October i, 1882.] 



THE TROPICAL AGRICULTURIST. 



285 



keeping them in repair. After heavy bursts of rain, 

 and with short crops and several miles of draijis to 

 keep clean, the work is not done, and wash is in- 

 tensified tliough expenditure be kept do\ra. Dramiiig 

 has been can-ied out now nearly universally upcountry, 

 and if drains be the means of stopping wash, Iiow is 

 it tliat .as soon as there is a heavy burst of rain all 

 the streams and rivers become iimnediately discoloured ? 



J. L. A. 



ABNOEMAL SEASONS AND NOT LOSS OF 



NITRATES (FROJI EXCESS OF WHICH COFFEE 



TREES OFTEN SUFFER) THE MAIN CAUSE OF 



SHORT CROPS. 



August 15th, 1882. 



Dear Sir, — Your correspondent "W." with his wonted 

 acuteness observes, tbat "the secret of the hidden 

 ailments under which our coffee is suffering is em- 

 bosomed in those spots where fertility still stands in 

 strange contrast to surrounding fruitleseuess." 



I believe that that secret is to be traced to unfavor- 

 able climatic inlluenoes, very frequently combined with 

 exhaustion of soil. I do not seek to explain all 

 the subtle influences comprised in the word "clim- 

 ate," but only to point out some of the more obviously 

 unhealthy conditions which are induced by unfavor- 

 able se.ason3. 



Let us consider what are the conditions necessary to 

 the production of good crops : thty are three— good 

 climate, good soil, and judicious cultivation, and the 

 most important of these is cUmalc: if we have poor soil 

 it can be ameliorated bv cultivation, but over climate 

 we have no control, though we may to some extent 

 modify its influences by cultivation. CHmate is synonym- 

 ous with season. 



As a proof of the effect of climate, I would instance 

 the Udapussellawa district, which, with Ihe exception of 

 a few estates, is by no meaus remarkable for its ricli- 

 ness of soil, but with its wonderfully favorable seasons 

 it has produced some of the best crops seen in recent 

 years. Unfavorable seasons produce unhealthy con- 

 ditions : in a season of too muth rain duriog the blossom- 

 ing period nitrification probably proceeds too rapidly, 

 and the tree unless provided witli an abundant supply 

 of soluble mineral food, absorbs too lar^e a pn^portion 

 of nitrogen, which induces an over r.apid cell formation ; 

 consequently the tree runs to wood, the sap of which is 

 ill-nourished, so tbat, even if blossom is formed, it docs 

 not set; the tree too, being weak, is in the most recipt- 

 ive couditi(m for the attack of leaf disease and other 

 enemies. It is noticeable that coffee, as it were disap- 

 pointed by an unfavorable season in its desire to crop, 

 appears to be thrown off its balance, the wood which 

 intended to blossom is spoilt, and the tree makes a 

 further effort towards reproduction, pushing out an 

 abortive spike out of its jjroper season, which further 

 exhausts the tree. These disturbed conditions above 

 soil probably indicate an equal disturbance below, aud 

 the balance once destroyed is not easily restored, though 

 even a good season may follow upon the bad one ; it is 

 probable therefore that a diseased condition of the 

 roots is induced which it will require a succession 

 of good seasons to restore to he.ilth : such a succession 

 of seasons it has not been our good fortune to 

 experience for the last 10 or II years ; now — even 

 given the return to normally favorable seasons — 

 wo should have to suffer from the weakness following 

 upon low cultivation and want of conditions of fertility 

 in the soil. 



In order to arrive at conditions favoring the utmost 

 fertility it appears reasonable to suppose that a 

 Xjroper balar.cu must bemaintaiufd between the mineral 

 and nitrogenous supply of food, and that therefore 

 in a wet season, when nitrification is proceeding rapidly, 



giving an over-abundant supply of nitrogen to the 

 tree, the effects of the season may be considerably 

 moililied by adding artificially to the soil a supply of 

 mineral food with little or no nitrogen ; in an over- 

 dry season or hot climate, the process being reversed. 

 Doubtless on such estates as are favored with a 

 limestone formation, the supply of mineral food is 

 better sustained alongside that of nitrogen, liian on the 

 majority of estates, which are without this natural 

 advantage, wherein is contaiued a hint as to the arti- 

 ficial addition of lime. 



In unhealthy condition of soil is, I believe, to be 

 found the explanation of the grub pest, a sort of fer- 

 mentation being very possibly set up, which would 

 provide the grub with fuugoid food, and if this \.y^,o- 

 thesis were correct, until the couditions were removed 

 there would belittle bops for the departure of the enemy. 

 Though the subject of nitrification will no doubt be 

 more ably handled by Mr. Wall and others, still, as 

 bearing incidentally upon my subject, I hope tbat 

 "X." and your other readers will pardon me if I 

 touch upon a question which I have frequently had 

 under consideration. 



If the deductions of "X" from Mr. Waringtou's 

 paper on the Rothamstead experiments were correct, 

 the first exhaustion from which our coffee trees would 

 suffer would be want of nitrogen, whereas the pre- 

 sumption is that, the reverse is the case, seeing that 

 the trees still retain the power to make wood, and 

 that the measure of restored fertility is mainly in 

 proportion to the amount of phosphate in the manure. 

 " X. " has overlooked the very material difference 

 between subsoil drainage by covered pipes aud our own 

 system of surface drains : by the former the rain 

 water is drawn through the soil by the suction of the 

 pipes and carried off to the streams, wbile by the 

 latter, after the complete saturation of the soil, only 

 the superfluous water runs off. The nitrates therefore 

 would only be carried down to the subsoil to be 

 taken up again by the roots as soon as they had struck 

 down to it. In a bare fallow such as our clearings 

 present for the first year or two after the burning off 

 of the jungle, the surface soil would naturally become 

 considerably exhausted of nitrogen and be in an uu- 

 favcuir.able condition for the support of young plant- 

 life ; still in our tropical climate there is probnbly much 

 compensation for the loss sustained by heavy rainfall. 

 In the exhaustion of nitrogen in the surface soil 

 I am of opinion that the reason is to be found why 

 supplies fail to such a large extent after the first few 

 years of a plantation's existence,* and also why cin- 

 chonas do not grow on a second planting. 



To sum up, my contention is, that to abnormal 

 seasons producing unhealthy conditions and a disturbed 

 balance we mainly owe our present infertility. By 

 abnormal seasons I would be understood t» mean 

 rain or drought occurring at the wrong time of year 

 and not that a heavy rainfall or a prolonged drought at 

 the proper season does us any great amount of injury : 

 on the contrary I consider that in the present heavy 

 rainfall lies the ch'cf promise for a good crop next 

 year upon such estates as are in a condition to avail 

 tJfinse.Jves of a good period of blossoming weather. 



Secondly that good cultivation, which means judi- 

 cious use of manure and tillage of the eoi', is capable 

 of modifying to a considerable extent the ill-effects 

 of abnormal seasons and giving us immunity from 

 other pests. 



And further that it is not to loss of nitrates that 

 Wrt are to look for the explanation of our present short 

 crops. — I remain, dear sir, yours faithfully, 



" W. D. B. 



* But there is great force in the popular planting belief 

 th;it the main reason why supjilies fail is that t!ie feedipg 

 rootlets of the established plants enter the stirred soil atd 

 rob the supplies of their nutriment. — Ed. 



