Vol. XIV. No. 341. 



THE AGRICULTURAL NEWS 



167 



li is true that this part oi the crop does not usttallj go 

 off the estate, and is either buried in the field after the crop 

 is taken off, or placed in cattle pensto serve as fodder and 

 litter thereby being converted into pen manure subsequently, 



No actual data are available at present for the propor- 

 tions of stover t" cars under Wesi Indian conditions; btil the 

 following information has been abstracted from results 

 obtained in other parts of the world. From this it appears 

 that the weight of the maize stalks obtained is slightlj larger 

 than the weight of grain, the figure actually quoted is that 

 1 ton of corn on the cob is equivalent to 2,290 It), of stover. 



Prom the results of analyses it further appears that in 



■ u to a crop of the dimensions already specified, the 



following weights of mammal material are removed in the 



stover: nitrogen 39'0 lb., phosphoric acid (i'dlb., potash 

 110 lb. 



( ombining these figures with those already quoted, vvesee 



that the total ounts of manurial material removed in grain 



and stover by a crop of 40 bushels of shelled grain per 

 acre are as follows: nitrogen 78 lb., phosphate lit Up., 

 potash 18 lb. 



This is equivalent to 4 cwt. of sulphate of ammonia, 

 \ !, cwt. of basic slag, -ib lb. ot sulphate of potash, or about 

 5 tons of good pen manure. 



It is often stated that maize is an exhausting crop, but 

 I think these figures demonstrate that at any rate maize 

 cultivation is no more exhausting than sugarcane, when due 

 regard is paid to the length of time that each is in the 

 ground. 



Maize is a three-months' crop, and at the rate of two 

 crops a year a return of this description involves loss of 

 manurial material at the equivalent rate of 5 tons of pen 

 in a year, if care is taken to return the stover to the 

 field. On a previous occasion I have shown that an 

 application of pen manure at the rate of 20 tons per acre 

 provides sufficient manurial material for the needs of a crop 

 of plant canes, first ratoons and possibly second ra 

 provided that care is taken to return the trash to the land. 



In the case .i| coin, provided that the corn stover or its 

 equivalent is given back to the land also, l'<i tons of pen 

 manure would give manurial material sufficient for eight 

 Crops of maize of Ml bushels each, or a total of 320 bushels of 

 grain in all. 



In concluding this discussion three p. .int.-- require 

 additional attention: the first of these is that maize is 

 essentially a shallow rooting crop, and its root system does 

 not as a rule travel much below the top f inches of soil. 

 (^i. equently thorough and frequeni tillage is necessary so 

 that the soil from a somewhat deeper level is brought to the 

 ' and made available to the needs of the plant; other- 

 wise, with continuous cultivation the upper layers of the soil 

 may tend to become permanently exhausted. 



Indeed this state of affairs co louts grajn growers the 

 world over, and is the origin of the normal rotations of grain 

 and roots practised. 



The second point is that witli maize, as with all crops, 

 a fact i limiting production is tin- water-supply available for 

 growth. 



I have sometimes heard it suggested that bj increased 

 i g greatly increased returns ol i rops such as sugar can 

 duced. While this is true within limits, it nin^t be 

 bered that these limits are quite definitely fixed by the 



supply; plants require a definite amount of water for 



the formation of unit weight of dr\ matter: the actual amount 

 varies in the case of different crop and, to some extent, with 

 conditions; but in the case of individual crops and conditions 



the value is roughly constant. With a limited water-supply, 



therefore, possible production is also limited, and manuring to 

 meet plant requirements in excess of this possible production 

 in the hope of securing very large yields, is merel] wast 



The third point is in relation to organr manuring. I do 

 not wish it to be thought from the foregoing that the - 

 tion is put forward thai fertility can lie maintained by means of 

 artificial manures alone. I have on many occasions reiti 

 my opinion that the maintenance of the control of organic 

 •matter is indissoluble bound up with the maintenance of 

 fertility of soils in the tropics. 



In the absence of it, the soil rapidly loses in tilth, which 



may perhaps be defined a> good mechanical conditi ■ombin- 



ed with the maintenance oi a favourable equilibrium in 

 relation to the various biological processes which go on in it. 



Turning now to the feeding value of corn, determina- 

 tions in the laboratory have shown thai an average sample 

 of Antigua corn has the following composition: — 



Range in Con- 

 necticut. 

 lt>-8 



lO-.v- 8-9 to 1-33 

 f>-5 1-4 73 



,.(, l.o ]_.£ 



1-5 14 2-4 

 69-4 



Moisture 



Protein 



Fat 



Fibre 



Ash 



Corbohydrates 



From this it follows that the values found for the 

 Antigua corn occupy a good average position over the range 

 quoted. Of course this result only represents one sample; 

 but there is no reason to suppose that this was not repre- 

 sentative. 



Questions are often raised in relation to the feeding 

 value of corn cobs, and the following analysis su] 

 information on that point: — 



i okn COBS. 



Moisture 8'7 



Protein 2'4 



Fat I 



Fibre 29 8 



Ash - 1 -8 



Carbohydrates 56 3 



The above results demonstrate that corn cobs have 

 a distinct feeding value and are by no means to be despised 

 as fodder. Incidentally it bears out the soundness of the 

 policy pursued on many estates of grinding the corn and cobs 

 together to form corn and col. meal, and feeding the product 

 to the estates stock. 



The foregoing notes are put forward in the hope that 

 they may serve to settle a number of points that have been 

 in dispute for many years, and at the same time correct one 

 or two fallacies concerning com which have from time [,, 

 gained currency. 



In the recent i '.esiv.i number ol ill Bulletin of the 

 Department of Agriculture, Trinidad and L'obago, mention is 



made of the cost of cultivation of this crop in tic West Indies. 

 In Jamaica it ranges l.etwe.-n £3 10*. and £5 per acre 

 a well managed estate could be run at £\. In St. Vincent 

 it costs about £4 an acre, and in Trinidad il appear- i 

 able to estimate that the cost should not exceed L'< 

 With a return of 8 tons per acre there was hope of 

 profit. 



