Place in the Rotation.—Burr clover is grown more in the sense of a catch crop and for pasture than in that of a crop to be marketed directly. Since it is grown in the winter and spring, it may be made to come in between various crops. On good producing lands of the South it has given satisfaction as a pasture plant for winter for many successive years without re-sowing by hand, when sown in conjunction with crab grass (Panicum sanguinale) for hay. Dr. Phares grew it thus in Mississippi for about 20 years. In June crab grass sprang up on the ground, and being cut when in blossom, produced a good crop of hay in August. A lighter cutting was again taken in October. The clover then took possession of the land and was grazed until spring, but not so closely as to prevent re-seeding in May, after which the plants died down.
By thus allowing the plants to mature seed, any crop may follow that can be grown after May. By following burr clover with cow peas, land may be much fertilized in one year. By reversing the process on land low in fertility, that is, sowing the peas first and the clover later, a much better growth of the clover will be secured. The seed may also be sown in corn and cotton crops, with a view to enriching the land. But it is only in the Gulf States that much attention is given to growing burr clover thus, and for the reason, probably, that the winters are too cold to admit of the plants furnishing a sufficiency of grazing at that season.
Burr clover is sometimes grown with Bermuda grass. The latter furnishes summer grazing. There is some merit in the plan, if the seed of the burr clover were sown from year to year. When the re-seeding of the plants is depended on from season to season there is difficulty in adjusting the grazing so as to admit of the plants properly re-seeding for the growth that is to follow. If the Bermuda grass is not closely grazed many of the burrs which contain the seeds may not reach the ground in time to germinate.
Preparing the Soil.—Since burr clover has much power to re-seed the land without preparation, it is more commonly reproduced thus. But, as with all other plants, it will grow more quickly and more luxuriantly on a well-prepared seed-bed, where it may be thought worth while to thus prepare the land. The cultivation given to such crops as corn, cotton or cow peas makes an excellent preparation of the soil on which to sow burr clover.
Sowing.—Usually, burr clover is allowed to re-seed itself after it has once become established in the soil. In this respect it is not unlike small white clover and Japan clover, but it does not grow so well as these on poor soil. Where not yet established, it must, of course, be sown where it is desired to grow it.
The seed is commonly sown in September or early October, but some growers recommend sowing in the burrs as early as June or July, that the tough surrounding which encloses the seed may have time to decay. When seed separate from the burr is used, it is sown in the months named. When sown on well-prepared soil, grazing should be plentiful from February onward.
Burr clover is more commonly sown in the burr. The burrs are usually scattered by hand and on land that has been pulverized, but it is easily possible, when the conditions are favorable, to obtain a stand on land that has not been plowed. Where seed is scarce, the burrs are sometimes planted in squares 3 feet apart each way, a limited number of burrs being dropped at one time. When thus planted, 1 bushel of burrs will plant several acres. The plants will soon possess all the ground, but to enable them to do so, pasturing must be deferred for one season. Whether sown in the burr or otherwise, it is better to cover the seed with the harrow.
One bushel of burrs weighs from 10 to 12 pounds. It has been stated 1 bushel of clean seed weighs 60 pounds. When sown in the burr, it is usual to sow 3 to 5 bushels per acre, but in some instances less is sown and in some more. When seed apart from the burr is sown 12 pounds per acre should suffice. In some instances it is sown on Bermuda sod, but the attempts to grow it thus have not always proved satisfactory. At the Louisiana Experiment Station it was found that the burr clover remained long enough and grew large enough to injure the Bermuda. Possibly closer grazing would have prevented such injury. When sown on Bermuda grass, June, July or August are the months chosen for scattering the seed.
Burr clover is also sometimes sown in corn and cotton to provide winter grazing, but when thus sown the object more frequently sought is to enrich the land. Both ends may be accomplished in some degree.
Pasturing.—Opinions differ as to the palatability of this grass. All are agreed that stock do not take kindly to it at first, but that they come to relish it at least reasonably well when accustomed to it. It is said to be relished less by horses and mules than by other domestic animals. It has been praised as a pasture for swine. It is more palatable in the early stages of its growth, and will bear close grazing, and also severe tramping. It will provide pasture for six months, but not so bountifully in the first months of growing as later.