16 Florida Agricultural Experiment Station

 FERTILIZERS
 In experiments at the Florida Station (12), results of which
 were not published until 1932, hairy vetch and Austrian peas
 gave best results when grown on land that received applications
 of superphosphate. Hence it was planned to apply superphos-
 phate in the fall to Plots 1 and 2 in which the two winter legumes
 were to be grown. Pecan experiments by this Station indicated
 that when grown on Norfolk fine sandy loam soil, trees should
 receive potash in the fertilizers.
 Consequently, it was decided to fertilize the experimental
 block with both phosphate and potash, and these materials were
 applied to all plots for uniformity. Both were applied in the fall,
 since the phosphate was needed for the cover crops at that time
 and the potash did not leach materially and could be conveniently
 applied with the phosphate.
 Applications of superphosphate and sulfate of potash were
 made broadcast just before or at the time the winter crop was
 seeded. Total amounts applied per acre annually were 300
 pounds of 16% superphosphate and 60 pounds of sulfate of
 potash. From 1930 until 1934, the B section of each plot re-
 ceived in addition annual applications of sulfate of ammonia at
 the rate of 340 pounds per acre applied broadcast over the soil
 during June or July.

 GREEN MANURE
 Plots by number, cover crops grown in each with total and
annual amounts of green material, calculated oven-dry matter,
and nitrogen returned to the soil by the legumes are listed in
Table 2. In considering the tonnage of green material it should
be pointed out that Crotalaria spectabilis did not make maximum
growth because the large trees shaded the land almost com-
pletely during the growing season, making it impossible for
the plants to receive adequate light. Therefore the amount of
green manure returned to the soil by this crop was lower than
it would have been in orchards of smaller trees where the sun-
light could have reached the entire area.
 The data in Table 2 show that the greatest amount of green
material was returned to the soil by hairy vetch and C. spectabilis
in Plot 2, with the growth of Austrian peas and C. spectabilis
in Plot 1 almost as heavy. Plot 4, in which the winter non-
legumes and a summer legume were grown, gave the heaviest