. Elementary principles of agriculture; a text book for the common schools. uch deeperin dry seasons than in wet ones. These facts have beenfound out by carefully washing the soil away from theroots, leaving them supported on poultry observations are easily explained when we con-sider the effect of tillage on soil conditions. Fig. 32 ?Herman Hellriegel (1831-1895) devoted his life to the study of thechemistry of plant nutrition. He was the first to discover the relation of thebacteria causing the tubercles on the roots of legumes to the fixation of freenitrogen. He made many othe
. Elementary principles of agriculture; a text book for the common schools. uch deeperin dry seasons than in wet ones. These facts have beenfound out by carefully washing the soil away from theroots, leaving them supported on poultry observations are easily explained when we con-sider the effect of tillage on soil conditions. Fig. 32 ?Herman Hellriegel (1831-1895) devoted his life to the study of thechemistry of plant nutrition. He was the first to discover the relation of thebacteria causing the tubercles on the roots of legumes to the fixation of freenitrogen. He made many other important discoveries in agricultural science. 50 Elementary Principles of Agriculture illustrates the appearance of the roots of a corn plantat silking time. 81. Shall Crops be Tilled Deep or Shallow? It is im-portant that we know the distribution of the roots inthe soils that are cultivated with plows; otherwise wemight plow too deep and destroy many roots. At oneof the agricultural experiment stations it was foundthat thirty days after planting corn, at the second. Fig. 32. The root development of a corn plant just beginning to tassel. FromPhoto made at Agricultural Experiment Station, University of Illinois. cultivation, the roots from the adjacent hills (three feetapart) had already met. A few roots had reached adepth of twelve inches, but the bulk of the roots werewithin eight inches of the surface. Six inches fromthe hill, the main roots were within two or three inchesof the surface. Midway between the drills they laywithin four inches of the surface. Deep plowing at thistime with shovel-pointed plows would certainly haveinjured many roots. The Plant as Related to the Soil 51 82. The Condition of the Soil has great influence onthe distribution of the roots. Wliere the surface layersare moist the roots will grow freely in these layers, butif dry spells come the plants will suffer more than plantsthat have been growing on soils less favorably supphedwith moisture. This e
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
