FARMING NOTES.

Wairarapa Age, Volume XXV, Issue 10713, 15 September 1913, Page 7

FARMING NOTES.

A SOIL-ENRICHING CROP. The cultivation of lucerne is deservedly receiving more attention in this country. It not only affords an abundance of rich fodder, but it does not suffer from want of moisture, as its roots penetrate to great depths in search of nourishment and moisture. The Agricultural Experimental Station at Colorado issued an instructive report on the subject. It remarks that the excellent results observed to follow putting land down in lucerne for 3 or more years leads to the conclusion that it enriches the soil. In a, certain sense this is the case, and the practice of seeding run-down land \ ta lucerne, and leaving in the lucerne for several years before breaking it up again to plant other crops, has been the salvation of this part of Colorado, and yet it does not follow that the lucerne plant does not require a large amount of plant food. There are but few crops which will equal lucerne in its' draft upon the resources of the soil in which it grows, but while other crops gather their food from a depth of 2, 4, »r sft, lucerne gathers its food from depths ranging from 6to 12ft; for example, it has, dwing to the.greater depth to which its roots penetrate, from three to four times the depth of soil to feed on. This is an. essential advantage,, especially if the upper portions of the soil from which the wheat plant has to draw its food has already been partially exhausted by repeated cropping, as has been the case in many instances in that State. Most of our cultivated plants depend wholly upon the nitrogen stored or applied to the soil for their supply; the lucerne plant does so only in part, drawing a portion of its supf ply from the atmosphere. Though it may gather large amounts of this element from the soil, it probably returns more in the leaves that fall and the plants that die than it takes from the soil. The statements of the -preceding paragraph may seem somewhat contradictory to one another, and apparently contradictory to what is an acknowledged and well-established fact, i.e., that cropping to lucerne benefits our soils, and does not exhaust it as one would infer from the amount of potash, for instance, which it r&moves. That the plant requires a large supply of plant food is very evi dent, for we find it contained in the plant, but its feeding roots which gather this food are almost wholly below the depth at which ordinary crops feed, so this portion of the soil is resting while in lucerne. Many of the plants die and rot, adding organic matter to the soil, and facilitating the solution by the mineral constituents used by other plants. Not only do the plants die out, as is to be observed in almost any field of lucerne, though I-have seen some in which this was not apparent, but every crop grown adds materially to the upper soil by that poi-tion of the plant which escapes being gathered as hay. The amount of leaves and stems which fall and rot on the surface of the soil each year is always considerable, and is, moreover, high in maniirial value; but the addition of fertilising substances td the soil, which is effected by planting lucerne, is perhaps more strikingly set forth by the facts pertaining to the value of the stubble. The stubble of lucerne taken to a depth of 6£in, assuming an ' ordinary stand, weighs nearly 6 tons, and contains over 361b of nitrogen, equal to about 2151b of nitrate of soda, in addition to 8 1-3 of phosphoric acid and 15-lb of potash. The lucerne roots, however, reach a depth of 9, 10, and 12ft, on account of which the whole root system of the lucerne can safely be credited with twice as much nitrogen, etc., as is found in the stubble taken to a depth of 6Jin. The commercial value of this material is considerable.