The effect of potassium soil amendments, trenching and foliar sprays on the mineral content, growth, yield and fruit quality of sweet cherry (Prunus aviumL.) and prune (Prunus domesticaL.)

Abstract

Potassium sulfate was applied to established, non-irrigated, K deficient trees on fine textured soil by banding, placing in augered holes and injecting into the soil. Additional trees received a heavy compost mulch in early fall. Trenches were dug in the fall beside trees to break roots and then were backfilled with K 2 SO 4 , dolomite lime or a combination of the two. One percent K solutions of KNO 3 or K 2 SO 4 were sprayed on trees four times during the growth season.Sweet cherry trees only responded to compost mulch applications within two years. August midshoot leaf K, leaf N and fruit size were Oregon Agricultural Experiment Station

Role of Foliar Fertilization on Plant Nutrition

“…K deficiency is difficult to correct in trees growing in acid clay and silty clay loam soils and response to soil-applied K fertilizers is slow. Foliar application or even trunk injections of K salts are effective for correcting the defi ciency in some trees like sweet cherry and prune (Robbins et al, 1982).…”

Optimum Timing of Potassium Nitrate Spray Applications to `French' Prune Trees

“…Potassium levels in the soil can vary widely within the same orchard and are not indicative of whole tree levels; levels in the soil can be high, yet low in the tree (Robbins et al, 1982). Leaf K has been considered a more representative measure of tree status than soil K (Davis, 1934;Lilleland and Brown, 1938).…”

“…The amount of leaf K is affected by the availability of soil K, degree of cropping, and fruit growth phase through the season. Application of KNO 3 as a foliar spray has been used to adjust tree K levels in prune (Robbins et al, 1982) and N levels in peach (Leece and Kenworthy, 1971) or by growers as an option in heavy cropping seasons when K supplies from the soil might be limited. Urea as an adjuvant has been reported to increase uptake of some nutrients, such as ureaenhanced phosphoric acid absorption (Okuda and Yamada, 1962).…”

“…Interactions between N and K levels in some fruit-bearing plants suggest an antagonistic relationship in which leaves of Kdeficient plants accumulate N, increasing the incidence and severity of K deficiency symptoms (Forshey and McKee, 1970;Leece, 1975), possibly by increasing K efflux from roots (Rosen and Carlson, 1984b). Potassium-deficient leaves accumulate putrescine Potassium deficiency is one of the most significant nutrition management problems in prune culture, accounting for leaf chlorosis, scorching, early leaf and fruit abscission, limb dieback, particularly in the upper canopy (Lilleland, 1932;Lilleland and Brown, 1938), and inferior fruit size and yield (Robbins et al, 1982). Under California conditions, K deficiency has been aggravated by excessive fruit production.…”

“…Availability of K to the tree from the soil is not limited to total soil K concentration, but is dependent on soil structure and irrigation, form of K, method of application (McKinnon and Lilleland, 1931;Robbins et al, 1982), equilibrium effects (Carlson and Uriu, 1981;Lilleland, 1946;Lilleland and Brown, 1939), and rootstock and cation balance (Rosen and Carlson, 1984a). Finetextured soils impede uptake of K (Lilleland, 1946), and, as these soils are poorly draining, K may not penetrate deeply into soils without the addition of gypsum (Carlson et al, 1974) or deep auguring (Robbins et al, 1982). The positional availability of K above all other nitrogenous compounds, a substance that has been used experimentally to induce K deficiency symptoms (Forshey and McKee, 1970).…”