534 FIELD CROPS 



cultivation, by covering with straw or other material, or 

 by sowing with some quick-growing crop like rape or sor- 

 ghum, is often successful. One of the best ways of eradi- 

 cating persistent perennials is to plow them under about the 

 time the plants are coming into bloom and then to cultivate 

 the land thoroughly enough during the rest of the season 

 with the disk or spiketooth harrow to prevent them from 

 producing leaves. The next season the land may be put into 

 a cultivated crop such as corn, cotton, or potatoes. A 

 smother crop may occasionally be substituted for the fre- 

 quent harrowings of the first year, with as good results and 

 with far less expense, though this method cannot be relied 

 upon, because of the difficulty of getting a stand sufficiently 

 thick in every part of the field to thoroughly smother the 

 weed growth. 



706. Weeds in Cultivated Fields. There is less excuse 

 for the presence of weeds in cultivated fields than almost 

 anywhere else. The seeds of our cultivated plants are large 

 enough so that they may be separated readily from weed 

 seeds, while the frequent cultivation which is given should be 

 effective in keeping down any weeds that appear after the 

 crop is planted. Cultivation sometimes fails to serve its 

 purpose because the work is not done frequently enough or 

 at the right time, or is not thorough. The most effective 

 cultivation may be given before the crop is planted. The 

 land should be well plowed, and if it is left without a crop for 

 any length of time during the growing season, it should be 

 disked and harrowed at intervals of a week or ten days to 

 kill any weeds that start. Small weeds are very rapidly 

 and effectively destroyed with a harrow or weeder. The 

 land should be harrowed just before the crop is planted, and 

 the harrowing may usually be repeated a few days later, 

 either just before or just after it comes up. 



