March r, 1884.J 



THE TROPICAL AGRICULTURIST, 



63^ 



Cryptogaraist's investigations, I confess I had not the 

 courage to write any more on the subject, as I well 

 kaew that botanically speaking Mr. IVIarshall Ward's 

 conclusions were absolutely perfect. 



During Inst season, having still the courage to 

 believe that fungoid pests can only attack plants 

 during a period (which may be either limited or pro. 

 longed according to inmate peowliarity of constitution 

 or to cnncomit '.nt circumstances) during whioli, from 

 some cause or other, some vital function is held 

 in abeyanc?, I adopted measures for placing 2,400 

 plants under expei imental observation and applied to 

 them twelve dift'erent artificial [mixtures in con- 

 junction with cattle manure. 



Although I am not yet prepared to generalize on 

 the results obtained, still I personally feel confident 

 that my very humble experiment has demonstrated 

 one fact with certainty ; and that fact is that 

 each of the various chemical mixtures has produced 

 a distinctly separate effect. 



A feeliug of profound diffidence is only natural 

 when one remembers that each square mile of country 

 may havp and generally does have separate and special 

 requiremeuts, and that measures which are simply 

 carried out because they had succeeded so well in 

 one locality are very apt to prove disappji"ting 

 in another or ev^u to induce unexpected complic- 

 ations wliich will talie much time and money to 

 remove. 



The preparations used by rae were as follows : — 

 Bonedust. 



Mineral phosphate. 

 Oilcake and refuse. 

 Lime, 



Sulphate of potash. 

 Do of magnesia. 

 Do of ammonia. 



Do of lime (gypsum) and (acidulous). 

 Nitrate of potash. 

 Chloride of ammonia. 

 Kainit. 

 Some of the mixtures from want of skill on my part 

 were evidently too stimulating; some tended to make 

 the trees ruu too much to crop, others to foliage ; 

 but i am at least thankful to say that my venture 

 was so far a success as to enable me to state without 

 hesitation that the experimental block cropped far 

 heiivier than any other portion of the 500 acres under 

 my management. 



After pruning and next blossom, I hope to be able to 

 judge better than I can at present, but I venture to 

 expres< au opinion that kainit, containing as it does 

 a large quantity of chloride, requires considerably 

 more skill to use to advantage against leaf disease 

 than some other forms of potash. 



The addition of gypsum appears to facilitate mat- 

 ters, and as kainit is so cheap, I consider it is well 

 worth the trouble to malce another set of experiments 

 in order to gain reliable information as to how it can 

 be utilized with success in conjunction with some of 

 the economical descriptions of nitrogenous manure 

 which are locally available. 



I foel disposed to hazard the opinion that where 

 potash has not given svtisfactory results it may poss- 

 ibly have been owing to the form in which it was 

 applied or to the amount and availability of the nitrogen 

 which aec mjiiauied or succeeded its application. 



We essentially require a slowly acting preparation, 

 if wo apply manure early, but we must as carefully 

 guard against a check as against a stimulant. 



I have only very recently had the good fortune 

 to obta'u a copy of M. Ville's delightful work on 

 artificial manures, and, while most respectfully recom- 

 mending it to the attention of my brother planters, 

 I beg to be permitted to again endeavour to show 

 ctnse why that most delicate of all operations, the 



investigation of the nutrition of leaf-cells, should be 

 regarded as an essential part of any attempt to un- 

 ravel the mysteries connected with tiie appearance of 

 fungoid pests on cultivated plants. M. Villu cle.irly 

 confirms the statement that phosphates are indispens- 

 able to sugarcane and gives au account of a most 

 interesting experiment conducted by M. de Jabruu at 

 Guadaloupe as follows : — 



tons. cwts. 



Normal manure ... 23 



Manure without Lime ... 20 



Do do Potash ... li 



Do do Phosphate ... 6 



Do do Nitrogen ... 22 8 



With no manure ... 1 4 



Professor Schrottky, has already announced his opin- 

 iou that superphosphates, nitrates and chlorides ap- 

 peared to increase the tendency to leat-disease, where- 

 as phosphate.", sulphates, &c., had an opposite effect. 



Now this conclusion was arrived at by experiments 

 most carefully conducted, not by applying these sub- 

 stances to the soil, but by a process of inoculation 

 or introduction through the cambium cells. 



M. ViUe's researches in regard to the require- 

 ments of beet-root would however lead one to con- 

 clude that everything depends on having a well- 

 balanced mixture, and this is precisely also the ex- 

 perience which I have gained from my humble little 

 experiments. 



In applying a chemical manure, the difficulty ap- 

 pears to be to find out how far we may trust the soil 

 to come to the rescue. If we trust to the soil to 

 supply alkalis we may very probably discover that 

 we have trusted in vain, and, hence, where super- 

 phosphate has been applied by itself or in conjunction 

 with cattle-manure to a soil deficient in alkalis or 

 too rich in iron, its effects have been must disappoint- 

 ing, whereas a simple mixture of bop'- dust and cattle 

 manure always maintains a well-earned reputation as 

 the safest and best of all applications to coffee. 



Now, we are told that phosphate is the dominant 

 constituent of sugarcane and we have also learnt that 

 its application (under fitting conditions) has had au 

 appreciable effect in checking an attack of '-rust"; 

 I fail therefore to lose confidence in the efficacy of 

 judicious constitutional treatment in tending to lessen 

 the liability of coffee to attacks ^.of Hemileia vast- 

 atri.i;. 



Potish is the dominant constituent of coffee, and 

 I still venture to inaiutain my long-cherished opinion 

 that leaf-disease is only a temporary embarrassment 

 which can be overcome by the following means : — 



1. The application of slowly aetiug phospho- 

 nitrogenous manures in conjunction with alkaline 

 preparations early in the season. 



2. Eapidly acting chemical manures in the form 

 of light-dressiufs during the monsoon and composed 

 of such substances as an analysis of the sod and due 

 appreciation of the effects of climate aud culture shall 

 indicate as desirable or necessary. 



3. Due regard to the importance of maintaining 

 the soil in good mechanical condition. 



4. Increased attention to the matter of change and 

 selection of seed with a view to obtaining increased 

 root-developing power. 



1 avail myself of the opportunity to append some 

 valuable extracts from M. Ville's delightful book 

 and from other authorities in the hope, now that 

 topical applications have had a fair trial, someone far 

 better able than I cm ever expect to be m.ay bo 

 induced to make a few more experiments in regard 

 to the likes aud dislikes in health and debility of 

 the plant, which for the last 21 years has afforded 

 me a most comfortable livelihood, and the cultivation 

 of which I still have every reaijon to regard as con- 

 stituting one of the safest of all iuvestiuects for cap. 



