LEGUMINOUS CROPS

Manawatu Standard, Volume LVI, Issue 261, 2 October 1936, Page 5

LEGUMINOUS CROPS

USE OF CULTURES, RESEARCH WORK PROGRESSES. Agricultural scientists have recognised for many years past the close association which exists between the root systems of legumes, such as peas, beans, lupins, lucerne, clover, etc., and soil micro-organisms. These microorganisms live in close association with the plant, on whose roots are formed large nodular masses rich in nitrogen. An important feature of this association between the soil organisms and the plant is that it renders it possible for leguminous plants to draw on the stores of nitrogen present in the air and render this available for plant foods. Not only is the. nitrogen, which when supplied artificially is a most expensive type of plant food, made available to the host plant to which the nodule is also attached, but also to the roots of non-leguminous plants growing in the vicinity. It lias long.been recognised that there are soils which do not contain these useful organisms. This recognition has applied in particular to lucerne, the successful establishment of which in many parts of New Zealand could not be attained until some means was devised of inoculating the soil with lucerne cultures. For the past seven years the Department of Agriculture has supplied farmers with cultures of the nodule-forming organism for the treatment of lucerne seed. In 1929, 280 farmers made use of this culture and the value of such treatment for lucerne has become so widely recognised by farmers that the numbers using it have steadily increased, so that for the past season the total reached 1458. FIELD TRIALS.

It is obvious now that, in the case of most of the lucerne crops which arc established, culture treatment of the seed is practised. At the Plant Diseases Division, Palmerston North, great care has been devoted to the preparation of cultures consisting of strains of bacterium which possesses good vitality, and this is a feature which requires stressing. In the meantime, a large amount of research work has been done on the cultures suitable lor other leguminous crops. During the past three seasons, in particular, experiments have been conducted in association with the Fields Division of the Department of Agriculture with bacterial cultures suitable for clovers, peas, and blue lupins. In the last season some 144 field trials with red and white clover, 13 with peas and 8 with blue lupins were conducted, and showed in a large proportion of cases an obvious improvement in establishment and vigour wherever inoculated seed was sown alongside uninoculatcd seed. The results have been so promising that supplies of the cultures are now to be made immediately available to farmers throughout New Zealand. Each kind of leguminous plant requires its own distinct strain of bacterium, though in the case of red and ■while clovers the same strain is quite satisfactory. Continuous research work is in progress also on the strains of nodule-forming bacteria lor these other farm crops, and great care lias to be maintained, in order to ensure that the cultures are sent out fresh and of good quality. Many farmers will recognise that quick and vigorous establishment of clovers is becoming bf increasing importance in sowing down pastures with the modern vigorous strains of rye-grass and other grasses which are now available. Clovers constitute the great fertility-building element of a pasture, and if better ryegrass and a more balanced stock ration are to be secured clovers will play a very important role in connection therewith. QUICK ESTABLISHMENT.

It has been found that, while many Now Zealand soils are already well supplied with clover nodule bacteria, many others aro not, and even in those soils which are well supplied the use of inoculum promotes a very desirable quick establishment. This establishment is secured at a very cheap rate, and in the case of the usual seeding of clover amounts to less than Od per acre, a very small premium to pay for insurance against failure. For peas and lupins, inoculum is of even greater importance, more especially on land which has not previously grown such crops. Commercial supplies of inoculum for these crops have in the past been imported to the Dominion, generally from America. Naturally, the cost has been high and, owing to the long period which elapses in transit, tlie cultures themselves are very often weakened and do not function readily. The cultures are being issued in bottles of four sizes and the smallest size contains sufficient inoculum to treat 301 b of lucerne, or 151 b of clover or 2001 b of peas or blue lupins. As has been mentioned previously, each of these crops requires a distinct strain of inoculum, that suitable for lucerne, for example, being quite useless for the treatment of peas. This development marks a distinct forward progress which will be of considerable practical value to New Zealand farmers who are so vitally interested in the proper establishment and deevlopment of the pastures, and also of such crops as peas and blue lupins.