ISHS Acta Horticulturae 415: VIII International Asparagus Symposium
THE FERTILISER REQUIREMENT OF ASPARAGUS ON AN ALLOPHANIC CLAY BASED VOLCANIC ASH SOIL |
| Authors: | J.A. Douglas, J.M. Follett |
| Abstract:
A fertiliser trial was conducted on newly established asparagus on a Typic Vitrandept, volcanic ash, andisol (Horotiu sandy loam) soil in the Waikato, New Zealand, which had been unfertilised for 6 years. Asparagus seedlings (Jersey Giant Syn 4) were planted in November 1987 with fertiliser treatments applied in 1988 and reapplied in 1990. A 25 factorial experiment with 4 rates of potassium (K) and 2 rates of magnesium (Mg), nitrogen (N) and boron (B) was laid down on 3 blocks pre-treated with different rates of P fertiliser before planting the asparagus. Asparagus spears were harvested in 1990 and 1991. Yield increases were only recorded with K application. Soil test values for P, K, Mg and B were all increased by the fertiliser application. Fern samples collected in 1989, 1990, 1991 and 1992 showed increased K concentrations but little or no change in the other nutrients. N and K were the main nutrients removed in the harvested spears but losses were small. On these volcanic ash, allophanic clay-based soils, the clay colloids do not bind K, and K deficiency is more likely to develop than N deficiency because N is held in the organic form. Consequently K is the major fertiliser required for asparagus production on these soils with a low requirement for N, P, Mg and B. | |
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