IS YOUR SOIL SOUR.

Taranaki Daily News, Volume LVII, Issue 134, 30 October 1914, Page 7

IS YOUR SOIL SOUR.

SIMPLE TESTS THAT EVERY FAR.UEiR CAN MAKE. (By S. TX Cornier, in the Country Gentleman.) The soil chemist tun make no other test that produce,; results of such great sijimfiraiK'i.' us a te.se for soil acidity. Limie ill tile form of car.bonaio oxercisis such a dominant and beneficial inlhience on tlie character of tlie soil, principally through correction of soil acidity, tiiat a-knowledge of its prcsuice or absence is of priime importance in estimating the fertility of a piece of land or planning corrective treatment.

It ir, not necessary to know how m«A lime there is in a given piece of land, but it is of fundamental importance to know tile, relation of the lime to ihe amount of acid present. Other things being favoraUe, an excess of limp means success with alfalfa and clover and a soil of j»ood general fertility, while an excess of acid means failure will alfalfa, clover and other legumes, and a soi: of much less satisfactory general fertility. Fortunately the test for soil acidify is so simple and requires so little chemical equipment that anyone with ordinary intelligence can nmke it for himself, particularly if the soil in question in well supplied with organic mat . r. The method is as follows: —Kill an ordinary drinking glass tiiu-iairu. hid o.

soft water —rain water or distilled vil i» ,o 11.. preferred—well water containing iime will not do at all —a:id a teaspoon lul of .strong ammonia water, a ! l . t.. thoroughly. If, after settling, the liquid remaindiscolored, the soil contains an ahum!' ance of lime and is not acid. Jf, on the other hand; the liquid tunn dark brown or black the soil is acid ,aml needs an application of lime. Varying degrees of acidity develop varying degrees of coloration, ranging from light brown in cmses of slight acidity to nearly black in the «ue of soils that are extremely acid.

The amount of organic matter in tlie soil influences the depth of color to a certain extent, but with a little experience it is easy to distinguish very acid soils from those that arc only siigh tly acid by the color of the solution. MUST BE HUMUS IN SOIL.

Tiiis method is frequently used by experiment station chemists and country agricultural agents as a rapid method of testing whether or not a soil needs lime. Obviously it is well adapted oniy to soils that con lain a considerable amount of organic matter, since :t is basjd upoii the fact that the organic mater in the soil —humus, it" is sometimes called —is insolnMe in ammonia when it is combined with lime, but is readily soluble in tile absence of lime, in which case it forms a dark-colored solution. This solubility of the humus or organic matt er of the soil accounts for rhe brjwnifih-oolored drainage water 'hat is found Slowing from acid swamps. The drainage water from limestone toils, on tvbc other hand, is always clear and sparkling. The ! itrnus paper test is fairly satisfactory for soil acidity, and it in about the only convenient one in use in case the soil does not contain enough organic matter to give decisive results by t'he method already described.

Blue litmus paper for making the test may lie obtained at nearly any chemist's, but care should be exercised to secure fresh paper, as it deteriorates rapidly and t'hen fails to react properlv. The litmus test is simplicity itself. Break open a moist clod and press 011 end of the strip of litmus paper firmly between the two pieces of soil for a few minutes. A change from blue to pin!, o.' red ind : cate3 acidity, and sonic idea as tc degree ot this condition, may be gained f»om the extent of tlie ehang,: of color and the rapidity of its occurrence

The object of both those tests is to determine I he relation between tile linn; and '.'he acid compounds in the sidl by testing for an excess of til? acid compounds. If add compounds are found, there can i-e no question, of course, but thr;! tlie soil needs the application 01 lime. NOT A SUBSTITUTE FOR FERTILISER. Another idea has been proposed 011 ihe basis of testing for an excess of lime carbonate by the addition to the coil of a few drops of muriatic acid. 'The presence of lime carbonate is indicated by the evolution of small hubbies of carbonic-acid gas. and some idea as to tilie jmotui' may be gained liy the extent and duration of the effervescence. The soil is not acid and does not require liming i£ there is enofigh lime carbonate present to be detected by this lather crude test. Lack of noticeable c'Tcrvesccnco, however, docs not necessarily mean that the soil is in an immediate nee 1 of liming. iUs a moderate c\cess of lime carbonate anight very easily ,-swipe detection by so erode .1 method. There is. aid always has been, a re•rrrttable tmUnw among some farmers to regard lime, as a panacea for all soil lils. Lime lias its place in r-oil treatment. an 1 it is a verv important place, too but two facts in this c"nn |, "tion should he 1 horoughlv understood. First, that lime cannot lake the place of manure or fertiliser; second, that it is of little or no 11 ;e except on aeiil .soda. The mere fact that tcets show that a soil is riot acid is a strong indication that it already contains lime carbonate. *n which case it would lie decidedly unprofitable to add more.

Natural limestone soils are famous tlie world ovi r for their (utility, and mid soi.s are equally notorious fir their tick of fertility. The good ell'eet of liming the latter class of noils is a matter of common knowledge. Rm.ll beim: the case, i! certainly is well worth while to test the soil for aeiditv by one or oilier of the methods suggested, and to confirm '..lie results bv a trial application of lime.