Gravelly loams, 29.

  Green-crop manures, 171, 183.
    benefits from, 185.
    best plants for, 185.

  Green manure-crops, 186.
    clovers as, 188.
    cowpeas as, 186.
    legumes as, 186.
    non-leguminous, 191.
    soy-bean as, 189.
    time for growing, 186.

  Gum in plants, 64, 66.

  Gypsum, 201.

  Habit of growth of roots, 11.

  Handles of plow, 93.

  Harrowing, 101, 158.
    objects of, 101.
    time for, 101.

  Harrows, 4, 102.
    brush, 102, 105.
    chain, 102, 105.
    coulter-toothed, 102, 104.
    plank, 102, 105.
    rolling cutter, 102, 103.
    spike-toothed, 102, 104.
    spring-toothed, 102, 103.

  Hay soils, 29, 30.

  Heat and the farmer, 5.

  Heat necessary for germination, 73.

  Hilling the crop, 169.

  Hilum, 77.

  Hoeing and soil water, 158.

  Hoes, 4.

  Horn shavings as fertilizer, 195.

  Horse manure, 176.
    losses when piled, 176.

  House plants, watering of, 51.

  How the bean gets up, 78.

  How the corn gets up, 79.

  Humus, 27, 38.
    influence on soil texture, 62.
    nitrogen in, 67.
    a source of nitrogen, 67.
    water-absorbing power of, 41.
    water-holding power of, 44.
    water-pumping power of, 43.

  Hydrogen in plants, 66.

  Hypocotyl, 78.

  Ice, work of, in making soils, 35.

  Insects, chewing, 117.
    how to combat, 116, 117.
    injure leaves, 116.
    sucking, 116.

  Insect pollination, 131.

  Inter-tillage, 164.

  Iodine, test for starch, 64.

  Iron in plants, 66.

  Jointer of plow, 95.
    value as a pulverizer, 95.

  Kainite, 199.

  Knowledge of flowers, value of, 134.

  Land plaster, 200.

  Laws of nature, 5.

  Leaf work, conditions necessary for, 114.
    interfered with, 115, 118.

  Leather as a fertilizer, 195.

  Leaves, 8, 108.
    digest food, 114.
    facts about, 108.
    functions of, 109.
    manufacture starch, 112.
    transpire water, 110.

  Legume family, 86.

  Legumes, definition of, 68.
    nitrogen fixers, 68, 186, 144.
    value as green manure plants, 144, 185.

  Leguminous plants, 68.

  Light necessary for leaf work, 114.

  Lily family, 86.

  Lime, 200.
    amount to use, 200.
    effect on sand, 200.
    effect on clay, 200.
    in soils, 149.
    its action on soils, 149, 200.
    sets free potash, 149.
    sources of, 171, 200.

  Lime stone soluble in water, 31.

  Loam, 28.