LIME VALUABLE

Wanganui Chronicle, Volume LXXXIII, Issue 20110, 31 March 1928, Page 24 (Supplement)

LIME VALUABLE

ESSENTIAL TO THE SOIL A FACTOR IN DISEASE CONTROL. Lime is said to constitute something like one-sixth of the total substances of the soil, but at the same time there arc comparatively few places where it exists in sufficient and available form to meet with their full requirements of plant growth. Lime is not a complete fertiliser, but it performs mauy functions in a more or less indirect way, and its presence is essential if the soil is to be maintained in a healthy condition.

In a direct way lime supplies calcium, one oi the 10 elements absolutely essential for growth. Lime facilitates the decomposition of organic matter by stimulating the soil bacteria to greater activity; it may, and often docs, materially alter the physical condition. of the soil, making heavy land easier to cultivate, and binding light soils more- closely together. Lime checks acidity as it arises from the

soil from decomposition and other causes, and, by its neutralising and other attributes, it indirectly stores nitrogen in the soil. Lime is an important factor in disease control, and is required fox the proper action of many of the artificial fertilisers that are applied. It tends to give cleaner ground, being destructive to certain weeds, promotes better root development, liberates some of the reserve foods locked up in the soil, and makes them available for plant needs. Lime has other attributes, and, altogether is perhaps the most important element that requires attention in to arable and grazing land. Washed Out by Rains. Lime becomes exhausted in several ways, particularly by being washed out by rains, From a plot at the Roth amsted experimental station as much as 250 lbs. an acre has been found in the gauge that catches the drainage water. Even though it may not be washed completely away, it may be carried down below the soil depth available to the roots of the most useful plants. The loss of lime is more pronounced in wet than in dry localt-

Liine is also used up when it acts on the soluble phosphate of super applied to the land; it has the valuable effect of causing the soluble phosphate to revert, ami while precipitating it in a very fine powder through the soil it saves the phosphate from being washed away. Considerable portions of lime are used up in soil on which sulphate of ammonia has been applied. Two methods are applied in turning limestone rock into a product suitable for agricultural purposes. The first is to burn and then crush it into what is known as ground lime; the second is simply to pulverise the stone to dust, making ground limestone. In whichever form it is applied to the soil, it must be in a fine slate of division to give the best results. According to Mr W. R. Paterson, principal of the West Scotland Agricultural College, for light soils and ■ soils rather lacking in organic matter the carbonate of lime is most suitable. Ground limestone and several of the I waste lines arc la the carbonate form.

For heavier soils and all rich in organic matter, such as peats, lime in the oxide form or slacked lime, gives the most marked effect. It has been computed that the average rate of removal of lime from the soil has been as high as the equivalent of 4 cwt of shell lime an acre per annum, or 7cwt of carbonate of lime. Once Every Rotation, Soil fertility can be best maintained by a moderate dressing of lime, once in every rotation. Taking a five-year-ly rotation, its maximum requirement would be the equivalent of one ton of ground lime or of 35 cwt of ground limestone. These amounts will generally last for seven years. In addition, they may be lightened proportionately, according to the quantity of limc-containcKl fertilisers applied. Lime may be used at almost any time during the rotation, and is best put on . whenever opportunity offers. It must be kept as close to the surface as possible as the tendency is for lime to 1 work downwards. If lime in a caustic form is used as a top-dressing to young grass, it should be applied in the winter, but carbonate of lime may be used at any time without affecting vegetation.