B ased on Table 4, rotational speed is propoTtiona] to: tie. timé ACt-63C 43 GO ON TO THE NEXT PAGE. 40000000004 Passage IV Composl consists largely of organic mattar that has been decomposed by bacteria that require oxygell. Com- post is used as soil fertilizer. Two.studies were dohe to examine the &ffect of compost usc on the growth &nd.yield of bean plants, Table 2 Percent of ,seeds that produced mature bean plants 10 Mixture of soil 'and: 20% coffee grounds 5010 coffee grounds 20% pine needles 50% pine needles 20% crushed eggshclls 50% crnshed eggshells 20% alfalfa 5090 alfalfa IO% piue needles, 50Yo. crushed eggsbells, 20% alfaLfa 20 30 60 Study I Four different materials were selected for compost- 50 i• ing-coffee grounds, pine needles, crnshed eggshells, and azfalfa (a plant). Each mateiial was placed in a separate container. A small amount of distillcd water was added to each material. The 4 containers were then left in a warm location for about a week to all,ow the materials to. decompose. During the week, the mateTials were stirred 'periodically and moisteyjed with distilled water. The decomposition process was considered cornplete when the temperature at the centeT of the material had risen to 40°C. For each type of compost, the pH, and the nitrogen, phos- phorus, and potassium contents were then determined (see Table l). 80 TabIe I Percent by dry weight of.. nitrogen phosphorus potassium Compost type Coffee gTounds Pine needles Ciushed eggshells Alfalfa pH 18 16 5 12 10 Study 2 Each type of compost was added to 2 different a]nounts of a given soil to create mixtures that were either 20Yo compost or 50% compost. A ninth mixture Gontained Iolo pine needles, 50010 crushed eggshells, 20(70 alfalfa, and 200/0 soil. Each rnixture was used to fill 5 pots. Ten bean seeds 141ere planted iri each pot. Al.1 pots ieceived the san]e amount of light and distilled water. After 6 weeks-, the number of matuie bean plants growing in the pots and the number of bean pods on each plant were counted for each mixture. The percent of seeds that produced matilTe bean plants for each mixture is shown in Table 2. Figure I shows, for those plants that produced bean pods. the. aver- age number of bean pods pIesent on inature bean plants growing in each mixture. nuxture of soil and: Figure I ACT-63C 44 GO ON TO THE NEXT PAGE. 40000000004
