The school and farmA treatise on the elements of agriculture . dle, or fallow, in order that it mightrecover from previous exhaustion and be ready forthe crops of the two following years. But this systemhas now been discarded by all progressive plan is far better. We have noted that plants need nitrogen, and thatthere is plenty of nitrogen all around and over the air can go through there is of course ni-trogen, and in a loose and mellow soil, especially ifwell drained, the air is present everywhere. But howare the roots to get hold of it? Unless changed intoa nitrat
The school and farmA treatise on the elements of agriculture . dle, or fallow, in order that it mightrecover from previous exhaustion and be ready forthe crops of the two following years. But this systemhas now been discarded by all progressive plan is far better. We have noted that plants need nitrogen, and thatthere is plenty of nitrogen all around and over the air can go through there is of course ni-trogen, and in a loose and mellow soil, especially ifwell drained, the air is present everywhere. But howare the roots to get hold of it? Unless changed intoa nitrate, this nitrogen is perfectly useless, as useless THE SOIL AND ITS FERTILITY. 25 for instance as for animals and human beings is themineral and other matter which may be turned intowheat by the wheat plant, but which they cannot usefor food until it is changed into grain by the growth ofthe plant. This leads us to the consideration of the most inter-esting as well as important family of plants, such asclover, peas, beans, alfalfa or lucerne and a few Fig. 3 —Root of a legume showing knotsor nodules or tubercles. The name of this family of plants is legumes, and theyare spoken of as legiiminons plants. In olden times,when our methods of harvesting and threshing werenot even thought of, the pods of peas, beans and lentilswere picked and gathered by hand. This was expressedby the old Italians or Latins as legere, and the wordlego, meaning T gather, was so changed as to formthe adjective legumiiiosae, which is Latin for legum-inous. Pull or dig up a clover plant, being careful to save 26 THE BASIS AND CONDITIONS OF FARMING. its roots. You will notice here and there on the farspreading roots little wart-like growths, knots ornodules, to which it is customary to give the name oftubercles. (Fig. 3.) These are due to parasiticplants so small as to be invisible to the naked have given to these little plants the generalname of bacteria, but there are many variet
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectagricul, bookyear1902
