TOP-DRESSING

Hokitika Guardian, 8 December 1930, Page 2

TOP-DRESSING

EXPERIMENTAL WORK IN CANTERBURY. A FURTHER REPORT. The current issue of the “Journa of Agriculture’’ conta ns a lengthy i\ I port by A. W. Hudson (Government Crop Experimentalst) and A. Y. -Montgomery oil the experimental work ol the Fields Division. The report covers 27 pages, which permits on'y a brief summary. The report is No. 2of a series, and deals with observational experiments with lime, phosphate potash and nitrogen for 1928-29 and 19H)-30. The following are comments on the responses to treatment-: LIME. Hitherto lime has not been viewed as an important limiting factor to tbe production of pasture in Canterbury These experiments show only 5 per cent of cases in which there is “no visible response.’ The 5 per cent, ol “doubtful responses” include experiments which have been down for one year only at e time of writing, A “slight response” is recorded in 29.5 per cent, of cases, While “fair to very good” responses are represented by 61 per cent, of the trials From the point of view alone of increased' benefit to stock in supplying lime through medium of the pasture, the writers are of the opinion that its use is justified in practically all Canterbury soils.

In many places the increased growth oi?, herbage, especially where superphosphate was used in addition leaves no doubt in our minds regarding the economic value of lining from the aiuction aspects. It is of interest to note that some of the highest responses to lime have occurred on the light to medium soils overlying shingle such as those in the vicinity of Sherwood and Lauriston in Ashburton County.

Duration of effect of lime: Experience from plots which have been down for several years on high-lime-response country indicates that the visible effect of- a dressing of 1 ton of carbonate of lime per acre should extend over a period of five or six years at least. Smaller quantities should give results which are more or less proportionate to the amount applied. The present series of experiments has not been down sufficiently long to enable general conclusions regarding the duration of effect from lime to be determined on them. On some soils the effect of lime was visible four to five months after application and generally speaking, the effect was much more marked in the second year than the first. SUPERPHOSPHATE, “No visible response” to super is recorded in 5 per cent, of the trials while 3.5 per cent are in the “Doubtful response” class 26.5 per cent, are recorded as “Slight response,” 33 per cent, under “Fair response,’ and 24 per cent, under “Good.” The “Very good’ and “Excellent” classes are liepresented by 7.5 per cent, and 1 per cent cases respectively.

In the cases of both' lime and super the classification of resonses is made more or less relative to the responses from the combination of lime plus super. Consequently the responses to the individual treatment appear relatively smaller—as was actually the case—than the response from the combination lime pins super.

in many of the experiments on the very light lands “fair” and in some cases “good” response can hardly be paying. It is noteworthy that on this class of land the use of super drilled into the ground at the time of sowing with any crop including grass, is undoubtedly paying. The nse of super as a top-dressing on established grassland is however, not productive . of sufficiently good results to encourage one into thnikng that it can he profitable, on the typical lower rainfall areas at least. Some method whereby super can be actually placed in the soil to a depth of 2in to 3in. may give much better results and is certainly worth trying.