THE MANURING OF THE CANE. 



obtaining a sweet cane. Private owners follow a rotation of clover, wheat, 

 cane (no ratoonage), and manure the cane heavily. 



In Louisiana the general rotation is plant cane, ratoons, and cow peas 

 ( Vigna, unguiculata} ploughed in as a green manure. 



In Mauritius it is general to grow cane up to third ratoons, after which 

 a green leguminous crop occupies the land for from one to four years. 



In Java the following rotations are practised 



1. Cane, 'ground provisions,' rice, ' ground provisions,' rice, cane. 



2. Cane, ' ground provisions,' rice, cane. 



3. Cane, rice, ' ground provisions,' rice, cane. 



In 'ground provisions' are included ground nuts, beans, maize, cassava, and 

 yams. 



Where the sugar cane forms the main crop in India, the following typical 

 rotations, amongst others, are given by Mukerji 19 : 



Bengal. High and light soils. Rice (May to September) ; pulse or oil 

 seed (October to March) ; jute (April to September) ; pulse or oil seed 

 (October to March); rice (May to September); potatoes (October to 

 February) ; sugar cane (February to February) ; rice (May to September) ; 

 pulse (October to March), &c. 



Punjab. Dhainea (Sesbania aculeata] or sun hemp, (Crotalaria juncea), or 

 cow peas ( Vigna unguiculata) cut in bloom in August ; potatoes (October to 

 February); sugarcane (February to February), pigeon pea (Cajanus indicus) 

 or rice ; potatoes ; sugar ; sugar cane. 



Whenever practised the absence of a rotation is a weak point in sugar 

 cane culture ; the rich fertile soils which are often met with in the tropics can 

 for a number of years support a continuous unvaried crop, but eventually they 

 must become barren. In certain countries, as Demerara, where abundance of 

 virgin soil awaits cultivation, proprietors can continually empolder new land 

 and allow that which has become barren to lie fallow, and after a space of time, 

 during which by the continued disintegration of the soil plant food has 

 become available, again plant the old abandoned land.* 



The effect of continuously growing cane on the same soil has not been, so 

 far as the writer is aware, distinctly studied, but the following quotation from. 

 A. D. Hall 20 with reference to the Eothamsted wheat experiments seems 

 broadly applicable also to cane culture : 



" Plot 10 has received an annual dressing of nitrogen only, in the shape of 

 ammonium salts since the earliest dates of the experiments. It will be evident from 

 the curve showing the crop production that, despite this long continued use of a 

 manure supplying but. one element of plant nutrition, the crop has been wonderfully 

 maintained. Whereas the average production over the whole period is increased by 

 the supply of minerals to the extent of 1'8 bushels, the nitrogen alone has produced 

 an average increase of 7*6 bushels, the unmanured plot being taken as the standard 



*See Note in Appendix. 



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