690 ANNUAL REPORT OF THE Off. Doc. 



Plowing the Ground. — Soils in which potatoes may be grown with 

 profit vary so much in character and in location that no hard and 

 fast rules can be laid down. But keeping in mind the nature of the 

 plant and its likings, we may make our practice conform to its needs. 

 The first consideration, as has betn said, is that of soil moisture. 

 We want conditions under which a supply may be held for times of 

 drouth. One method of securing this is by deep plowing. The 

 storage capacity of land is increased by dieepening the soil, as that 

 is the part of the earth that contains organic material in such form 

 that moisture is held as in a sponge. The deeper we plow, the more 

 soil we have of such texture that the water of rains is received and 

 held, provided the percentage of humus is maintained by increasing 

 the supply as we increase the number of cubic inches of soil upturned 

 by the plow. Within certain bounds we may make this rule for our 

 guidance: The depth of plowing should be proportionate to the per- 

 centage of humus. But the potato requires an abundance of this 

 material, and if our soil is properly stocked with it, the plow should 

 go deep. Depth in plowing is a relative term. I know successful 

 growers on land that will not permit a greater depth than six inches. 

 Thev feed that six inches well, and make monev. Preferablv, how- 

 ever, the plowing should be deeper. Where six inches is a normal 

 depth, seven should be gotten if possible. Where eight inches is a 

 usual depth, nine inches should be sought. 



Kind of Plowing. — I like the rule given above respecting the depth 

 of plowing. If a thin sod be buried deeply, and soil deficient in 

 humus be placed at the depth the tubers shall form, a clayey soil 

 will give disappointing results. Worst of all, a layer of soil deficient 

 in humus, either in clays or sands, is utterly unfit material for the 

 soil mulch that we make at the surface by tillage for the retention of 

 moisture. If the amount of organic material be small, it should 

 not be distributed throughout too many inches of soil by very deep 

 plowing. It is better to sacrifice the benefits of depth under such 

 circumstances to insure fair texture of the soil in which the tubers 

 form and of that at the surface. This caution is for those only who 

 from necessity plant land not well fitted for potato-growing. "VMiere 

 the soil is supplied with such a store of humus as the potato de- 

 lights in, depth should be secured by deep plowing. It was Ben- 

 jamin Franklin who said, "Plow deep while tihe sluggard sleeps," and 

 while the advice is much quoted and is wise within proper bounds, 

 I venture the opinion that if the revered author were to return to 

 earth and note the decrease in the humus-content of our American 

 soils he would modify the statement so far as to say that the depth 

 should increase only with increase of hnmus-produeing material 

 added in sods and manure. 



The Plow. — There are breaking-plows of many models. In respect 

 to the kind needed for turning sod land for potatoes, let us reason 



