HUMUS AND POTATOES.

New Zealand Herald, Volume LX, Issue 18387, 1 May 1923, Page 12

HUMUS AND POTATOES.

The importance of maintaining the organic // matter content of potato soils was the subject of partioular reference by an instructor of agriculture the other day in the Commonwealth. He said that good results are obtained from virgin land is jvell known to all, but few pause to consider why. On the other hand, it is known that the continual cropping of the soil without any system of returning organic matter 'eventually leads to reduced yields, especially during years of Uncertain rainfall. The potato demands a loose, friable soil for maximum production, and any soil which tends to compact _or quickly dries out is unsuitable. Virgin soils begin well supplied with organic matter, are usually of suitable texture and have the power of retaining moisture. Farming practices should be such as to secure as nearly as possible a similar condition in the soil for all times, and this is only possible by practising suitable rotation. "The present cropping system potatoes and cereals—does not tend to the upkeep of the organic content, and it is therefore essential that a cropping system be evolved which will allow of the soil being supplied either with animal -manure or the humus obtained bv turning under green crops. For this reason the growing of potatoes should go hand in hand with stock-raising, either as dairying or sheep-raising. Where this class of mixed farming is practised it is possible to grow fodder for grazing, at tho same time allowing the supply of' the necessary organic matter of the soil. "The advantages of green manuring are outstanding during dry periods. Last year, when a very dry spell occurred during the latter part of the crop-growing period, it was particularly noticeable that the yields were obtained from areas cropped under a system such as that advocated. I could give a number of instances, but the outstanding one was the case of a farmer who turned under a crop of barley during the winter previous to potato-planting. On this field a tally of 30 bags of potatoes were dug in one day by a digger, whereas on adjoining farms without the green manuring the tallies were in the vicinity of eight to 12 bags a day."