Arizona Agricultural ExpiiRiMi^NT Station 259 



The west 80 acres was divided into five fields, three of which con- 

 tained 20 acres each, and two 10 acres each. Four methods of eradi- 

 cation were tried out on these fields: close pasturing with sheep, in- 

 tensive cultivation of intertilled summer crops, dry fallow in summer 

 followed by grain in winter, and continuous dry fallow. 



The first field contained 20 acres. It was plowed in September 

 and October of 1915 when very dry and hard, leveled and bordered in 

 November, and seeded to barley in December. The dry plowing in 

 1915 served to check seriously the Johnson grass, and as a result very 

 few plants were showing above the grain while the latter was still 

 standing. The grain was bound about the middle of May, 1916, and 

 the ground was held dry until the middle of June, at which time about 

 275 sheep were turned in on it. Between the time of removal of the 

 grain and coming of the sheep, a considerable growth of Johnson grass 

 had sprung up uniformly over the field. None of this was allowed to 

 mature seed. After the sheep came, the field was irrigated at frequent 

 intervals in order to force as rapid a growth of Johnson grass as pos- 

 sible. The sheep kept it eaten very close to the ground, and. as a result, 

 the propagating rootstocks of the grass were showing marked lack of 

 vigor by the fall of 1916. In the middle of November, 1916, the land 

 was prepared and seeded to barley for pasture, and it is believed that 

 by the end of another summer the Johnson grass of this field will either 

 be almost totally destroyed or well under control. 



The remainder of the west 80 acres had been in grain sorghums 

 for a number of years, and the University did no work to eradicate 

 Johnson grass on it in 1915, except to mow some of it and burn over 

 some of the worst of it. Some of the laterals were so badly infested 

 that it was deemed advisable to fill them with straw and burn them out. 

 The first 10 acres of this part was plowed in February preparatory 

 to putting into Egyptian cotton. In order to make this land irrigate 

 perfectlv it was all replowed once and part was replowed a second 

 tune. In this way the grass was constantly disturbed until the mid- 

 dle of April. The cotton was not planted until this late date on 

 account of the work necessary to level the land properly. A cultivator 

 equipped with 8-inch sweeps was put to work in this field in the latter 

 part of April, and was kept going whenever any grass appeared above 

 the surface of the ground. The weeds in the rows were removed by 

 hand hoeing. By the time the cotton had become large enough to shade 

 the ground very little Johnson grass was appearing, and in the latter 

 part of the season the few plants left were almost all from seeds which, 

 presumably, were brought in by the irrigating water. 



