Wild. — Soils of the Wairau Plain. 415 



the sea. Until the early settlers had considerably increased by artificial 

 means the height of the natural levees bordering the rivers the whole dis- 

 trict was subject to periodical floods. Even yet the district is not immune : 

 in December, 1914, a large area was inundated by a Wairau flood, and 

 hundreds of pounds' worth of crops just ready for harvesting were destroyed. 

 Indirectly the floods are useful, for they are active agents in renewing the 

 soil and in building up the plain. Cases have been brought to the notice 

 of the writer of fences built by the settlers of fifty or sixty years ago 

 which are now completely buried by the flood-deposits of less than half [a 

 century. 



We now have the key to the nature of the soils. Examination in the 

 field and mechanical analysis in the laboratory show that all grades are 

 represented, from gravelly and sandy soils in the inner area to fine-grained 

 silts near the coast. If grouped according to their physical properties, the 

 soils fall roughly into bands parallel to the present coast-line, but there are 

 two notable exceptions to this arrangement. One is the alluvial fan of the 

 Taylor River south of Blenheim, some hundreds of acres in extent. The 

 soil here is gravelly, yet very fertile, and has proved itself capable of 

 maintaining excellent lucerne-fields, and this is no doubt largely due to the 

 excellent drainage and water-supply provided by the widely spreading 

 underground channels of the Taylor River, and to the fact that the area 

 lies well to the sun. The other exceptional area is in the north-east corner 

 of the district, where the band of gravel from the Awatere River already 

 referred to is much wider, as, indeed, it would be expected to be from 

 geological considerations. Here the soils are .extremely gravelly, and 

 ploughing has not yet been attempted, but sheep do very well there. 



Chemical analyses show that the soils are well stocked with plant-food 

 in an available form, and this is in accord with the remarkable crops they 

 bear. Large yields of excellent malting barley are still obtained, though the 

 yields are not now equal to those obtained by the last generation of farmers. 

 This is generally ascribed to continuous cropping without manures ; 

 thorough cultivation is the usual preparation for the crop, and the tradi- 

 tional practice is to " plough three times." The most important crops 

 taken at the present time are oats, barley, peas, clover, lucerne, and such 

 forage crops as rape, mangels, maize, &c, together with a small area of 

 potatoes. The area devoted to roots is necessarily restricted by the scarcity 

 and expense of labour. The fertilizer most commonly used is superphos- 

 phate, which even on clovers gives better results than basic slag, notwith- 

 standing that there is not an excess of lime in the soil. The superiority of 

 superphosphate is probably due to its stimulation of root-growth, for the 

 district is one of low rainfall. Nitrogenous and potash manures have 

 been found to produce no appreciable effect. 



The Wairau Plain is widely and favourably known for the production 

 of seed of great vitality and high germination-capacity. Thousands of 

 bushels of garden peas are annually exported for seed, and the lucerne seed 

 that gives best results in New Zealand is that grown in Marlborough. A 

 considerable quantity of red clover and cowgrass seed of excellent quality 

 is also harvested, and small areas are given up for the raising of mangel, 

 carrot, and flower seeds. Seed-raising is for the most part done on the 

 contract system, the farmer supplying the land and labour, and the other 

 party, usually one of the large seed-merchants, providing the seed and taking 

 over the produce at a specified price. 



