Agriculture Reference
In-Depth Information
reduced plant cost because of the ei ciency of this technique; the root system
of the rootstock is separated from that of the seedling, which assures better
sanitary conditions, and it can be inspected at transplant time; plants with a
better root system and with a more uniform growth in the fi eld are obtained.
Field preparation
Land preparation for avocado does not dif er from that for other tree crops.
Development of a drainage system is a prime consideration. Subsoiling or
ripping down to at least 0.5 m or more, preferably running diagonally across
the slope to allow subsurface movement of water, aids drainage. If soil pH
needs adjusting, this could be done during the fi nal stages of land preparation.
Cover crops, such as legumes or grain, can be preplanted a year before orchard
planting to increase organic matter and minimize erosion and root rot.
Transplanting and plant spacing
The use of grafted, container-grown trees has dramatically minimized
transplanting mortality. Polyethylene bags can be removed with all the
soil intact around the roots. Soil in the planting hole should be moist but
not wet. In dry areas, application of water in the holes a few days before
transplanting is advisable to moisten the soil. In the tropics, transplanting
can be done during the dry season, if irrigation is readily available; otherwise,
transplanting should be done at the beginning of the rainy season. In the cool
subtropics, where low winter temperatures can be expected, young plants
may need to be protected or transplanting delayed until the coldest period has
passed. In Peru, some growers prefer to plant the rootstocks in the fi eld and
later graft or bud on to them; this results in a more vigorous growth of the
plant during the initial years.
The cultivar's natural growth habit (spreading or erect), vigour of the
rootstock, and the environment and soils are major determinants of the
mature tree size, and this infl uences spacing and the continued productivity
of the orchard. Close spacing is sometimes used, with later thinning to obtain
maximum benefi ts per unit area. Initial close spacing can be justifi ed only for
precocious cultivars and is benefi cial only if trees are judiciously thinned when
this becomes necessary. For non-precocious cultivars, the yields obtained
before tree thinning becomes necessary may not justify the additional cost.
Traditional spacings in Florida are 7.5-10.5 m in rows and 7.5-12 m between
rows, which precludes canopy overlap. Narrower spacings of 4.5-6 m in rows
and 6-7.5 m between rows lead to higher yields while the trees are young.
In South Africa, similar narrow spacing of 7.5 m × 7.5 m (177 trees/ha) is
recommended for 'Fuerte' and 7 m × 7 m (204 trees/ha) for 'Hass', requiring
