TOBACCO of High Quality Produced Following a Natural Weed Fallow

Early settlers soon observed that virgin lands produced good yields of tobacco and a leaf having & finer texture and lighter body than that grown on the older cultivated areas. It was chiefly this fact that led the early growers of tobacco constantly to clear new lands every few years until most of the land suitable for tobacco in the tobacco-producing areas had been brought into cultivation. It then became necessary for the grower to attempt to find other methods to produce a suitable product. Systematic crop rotation and the use of commercial fertilizers were tried as a means of securing a product of the desired yield and quality. These practices have not proved satisfactory on all soils and with all crop combinations.

It has recently been demonstrated that tobacco fertilized intelligently and grown after a natural weed fallow of sufficient duration possesses in a large measure those characteristics which are found in the crop grown on virgin land. The term “natural weed fallow” is here applied to areas which are not cropped for 1 or more years and are allowed to develop a spontaneous.weed cover. When bare fallow was substituted for the weeds there was a rapid decline in the yield and quality of the tobacco after the first 2 or 3 years, as shown in figure 71. This fact illustrates that the weeds are the keystone of the system.

While this system may not always be applicable where there are complicating diseases such as bacterial wilt and nematodes for which the prevailing weed growth furnishes host plants, it will be suitable over other large areas. There are also economic relations to be considered, such as the fact that there are some districts in which good tobacco soils are scarce and high priced; but the system can be used to advantage where the necessary land is available and where it is desired to produce leaf of the characteristics previously mentioned.  It must be remembered also that for some purposes of manufacture a thin, light-bodied leaf is not desired.

The general effect of the weed fallow is to promote a quick start and a rapid and uniform growth of the tobacco plants till maturity.  The beneficial action of the natural weed fallow on the tobacco is reflected in a uniformly high market value per pound and value per acre for the crop. This in turn demonstrates that the product meets the current demands for manufacturing purposes, especially the production of cigarettes and pipe tobaccos. Intelligent fertilization of the crop and more extensive culture following natural weed fallow of sufficient duration should aid in solving the problem of keeping the total production of tobacco within proper bounds and reducing the proportion of low-grade leaf in the crop.

James E. McMURTREY, Bureau of Plant Industry.

FIGURE 71.―A, Continuous tobacco, no cover crop, showing irregular and stunted growth; B, tobacco after 2-year bare fallow; C, tobacco after 1-year bare fallow; D, tobacco after 1-year weed fallow; E, tobacco after 2-year weed fallow.