MaKCH 1, 1S87.] THE TROPICAL AGRICULTURIST 



5S3 



it has come to be regarded amongst them as a cardinal 

 necessity of successful cultivation, and the proposal 

 that they should use no manure at all for a time will 

 doubtless seem to some a very stiikiug aud railical 

 change, aud its very novelty might detei them from 

 putting it to a practical test. It may be useful, there- 

 fore, to look more closely into the proposal. 



The use of lime for agricultural ]) irposes is no new 

 thiug. It is as old as the history of agriculture 

 itself. The beneficial effects of lime when applied to 

 certain soils were known centuriei^ before the nature of 

 its action was understood. Indeed it is only within the 

 last half century that men have leirnt why the addition 

 of lime is frequently of so great advantage- In all the 

 old civilised countries, aud now in many parts of 

 America, lime is regularly added to certain kinds of 

 soils. In England it has passed into a saying — too 

 general, no doubt, as such sayings usually are — that 

 " the use of lime is the foundation of good husbandry." 

 In Victoria, where many, probably the mMJority, of 

 tbe cultivators of the soil have commenced their work 

 without the advantage of the many sound traditions 

 founded on gf^uerations of experience which serve as a 

 guide to farming men in the old world, anl have had to 

 take things as they found them and work out methods 

 of practice for themselves, it is not surprising that the 

 proper use of lime, an 1 indeed tln^ rational use of all 

 manures, should not have been clearly undfrstood. 



Lime, when applied to the soil, has a fourfold action. 

 Firstly, it serves, like all other manures, as food for 

 the plants themselves ; secondly, it alters the texture 

 of the soils, stiffening sandy ones,* aud loosening clays ; 

 thirdly, it assists in the decomposition of the soils, 

 more especially of the vegetable atcumulatious con- 

 tained in them, and thereby sets free and acceasihie to 

 plants those substances needful for Vfge'.able growth ; 

 aud fimrthly, it neutralises the acidity of >onr soils, and 

 renders them sweet and healthy. We ni'iy still add a 

 fifth benefit which results from the use of lime, namely, 

 tbat it discourages the growth of raany kiu'ls of woi^ds, 

 and drives away several injurious grubs, notably the 

 wire worm 



As regards the necessity of lime as a plant food, it is 

 only necessary to point to the raany instances of sods 

 poor in lime bi-ing of very low fertility, and the good 

 effects ohtainrd in hunh cases by the ;^ldition of "manures 

 containing lime. For purely manurial purpos'S the 

 most usual way of applyuig lime is in the form of 

 gypsum, or sulphate of lime. Some comparative ex- 

 periments conducted by Ville, in France, gave, the 

 following results : — 



Wheat. Beetroot. Potatoes. 

 Bushels Tons Tons 



per acre, per acre, per acre. 

 Without lime 41 18| 8 l-5th 



With lime (gypsum) 43 201 11 l-7th 



In another case clover was experimented upon by a 

 German experimenter, Korte. The clover was top 

 dressed with gypsum ; and in this case the effect varied 

 considerably according to the time at which the dress- 

 ing was applied, this variation being of course due to 

 the effects of the season. Thn yield from each small 

 experimental plot was as follows : — 



The undressed plot yie'ded 100 lb. 



The plot dressed on the 30th March yielded 132 lb. 

 The plot dressed on the 13th April yielded 140 lb. 

 The plot dressed on the 27 rh April yielded 1.50 lb. 

 Of the effect of lime in the form of gypsum on peas 

 and beans there are several recorded instances; with 

 weak and sickly plants people have described its 

 action as simply "magical;" such effects being pro- 

 duced, however, as it is necessary to bear in mind, 

 only in such soils as are absolutely deficient in lime. 

 It has also been observed that lime, in its action 

 simply as a manure, hastens the development of crops 

 and brings them to early maturity. 



As regards the action of lime on the texture of soils, 

 it is to be remarked that whilst slaked linne or marl 

 may always be added with good results to clay soils, it 

 must be used spoaringly and with canMon to light sandy 

 ones. Five, ten, and even twenty tons to the acre, may 

 be worked into a clay field ; the clay will be loosened, 



* Is this a fact ?— Bd7~ 



and be less liable to harden during droughts, and its 

 fertile qualities improved. But such a quantity added 

 to a sandy soil would be likely to have disastrous results, 

 rendering it so light and porous* that it would retain no 

 moisture. But small doses of lime may be applied to 

 light soils with advantage, the effect beinjf frequently 

 to bind them together. 



It is the third and fourth effects, above mentioned, 

 of the use of lime with which we are most concerned 

 at present. Sandy soils, such as those at Caulfield 

 aud Brighton, coutaiu in their natural condition only 

 a small proportion of vegetable detritus, or, as it if 

 called, humous matter; and as they are light and 

 porous, their fertility is readily washed away by the 

 rain, after they have been cleared of tbeir native pro- 

 tection of verdure. But their couditiou becomes 

 entirely changed after several years of cultivation with 

 heavy ma,nuriug. The composition of stable ,or farm- 

 yard manure is very variable, but a good sample may 

 be taken to contain 70 per cent moisture, 25 per cent 

 vegetable matter without nitrogen, 3 per cent sand and 

 other useless mineral matter, and 2 per cent of useful 

 fertilising ingredients. The mointure of course counts 

 for nothing, and has little effect one way or another 

 upon the manure beyond iucreasing its weight. The 

 really valuable substance for which the farmer or 

 gardener pays when he buys farm yard manure is the 

 2 per cent of fertilising matter. The 25 per cent of 

 nonfertilising vegetable matter is not, however, to be 

 left out of account in calculating the value of the 

 manure, for it has this effect, that it locks up that 2 

 per cent of really valuable fertilising matter so that 

 the plants cannot get at it. And until the vegetable 

 matter of the manure is decooiposed and the fertilising 

 matters liberated, the buy-T of farmyard and stable 

 manure can get no return for his outlay, he, in fact, 

 locks up his capital in the manure ; and it t'skes a long 

 time for the ilecomposition of the manure to tnka 

 place, 80 that for the first y^^ar, not more than 1-10 th 

 to l-5'..h of the total value of the manure can be realised. 

 The remaining 4-5ths becomes stor«d up in the soil, 

 except what is washed out by the rain. 



So f.ar, therefore, it may be considered that this 

 vegetable mitter containi-d in the manure is not only 

 useles.s, but ab'-olutely liisadvauuigeous, since it prevents 

 the farmer from gniiiing a fuii return fo- his capital 

 laid out. But it is not Hl.Dge'b'r useless, fur (his vege- 

 lable substance is n ^t r a^lily w.i he>l away by tcie rain ; 

 it it were so then the 4-5fhs of unused ff-rtilijini; iugre- 

 dients would be wholly lost ; but inasoauch as they are 

 locked up in the vegetable matter, which in its turn is 

 not readily vvashed out by the rain, then they also for 

 fhe most part are retained in the soil. It results 

 therefore, that after several years of heavy dressings 

 of farmyard or stable manure, a soil accumalates a large 

 quantity of vegetable, or as it is called, organic matter, 

 together with its contiiaed fertile ingredients. And the 

 soil esp"cially if it be a sandy one, is greatly benefitted 

 bj' this accuinulation, since it is prevented from having 

 its fertility wash-d away with the drainage waters. 



This accumulation in time becomes verj' great. 

 Lawes and Gilbert, to whose work we have had occa- 

 sion of late to make frequent reference, found that a 

 plot of land on which they grew wheat for 40 years 

 consecutively, and .vhicli they manured i^very year 

 with 14 tons of farmyard manure, had accamulited 

 5000 lb. nitrogen to the acre, a result very noteworthy 

 when it is borne in mind that wheat is very exhausting 

 to the nitrogen of the soil. 



But there is n. degree beyond which this accumulation 

 cannot be allowed to proceed without injury to the 

 condition of the soil. For the organic matter in the 

 siiil after a time generates vegetable acids which render 

 the land sour, and everyone knows that a sour soil, 

 will not grow satisfactory crops. When this stage 

 has been reached it is absolutely necessary to add lime. 



If then a certain amount of lime is addeil, it will 

 sweet(!n the .soil, an! it will do no more. But if still 

 more lime be ailde.l, it will set those fertile ingredients 

 free for the nourishment of the crops. In other words, 

 the lime renders active those substances which hitherto 



* E'ltirely inconsistent with the previous statement 

 about stiffening. — Ed, 



