Effects of seven different irrigation systems for `Fuji' and two irrigation systems for `Gala' on five rootstocks on tree growth, water use, and mineral nutrients were studied. All forms of drip system used significanly less water than sprinkler systems. Patial root drying sprinkler system used 50% less water than full sprinkler. Application of partial root drying drip at 50% rate of full drip was not sufficient and trees had to receive 75% of full drip to survive. Trees under full sprinkler used about 28 inches of water while those with drip used less than 8 inches of water during the 2003 growing season. Leaf minerals, particularly N and K were affected by irrigation systems. Trees with buried drip required less water than those with above-ground drip system. Calculation of water requirement on a tree-use basis provided an excellent guide for irrigation.
The increasing trend in the world population and decreasing trend in the suitable land for fruit production, combined with a shortage of water, mandate the use of efficient methods of irrigation and establishment of high-density orchards that require size-controlling rootstocks. Method of irrigation and vigor of rootstock are among the most important factors affecting uptake of mineral nutrients, and thus tree growth and fruit yield and quality attributes of apple (Malus domestica). In a long-term experiment, effects of two irrigation methods and four rootstocks on water use, tree growth, fruit quality, and leaf mineral nutrients were studied in ‘Pacific Gala’ apple. The experiment was conducted in southwestern Idaho, which represents the high desert conditions of the Intermountain West region of the United States. Evapotranspiration-based irrigation scheduling (ETc), adjusted by percentage of ground shading, was used for sprinkler and drip systems. Significantly lower volume of water was applied to the trees with drip irrigation than those with sprinkler irrigation system. Leaf calcium (Ca) decreased but leaf potassium (K) increased with rootstock vigor, resulting in the greatest leaf Ca but lowest leaf K in trees on ‘Budagovsky 9’ (B.9). Fruit weight and yield per tree in ‘Pacific Gala’ on ‘Nic 29’ (RN29) rootstock was higher than those on B.9 and ‘Geneva 30’ (G.30) rootstocks. ‘Pacific Gala’ on B.9 rootstock had smaller trees and fruit size but higher fruit starch degradation pattern (SDP), suggesting earlier fruit maturity on this rootstock. On average, ‘Pacific Gala’ trees with drip irrigation had larger fruit and higher leaf magnesium (Mg) and manganese (Mn) but less fruit color and firmness and lower leaf Ca, K, zinc (Zn), and copper (Cu) than those with sprinkler system.
The art and science of horticulture and horticultural crops are integral parts of Iranian’s rich and ancient culture and modern economy. Many deciduous fruit, flowers, and vegetables are native to Iran (Persia), and from there, they were distributed to the rest of the world through the Silk Road established by the Achaemenid, the Royal Pars Dynasty. Variations in climate and presence of numerous mountains, lakes, rivers, and natural springs have created a unique country capable of producing all types of fruits, vegetables, and flowers. Apples and other deciduous fruits are commercially produced in mountain ranges of Alborz and Zagrous and in many central provinces of Iran. The Caspian Sea area in the north of Iran is one of the most unique regions in the world where mild Mediterranean climate meshed with the adjacent Alborz mountain ranges has created a home to numerous species of edible horticultural plants, ranging from tea to cherries and pomegranates. Pistachio, olive, citrus, banana, and date are produced in Kerman, Fars, and Khuzestan regions. However, the Iranian horticultural industry faces many challenges, including global and regional political issues. Although some attempt has been made to preserve invaluable germplasm, a large number of native fruits, vegetables, and flowers are becoming extinct. Postharvest transportation and storage of horticultural crops is one of the most important issues facing Iranian horticulture. The future of horticulture in Iran can potentially be bright, and horticultural products have the potential to replace the oil income after reserves disappear, particularly if peace prevails in the region.
Effects of various concentrations of Dormex (hydrogen cyanamide, a.i. = 49%), pelargonic acid and endothalic acid, applied at 60% and full-bloom, on fruit set and yield of `Early Spur Rome' apple and `Redhaven' peach were studied over 2 years. A full-bloom application of Dormex at 0.25% and 0.31% (% formulation) alone or 0.125% endothal followed by a post-bloom thinner reduced fruit set and increased fruit size in apple. A double application of endothal at a rate of 0.125%, once at 70% bloom and again at full-bloom, also was effective in thinning and increased fruit size in apple. Pelargonic acid was effective in thinning in apple when applied at a rate of 0.187% at 60% bloom and again at full-bloom. Return bloom in apple was better when blossom thinners effectively thinned blossoms. Dormex application at a rate of 0.31% at full-bloom showed the highest return bloom in apple. All three chemicals were effective in thinning in peach when they were applied before complete fertilization. However, only 0.31% Dormex application at full-bloom was effective in thinning peach when a high rate of fertilization had taken place.
Blossom thinning of `Early Spur Rome' apple (Malus domestica Borkh.) and `Redhaven' peach (Prunus persica L.) with hydrogen cyanamide (Dormex, 50% a.i.), endothalic acid [(Endothal, 0.4 lb a.i./gal (47.93 g a.i./L)], and pelargonic acid (Thinex, 60% a.i.) was studied in 1995 and 1996. Full-bloom applications of hydrogen cyanamide at 2 pt formulation/100 gal (1288 mg a.i./L) and 2.5 pt formulation/100 gal (1610 mg a.i./L) or endothalic acid at 1 pt formulation/100 gal (59.9 mg a.i./L), once at 70% bloom and again at full bloom, reduced apple fruit set. Pelargonic acid was only effective in thinning apple blossoms when applied twice—at 40% bloom and again at full bloom—at 1.5 pt formulation/100 gal (1.12 mL a.i./L) per application. Pelargonic acid marked apples in 1995 but not 1996. Neither hydrogen cyanamide nor endothalic acid marked apples. A single full-bloom application of hydrogen cyanamide, endothalic acid, or pelargonic acid effectively thinned peach blossoms in 1995; however, in 1996, only hydrogen cyanamide at 2.5 pt formulation/100 gal effectively thinned peach blossoms. Peaches did not show fruit marks with any of the peach blossom thinners.
Esmaeil Fallahi and Thomas Eichert
Foliar fertilization is a common practice to supply crops with mineral nutrients, especially under limited soil nutrient availability conditions. However, foliar-applied nutrients have to overcome the barrier properties of leaf surface to be absorbed by plants. Various pathways are reported to explain the penetration of foliar nutrients through the leaf tissues. Meanwhile, we believe that air humidity is one of the main controlling factors in this process since it controls both the actual nutrient concentration on the leaf surface as the driving force of absorption and the permeability of the leaf surface. Postharvest and prebloom foliar nitrogen sprays are applied to enhance flower bud vigor, and calcium (Ca) is applied directly to fruit during the growing season to reduce fruit susceptibility to physiological disorders. Micronutrients typically are applied in foliar sprays to uniformly distribute the small quantities of these required nutrients. In this report, we focus on the principles of foliar nutrient uptake and impacts of foliar urea and Ca sprays on fruit quality attributes of ‘Fuji’ apples (Malus domestica). Based on our studies, a ground application of urea is critical for a higher production of ‘Fuji’ apple.
Esmaeil Fallahi, Bahar Fallahi and Michael J. Kiester
In a long-term study between 2008 and 2011, the use of crop evapotranspiration (ETc), when a precise crop coefficient value (K c) was used, provided a reliable irrigation scheduling for determination of water requirement for ‘Autumn Rose Fuji’ apple (Malus ×domestica Borkh) fully mature trees. Water use, yield, and fruit quality attributes at harvest were examined under various irrigation and nitrogen (N) systems that were scheduled using ETc. Trees with a full sprinkler (FS) system received ≈39% to 41% more water than those with a full drip (FD) system during the period of 2008–11 growing seasons. On average, mature trees with an FS system received 5927.6 L (944 mm), whereas those with an FD system received 3610.3 L of water per tree (554.9 mm) per growing season over the period of 2008 through 2011. Fruit from trees with FS and FD were larger, whereas those with 50% FS were smaller than those from all other treatments. Trees with 50% FS treatment received a higher volume of water but had smaller fruit size than those with 50% FD or 65% FD. Averaging values over 4 years revealed that applications of any form of deficit irrigation (DI), either by microjet irrigation or drip, increased fruit soluble solids concentration (SSC) and firmness but decreased water core at harvest. Considering yield, and quality attributes in this study, a well-calculated ETc-based FD irrigation system is recommended over any other irrigation regime. If application of deficit water is mandated, application of 65% FD is preferred over 50% FS, as trees with 65% FD treatment received less water while had larger fruit than those of 50% FS. Trees receiving 80 g N/tree had lower fruit color and russet than those receiving 40 g N/tree. However, other yield and quality attributes were unaffected by the rate of N fertigation.
Esmaeil Fallahi, James R. McFerson and Bahar Fallahi
Many fruit growers in the Pacific Northwest region prefer to use a sprinkler system to produce high-quality fruit and to establish a cover crop in the orchard. However, water shortage mandates the use of more efficient methods of irrigation, such as drip. In this long-term experiment, the effects of seven irrigation systems for `Fuji' and two irrigation systems for `Gala' on five rootstocks on tree growth, water use, fruit quality, and mineral nutrients were studied. All forms of drip systems used less water than full micro-sprinkler (SP). Partial root drying sprinkler (PS) used 50% less water than SP. Trees with partial root drying drip and deficit drip had to receive 65% of full drip to survive. Each `Fuji' tree with SP used about 5397 L of water in 2004 and 5833 L in 2005, while each tree with full drip used 2403 L in 2004 and 3438 L in 2005. Thus, trees with full drip used 41% to 55% less water than those with SP system without any reduction in fruit quality. This leads to a major savings in the cost of fruit production. Fruit weight in trees with full drip was always greater than those with PS or deficit drip. Fruits with SP system had lower soluble solids than those with PS. Fruits from trees with partial drip had a higher starch degradation than those with other systems. Leaf minerals, particularly N and K, were affected by irrigation systems. `Pacific Gala' trees on B.9 rootstock were more precocious than those on Supporter-4 rootstock. In general, `Pacific Gala' on RN-29 had better tree performance and fruit quality than those on other rootstocks. The calculation of water requirements on a tree-use basis provided an excellent guide for drip irrigation.