ECONOMIC USE OF FERTILISERS.

Otago Witness, Issue 3414, 20 August 1919, Page 10

ECONOMIC USE OF FERTILISERS.

Although crops draw from the soil several necessary constituents, generally speaking the farmer is mostly concerned with three —phosphoric acid, potash, and nitric acid, or nitrogen. Some manures supply one, some two, and some all three. Their action is more or less direct in supplying the growing crop with its particular requirement. There is no royal road to the successful use of manures; it is a matter which requires a deal of study in respect to the manner in" which they should be used, and the amount to use. The conditions which should influence a farmer in buying any particular manure may well be considered. We have the soil, the crop, the object for which it was grown, and the season of its growth and the length and period of its growth; so that it is not an easy matter to say right away what manure should be used. The soil cpnstitutes the raw material from which all wealth comes. The soil is the farmer's raw material; and, like the manufacturer, he by his skill and knowledge and manipulation produces the finished article just as the manufacturer does from his raw materials. The manufacturer gains a reputation for his goods by their quality, due to a careful selection of the raw product. So, too, with the agricultural industry; it is not possible to secure good crops unless the soil is good; and, as the agricultural and pastoral industry is the' biggest and most important industry in the world, it is surely essential to use the best of manures, seeds, and tillage methods. In a word, farmers have got to manure intelligently and increase their .knowledge of the subject, and study the peculiarities of their soil. It is worth while giving a thought to the origin of soils, their formation, and the changes they have undergone. No two soils are exactly alike; their variability is surely a very good reason why we should endeavour to understand them, as in farming more than in the manufacturing industries it is impossible to conduct the management by rule of thumb. Soil analysis is of some use in helping the giving of wise advice on the right system of manuring. It is so much evidence, and all possible is requisite to enable proper treatment. Then the plant is fully as important as the soil; there is the matter of whether the intended crop is shallow or deeprooted, a material factor in manuring, and yet many a farmer sows without giving a thought to this aspect of the matter. Compare, for instance, wheat,- lucerne and beans as against oats, barley and turnips; the three last-named are more shallowrooted than the first three. The shallowrooted crops should receive their manurial application at the top of the soil, in contrast to the deep-rooted plants, which would require the manure to be deep and well worked in. Then it is worth while considering whether the crop roots downwards or not. Mr H. E. P. Horsdell, in an address to farmers (says the Farmer and Stock Breeder), emphasises this aspect of the subject very forcibly. He says that he more than once saw strawberry growers apply soluble manures down the centre of the rows of their plants. He had asked one man what he was doing, and was told he was giving the strawberries a "buckup." "But," he replied, "when you give a man a whisky and. soda, you don't pour it down his back." The man agreed. "Well, then," he said, "why don't you give the strawberry plants the manure so that they can get it?" and he then explained to the man the root habits of strawberries, which throw their roots down. Of ocurse, tho plants got a certain amount of benefit, but to obtain the full benefit of the fertiliser it must be applied to the top (subject to not injuring the leaves), or, better still, by making rings round the plants. He knew many big strawberry growers who for some years had been in the habit of "ringing" their plants when applying manures. 'On the other hand, they had the question of the habit of bush fruit which the average farm hand did not know much about. Bush fruit and trees threw their roots out as far as tho branches went above ground, and it was no use feeding them by applying manure near the stem, which was waste. His point was that if they studied the root habits of plants they could gain this information, and so place the manure where it was required. There is the object for which the manuring is being done to be considered — whether for leaf wood or stem, or for flower leaf and fruit, as seed of, say, a

cereal crop. Then, finally, it is worth whilo giving a thought to the season, length and period of growth. Some crops grow throughout the winter; others did not, but were sown in the spring and hai'vested in the summer or autumn. A crop all the time, which is supplied by the bacteria working in the soil. We know that bacteria are more or less dormant during the cold weather, and it is reasonable, therefore, to supply a growing crop with manure, if only to make up with the summer crop, which is fed freely by active bacteria. In a sense, nitrates or ammonia supply the growth to a plant, while phosphates and potash are necessary for the formation of fruit and seed. It is evident, therefore, that one should endeavour to supply those fertilising ingredients and soil conditions which the plant demands for its vigorous growth; otherwise our expensive tillage and manuring work is largely useless.