GREENS. The formation and maintenance of fine turf for putting greens has been the subject of systematic research in America since 1919. This article is a summary of the chief results that have been published in The Bulletin of the U.S. Golf Asso ciation Green Section (Washington, D.C.) The finest turf is composed of certain varieties of bent grass. The best is velvet bent (Agrostis canina). Then comes creeping bent (A. stolonifera) and then common bent (A. vulgaris); sea side bent (A. maritima) is also used on suitable soils. Red Fescue (Festuca rubra) is a beautiful fine grass, but does not form a dense turf when cut very close, owing to the axils from which the young shoots arise being well above the ground. In the bent grasses these axils are so low that they are not injured by the very close cutting that is necessary on a golf green.
The best seed to use is South German mixed bent, which usually consists of 8o to 85% of A. vulgaris, of A. canina and a trace of A. stolonifera. This should be used at the rate of 3 to 5 lb. per 1,000 square feet.
The vegetative method of propagation has been successfully applied to creeping bent, which is almost a non-seeding variety. The runners or stolons are strung out in rows in a nursery. With proper attention to cultivation a dense mass of these stolons are produced in a few months. They are cut up into lengths of about sin. and broadcast on the ground, that is prepared as for sowing. There should be one piece of grass to each square inch. The whole is covered about kin. with a fine compost and lightly rolled. With daily watering for about two weeks each piece of grass that con tains a node will root, under favourable conditions, and with proper treatment a perfect turf will result. There are a great many strains of creeping bent. The American workers have selected two, called "Metropolitan" and "Washington," which are most suitable from their resistance to the fungoid disease known as brown patch, and from the fact that the blades of grass grow vertically upwards. "Metropolitan" seems to be slightly the better for the climatic conditions in Great Britain. Velvet bent can also be propagated by the vegetative method, but it does not spread so rapidly. The turf is even finer than that obtained with creeping bent.
The American workers have definitely established the fact that it is most advantageous to apply fertilizers that will slowly render the soil markedly acid, the optimum being about pH 3.8. It has been found that at this reaction the fine grasses grow luxuriantly, whilst coarse grasses, clovers and most weeds and also worms and grubs disappear. This result is achieved by regular dressings of either the sulphate or phosphate of ammonia, the former being generally used because of its lower price. To avoid scorching the grass it should be applied at the rate of 3 lb. per i,000sq.ft., and well watered in by a fine spray immediately afterwards. If a water supply is not available it must be applied on a rainy day. The dressings should be given every fortnight or every month from March to September. During hot dry weather it is advis able to limit the amount to 2 lb. per ',coo square feet. On a very alkaline chalk soil it may take from three to four years to reach the desired acidity. After this the amounts used can be decreased. It must be added that sulphate of ammonia should not be used on young grass. Further, that treatment with lime, basic slag or any other alkaline fertilizer is most undesirable.
Systematic topdressing has been shown to be essential, particu larly with bent greens under treatment with sulphate of ammonia. Otherwise a mat of fluffy turf will develop, which it is impossible to cut and which is most undesirable for putting purposes. The compost should be made up of equal parts of loamy soil, sharp sand and well rotted stable manure, leaf mould or other organic matter. It should also contain about 20 lb. of ammonium sul phate per load (cubic yard). The whole must be well screened so that there are no lumps to interfere with play. One load is broadcast over 5,000sq.ft., well worked into the roots with the back of a rake and then lightly watered, especially if it contains any sulphate of ammonia. This dressing should be given monthly from March to September. The old practice of using one heavy dressing of manure in the winter is objectionable and harmful, as it tends to smother the grass and seriously to increase the risk of infection from grubs and worms.
The risk of trouble with earth worms and grubs like leather jackets is much decreased if the soil be rendered sufficiently acid. Before this result is obtained, worms are best removed by use of mercuric chloride (corrosive sublimate). Three ounces are dis solved in a wooden bucket. The solution is poured into a 5ogal. tank and well mixed. This is distributed over 1,000sq.ft. and then the ground is thoroughly soaked with water. It must be re membered that it is a deadly poison. The operation must be car ried out on a mild day between November and April. Where there is any risk of infection by leather jackets or similar grubs, the addition of 5 lb. of arsenate of lead to each load of topdressing will give excellent results.