i6o 



NATURE 



[October 8, 19 14 



through the soil and removal of the water charged 

 with salt. Without drainage the greater the quantity 

 of water used the greater the eventual damage to the 

 soil, for thereby the subsoil water-table carrying the 

 salts is lifted nearer to the surface. With a properly 

 designed irrigation system the danger of salting ought 

 not to occur ; there are, however, many tracts of land 

 where the supply of water is too limited to justify 

 an expensive scheme of irrigation channels with 

 corresponding drainage ditches at a lower level. 



Take the case of a farmer with some water from an 

 artesian well at his disposal, with perhaps little rain- 

 fall, with land subject to alkali, and no considerable 

 natural fall for drainage. If he merely grades the 

 land and waters it, sterility rapidly sets in ; the only 

 possibility appears to be to take a comparatively 

 limited area and to cut out drainage ditches or tile 

 drains 4 or 5 ft. below the surface, even if they have 

 to be led into a merely local hollow that can be 

 abandoned to salt. The bed thus established must 

 then be watered at any cost until there is a flow 

 in the drains, after which the surface is immediately 

 cultivated and the crop sown. There should be no 

 further application of water until the crop covers the 

 land, the use of water must be kept to a minimum, 

 and by the ordinary methods of dry cultivation 

 evaporation must be allowed only through the crop, 

 not merely to save water, but to prevent any rise of 

 salt. With a loose surface and wind-breaks to mini- 

 mise evaporation it has thus proved possible to grow 

 valuable crops even on dangerously alkaline land. 

 Superphosphate and sulphate of ammonia have proved 

 to be useful fertilisers under these conditions ; both 

 tend to prevent the reaction of the soil becoming 

 alkaline, and the calcium salts of the superphosphate 

 Tninlmise the Injurious effects of the sodium salts that 

 naturally accumulate in the land. On the other hand, 

 nitrate of soda Is a dangerous fertiliser. Attempts have 

 been made to reduce the salts in the land by the 

 growth of certain crops which take up a large pro- 

 portion of mineral matter, but I have not been able 

 to ascertain that much good can be thus effected. 

 Sugar-beet and mangolds do appreciably reduce the 

 salt content, but are scarcely valuable enough to pay 

 for such special cultivation and the limited irrigation 

 water ; the best thing appears to be to grow salt- 

 bush on the non-Irrigated margin of such areas, if 

 only to prevent the efflorescent salts from blowing on 

 to the cultivated portion. 



Let us now turn to the problem of land reclamation 

 as It occurs in north-western Europe. There are two 

 main types of land that have hitherto been left waste, 

 the peaty and the sandy areas. Of the peaty areas we 

 can distinguish again between the low-lying moors 

 bordering the lower courses of the great rivers ; for 

 example, In England near the mouth of the Trent, 

 and the upland peat-bogs of which Ireland furnishes 

 so many examples. They have these features In 

 common — an excess of water, a deficiency of mineral 

 salts, and, particularly In the upland bogs, a strongly 

 acid reaction ; but they possess great potential wealth 

 in their richness In nitrogenous organic matter. It Is 

 }n Germany and Holland that the methods of bringing 

 into cultivation these moors have been most com- 

 pletely worked out ; In Germany, for example, it is 

 estimated that there are about five million acres of 

 moorland of which about 10 per cent, are now under 

 cultivation. The reclamation process must begin by 

 drainage, which may be carried out by open ditches, 

 but Is most satisfactorily effected by pipes, despite the 

 greater cost. The water-table must be kept some 

 3 ft. below the surface. In districts which afford a 

 market for peat, as, for example, on the Teufelsmoor 

 near Bremen, the reclamation often begins bv cutting 

 out the peat, the lower layer of firm peat being won, 



NO. 2345, VOL. 94] 



dried, and sold for fuel. The upper spongy peat can 

 be used for litter, but some part at least must be 

 thrown back. Where the burning peat is thus ex- 

 tracted the excavation is in places pushed further until 

 the underlying sand is reached, and enough of this is 

 dug to spread over the reclaimed area to a depth of 

 4 or 5 in. and mixed by cultivation with the spongy 

 peat. Even when the peat is not removed, pits are 

 often made In order to sand the land, so great an 

 improvement does it effect in the character of the 

 crops. However, sanding Is not possible everywhere, 

 and there are great areas under cultivation where the 

 reclamation begins with drainage, followed by the 

 cultivation of the immediate surface without either 

 sanding or the removal of the burning peat, which 

 indeed are Impossible over large areas, but are carried 

 out by the owners of small farms little by little. 

 Special tools are required : certain forms of disc- 

 ploughs and harrows give the best results ; heavy 

 tools for large scale cultivation by steam or electricity 

 are furnished with broad roller-like wheels ; even the 

 horses must wear broad wooden shoes. 



The next stage is the manuring, and it has only 

 been the development of the artificial fertiliser industry 

 during the last half-century that has rendered the 

 cultivation of this type of land possible. On the allu- 

 vial moors where the ground water has always been 

 alkaline, the peat Is rich in calcium and no treatment 

 with lime and marl is necessary (the English fens 

 afford an example of this type of soil), but on the true 

 peat-bogs (Hochmoor of Germany) the manuring must 

 begin with a good dressing of burnt lime, or, better, 

 of marl or ground chalk. For meadows and pastures 

 two tons per acre of lime, or twice as much of 

 carbonate of lime, should be applied ; the amounts may 

 be halved for arable land. This must be followed by 

 about 5 to 8 cwt. per acre of basic slag and an equal 

 amount of kainit, which applications should be re- 

 newed in the second year, hut then diminished in 

 accord with the cropping. However, some phosphoric 

 acid and potash salts must be continuously supplied, 

 with occasional dressings of lime or chalk on the acid 

 peaty areas. These latter also require in their earlier 

 years nitrogenous manures, for the peat Is slow to 

 yield up the nitrogen it contains. The fertilisers 

 should be nitrate of soda or lime, never sulphate of 

 ammonia. The whole success of the reclamation 

 depends on the use of these manures, as the peat in 

 a state of nature is almost devoid of both phosphoric 

 acid and potash; on the acid peats, again, normal 

 growth is only possible after a neutral reaction has 

 been attained by the use of lime or marl. With this 

 manuring it Is found to be easy to establish a good 

 meadow herbage in a very short space of time ; it 

 is not even necessary to get rid of the surface vegeta- 

 tion of Erica and other heath and bog plants. The 

 manure Is put on and the surface Is worked continu- 

 ously with disc-harrows and rollers, but never deeply; 

 a seed-mixture containing chiefly red, white, and 

 Alsike clovers, Lotus uliginosus, rye-grass, Timothy, 

 and cocksfoot. Is sown in the spring and soon succeeds 

 the native vegetation. 



It is Impossible to say what is the cost of the re- 

 clamation of moorland In this fashion ; the big expense 

 Is the drainage and the construction of roads, both of 

 which are entirely determined by local conditions. But 

 of the value of the process when accomplished there 

 can be no doubt. I have seen a case quoted from the 

 Ostfriesische Zeitung, where a piece of moor bought 

 for 75L was reclaimed and sold for 900L ; and, best 

 test of all, one may ;.ee in places like the Teufelsmoor, 

 near Bremen, families living in comfort on thirty to 

 forty acres of what was once merely wild moor with 

 no productive value. 



Of even greater Interest In England Is the reclama- 



