tions of the
Bureau of Plant Industry, a number of fertilizer experiments on pecan
orchards, involving a study of several soil types suitable for nut
production and attempting to ascertain the proper fertilizer
requirements for the pecan on these soils. While these experiments have
been running only five years, which in point of time is very small in
the life of a pecan tree, yet the different fertilizers employed already
show some highly interesting results, sufficient to indicate that
certain fertilizer applications undoubtedly influence the growth of the
tree, its productiveness, and quality of the nut produced.

The experimental fertilizer mixtures are all prepared here in Washington
in a fertilizer-mixing plant on the department's Arlington Farm, on the
Virginia side of the river. The fertilizer house is well stocked with
all of the various fertilizer substances used in agriculture, ready for
mixing; nitrate of soda from Chili, potash from France and Germany, and
our own far western states; cottonseed meal from the South, tankage and
dried blood from the slaughter houses of Chicago and Omaha, Tennessee or
Florida phosphates, and acid phosphate, ammonium sulfate from the coke
ovens of Pennsylvania, Thomas slag from England, in short, all sorts of
commercial materials from near and remote sources, for study and use in
fertilizers.

(Slides were then shown of the exterior and interior of the plant where
literally thousands of experimental fertilizer mixtures are prepared to
study the requirements of the various soils and crops, and are then
shipped in freight cars to the various experiment places. Two slides
showing the application of fertilizer in a large orchard where tractors
are employed in carrying on the various cultural operations and also in
a small orchard where hand labor is employed, were also shown).

The scheme of fertilizer experimentation adopted in this work is rather
complete and so planned as to include fertilizers carrying the principal
fertilizer constituents, phosphate, ammonia and potash, singly, in
combinations of two elements, and in combinations of three elements, in
various proportions in a regularly graded manner. The following scheme
illustrates these mixtures of different analyses, the first figure
denoting the percentage of phosphate, the second the percentage of
ammonia, and the third the percentage of potash in the fertilizer. The
various mixtures are numbered consecutively.