1. Ashrif, M. I. and Thornton, I., Effects of grass mulch on groundnuts in the Gambia. Expt. Agric. 1, 145?152 (1963).
2. Beckenbach, J. Gourley, J. H., Some effects of different cultural methods upon root distribution of apple trees. Proc, Amer. Soc. Hort. Sci. 29, 202?204 (1922).
3. Bull, R. A., Studies on the effect of mulch and irrigation on root and stem development in coffea arabica L. I. Changes in the root system induced bymulching and irrigation. Turrialba 13, 96?115 (1963).
4. Chiba, T., Studies on orchard soil management. Part 8. The effect of some organic mulches on the behaviour of young peach trees. Bill. Hort. Research Stat. Hiratsuka No. 6, Hiratsuka, Japan (1967).
5. Eggert, R., Kardos, L. T., and Smith, R. D., Relative absorption of phosphorus by apple trees and fruits from foliar sprays, and from soil applications of fertilizers using radioactive phosphorus as a tracer. Proc. Am. Soc. Hort. Sci. 60, 75?86 (1952).