Conditions that tend to dwarf the plant, to make it more erect or bushy and to hasten matur ity are (1) planting late in the season .nd (2) growing the parent seed in high latitudes.
Soil.—The cowpea is adapted to a wide range of land, being able to make some growth on prac tically all soils except those that continue wet during the summer. Near the northern limit of its cultivation, sandy and loamy soils are prefer able, as they hasten maturity. There its best use is for soil-improvement, which indicates that its usual place is on soil too poor or otherwise un suited for the successful growth of red clover. A moderate degree of acidity is not fatal to its thrifty growth.
Climate.—The cowpea is a native of a warm climate and is very susceptible to frost. Near the northern limit of its cultivation it must be started as early as the season is well settled, so as to give time for it to reach the desired degree of matu rity ; but planting should be deferred until the soil is fairly warm. In the Gulf states, the earliest practicable date for sowing is the latter part of April, but this is usually at a disadvantage except when two crops per year are desired on the same land. May and June are the months preferred in the South. In Delaware, the latter part of June and early part of July have been found more de sirable dates for sowing cowpeas than late May and early June. Early sowing has a tendency to cause the production of an excessive growth of runners, and may even change the habit of bush varieties. While moderately early planting usually increases the total yield of forage and the amount of tangling, rather late planting affords a larger yield of seed and tends to the development of a bushy plant.
Planting.—Land on which cowpeas are to be grown should be plowed and well harrowed. Then planting may be done either in drills or broad cast, the method to be used depending on a num ber of conditions. Broadcast sowing reduces the labor but increases the quantity of seed. Usually, when soil and season are favorable, broadcast sow ing gives a somewhat larger yield of hay, but in seasons of drought, dr ill ing and subsequent cultiva tion make a fair yield more certain than broad casting. To broadcast cowpeas they may be sown
by hand and afterwards disked or cultivated into the loose soil, or they may be put in with a grain drill with every tube open. On sandy soil they are sometimes sown broadcast and plowed in shallow. In drilling cowpeas, the distance between the rows is usually thirty-two to thirty-six inches. The seeds are dropped either by hand, by a one-horse planter, by the modern corn-planter in which the cells in the dropping plates may be filled to fit the peas, or by the grain-drill with most of the outlets closed. The grain-drills best adapted to this pur pose are those having gravity or friction feeding devices, as the force feeds crack a much larger percentage of the peas. Drilling and cultivation usually afford the larger yield of seed.
The seed.—The preferred quantity of seed for sowing broadcast is four to six pecks per acre, but varieties with large seeds may require a larger amount. For planting in drills, two to three pecks per acre are usually sufficient when the rows are wide enough to permit cultivation. At the Arkan sas station, it has been found that the common practice mentioned above involves a larger quan tity of seed than is necessary. In case drilled and cultivated cowpeas are to be mown, care must be taken to cultivate level, using ordinary culti vators, or, in the South, heel scrapes. In the South, cowpeas are often sown broadcast or drilled among the growing corn. The seed is planted when the cultivation of the corn is nearly or quite finished.
Inoculation has never been found necessary in the South because of the general prevalence in southern soils of the germ that causes the devel opment of tubercles on the roots of cowpeas. However, there may be small areas in which this crop is seldom cultivated, where at first it will be an advantage to use as inoculating material 1,000 or more pounds per acre of pulverized soil from a field where cowpeas have recently grown and developed abundant tubercles. In a number of localities in the northern and western states, when cowpeas were first introduced, few nodules devel oped on the roots; whenever this occurs the need for inoculation is indicated.