TO PRODUCE FRUIT

Wairarapa Times-Age, 6 January 1939, Page 9

TO PRODUCE FRUIT

HOW TO FEED TREES. The feeding of fruit trees is a matter calling for considerable care. It is so easy to.encourage growth at the expense of the crop; yet a starved tree is fully as unsatisfactory as an overfed one. The three principal plant foods are nitrogen, phosphates and potash. Lack of nitrogen in the soil will show itself in poor growth and small fruits, while a deficiency of potash will cause leaf scorch in apples and badly coloured fruits all round. It should be noted that leaf scorch is frequently mistaken for scab, or some similar fungoid disease, but in reality it is purely physiological. Symptoms are the browning and dying of irregular patches on the leaves, but there is no darkened ring of diseased tissues on the margin of each dead area, as with a fungal attack.

Potash can be applied to the soil in several forms, sulphate of potash and kainit being commonly used in the case of fruit trees. The former can be applied now at the rate of from half to one ounce per square yard, distributed evenly over'the surface of the ground for a yard or more outside the spread of the branches. Kainit is not a particularly good summer fertiliser, and is best applied in the early autumn. It does not contain so much potash as the sulphate, so the dressing can be at the rate of from half to one ounce per square yard. Nitrogen may be either

organic or inorganic in form. The former is obtained from animal or vegetable sources, such as blood manures. fish meal or material from the compost heap. Inorganic nitrogen is of mineral origin, two forms commonly applied being nitrate of soda and sulphate of ammonia. It is these that are of most service for application now, as” they are readily soluble, and soon become available as plant foods.

Organic nitrogen lingers in the soil for a much greater length of time, and can be more profitably employed in the autumn or early spring. Both nitrate of soda and sulphate of ammonia should be used with caution, as they are liable to cause scorching if used in excess quantity. In all these matters the home gardener will be wise to learn by experience and not rely exclusively on the written word. If after application there is no sign of increased growth it may be assumed that too little fertiliser has been given, while an excess of vigour will suggest the advisability of a lighter application next season. Phosphates are not often needed in great quantity by fruit trees. An application of superphosphate at two ounces per square yard every secand year should suffice. Superphosphate is a fairly quick acting fertiliser, and can be applied now, but it should not be mixed with nitrate of soda, as there is a wasteful chemical interaction between the two fertilisers. It can, however, be mixed with sulphate of ammonia and sulphate of potash.