effect of soil mulch, 55.
depth of planting seeds, 81.
effect of lime on clay soil, 42.
effect of working soil when wet, 26, 45.
exclusion of oxygen by leaf, 113.
film water, 50.
growth in length of roots, 16.
heat necessary for germination, 73.
how food and water get into the root, 18, 19.
how soils are warmed, 58.
how soils lose heat, 59.
importance of roots, 7.
moisture necessary for germination, 71.
no starch formed in dark, 112.
osmose, 18, 19.
plants contain albuminoids, 64.
plants contain ashes, 65.
plants contain cellulose, 63.
plants contain gum, 64.
plants contain oil, 64.
plants contain starch, 64.
plants contain sugar, 64.
plants contain water, 65.
power of soils to absorb rain, 40.
power of soils to hold water, 44, 45.
power of soils to pump water, 43.
roots absorb moisture, 9.
roots take food from soil, 9.
roots produce new plants, 10.
roots need air, 21.