DEFICIENT PASTURES

Pahiatua Herald, Volume XXXVIII, Issue 11559, 25 September 1930, Page 2

DEFICIENT PASTURES

W AIR A RAPA DISTRICT. (N.Z. Journal of Agriculture.) The collection of samples of pasture from this phosphate-deficient district has been continued-, and the. results of the analyses are supplying interesting information on seasonal and other data. The district is a vc-'V large one, in which, while it contains the most phosphate-deficient pastures yet met with in New Zealand, giving rise to “Waihi disease” in cattle, certain areas afford soils of great fertility and pasture of high nutrient value. Clovers are in no area generally deficient, and the calcium content is as a rule good, and in cases even high. Insufficient micontaminated samples have been received to determine the natural iron content, but in cases there is evidence of excess of manganese which is often found with iron deficiency.

Waihi d iseaese is due to deficiency of phosphorus in the diet of the cuttie. This trouble presents the simplest deficiency disease which occurs in New Zealand, the evidence being convincing and continuous from the ssoil. the pasture, and, the animal. The chain of reasoning one seeks to establish in all other deficiency cases is in this complete and satisfactory. Briefly, (I) the soil is found to be deficient in available and total phosphoric acid by chemical analysis; (2i treatment of the soil with phosphates banishes the disease in cattle thereon depastured, provided the climatic conditions allow the ready absorption of the phosphates by the pasture ; (3) the untreated pasture on chemical analysis gives a very low result for the phosphorus content, (4) on topdressing with phosphates the phosphorus content of the grazed pasture mot necessarily the hay) immediately rises if the rainfall is sufficient; <sl the animal ishowk a train of definite si nxptems suggesting lack of phosphorus in the diet, swollen joints and lameness in the cattle affected being prominent; (6) treat ng the animal with (a) phosphate lick, (b) superphosphate in the drinking-water or drenching with syrup oi phosphate of iron, or (c) grazing on top-dressed pasture cures the disease The results of analysis of pasturesamples collected in the four seasons of the past year are now available for .seven different farms representing six different areas ill the Wairarapa. Most ol the samples are badly contaminated by earthy matter, as shown by the high alumina content. The iron and manganese are probably much too high from this cause. Cow pastures in North Wairarapa are represented by those of Mauricevdle and Haniua farms. those, in South Wairarapa by Pgatherston. and Dalefiekl farms. Sheep pastures are represented by two Mqsteiton farm® and a Martinborough, farm. In all of these the phosphoric-acid content increases to the maximum in th c spring, falling with the summer and reaching the lowest figure in the autumn. The calcium is lowest in the winter an.l tends to increase with the progress ot the seasons, giving the, maximum figures in the autumn. Nitrogen j'n every case attains its .maximum content in the spring' falling to the lowest in the autumn.

A number of farm,. in various local ii.es yielded samples for three seasons of the year, no sun nier samples having been collected. In all of those in which figures for winter, spring, and autumn samples are available the atitumn samples-isho-iv the lowest phosphoric-acid content, while the calcium usually rises in the autumn. Farms which previously showed an unusually low .pliOsphori?acid content in the pasture have again exhibited the same deficiency, thiiis confirming the first finding published, tliat some Wairara.paj pastures contain the least phosphoric acid of any met with in New Zealand. An interesting tact elicited in connection with the analysis c f the Wainuapa. pastures is that the percentage oi carbon d.oxide (carbonic-acid, gas) luiind .in the pasture- ash calculated on the dl'v matter i, s roughly proportional to the clover percentage. It may thcrclorc prove of considerable assistance in assessing the influence of the clover in the composition of the pasture, and even render a botanical analysis unnecessary.

Although leaching is one of "he moist prominent faults in a coarse, airborne pumice soil, it is noteworthy thal Waihi disease never develop,s oil such soils.

Wairarapa pastures are providing mbst interesting information regarding the seasonal effect on tile miner i! content. Well-marked phosphate deficiency is shown in seme, of the poorer pastures, with evidence of disease in stock, mineral supplements feed n r and tnp-dressbig experiments have been instituted.