Sward Deterioration

Manawatu Times, Volume 60, Issue 196, 21 August 1935, Page 12

Sward Deterioration

Improvement of swards by whatevc means it is carried out is always relatively costly undertaking. Tli causes of deterioration, some of whic can be eliminated, aie therefore of nu ment. Among the common causes arc (1) Lack of. adequate and availabi supplies of the materials needed in tli nutrition of the plants it is desired t have prominent in the pastures. As - rule the remedy for this is suilabl top-dressing, but at times improvci drainage is called for as a means o fostering the action of small soil organisms which improve the avai ability of plant-food materials, cspeci ally nitrogenous onesReplacement of rye-grass and cocks foot by brown-top or other twitches, re placement of white clover by sucklin' clover, the ingress of flat weeds, sue! as rib-grass and dandelions, all are in dicative of lack of fertility leading t< deterioration of pastures and giv c pro mist; of most satisfactory results fron feqvdressing, provided the deteriora tiou has not proceeded to such an ex tent that the' superior species have dis appeared altogether, but still persist although weakened and inconspicuous. If improved fertility through suet measures as top-dressing and drainage is needed, then until it receives the attention the sowing of good seeds oi species with requirements above the current level of fertility tends to be futile. At times this seems to be ignored completely. For instance, a sward inferior because of deficiency of plantfood is broken up and arable crops, which impoverish the soil, are grown before the land is again sown in grass. Actually it is not reasonable to expect an improved permanent pasture until the fertility is mado greater than it was prior to the impoverishment by the exhausting crops. In such circumstances any cropping prior to the sowing of permanent pastures should serve to increaso instead of to deplete the fertility. Though this may seem obvious, in practice it is ignored in those many cases in which such crops as oats, maize and millet precede permanent pasture, especially when, the fertility of the land tends to be below the requirements of the class of pasture sought. If prior cropping has worn out such land, then liberal fertilising should be linked with the sowing of permanent pasture. (2) Unsuitable grazing-management often is a substantial factor in sward - ictcrioration. A very common form of unsuitable management consists of over-severe grazing in the winter and oarly spring, which has an especially larmful influence on the composition of pastures, when, as frequently, it iccurs in conjunction with undergrazing n the summer and autumn. In pastures which are repeatedly overgrazed n tho winter and spring and uiwlcr;razcd in the summer and autumn there nay occur readily a decline in perennial ye-grass and an increase in brown-top mless the fertility is above th c aver--ge level.

(3) A most serious cause of rapid and extensive deterioration of pastures, commencing from a few months after their establishment, is being removed speedily with extension in the use of certified seed of such plants as ryegrass and clovers. The use of strains of these plants, which really are not capable of persisting, even under very favourable conditions of soil anad cli- j mate, has led to much past rapid do | terioratidn of pastures. A farmer who ; tolerates such deterioration in the in- 1 turo can blame only his failure 1o make ute of the advances in our grass-1 land work. I

(4) Because of the ravages of grassgrubs, pastures may contain so few plants of valuable species as to warrant ploughing as a first step towards the establishment of a good sward by resowing. On tlio other hand, if the damage caused by the grubs is not too extensively it usually is distinctly help+'uli to concentrate, as far as possible,

the feeding-out of hay, roots and other fodder on the areas infested with the grubs. At times the feeding-out ot hay made from herbage in which seed production has taken place brings about the surface-sowing of valuable species in useful amounts. Suitable top-dressing assists by building up the vigour of injured plants, thereby enabling them to develop new roots and to survive.—N.Z. Journal of Agriculture.