the plant, the more active are all its functions and the more sugar it will make. But unless rainfall and temperature are favorable, a suitable soil does not necessarily ensure a honey crop. Sladen gives a most interesting example in England, showing the dependence of nectar secretion on climate, even when the soil is suitable. Heather, in order to yield well, requires not only a peaty surface soil but also a suitable subsoil. In one region near the coast a whinstone subsoil is considered of no value for honey, although the heather grows well and flowers profusely on it. But in the West, where the climate is milder and more moist, a whinstone subsoil gives excellent results. It is even more strikingly shown that a good soil alone does not insure nectar secretion in the case of honey plants which bloom several times during the season, but fail to yield nectar during one or more periods of blooming. Giant sainfoin in England blooms first about June 10, and yields a crop of honey if the weather has been suitable. It blooms again in July, yielding the main honey crop. There is a third period of bloom in middle August, when it yields no honey. In the San Joaquin Valley, California, there are four crops of alfalfa. The first and last crops yield little if any honey; but the second and third, says Richter, if proper climatic conditions prevail, give a great abundance of nectar. A plant may make a fairly good growth on an unsuitable soil, the bad effects of which may appear only in the flowers and fruit, as often happens in the alkali lands of the western states.
It is most important that beekeepers should know that, as regards their adaptation to soils, most plants may be divided into two great groups: plants which grow best in lime or limestone soils, sometimes called calciphiles (lime-lovers) or calcicoles (lime-dwellers); and plants which avoid lime soils and succeed best in acid or sour soil, calciphobes (lime-avoiders). They are common on sandy soils, and hence are sometimes called silicicoles (sand-dwellers). A study of the relation of plants to soils led Unger to divide them into those which grow on limestone only; those which prefer limestone but will grow on other soils; those which grow on sand only; and those which prefer sand but will grow on other soils.
The value of lime in growing crops is recognized in many aphorisms; as, “Lime is the basis of good husbandry,” and “A lime country is a rich country.” All of the legumes, as the clovers, alfalfa, sweet clover, and sainfoin grow better on limed soils because they form more tubercles on the roots, and the plants are richer in nitrogen than those grown on unlimed soil, as acid is injurious to the nitrogen-fixing bacteria. Kerner found that when plants accustomed to a lime soil were grown in a soil devoid of lime they presented a miserable appearance, with scanty flowers which ripened only a few seeds; while, on the other hand, plants accustomed to sand, when grown in a soil containing lime, soon withered and died without flowering at all.
It is well established that the clovers are most abundant, grow most vigorously, and, other conditions being favorable, yield the most nectar on soils rich in lime. As a rule they are excellent honey plants on the glacial soils of the northern United States. Other extensive areas underlaid by limestone are the Great Appalachian Valley, the Nashville Basin of Tennessee, the Blue Grass Region of Kentucky, and the Ozark Uplands. It is estimated that these limestone areas comprise 68,000,000 acres. Owing to the leaching out of all the soluble salts by heavy rains, most soils in the eastern United States require an application of lime for a good growth of the clovers.
While lime is removed by frequent rains from the soils of the Eastern States as rapidly as it is formed, in the semi-arid Western States where the average annual rainfall ranges from 20 to 10 inches or less, lime is steadily accumulating in the soil as the rocks decay. But many other alkaline salts, which are intensely injurious to vegetation, also remain in the soil, as black alkali and white alkali. Black