NATURE’S FERTILIZER

Dominion, Volume 34, Issue 139, 8 March 1941, Page 8

NATURE’S FERTILIZER

- The Worth Of Animal Manure WHAT EXPERIMENTS SHOW On a visit to Massey College this week I found a most interesting experiment in progress. It was designed to measure the worth of animal manure, and in this case sheep were the stock .employed, but the principles equally apply to cattle. As yet the experiment has not been carried on sufficiently long to permit of publication in the accepted scientific manner, but the results today are sufficiently conclusive to be appreciated by a layman. Two effects are clearly’ proved, first, the value of the animal’s manure in promoting pasture growth ; and, secondly the relative influences of dung and urine upon the grass and clover contents of a pasture. These latter results are quite remarkable. In answer to an unspoken question that may arise in readers’ minds,, as to what practical use these experiments may be, this reply may be given: The experiments provide definite evidence as to the important part played by this “nature’s fertilizer” in the promotion of pasture growth, and as the research, people say—“ Farmers will always, find the way to apply knowledge if convinced of its value.” That .is a very real compliment, and one wliich we endorse. So now let us state the case and see what farmers can make of it.

Twelve months ago a first-class sowing of mixed pasture was made on a patch of rich ground, good alluvial country, 'near the Plant Research Station at Massey College. When ready for grazing this was sub-divided into a number of small plots, each about a square chain in area and since July these have been specially grazed. The stock used were wethers, and, as necessary, these were fitted with a system of harness so that their dung or urine, and in some cases both, could be trapped. The plots were then grazed in rotation and over the whole period two received “full return” (all animal manure went on the pasture as is normal) ; two received no return (all animal manure being trapped, and the pasture receiving no manure whatever) ; two received urine only; and a final two dung only. . , . On inspection it was found that even in this short period of eight months, from July 1, the no-return pasture bad seriously deteriorated; that the dung-only pasture looked well, but was almost wholly composed of clover, and very short of grass; w’hereas the urine pasture was strong in grass and quite good in clover. As figures later given show, these visual impressions are borne out by actual measurement. These results are on good country, well fertilized, and sown in pedigree seeds. On second-class or poor land, results should be decidedly more pronounced. The whole area had received at sowing .a tou of lime and four cwt, super, an acre. Pasture Analysis. From December 20 to the end of February, the yield from the no-return pasture was 100 points (40 per cent, rye and 0.50 grass to 1 of clover) ; from dungonly pasture 117.5 points (30 per cent, rye, and 0.40 grass to 1 of clover) ; from urine-only pasture 118.8 points (60 per cent, rye, and 1.83 grass to 1 of clover) ; from the full-return pasture 128.2 points (70 per cent., and 1.48 grass to 1 of clover). ■ The relationship between grass and clover varies enormously, and the ruling factor in promotion of grass growth is without question the urine manuring. Note, too, how the no-return pasture has fallen in productivity during the short period of only eight months, despite its presence on naturally fertile soil with the addition of lime and super generously applied—it has lost 22 per cent, of its productive value under such circumstances, and this states rhe case mildly, for this over-all measurement was taken during clover’s favourite season, and, be it noted, the (no-return) pasture is a clover dominant one.

A surer indication of relative yields fairly typical of a full season’s rounds is given by the 20 days’ yield of December 3 to 22. Then the full-return pasture yielded 17441 b. of balanced herbage, grown to a height of five inches and containing 56 per cent, of rye. Hie noreturn pasture yielded only 11271 b. of clover dominant pasture, grown to three inches, and containing only 27 per cent, of rye. The full-return pasture produced more than 50 per cent, extra feed. I asked whether these weights truly indicated the value of nourishment provided and was given figures to show that the protein percentage and the ash percentage were the same from each pasture, so this quite disposed of any fear that, the stronger growing herbage lacked nourishment.

Simply stated, without urine the grasses content of this pasture dropped from 50 per cent, down to 20 per cent, only of the pastures content, as at the end of January, and, as previously noted, there was an over-all decline of 22 per cent, in pasture growth when it was deprived of animal manure under the most favourable circumstances, with a 35 per cent, decline in December growth. Conversely, this must mean that a very great proportion of pasture growth is promoted by “Nature’s own fertilizer.” Practical Aspect. Inquiry as to the relative fertilizing value of dung and urine brought the following information: Dung provides the phosphate and some nitrogen, but this latter is a rather unavailable form. Urine provides potash, as well as nitrogen, which is in a very available form. A grown sheep daily provides 2:{lb. of dung and one gallon or urine; a dairy cow from 40 to 601 b. of the former and four to six gallons of the latter. Both are “highly available” manures, i.e., readily taken up and used by plants. It appears that land uses super and lime, under typical New Zealand conditions, to build a pasture, and that this can then be largely maintained by manure returned from grazing animals. If this is well handled it appears possible that such maintenance would be effected for a considerable period over a large proportion of our pasture. And to assist this maintenance, we have an assured and ample supply of lime at hand, whatever may befall.

Potash is now unobtainable from overseas, and nitrogen practically so, and super may be in short supply. So placed we must do the best we can with Nature’s manure. How valuable this supply is would soon be appreciated were it in labelled bags, stacked high. How it may he utilized to lies) advantage is a practical farming problem, and on this two suggestions are advanced That most patently observable is the cowshed supply on dairy farms, A growing practice in Taranaki is to trap this, pump it into a tank, and distribute it over pastures. Similarly, sheep farmers could utilize manure from yards and woolsheds for the fertilizing of crops. But both these special efforts cover only a portion of the supply; much larger is the vast quantity returned over pastures as the animals graze. It is held that this can be best made use of when a rotational grazing policy is followed, and that its effectiveness then is greatly assisted by use of harrows to an utmost degree. Results of this research provide much food for thought, and application of the knowledge may bo before long a problem of the utmost moment.