Manure to be most effective should be plowed under where its constituents will come in contact with the roots of the crop. Manure should not be covered so deep as to prevent fermentation. On clay soils the covering should not be over four inches, while with sandy soils. a six-inch covering is not considered too deep.

Heavy applications of manure during dry seasons may result in a physical injury to the soil, due to a lack of moisture to cause the organic matter to decay. For this reason it is a good plan to irrigate the ground in the fall before applying the manure and plowing or spading it under.

Fresh manure may be injurious to potatoes, as it tends to produce scabby, undesirable tubers. For this reason in manuring land for this crop well-rotted manure should be used.

The amount of manure to apply depends upon the kind of soil and the quality of manure. Generally about 50 pounds for every 100

Fig. 2-Hill Selection versus Bin Selection:
Hill Selection-Average Weight of Two Hills Shown on Left, 5 pounds.
Bin Selection-Average Weight of Two Hills Shown on Right, 3 pounds.

square feet or 10 tons per acre is considered a good average application for ordinary farm crops, while 20 tons per acre is often not considered excessive for light sandy soils in the production of potatoes. Usually when such heavy applications are used, the manure is well rotted. Too liberal applications of manure are often wasteful, and better results are generally realized by the use of frequent light appli cations.

IRRIGATION BEFORE PLANTING

If irrigation is necessary before planting, it should be given before the ground is spaded or plowed. The coarse dirt mulch left on the surface by the rake or harrow retains sufficient moisture in the soil for sprouting the seed and for the early development of the plant. An irrigation after spading would cause the soil to pack too much and a second spading would be required.

SEED POTATOES

The Experiment Station has tested a number of varieties of potatoes during the past five years, with the result that Great Divide, Burbank, and Peerless were the highest average producers, in the order named. These varieties have been grown in Nevada for many years and indicate the value of well-selected home-grown seed as compared with that introduced from other States. The Netted Gem, commonly called the "rough-skinned Burbank," is advancing in popularity in several potato districts of Nevada.

A small amount of seed was grown in 1917 of each of nine leading varieties of potatoes which are being tested in different Western States under irrigation, the object being to obtain a sufficient amount of seed for a test of these varieties in 1918 in comparison with our present high producers. Included in this list are Producer, White Rose, American Wonder, Pride of Multnomah, Earliest Fall, Snow (California), Early Prize Taker, Scotch Rose, and Snow (Oregon).

4

Fig. 3-A Potato weighing 10 to 12 ounces properly cut for seed.

SEED SELECTION

The most successful method of securing seed potatoes is to go through the field at digging time and dig the strongest plants that appear most productive. If the hill has the proper number of uniformshaped tubers that are free from scab or other disease, the potatoes from this hill should be saved for seed. By this method in a very short period of time the farmer, with the help of two or three boys, can obtain excellent seed for planting the following year. This method is more expensive than getting seed from storage, but the increased production the following year pays many times for extra labor involved in gathering the seed.

For this reason the seed should be secured in the fall when the grower has the opportunity of knowing how the potatoes were grown and that they were properly stored through the winter months so that their germinating power has not been impaired.

PROPER STORAGE OF SEED IMPORTANT

Seed potatoes should be so stored that they will remain dormant during the winter. Potatoes that have been affected by chilling or heating during the period of storage will not produce a perfect healthy stand when planted the following spring. During storage of potatoes in Nevada the past winter, heating followed freezing in many cases. In some instances the freezing was so severe that decomposition of the tissue took place, causing the starch to change to sugar. This seriously impaired the vitality of the seed, and led to the poor weak development of potatoes in many of our fields the past season.

Growers may realize good crops of potatoes from seed taken from the general lot in the spring, but a marked increase will be noted in

Fig. 4-A Machine used in cutting large quantities

of Potatoes for Seed.

the production of good uniform potatoes when the seed is obtained by the method of hill selection from the field in the fall.

TREATMENT FOR DISEASE

The following treatment is recommended for the prevention of scab and other diseases: All seed potatoes should be soaked in a solution of mercury bichloride (corrosive sublimate), 4 ounces in 30 gallons of water, for one and one-half hours. Formalin treatment will not kill rhizoctonia as completely as mercury bichloride. The solution should be placed in a wooden barrel or tank. It corrodes metal. It should be

poured out and made up fresh after it has been used to disinfect four lots of potatoes. It is poisonous if eaten, but is not poisonous to the touch. Treated potatoes should not be eaten or fed. After the potatoes have been treated, they should be stored in new sacks which have been similarly disinfected in the solution.

The formalin treatment is as follows: Prepare the solution by adding one pint of 40 per cent formaldehyde to 30 gallons of water. Place the sacks of potatoes in the solution and leave submerged for two hours. After removing from the solution the potatoes should be dried, cut and planted. However, if stored for a short time, they should be returned to the same sacks which have been disinfected by the solution.

CUTTING THE SEED

The potatoes should not be cut in pieces less than one ounce in size, and the best crops will be obtained where the pieces are from one and one-half to two ounces. The seed piece should have two good eyes.

Fig. 5-Excessive Sprouting saps the vitality of the Potato for Seed.

Where more than this number of eyes is present or where larger pieces are used, the soil must be very fertile and the seed pieces must be planted farther apart in the rows, otherwise the percentage of small tubers may be too great.

A good method to follow in cutting the seed is to begin cutting from the stem end, diagonally across the potato, being careful to cut the seed end so that too many eyes are not left in one piece.

The seed should be planted not later than the day after being cut. If exposed to warm windy weather for any length of time, too much moisture may be lost and the seed may be injured by excessive drying. A common practise in Nevada is to place the cut seed loosely in the disinfected sacks and store for a time in a well-ventilated place, being careful not to stack the sacks in a large heap. This often injures the

seed by causing it to turn black before the moisture has evaporated from the cut surface.

SPROUTING THE SEED

Certain growers in Nevada have used the method of sprouting the seed where early potatoes were desired. The general method followed consists in placing the potatoes on a clean floor about six inches deep, where they have access to the light, for about a month. The potatoes are turned every few days in order to obtain uniform sprouting. When the potatoes are handled carefully by this method, very little injury is caused by the breaking off of the sprouts and excellent results are realized.

GREENING SEED POTATOES

This practise consists of removing the seed potatoes from storage in the spring before sprouting has commenced, spreading them over a clean area in a layer about 6 inches deep, and exposed to the light, and

turning them about every ten days. This treatment produces a green tough skin which is not easily rubbed or broken. It has been used in preference to the corrosive sublimate or formalin treatment by the Colorado Station in the prevention of disease. This practise is not common in the potato districts of Nevada.

RATE OF SEEDING

Where one-ounce seed pieces are used, the potatoes should be planted in rows 3 feet apart and about 15 inches apart in the row. With twoounce seed pieces the distance apart in the row may be 18 inches.

The amount of seed required per acre with different sized seed pieces is shown in the following table: