FARM AND DAIRY

Taranaki Daily News, 8 June 1932, Page 16

FARM AND DAIRY

ENRICHING PASTURES.

EXPERIMENTING 'WITH LIME. Some interesting results of research work on the mineral content of grass were referred to in the course of lectures to the Rochdale and Blackburn Agricultural Discussion Societies by Dr. Hanley; one of the leading authorities on grassland improvement, and now the principal of Armstrong College and in charge .of .Cockle Park, states the Manchester Guardian. Dr. Hanley said experiments had been carried out in different parts of the country. .' On millstone grit in York*' shire, where the conditions approximated. to those .in East Lancashire, some new and striking results had been obtained from the use of lime. To ascertain the effect on the lime and phosphate content of grass induced by the application of those minerals, the herbage had to be repeatedly mown at intervals. of about three weeks, and the amount taken, off approximated that which animals would eat if they were grazed during the season. •

From land in its natural state and untreated the herbage was found to contain about 511 b. of lime an acre; in other words that was about the quantity of lime that stock would get from this medium during the grazing season. On an adjoining plot which had been limed the amount of lime id' the herbage was increased to 112jlb. an acre. That, said Dr. Hanley, was very-re-markable, and was of a vital importance to people concerned with milk pro; duction, because: there was some 'dvi-i dence—although it was not’ proved' up t<s the hilt—that the amount of lime the cows obtained was reflected tq some extent'in the quality of the milk. He believed it had some effect on the amount of solids in the milk, and it was also extremely probable that the breeding capacity of the stock depended very much indeed on the mineral supply and particularly on the lime supply. ' Some interesting facts had also emerged relative to the use of phosphoric acid. On the plots on which the lime content of the grass was increased. from silb. to 112Jlb. by the application of lime, it was found that when a dressing of phosphates was given the phosphoric acid obtainable through the herbage was increased from 12 Jib. to 44Jib. AIM OF FALLOWING. STORING CAPILLARY MOISTURE. Successful fallowing • depends chiefly upon the success with which the rains that fall during any season of the year are stored and kept in the soil until needed by the plants in their growth. The rain that falls on the land is- disposed of in three ways; under ordinary conditions a larg- portion runs off without entering the soil; secondly, a portion enters the soil but remains near the surface and is rapidly evaporated back into the air; thirdly, a portion enters the lower soil layers from which it is removed at later periods by different processes. The runoff is Usually large and is a serious loss, especially in undulating country, and in dry districts owing to the hard, sun-baked nature of the soil; this runoff is greatly diminished by cultivation, 'but it is not possible wholly to prevent it under any conditions. If, as a result of proper ploughing and cultivation, the upper soil is loose ,and porous, the rain is allowed to soak quickly into the soil away from the action of wind and sun. From that temporary reservoir the water will move slowly downward in obedience to the pull of gravity to the greater soil depths, where it may be stored until needed -by the crop in the form of a thin film of moisture around the soil grains. This water is known as capillary water. It cannot be seen as a liquid, hut its presence may 'be recognised by its effect upon the colour of the soil.

It is capillary water alone that is of value in crop production, and it supplies the wheat plant with water containing dissolved food constituents /necessary for its growth. If a stone is immersed in water and withdrawn it is surrounded by a film of moisture which clings to the surface. If a handful of gravel is treated in the same manner, a film of moisture surrounds each piece of gravel, but it is obvious that owing to the greater surface area the gravel will retain more water than a stone of the same size. So, too, the finer the soil grains, the greater the -water-holding capacity.

I Soil is composed for the most-part of particles of disintegrated rock which ■'vary, greatly in size, the largest often 500 times the size of the smallest, and of which as many as 15J billions/ of particles may be contained in a cubic inch. This very large number of soil grains found in a small amount of soil makes it possible for the soil to hold very large quantities of capillary •water. The surface area around which moisture can ding in a. cubic foot of soil has b(>eh carefully estimated at /from a quarter of an acre to four acres. .