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MANAGEMENT OF THE GROWING CROP
Cultivation.—Almost invariably judicious cultivation of potato land is profitable. It is secondary to good preparation of the land. The object is not primarily to destroy weeds, although this may be a consideration. To-day intelligent farmers till to increase yield. Tillage is manuring. No better illustrations of this fact can be found than the tillage experiments of Roberts and others at Cornell University.' In these trials potatoes were grown several years in succession, without manures or fertilizers, upon the same land, and yields varying from 300 to 350 bushels per acre, or three to four times the average yield of the State, were secured for several years. This illustrates the value of tillage, but in its entirety is not necessarily a good practice. Tillage destroys humus, and as this is one of the most essential constituents of a good potato soil, a rotation of crops is advised to aid in maintaining the supply. Tillage may be overdone, especially deep tillage in dry, weather. During such a time only sufficient shallow tillage should be given to maintain a mulch.
At Cornell from seven to nine cultivations seemed to be most profitable, or about every seven to ten days until the potato-vines meet in the rows. Tillage must be given when necessary. The right number of cultiva
? (N. Y.) Cornell Bul. 140, PP. 389-390; 191, p. 192.
tions will vary with each year and the class of soil. The Ohio Experiment Station found that thorough culture encouraged vigorous growth and aided the plants to resist fungous troubles.
The objects of tillage, then, are:
1. To increase the crop-producing power, presumably by :
(a) Liberating plant-food.
(c) Conserving moisture by the aid of a soil mulch. ; (d) Pulverizing the ground, so that every shower
of rain can enter the soil and not flow off,
transporting the fine soil particles. 2. To keep weeds in check.
System of Culture.—Hills.—Generally hills—that is, where potatoes are planted in checks—are unprofitable because there are not enough plants per acre and the yield is too low; hence the system is little used unless a piece of land is very weedy.
Drills.—By “drills” it is understood that the soil is thrown toward the potatoes, leaving a depression or furrow between the rows. This system is used for irrigation, when the water flows between the rows. It is also practiced in humid climates, where the temperature does not go high-as, Northern England, Scotland, etc.—and on wet soils and in wet seasons. Often the “furrowing” injures roots and reduces the yield, but many growers claim that the ease with which the potatoes can be dug from drills compensates for any loss in yield. The objection to level culture is that
1 Ohio Bul. 76, p. 47.
difficulty is experienced in securing machinery which will dig all the tubers.
Level Culture.- In this system the potatoes must be planted a little deeper than in the case of the other two, to reduce the percentage of sun-burned tubers. This system is advocated throughout most of Eastern North America, as, among other things, the quality of
the potatoes is better, owing to the ground being cooler. Its use has been found advisable at such various points as Cornell,' Louisiana, North Carolina,: Wisconsin,' and Arkansas Experiment Stations, while the Maryland® Station, in a trial lasting six years, found little difference between level and drill culture, but the slight variation was in favor of level culture.
Method of Cultivation and Tools Used.-About a week after planting the spike-tooth harrow should be run over the land, preferably in both directions, if a mulch is not made by one harrowing. This destroys young weeds and brings more seed up to germinate, which may be killed by another harrowing a week later. When the potatoes appear, the weeder (Fig. 30) will be found the most serviceable implement for holding the weeds in check and maintaining the mulch. It may
1 (N. Y.) Cornell Bul. 140, p. 390; 156, p. 175.
? La. Bul. 22, p. 705.
be driven across the rows after each cultivation until the potatoes are 9 or 10 inches high. As a good horse and man can do twenty acres a day, it is quite expeditious and generally satisfactory.
Generally speaking, it is advised to cultivate widely and deeply from 4 to 6 inches the first, and, in some cases, the second time after the potatoes appear, then reduce the width and the depth to one inch or so. The first and second cultivations may be given with a five-tooth cultivator (Fig. 31), or a sulky cultivator (Fig. 32) may be used. The spring-tooth cultivator (Fig. 33) is found to be a very useful tool for inter