Perhaps tho best method of using the acid superphosphate manures would bo to mix them intimately with one-quarter their weight of good Peruvian guano, and one-quarter their weight of cane ash, and apply the mixture at the rate of 5-8 ewt. an acre, according to the mechanical condition of tbe soil, and its more or less effective drainage. A good mixture for most soils consists of Peruvian guano, eane ash (or burnt begass), and stable manure or compost heap, to which mixture one-quarter its weight of gypsum might be added. This last ingredient supplies lime, which has already (p. 1864) been alluded to as of primary importance. Lime is equally well supplied by chalk, unturnt limestone, or broken sea-shells ; it should never be applied in the caustic (burnt) state.
Sulphate of amrnonia and nitrate of soda aet us powerful stimulants, but the plants feel a great relapse shortly afterwards. Moreover, nitrogenous manures do great harm in another way, by increasing the albuminous matters in the oane-juice, to the double detriment of the sugar, first by reducing the amount of sugar in the plant, and next by destroying a portion of the sugar in the already-extraeted juice during the process of manufacture.
Manures Produced on the Estate.—The waste produced on a sugar estate consists of the follow ing materials :—(1) The " trash," or dead leaves which are stripped from the canes during growth, as well as the " tops" which are not used for planting ; (2) the " begass," or crushed cane from which the juice has been (more or less perfectly) extracted; (3) the " feculeneies" collected in the clarifiers, &e. ; (4) the " dunder," or wash-waters, containing salts in solution and other matters. To these must be added the night-soil and dung accumulated on an estate.
The leaves should be hoed in as fe.st as the trashing (p. 1867) proceeds ; but this cannot be done in localities frequented by the white aut. In such eases, the vegetable matter must first be fer mented in tanks uuder sufficient moisture to repel ants, and then ploughed or trenched in between the rows of canes. The sa,me applies to the waste cane-tops.
The begass may be carried back to the fields by the carts which bring in the canes, and imme diately ploughed or trenehed into the soil. But the general plan is to use the begass for fuel, and return only its ashes to the soil. Burning reduees the ashes to an insoluble condition, and their value is greatly diminished. The question of returning the begass to the soil depends upon the circumstances that the estate requires both manure and fuel, and that the fresh begass will afford either one or the other (but not both); consequently the one not so supplied must he derived from other sourees. The highly-concentrated form in which cane manures are now supplied, and the
invention of furnaees for burning undried begass (p.1876), are inducementa to adhere to the current custom. Thus only the ash of the begass can be counted on as manure. This amounts to about 5 cwt. from each 100 tons of cane crushed and burned ; its manurial value is 8s. a ewt. It should be pre served with the other waste under a shed out of the rain till used. There will probably be an additional 5 ewt. of ash from other sonrees (trasle wood, Sce.), worth about 68. a ewe The feeulencies and skimmings, say 6 tons (from 100 tons of cane), if preseed as soon as col lected, yield 3 tons of juice and 3 tone of eake ; this cake, dried, with or without previous fermen tation, yields ton of dry nitrogenous manure, worth 31. The sediment of fermenting-vats, also contaieing some nitrogen, say 4 cwt. when dry, would be worth 10s.
The " dunder," being to the extent of used over again daily in making up the wash, would leave to be dealt with as manure, say 800 gal. or 4 tons (from 100 tons of cane). It would dry to about ton, aud be worth about 31.
Green-soiling, Rotation, Fellows, and Tillage,—" Green-soiling" consists in planting beans. lucerne, indigo, or other plants, between the eane-rows (when canes are first planted), and plough ing them in whilst they are green and succulent ; this has a powerful fertilizing effeet. Indigo planted by a drill (in regular lines), just at the commencement of the rains, may, in 2 months after, be uprooted, laid along near the roots of the young canes, and moulded over. If cut to within a few inchQa of the ground, when they have attained a good growth, they will furnish another fine bushy plant before the end of the rains ; this may then be rooted up and moulded over as the first. The indigo-plant is continually appropriated to this end by the native,s of India, although not until the colouriog matter (see Dyestuffs—Indigo, pp, 858-61) has been extracted, and the plant becomes partly decomposed. The greatest good can only result from ploughing in plants whilst quite green and succulent, and the best time for the operation is just before they blossom. In Demerara, the castor-oil plant (see pp. 1380-2) is highly esteemed for the purpose ; and the same may be said of the pigeon-pea (Cajanus incliaus) in the W. Indies and Australia.