CARE OF PASTURES

New Zealand Herald, Volume LXXI, Issue 21916, 27 September 1934, Page 5

CARE OF PASTURES

POPULAR METHODS SOIL AND CONDITIONS BY H.B.T. Throughout the North Island a considerable amount of surface sowing to thicken up weakening pastures is done in the spring, and an insight into the soil processes and conditions necessary to secure a successful " take " should aid in avoiding disappointing results. There are still a great many farmers on country suitable for ploughing who favour breaking up the sward, and, after taking out a crop of some sort, laying it down again in completely new pasture. Undoubtedly, if properly done, good results can be secured by this method, but it has one or two disadvantages. In order to grow a profitable crop on the land prior to regrassing, the farmer is compelled to plough to a depth of at least four inches. This may be quite satisfactory for a deep-rooted cereal or tap-rooted root crop, but it destroys the consolidation so essential for shallow-rooted, superior grasses. It buries the animal manure and vegetable matter at too great a depth to be available to the bacteria which should convert this into food for the young grass plants, for these require a supply of air to enable them to survive, and directly the actual surface commences to reconsolidate with the trampling of animals, the air supply is cut off and bacterial action ceases, except close to the surface. If grass sowing were not preceded by cropping, as is usual, and the depth of ploughing did not exceed two inches, it would be an almost ideal soil preparation, except perhaps that the use of the land would be lost for an unnecessarily long period. Result of Poaching Unfortunately grass land cultivation, combined with surface-sowing, has waned in popularity, because, in nine cases out of ten, it is not done thoroughly. To understand the amount of cultivation that is necessary, one must realise that the soil bacteria, which prepare the food for absorption by the plant roots, require suitable food and a suitable medium in which to live, and also must have a constant supply of air, warmth and moisture. Where land is heavily stocked with animals, the actual surface for an inch or so becomes too hard-packed to admit readily air and moisture, and animal manure and decaying vegetable matter does not easily incorporate with the soil. Especially is this the case when land is heavily stocked during the winter, when the surface becomes poached to a certain extent. An extreme illustration of this can be seen in any regularly-used sheep or cowyard, where all bacterial action is smothered and killed right out, and in spite of abundant manure and other plant food the soil refuses to grow anything for some years afterwards, unless, of course, it is thoroughly worked up to encourage the re-establishment of bacteria. v~~ • "

Indications that bacterial activity is on the wane in any pasture £re the intrusion of tap-rooted weeds, bare patches and mosses, and the general weakening of the better grasses. These low types of growth require less available nutriment than grasses, and hence can thrive where there is little bacterial activity. Harrowing of Pastures

Harrowing pastures with implements which do not penetrate and thoroughly loosen up the actual surface does little more than scatter the animal manure which is lying insoluble on the surface. To be effective, the tynes or blades of the implement used must penetrate the surface for at least an inch, and should so thoroughly loosen it that the manure is mixed with the soil, and air and moisture can freely penetrate. Breaking up the actual surface crust in this manner helps to conserve the moisture in the soil, and yet allows it to rise, by capillary action, high enough toward the surface to supply the pasture grasses. Manure is introduced and thus kept always at their peak production.