SOIL FERTILITY

Southland Times, Issue 23141, 6 March 1937, Page 14

SOIL FERTILITY

Practices to be Condemned i USE OF FARM YARD MANURES Systems of fanning that provide for a return of the largest possible proportion of the plant food constituents removed in crops are those that, most easily maintain the fertility of the sou. It is therefore evident that live stock farming in general is the least exhaustive of soil fertility, provided the excreta of the animals is .carefully saved and returned to the soil. In the rearing of animals for meat about 90 per cent of the plant food consumed by the animals is voided in liquid ana solid excreta. If this is carefully saved and returned to the soil depletion of soil fertility will be exceedingly, slow. In dairying, where the milk is sold, a somewhat larger proportion of the plant food elements is sold .from the farm, says an Australian writer. Even here the total amount is relatively small, and may be offset by the plant food in concentrates purchased for the dairy. If the milk is fed to pigs and calves, and only the butter is sold, the exhaustion in the long run will be no greater than in meat production. It is therefore evident that the type of farming is closely related to the maintenance of soil fertility. All types of live stock farming come closest to maintaining permanent fertility. In new countries it is not an uncommon practice for farmers to dump the manure from stables into a nearby stream in order to get rid of it. It is also a common practice to burn stacks of straw and the stubble of the field in order that the soil may be freed of rubbish and easily ploughed and cultivated. Such practices are to be condemned, for in the long run they encourage soil depletion. Where land, is cheap and fertile and labour expensive the immediate returns from applying manure may not justify the cost of its application, but in a long term of years it will prove profitable. A farmer should be far-sighted enough to calculate what the result will be in a lifetime. There should be more profit m the removal of 50 crops in as many years where fertility has been maintained or increased, and where the crop yields have been increased than there is in the removal of 50 crops with a constantly decreasing yield. In the first case, the land is left in good condition for the succeeding generation, in the second in bad condition. ■ ... Farm yard manures, increase fertility by the direct addition of plant food and by increasing the organic matter of the soil. They increase the water-holding capacity of the soil, improve its physical condition, introduce various forms of bacteria, and encourage the multiplication of desirable bacteria. Soil fertility is a problem of farreaching economic importance. The principal items of expense in general crop production are labour of men and horses, equipment, seeds, and land rental. These cost no more for a productive area than for one of low productivity. In fact, the productive soils are generally ploughed and cultivated at less cost of time, and energy than those of low productivity. Every hundredweight of product over that required to meet the cost of production is profit.