Vol. XIII. No. 313. 



THE AGRICULTURAL NEWS. 



137 



Rotation of Crops. 



The considerations which determine the order of 

 cropping land in any locality are many. There are, 

 first of all, factors pertaining to soil and climate to be 

 studied, the requirements of live stock, and the 

 limitations imposed by existing transport facilities 

 and the demand of the market. Then again labour 

 conditions may render impracticable certain systems 

 of cultivation, as may also the prevalence of certain 

 pests and diseases Though in some instances not 

 easily planned, it is well recognized that a systematic 

 alternation of crops is an essential feature of intensive 

 agriculture, particularly where annual crops are grown 

 principally. There is of course, on the other hand, no 

 logical objection to confining the land to a single crop 

 provided the climate, the provision of plant food, 

 labour conditions, demand and the like can be rendered 

 constant. 



We find in the Tropics very fow systems of 

 rotation compared with what are seen to e.xist in 

 temperate countries, and it may be interesting to 

 enquire into this circumstance. In the first place 

 there are very few crops, with the exception of cotton 

 and provision crops, that will lend themselves to any 

 system of alternation. Hence the growing of the 

 same crop on the same land year after year is not 

 a matter of choice but of necessity Since thi.s is so, 

 it is well to appreciate the fact that one must 

 endeavour to provide in other ways for these crops the 

 advantages which annual ones receive from a system 

 of rotation. Permanent plants being confined to the 

 same land have not the same chance of resisting 

 disease, or rather of avoiding infection as those crops 

 whose position is constantly being changed. Perma- 

 nent crops may therefore reasonably demand the 

 growers special attention in this respect. Then again, 

 plant food in the soil is likely to get unbalanced, and 

 possibly also the bacterial activity, on which soil 

 fertility largely depends. The soil conditions and 

 manurial requirements should therefore be carefully 

 studied. 



It is well known that in many places mixed 

 plantations of coffee and rubber and the like have been 

 established, and in a way this constitutes a kind of rota- 

 tion; though it should, more strictly speaking, be 

 termed a crop community. Such a community can 

 be augmented beneficially by the growing of green 

 dressings and cover crops. Although not always 

 recognized as such, a permanent pasture is a plant 

 community, and if properly constituted, there should 

 not be any inordinate struggle for existence. Grasses 

 with different habits make different demands, and 

 leguminous plants have entirely a life of their own. 



But in the case of a pasture, continuity is more 

 apparent than real, since the herbage on the pasture is 

 constantly undergoing a change in its fiora. A slight 

 excess of phosphate in the soil will cause the legu- 

 minous plfints to develop in excess; a slight rise in ihe 

 nitrogen content will be followed by a Hush of the 

 coarser feeding Gramineae. 



It is evident that annual crops, or rather crops 

 which are not permanent, can by rotation be moved to 

 advantage both biologically and economically, so as to 

 maintain in a natural way a proper balance of the 

 factors determining successful production. The preserva- 

 tion of this balance in the case of permanent crops 

 depends upon an intimate knowledge of the plants' 

 requirements, and upon ability to see exactly to what 

 extent conditions of environment are changing from 

 time to time. 



Rubber Position in Brazil. 



Mr. G. B. jMitchell, H.M. Consul at Para, has 

 reported recently on the depressed condition of affairs 

 in the Amazon States as regards rubber growing. 

 Part of this report appears in The Board of Trade 

 Journal for March 5, 1914. It seems that the 

 present position, which is really a desperate one, is 

 ascribed to many causes — to Eastern competition, to 

 'corners' on the European rubber market, to high 

 freight, and excessively high cost of living and therefore 

 of production. The principal expUnit.ion seems to be 

 that the local product is burdened with taxes and 

 charges which it cannot bear against the rivalry of 

 increasing ([uantities of other rubber more cheaply 

 produced, though it may possess slightly inferior 

 qualities. 



Although wild rubber costs nothing in the 

 first instance, and the utensils for its preparation 

 are of the most primitive description, whilst the 

 smoking also costs nothing, nevertheless the product 

 has to supply an expensive living to many hands 

 before it reaches the consumer. It is generally 

 believed that a kilog. of rubber costs 5 milreis (6s. 8ci.) 

 to deliver at Para. The price at present paid in the 

 Para market for a kilog. of the best up-river fine hard 

 Para is 36 milreis (about 4s. lOd.). Then the State 

 levies an export duty of 22 per cent, of the value, or 

 20 per cent, if exported in boxes of native wood. 

 Add to these costs the freight to Liverpool, Hamburg 

 or New York, and the various commission charges, and 

 it will be seen that rubber is overburdened to an 

 impossible extent. But that is not all. On the top of 

 all these charges has recently been levied a super-tax 

 of 100 reis (l'6fi.) on every kilog. exported, the proceeds 

 of which are to be devoted to the formation of a fund 

 for the proposed 'co-operativa'. The question is now 

 being asked — How is this money to be raised? And if 

 the Association, which it is desired to finance, does 

 succeed in getting all the Amazon rubber into its hands, 

 will it be able to withstand the law of supply and 

 demand in face of the competition of rubber from other 

 places? 



The only remedy against the collapse of the 

 Brazilian rubber trade would seem to be a complete 

 removal of all artificial hindrances, thereby giving the 

 product a chance of standing for its existence on its 

 own merits. 



