THE EFFECT OF LIME ON CORN CROPS.

Otago Witness, Issue 2861, 13 January 1909, Page 8

THE EFFECT OF LIME ON CORN CROPS.

I ihe repeated use of chemical manures is | sometimes said to have an injurious effect ' on the soil, and the gradual and complete failure of both wheat and barley when treated continuously with ammonia salts is ' a well-known case in point. The immense 1 value of lime as a restorative is, however, perhaps not so well known, and its power ! tor good is so great and so wide-reaching ! in Jts action that one wonders why it is ; not more used and appreciated. Its effects J at Woburn on corn treated in the manner above described .have been remarkable, and , well repay practical study, for in a year or j two crops that have gone down to zero i ha\e been made to yield respectable returne through its agency. One of its most valuable qualities is its well-known lasting effect, and this has been clearly brought out in the experiments, for though it was | originally applied as long ago as 1897, the I good which it has done has lasted at least , nine years, and it has now been practically 1 proved that a dressing of 2 tons per acre j will be serviceable for at least this period. I It takes time, however, to produce its best I effe-ot ; indeed, as proof of thie it is very j interesting to note that considerably larger | crops of wheat and barley have been grown i in the last three years (1905-7) from the | liming done as long ago as 1897 than from the recent liming in 1905 (scwt). It is , true thai the latter was much smaller in amount than the 1897 dressing, but the j fact so prominently brought out year by year is the permanent and gradual value which liming • po->9*ses, which is known to f experienced agriculturists, and this has been ' shown, too, wheie a second dressing of | 2 tons was applied in 1905. Here it might, ! perhaps, be supposed that this comparatively heavy dressing would give better results in the early stages than the lighter drossj ing ; but this has by no means been the rule, though this second dressing has not been applied on \irgin soil, but to that previously limed. The gradual effect ia anyhow brought into prominence, although it must be allowed that more striking effects have been produced by smaller amounts (scwt and 1 ton) both with barlej and wheat on land Intherlo unlimod 1 . E\ en so, ho\ve\<?r, "a gocd deal larger return lias each year been ha-ivesied from the land dressed in 1897- than from thai dre«od with scwt on hitherto unlimed land, and as tin* is the ca=e both wjfth barley and wheat it tends to prove thai, nine years v by no means thr> limit of a profitable application (especially as a repeated do-ac Lias produced rso geed ivitlx I wheat), rvnd seems to indicate that general I (one in the land can be set up for yeara Ly a fairly heavy dressing — j,nd economically, too, in spite of tho modern doctrine of little and often, though even then sewt has made itself felt for several jears on wheat and barley; and whether mineral manures are added or not to the nitrogeot-a diessing, the remarkable effect of the lime i 3 much the same. Barley and wheat ha^e not been affected to the same extent by liminer, and the reason why the form?r has derived more benefit t'k.rx the v. heat is surmised to be due to its surface roots, fiince plants of thi« description are le^s capable of fi'iding their own supplies of nourishment than cieepc-r -mooted onca like , wheat. However, the ten-year-old dressing I ha*> helped" the wheat a, lor, anJ is still ' doing so, although fre*h doses on rhe top \ of tlu6 have net been a fliccc-jS, and. a.% a ; matter of fact, tho wheat as i\eil as the Larley ha-s oftener than not in the last | thrac years (1905-7) exceeded in yield the > average of the 10 yea-M (1897-1907), worn j ■ out though the old lime might be supposed to be. i Another valuable effect of lime ha? been > to rij*ea the c-Ora earlier, which bears out •

; the experience of farmers, "and this wai > obvious last year in the early part of July. , It has also been of some use in improving quality, and .has sometimes been of distinct value in increasing the bushel weight. Quality, we all know, is much affected by ths nature of the manure, whether the crops be farm or garden ones, and an examination of the quality of the corn, as I judged from the bushel weight — which is 1 not a bad g-uide — enables us ..-o draw some interesting conclusions. Nitrogenous manures alone, as one might suppose, do not give the beat results in this way, nor in money value. The latter is not found to vary much, however, though in the case of nitrogenous artifioial manures or with dung it is satisfactory to find the money value, ! according to the published figures, followj ing the bushel weight. Thus in the last few years at Woburn nitrate of soda has consistently given a comparatively low • -weight per bushel, and the price has been j in the same direction; but rather more so with barley than with wheat, as might be expected. Yard manure, on the- other hand, has invariably produced corn high both in value and weight, while ammonia salts have not as a rule produced corn of high market value, and it has been amongst the low weights, even when lime has been used. Where, however, phosphates and potash have been used in conjunction with nitro- ! genous mineral manures it is very in- ! etructive to notice that the bushel weight ! does not suffer, and also that there is a very marfced Increase in the quality of corn. It is significant, too, that this inj crease has of late years been more pronounced with wheat than with barley, wheat having fallen off a good deal in yield where no nitrogen was u<*ed; but after having apparently exhausted the ground of its most needed food it clearly seems to respond more readily than barley to th© assistance given by nitrogenous manuring. The value of a mixed manure is therefore evident, both for quality and quantity, and fresh evidence of its superiority over special manuring for crops of all sorts is constantly being afforded. — Gervaise Turnbull, in the Field.