. Agriculture for southern schools. ■■> : A ,.^- \.^. I Fig. 57. — Tubercles on the Roots of a Young Vetch Plant are at work making the soil rich. These knots are roottubercles or root nodules (Figs. 56, 57). The farmers tiny helpers. — Each tubercle is a busy go AGRICULTURE workshop inhabited by multitudes of germs, so small that2S,cx)0 of them could be placed side by side on a line oneinch long. These germs are actively at work helping thefarmer. The tubercle in which they live serves as a housefor them. It is really a fertilizer factory, and the germsare the workmen, busy making fertiliz
. Agriculture for southern schools. ■■> : A ,.^- \.^. I Fig. 57. — Tubercles on the Roots of a Young Vetch Plant are at work making the soil rich. These knots are roottubercles or root nodules (Figs. 56, 57). The farmers tiny helpers. — Each tubercle is a busy go AGRICULTURE workshop inhabited by multitudes of germs, so small that2S,cx)0 of them could be placed side by side on a line oneinch long. These germs are actively at work helping thefarmer. The tubercle in which they live serves as a housefor them. It is really a fertilizer factory, and the germsare the workmen, busy making fertilizer that will beused by the plant on the roots of which the tuberclegrows. The plant on which the tubercle forms is calledthe host plant. It furnishes the germs in the tuberclewith starchy food made by the leaves. In exchange thetubercles send up through the sap a fertilizer rich innitrogen. This fertilizer nitrogen is constantly beingmade by the germs in the tubercle from the nitrogen gasin the air. The farmer can help the germs to manu-facture fer
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Keywords: ., bookcentury1900, bookdecade1900, bookidcu, booksubjectagriculture
