Effect of paper mulches on soil temperature, soil moisture and yields of certain crops

does not appear. First page follows. The first large commercial use of paper as a soil covering or ‘mulch’ was made in 1914 by C. F. Eckart, manager of the Olaa Sugar Company in Hawaii, where it was found that when the mulch paper was applied over the row of seed cane, injury from weed growth was reduced. The use of mulch paper on sugar cane has not developed, but it has been found very useful in pineapple culture and is used at present (1931) on approximately 80 per cent of the pineapples grown in Hawaii. Hartung(6) experimented with paper mulch as a surface covering in connection with problems dealing primarily with the use of fertilizers in the production of pineapples. The paper which he used was made of raw paper felt stock saturated with asphalt and coated with asphalt on both sides of the sheet and given a light coating of talc or soapstone which gave it a grayish brown color. He found that perforated paper did not control weeds as efficiently as nonperforated paper, and that the available soil moisture during a period of 159 days was practically the same under the perforated and nonperforated papers. Where the nonperforated mulching paper was used, he found that ammonification and nitrification of organic and ammoniacal nitrogen was more uniform, and that the soil-moisture content was maintained in a more favorable condition for plant growth than had hitherto been achieved in general pineapple culture. When black paper was used, the soil at a depth of 3 inches was from 3.0° to 4.5° F warmer and there was an increase of 20 to 25 per cent in crop yield.