114 FROGHOPPER BLIGHT OF SUGAR-CANE. 



MANURING. 



The manures iu general use in Trinidad for sugar-cane are as 

 follows : — 



Natural Manures. (1) Pen Manure. 



(2) Sheep manure from Venezuela. 



(3) Lagoon mud. 

 Chemical manures. (4) Sulphate of Ammonia. 



(5) Niti'ate of soda. 



(6) Lime. 



(7) Nitrolim. 



It is by the judicious use of manures that the planter can alter- 

 the condition of the soil so as to produce conditions which have been 

 shown to be unfavourable to the froghopper and to the spread of blight. 



By far the most important is the ordinary pen-manure formed by 

 the droppings of the animals on bedding which usually consists of 

 cane trash. 



The scarcity and increase in cost of manual labour is bringing about 

 a rapid increase in implemental tillage, and a consequent inci-ease in 

 the stock kept for haulage purposes. There is however still room 

 for much improvement and it should be the aim of ever^' estate to have 

 ever\- acre of the land heavily pen manured once in every replanting of 

 the sugar cane. 



The amount usually put in is from 10 to 25 tons per acre. I have 

 seen on one estate 100 tons per acre put on a small field as an experiment 

 but there is little doubt that the manure used for this application would 

 have been better a^Dplied to a larger area. 



Sheep manure has been used on one estate to a considerable 

 extent and it is worthy of note that this estate has suffered little from 

 blight. The manure is imported from Venezuela. 



Lagoon mud is used with good results by some estates bordering on 

 the Oropuche Lagoon, and fields treated with 10 to 20 tons of this per 

 acre are considerably improved and do not appear to suffer so severely 

 from blight. 



The use of artificial manures is a more difl&cult problem, nitrate 

 of soda is known to have a bad deflocculating effect on clay soils, and 

 the continual use of sulphate of ammonia in soils deficient in lime, as 

 are most of the Trinidad soils, becomes more and more injurious. 



As a stimulant to the canes to counteract blight they are probably 

 best used well before the advent of blight on fields where it is expected 

 to occur, in order to get the canes into a vigorous resistant state. They 

 are apparently of little value if applied to an already blighted field and 

 still less so if the blight is accompanied by drought, in which case the 

 whole effect of the manure is lost. 



Continual applications of artificial manures must be counteracted by 

 applications of lime. This is already done by many estates, but seldom 

 to the necessary extent. The anah'sis given above for damaged and 

 undamaged soils show the importance of soil acidity in connection with 

 blight, and heavy applications of lime are necessary to eliminate this. 



The effect of such applications to lands subject to blight must not be 

 expected immediatelj- nor will they be for ever after free from injury, 

 but with proper agriculture there should be a gradual return to soil 

 conditions under which damage is less likely to occur. 



