ISHS Acta Horticulturae 383: Mineral Nutrition of Deciduous Fruit Plants
USE OF RAPID TECHNIQUES FOR ESTIMATING THE N STATUS OF FERTIGATED APPLE TREES |
| Authors: | D. Neilsen, E.J. Hogue, L.C. Herbert, P. Parchomchuk, G.H. Neilsen |
| Keywords: | Malus domestica Borkh., soil solution, Spad chlorophyll meter, suction lysimeter |
| Abstract:
Two procedures, measurement of soil solution nitrate-N accessed through permanently installed suction lysimeters, and measurement of leaf chlorophyll using the Minolta SPAD chlorophyll meter were assessed as to their usefulness in determining the response to N fertigation of five apple (Malus domestica Borkh.) cultivars (Royal Gala, Fuji, Spartan, Jonagold, Golden Delicious) on M.9 rootstock. Over a twelve week period, trees received three 200 ml doses of N as Ca(NO3)2 solutions with concentrations of 0,2,4,8, or 16 mM N. Differences in soil solution N, leaf chlorophyll and plant growth in response to added N were measured. Nitrate-N concentrations in 0 and 2 mM N treated soils declined over time indicating that supply was insufficient and resulted in less growth, whereas solution concentrations remained almost constant for the 4 and 8 mM N treatments, which had better growth. The concentration of nitrate-N in soils treated with 16 mM N solutions increased rapidly over time indicating an over-supply of N fertilizer. Leaf chlorophyll increased with added N and was also influenced by cultivar. Royal Gala and Golden Delicious had lower chlorophyll readings than the other cultivars. Thus, interactive nutrient management for fruit trees grown under irrigation becomes possible using rapid methods for monitoring soil and plant nutrient status and fertigation. | |
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