In Year 2, total N and dry matter increased from harvest to dormancy in 0N plants but decreased in N-fertilized plants. Plants grown with 0N also allocated less biomass to leaves and fruit than fertilized plants and therefore lost less DW and N during leaf abscission, pruning, and fruit harvest. Consequently, by Jan. 2004, there was little difference in DW between 0N and 50N treatments; however, as a result of lower N concentrations, 0N plants accumulated only 3.6 g/plant (9.6 kg-ha⁻¹) of N, whereas plants fertilized with 50N accumulated 6.4 g/plant (17.8 kg.ha⁻¹), 20% of which came from ¹⁵N fertilizer applied in 2002. Although fertilizer N applied in 2002 was diluted by non-labeled N applications the next year, total N derived from the fertilizer (NDFF) almost doubled during the second season, before post-harvest losses brought it back to the starting point.Keywords: Dry matter, Nitrogen partitioning, Plant, Actinidia Deliciosa vines, Reserve N, (15)Nitrogen, Rabbiteye blueberry, Soil N, Soil, Fate, Growth, [superscript 15]N, Nitrogen removal, Vaccinium corymbosum, Ammonium, Translocation, Nitrogen use efficiency, Yield, Fertilization, Culture, Ericacea

Effect of Postharvest Soil and Foliar Application of Boron Fertilizer on the Partitioning of Boron in Apple Trees

This study was carried out on mature `Delicious' apple trees (Malus domestica Borkh.) on EM 9 rootstock. Labeled B (99.63 Atom % 10B) was applied as boric acid. Treatments were postharvest foliar B at 375 mg·L–1, postharvest foliar B (375 mg·L–1) plus urea (2.5% wt/vol), and a soil application at the same per-tree rate as the foliar treatments (16 g boric acid/tree). Postharvest foliar B applied with or without urea was efficiently transported from the leaves into storage tissues for the next year's growth. However, soil-applied B remained mostly in the roots while very little was translocated to the above-ground portions of the tree at full bloom. When urea was added to a foliar B spray, the amount of B in the roots and flower clusters increased at full bloom. Although increasing the efficiency of foliar B applications may not be necessary, combining urea and B into a single application is recommended when growers want to apply both N and B. Shoot leaves from all treatments collected late in the season (midsummer) had similar B concentrations, even though treatments altered the amount of added B that was present in different tree tissues early in the season.EEA Alto ValleFil: Sanchez, Enrique Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Righetti, Timothy L. Oregon State University. Department of Horticulture; Estados Unido

Identifying nutrient deficiency and toxicity in red raspberry

The Pacific Northwest leads the United States in red raspberry production. Many factors affect yield, including nutrition, weather, pests, and water. Most nutritional problems can be quickly solved once you know the specific problem, but an accurate diagnosis is difficult. Foliar nutrient symptoms can be helpful, if you recognize specific nutritional disorders and if you're aware of the limitations involved in basing a diagnosis solely on these symptoms. Different nutritional disorders can produce symptoms that are very similar to each other. Some diseases and pests also produce symptoms that mimic nutritional disorders. Other nutritional problems only produce symptoms when the problem is so severe that corrective measures may be too late. Nutrients typically found to be deficient in Pacific Northwest red raspberries are nitrogen, phosphorus, potassium, sulfur, magnesium, copper, boron, and zinc. Manganese is the nutrient most likely to be present in toxic quantities because levels increase under the acid conditions that commonly occur. Boron toxicity can result from overfertilization. Other toxicities are rare in the Pacific Northwest. This publication is intended to help you diagnose nutritional problems. What follows is a brief summary of the roles each element has in plant growth or development and each element's normal level in red raspberries. Also included are summaries (in percentages) from the Oregon State University Plant Analysis Laboratory for nearly 500 Pacific Northwest red raspberry samples analyzed in the last 15 years. These summaries are included to give you an idea of how common or rare specific deficiencies or toxicities are in Oregon and neighboring states. Photographs and descriptions of common foliar symptoms are also presented. For fertilizer recommendations, contact your county Extension office.Published September 1991. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Effect of Postharvest Soil and Foliar Application of Boron Fertilizer on the Partitioning of Boron in Apple Trees

This study was carried out on mature `Delicious' apple trees (Malus domestica Borkh.) on EM 9 rootstock. Labeled B (99.63 Atom % 10B) was applied as boric acid. Treatments were postharvest foliar B at 375 mg·L–1, postharvest foliar B (375 mg·L–1) plus urea (2.5% wt/vol), and a soil application at the same per-tree rate as the foliar treatments (16 g boric acid/tree). Postharvest foliar B applied with or without urea was efficiently transported from the leaves into storage tissues for the next year's growth. However, soil-applied B remained mostly in the roots while very little was translocated to the above-ground portions of the tree at full bloom. When urea was added to a foliar B spray, the amount of B in the roots and flower clusters increased at full bloom. Although increasing the efficiency of foliar B applications may not be necessary, combining urea and B into a single application is recommended when growers want to apply both N and B. Shoot leaves from all treatments collected late in the season (midsummer) had similar B concentrations, even though treatments altered the amount of added B that was present in different tree tissues early in the season.EEA Alto ValleFil: Sanchez, Enrique Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Alto Valle; ArgentinaFil: Righetti, Timothy L. Oregon State University. Department of Horticulture; Estados Unido

Response of Higbbush Blueberry to Nitrogen Fertilizer during Field Establishment-II. Plant Nutrient Requirements in Relation to Nitrogen Fertilizer Supply

A study was done to determine the macro- and micronutrient requirements of young northern highbush blueberry plants (Vaccinium corymbosum L. ‘Bluecrop’) during the first 2 years of establishment and to examine how these requirements were affected by the amount of nitrogen (N) fertilizer applied. The plants were spaced 1.2 × 3.0 m apart and fertilized with 0, 50, or 100 kg·ha⁻¹ of N, 35 kg·ha⁻¹ of phosphorus (P), and 66 kg·ha⁻¹ of potassium (K) each spring. A light fruit crop was harvested during the second year after planting. Plants were excavated and parts sampled for complete nutrient analysis at six key stages of development, from leaf budbreak after planting to fruit harvest the next year. The concentration of several nutrients in the leaves, including N, P, calcium (Ca), sulfur (S), and manganese (Mn), increased with N fertilizer application, whereas leaf boron (B) concentration decreased. In most cases, the concentration of nutrients was within or above the range considered normal for mature blueberry plants, although leaf N was below normal in plants grown without fertilizer in Year 1, and leaf B was below normal in plants fertilized with 50 or 100 kg·ha⁻¹ N in Year 2. Plants fertilized with 50 kg·ha⁻¹ N were largest, producing 22% to 32% more dry weight (DW) the first season and 78% to 90% more DW the second season than unfertilized plants or plants fertilized with 100 kg·ha⁻¹ N. Most DW accumulated in new shoots, leaves, and roots in both years as well as in fruit the second year. New shoot and leaf DW was much greater each year when plants were fertilized with 50 or 100 kg·ha⁻¹ N, whereas root DW was only greater at fruit harvest and only when 50 kg·ha⁻¹ N was applied. Application of 50 kg·ha⁻¹ N also increased DW of woody stems by fruit harvest, but neither 50 nor 100 kg·ha⁻¹ N had a significant effect on crown, flower, or fruit DW. Depending on treatment, plants lost 16% to 29% of total biomass at leaf abscission, 3% to 16% when pruned in winter, and 13% to 32% at fruit harvest. The content of most nutrients in the plant followed the same patterns of accumulation and loss as plant DW. However, unlike DW, magnesium (Mg), iron (Fe), and zinc (Zn) content in new shoots and leaves was similar among N treatments the first year, and N fertilizer increased N and S content in woody stems much earlier than it increased biomass of the stems. Likewise, N, P, S, and Zn content in the crown were greater at times when N fertilizer was applied, whereas K and Ca content were sometimes lower. Overall, plants fertilized with 50 kg·ha⁻¹ N produced the most growth and, from planting to first fruit harvest, required 34.8 kg·ha⁻¹ N, 2.3 kg·ha⁻¹ P, 12.5 kg·ha⁻¹ K, 8.4 kg·ha⁻¹ Ca, 3.8 kg·ha⁻¹ Mg, 5.9 kg·ha⁻¹ S, 295 g·ha⁻¹ Fe, 40 g·ha⁻¹ B, 23 g·ha⁻¹ copper (Cu), 1273 g·ha⁻¹ Mn, and 65 g·ha⁻¹ Zn. Thus, of the total amount of fertilizer applied over 2 years, only 21% of the N, 3% of the P, and 9% of the K were used by plants during establishment.Keywords: Fertilizer rate, Vaccinium corymbosum, Nutrient partitioning, Macronutrients, Plant dry matter, Reallocation, Integrated plant nutrient management, Micronutrient