MR MacIVOR ON AGRICULTURE.

Waikato Times, Volume XVI, Issue 1367, 5 April 1881, Page 3

MR MacIVOR ON AGRICULTURE.

Thb aboYC-nnined gontleman who is now in the Waikato and who will it is understood give the Cambridge Farmer's Club the benefit of his experience in the form of an address, delivered a lecture recently in Victoria from which we havo culled the following Ancient Agriculture. The Roman huebandmen of the firet century were as conversant with the essential features of cultivation as the British or German farmers of the early part of the present century. It was not difficult to understand why agriculture remained during the long interval in such an unprogressive state. The element " mind," played no part in the operations of the farmer ; the practical men kept to what had been tried, and acted accordingly. If his neighbour made a successful trial he imitated his example, and this was his only method of progression — he knew no other. The dovelopement of any industry by mere empirical experience soon reached a limit, beyond which it could not go. Eighteen centuries ago this limit had been reaohed, and in the interval agricultural progression moved in a circle. The farmer knew nothing about the nature of ploughing or of the composition of the soil, atmosphere, and plants. Chemistry, however, the science which impaitcd that information, was not born until the latter of the last century, and it would therefore be at once evident why farming remained for bo long a period in pretty much the same condition as wheu Ctesar stalked the earth. The early attempts to apply science to agriculture were met with much opposition from those who were most Hkely to be beuefitted by her teachings, viz., the farmers. If science questioned the correctness of one of their explanations, they imagined that she was disputing their facts. It would be his (Mr Mclvor) endeavour to show those present what science had already done for the farmer, and what it might yet do to assist him. It would first be neces&ary to explain to them the Composition of Plants. They consisted of water, combustible matter and mineral matter, or ash. Combustible matter consisted of charcoal, the elements of water (hydrogen and oxygen), and nitrogen. The latter in a free state, constituted four fiftho of our atmosphere, and thero was over-lying every acre of tho earth's surface upwards of 32,000 tons of this gas. Starch, sugar, vegetable fibre, dextrine and gum were the heat-producing and fat-forming constituents of our food, and they were all composed of carbon and elements of water only, whereas the fleshforming constituents of our food contained, in addition to these three elements, nitrogen as an essential component. The ash of plants consisted of phosphoric acid, potash, lime and other familiar substances. Mr Mclvor then referred to the following diagram, which will be found in his work on "The Chemistry of Agriculture," under the head — Ultimate composition of the organic matter of dried vegetable produce."

The whole of the carbon, oxygen and hydiogen in plants was taken from the air and water, whilst the ash constituents and the nitrogen (the latter in the form of ammonia and nitre) weie taken fiom the soil. In order to be fertile, soil must ha\e an abundant supply of each and all ol the substances necessary to build up the structure of plants, the absence ot one of them being fatal to the growth of a crop. The

Constitution of the earth. should bo divided mto three cl.ibsess. — Xt Clay, H.iud, and undeooinposod vegetable matter, which, without in themselves acting as plant food, served to maintain the purely mechauical conditions necessary for the growth of the plaut. 2nd Available plant food. 3id. Locked up oi uuavailable plant food. The quantity of available food pie^ent, even in most fertile soil rarely exceeded one and a half per cent, and thin quantity contained the various constituents in variable quantity according to the class of land. The productiveness of the Hoil was dependent upon the constituent which occuued in the noil in the least abundance. For example, a soil naturally poor in potash, after tho removal of two or three crops, would become exhausted or unproductive through the removal of the supply of that sub&tcince, and the land would icfuse to yield a piofitable crop of the same kind until tho potash had been restoied in proper quantity. The same would apply to a soil poor in phosphorus or any other substances found in the ash of plants. Fertility depended upon the least abundant constituent of the plant food in the soil. A .simple manner of ascertaining in what substances a soil was deficient consists in setting aside a small extent of land, divided into little pots, to each of which a different manure could be applied, and the manure which yielded the bests results under the circumstances contained the substance jwhich the soil required. This was a much more reliable means of acquiring a good Knowledge of tho wants of a noil than any ordinary chemical analysis. Naked fallowing was an excellent operation for rebtoring I tho impaired fertility of land, but was «ot a substitute for manuring, in so far as Tit involved the working up of the capital and not its interest. Sowing down with grass and depasturing of sheep were very benelicial to many soils, especially to those rich in locked up food, but to light lands of a poor character Bheep could not greatly improTe the soil, as they took from it the substance necossary to form bone, yoke of wool, &c. Green manuring consisted of ploughing in of a green crop as a fertiliser, but although very beneficial in clearing the land of insect pests, it was not a substitute for true manuring, for it added nothing to the soil which could in »ny way whatever prevent improvement. It prepared or made soluble the food already existing in the soil, thus rendering it available to succeeding gram or other crop. Rotation of Crops. where practicable, was an excellent means of keeping the land clean, and of obtaining increased yields of wheat or other cereal. 3?or example, a better crop of wheat was obtained after a pea crop than after another wheat crop. The beneficial influence of peas waB attributable to the shedding of leaves during the growth of the plant and the large amount of easily decomposable roots left in the soil to yield food to. the succeeding. In laying down a system of rotation, shallow looted plants should alternate with the deep-rooted ones and two cereal crops should not be taken in succession off the same land. Asmatters stood at present agriculture would not pay so far as the produce weuld meet the requirements of the population. The export of wheat would net pay owiag to the cost of production, the charges of freight to England, and the keen competition with "American wheat, which could be landed in London at a lower price than the Victorian farmers could growit. Suoh being* the case, he advised the farmers to turn tfcefr attention to other production

which would pay better than wheatgrowing. He firmly believed that the manufactre of beet-root sugar would ultimately become one of the staple industries of the country ; bat that could not be well established until the farmers showed a willingness to encourage capitalists to invest money in the establishment of necessary expensive works in connection therewith. He also believed dairy produce and butter exportation would pay the farmer. It was very easily preserved, and would he was confident, amply recoup the farmer for his trouble if that industry were only fairly tried. With the exporttation of sugar and butter he had every hope of making farming pay outside of the produco required to meet the requirementa of the colony itself.

Clo\r H.iy I J'ota-I Peas. Grain Stray I toe;.. 1 C.nrbon Hydrog-en . Oxy gen Nitrogen Ash, including sulphur and phosphorus. 47 - 4 37 8 44-0 58 4f7 i"5 IC-5 62 l"2 46-. 4 6-. 5-8 434 2 3 1»9 S"J 38" ♦ o 4 77 4°4 '° I* .-.I 7'O Sulphur Phosphorus . lOO'O lOO'O lOO'O IOO'O 100 O I o'iß 0-28 I o'oß 0"21 ""34 O'l2 O- 3 C i 02S