SUCCESSFUL METHOD OF PREVENTING SOIL EROSION WITH TREES

Wanganui Chronicle, 8 March 1947, Page 7

SUCCESSFUL METHOD OF PREVENTING SOIL EROSION WITH TREES

PLANTING DESCRIBED Practical information on the value ot tree planting on hill country subject to soil erosion has been supplied to the Rangitikei Catchment Board by Mr. G. M. Newman, ot Patutahi, Poverty Bay. After receiving requests front farmers with erosion problems in the Rangitikei district, as to the best methods of tree planting to be employed, the board wrote to Air, Newman and in reply has received a detailed report as on methods adopted with success on his farm.

Mr. Newman stated that his property consisted of 1600 acres, approximately 900 acres being very easy hill country with heavy tertile clay subsoil to a great depth, the altitude of the property ranging from 400 ft. to IOOOtt. above sea level. This area was subject to the surface creeping downward, mainly from four to 12ft. With little rock, gullying was extensive and active when he purchased the land 28 years ago.

The balance of the farm,'about 700 acres, consisted of fairly steep hills with light clay subsoil, papa rock gullies and very little erosion. Over the years the planting of golden willows in all gullies had been very successful, in spite of many setbacks caused mainly by heavy rains scouring out trees before the roots had obtained a sufficient hold.

“My plan was to work over all stable country at head and sides ot gullies and coniine eroding area. As these trees held, planting was extended downward with cuttings taken from parent trees nearby. With head and sides held well back from the broken area, the guliies deepened and levelled themselves except at the top, where the fall from the planted top would be very steep but on willow roots," Mr. Newman added. “For ail planting I used lift, cuttings, three to six inches thick at the base, always sunk not less than 3ft. deep and well rammed. Of some 3000 golden willows, gully and spaced planted over 900 acres, I used very little protection from stock. The loss from barking was negligible, but until a fair number were established there was perhaps a 10 per cent, loss through cattle rubbing and loosening and lilting up in the ground. "Gully planting was done in September wnen main floods were past. Space planting is better done in August. Horses must be kept from the willows for the first two years. For gully planting, silver poplar would nave been more usetul and I am now using them. For space planting 1 am now using the handsome Lombardy poplar. At least five to the acre will nave to go in to permanently hold the land in places. As I have to transport these trees and to avoid rubbing by cattle, I am winding a short lengtn of old rusty barbed-wire around each tree to a height of 6ft. or so, staples and wire to be removed after two years . Some farmers have used burnt sheet iron for protection from stock and opossums.

“The cost of the work I have already done would not amount to more than 10s per acre and the saving ot land ,the complete elimination, ot bogged sheep in the gullies has been well worth the trouble and the carrying capacity of the 900 acres is now nearing the two-ewe-to-the-acre standard. Less than 100 tons of super have been used during the 28 years.

"With the trees I have used there is no loss of grazing, the rye is predominant as far as the leaf fall extends and right up to the bole. What were barren areas of moving clay are now well grassed under the willows. Black Lombardy and silver poplar with golden willow (which give straight cuttings) would be my preference. Some macrocarpa would be useful for frost shelters, but too many would lessen the grazing area and dry out the soil too imuch. Oak, totara, and kowhai would, I think, be much too slow in growth to stabilise any area that was moving or eroding. The thorny acacia is a most usetul tree, a leguminous soil builder and especially the "shipmast" variety will be of great use in temporary fenced areas," Mr. Newman stated.