SEED-POTATOES.

New Zealand Journal of Agriculture, Volume XVIII, Issue 5, 20 May 1919, Page 297

SEED-POTATOES.

EXPERIMENT AT WERAROA REGARDING SIZE, ETC

By

W. DIBBLE,

Assistant Agriculturist.

The object of this experiment was to obtain data as to the most profitable and economical size of cut or whole potato for seed purposes, and at the same time to test the best depth at which to plant the seed as a preventive against blight. Particulars of the variations of seed used will be found in the table on next page.

A level piece of land of even quality throughout, with a good average depth of soil, was selected for the experiment. The soil in question is rather heavy alluvial, with a porous subsoil. It had been laid down in grass from 1912 to 1918, and continually used as a night paddock for draught horses. Prior to 1912 it was heavy bush land.

On 1st August, 1918, the land was ploughed with a ■ threefurrow plough drawn by an oil-tractor, at a depth of 6 in., turning a 12 in. furrow. On 30th August the land was disked twice. On 5th September it was again ploughed, a double-furrow plough being used, at a depth of 8 in., turning a 10 in. ' furrow. The soil was then given a thorough cultivation and brought to a loose and friable condition. A few loose tufts of grass were showing, indicating that . not sufficient time had elapsed to permit of them rotting before the second ploughing. - On 12th September the land was moulded up in. ridges with a double mouldboard plough, at a depth of 8 in.

The potatoes were planted on 13th September. The seed chosen was the Up-to-Date variety, procured from the Ashburton district. To all appearances the tubers were healthy and sound,. but on being cut some were found with signs of disease. The manure used was superphosphate, 5 lb. 7 oz. being applied to each drill, equalling 1 cwt. 3 qr. 27 lb. to the acre. The drills were 6 chains 28 ft. in length and 2 ft. 6 in. between rows. The sets were graded and planted as follows : 339 sets in each drill, planted 14I in. apart, and covered with soil to an average depth of 8 in. The weather conditions at time of planting were perfect, and the land was in good order.

During December, when inspecting the different rows of potatoes, it was specially noticed that there was little difference in the growth of each row. As regards blight, although the haulms seemed badly affected during part of the growing-period, the tubers were comparatively free from disease. In my opinion, the unusual depth at which the potatoes were planted prevented the disease from spreading to the tubers. The crop was sprayed with bordeaux on 6th December.

The potatoes were lifted with a potato digger on 23rd April. The proportion of table and seed sizes yielded were two and one respectively.

My own experience, extending over a long period when growing potatoes in the Auckland and Waikato districts, is that cut seed planted in well-prepared and drained soil proves the most economical not only in the saving in weight of seed, but also in obtaining better results; and, further, that where facilities will allow in well-prepared land potatoes should be planted deeper than is customary, as a preventive against blight.

Experimental Orchard for Canterbury. -An area comprising 4 acres of orchard and 4 acres of grassland, situated at the corner of Harewood and Isleworth Roads, Papanui, Christchurch, has been leased by the Department from Mr. R. Herdman Smith for the purposes of an experimental orchard, and was taken over on 1st May. A scheme of experiments has been arranged and is being put into operation forthwith. The area will be under the supervision of the District Orchard Instructor, and a working overseer has been appointed.

The Vintage and Table-grape Production. Owing to unseasonable weather the vintage in all vine-growing parts of the Dominion was fully a month late this season. The make of wine is estimated at 48,000 gallons, or about one-fifth less than that of the previous vintage. The production of table grapes has also been less this season owing to the same causes. The yield from 850 glasshouses is estimated at a total of 457405 lb.

Elimination of Waste. — As a result of official supervision of the discharge of foodstuffs at docks in the United Kingdom during three months of last year over 1,000 tons of poultry-feed was salved from ships by sweeping out the holds, &c. Steps were taken to improve methods of discharge in order to avoid such losses in future.

' Drill. Particulars of Seed. Weight of Seed / Weight of Seed planted. Equivalent per Acre. Yield of Drills. Equivalent Yield per Acre Table. Small. Total. lb. Cwt. lb. lb. lb. Tons. I Large tubers, 2 in. and uplb. 7° Cwt. 25-68 lb. 352 lb. ' 173 lb. 525 Tons. 9-63’ wards in diameter, uncut 7° 25-68 352 173 525 9-63 2 wards in diameter, uncut Small tubers, i-J in. in dia23 8’43 285 140 425 7’79 meter, uncut 23 8'43 285 140 42.5 7’79 3 meter, uncut Medium , tubers, i J in. to 6o| 22-19 212 IOO 312 5-72 2 in. in diameter, uncut 6o| 22-19 212 IOO 312 5-72 4 2 in. in diameter, uncut Large tubers, cut in three 23 8’43 300 145 445 8-i6 (control drill) 23 8’43 300 145 445 8-i6 5 (control drill) Large tubers, cut in halves 31-2-n-55 4IO 200 610 11-19 6 Medium tubers, cut in halves 23i-8-62 327 160 487 8-93 7 Medium tubers, cut in three 19 6-97 345 165 5io 9’35 (control drill) 19 6-97 345 165 5io 9’35 8 (control drill) Small tubers, cut in halves 12 J 4-58 352 168 520 9-53

The table potatoes throughout were an even and excellent sample. Particulars of seed, yields, &c., are given in the following record :■ —