tailieunhanh - Fruit growing in the tropics - Part 6

6 Control over the growth rhythm As explained in Chapter 3, the large majority of branched fruit crops lay down floral buds on resting twigs. In many tropical regions these crops are not exposed to sufficient stress to curb and synchronise shoot growth. As a result they tend to flower and fruit poorly and this aggravates excessive, non-synchronous shoot growth | 6 Control over the growth rhythm As explained in Chapter 3 the large majority of branched fruit crops lay down floral buds on resting twigs. In many tropical regions these crops are not exposed to sufficient stress to curb and synchronise shoot growth. As a result they tend to flower and fruit poorly and this aggravates excessive non-synchronous shoot growth also during the period when floral buds for the next crop should be laid down. It was also noted that rather than excessive flushing extended twig rest may occur particularly in older trees. Where this happens forcing bud break to obtain an early harvest can be very beneficial. In this chapter growing techniques are discussed to overcome this problem. First treatments are presented that strengthen and extend the natural stress in order to curb late flushing towards and during the period that floral buds are laid down. Second come techniques to force bud break ensuring synchronous flushing. These techniques are also used to advance flowering in case twigs rest much longer than necessary to form floral buds. Increasing stress for better flowering Traditional soil root treatments Traditional methods to reinforce environmental stress include Root pruning Removal of the top soil under the tree Pouring salty water in a shallow ditch surrounding the tree. The principle is to strengthen the effects of the dry season making it more difficult for the roots to absorb moisture. Roots in the topsoil are cut with a spade near the drip line of the canopy. Salty water is also poured along the drip line. Removal of topsoil starts close to the trunk the soil is hoed towards the drip line. Control over the growth rhythm 47 These methods are laborious and crude roots are damaged salts need to be washed out during the wet season . A more delicate alternative might be to remove the mulch under the tree row by raking it to the drip line. Young vigorously growing trees in particular may benefit from this treatment. If the trees .