ROTATION OF CROPS.

Manawatu Herald, Volume XXXIV, Issue 1052, 4 June 1912, Page 4

ROTATION OF CROPS.

I t is known that any crop will decrease in its productiveness it it is planted in the sumo piece oi ground year alter year. Tho reason lor this is apparent. Tho crop is taking out oi tlio soil tho same kind oi food each year. This food is not put back at an equal rate, with the result that tiic soil is exhausted and is said to ho

“sick.” tor instance, turnips take largo quantities of potash, lime, phosphoric acid, and soda out ol tho ground, if turnips were planted year after year in tho same piece of laud these food constituents would he all used up and the laud rendered practically useless. A crop like barley, therefore, which requires less potasii and lime, should be sown alter tho first crop of turnips. Tho barley should he followed by clover and tho clover by wheat. Other crops which use more of other kinds of food than those already mentioned may be planter! subsequently with advantage, tins change in the crops is generally known as •'the rotation of crops,” and there are many rotations in use. A favourite one is known as tho modihed Norfolk system, and is as follows; — runups for roots), barley, clover, wheal. The Cumberland system is, oats, roots, wheat (or barley), clover, grass; and the ISouth Lancashire system, potatoes, wheat, barley, clover, grass. A great deal, however, depends upon tho nature ol the land. The rotation of crops is also of mechanical value to the soil. The land is ploughed deep for turnips and tho rows planted sufficiently wide apart to permit the soil being continually stirred and weeds gruboed while tho crop is growing, liarley is not deep rooted, while the clover —the third crop—semis its roots down deep, thus improving the texture ol the soil. It is only by carrying on a proper rotation of crops, by systematic running, and by the judicious application oi fertilisers, that tho farmers ol this country will ho able to keep up their - heavy export of lirst-elass sheep and dairy produce and yet maintain the lertihty of their laud. A rotation frequently adopted in .New Zealand is as follows: —Wheat, turnips (sown hr November), oats or barley, cultivated grasses or clover. A permanent pasture is thus established. When tho cultivated grasses have to bo renewed the same course is followed. There is one more effect that the rotation has, and I Mat is, it reduces to a minimum the chances of attacks from blight. If the same crop wero planted year after year thou there is every opportunity for the blight peculiar to that crop increasing, whereas if the crop is changed, that blight will speedily disappear.