250 THE farmers' handbook. 



Another method is to leave the land out for a year in the same way, but 

 to plough it either late in the winter or early in the spring or summer. 

 This gives better results, but it does not completely clean the land. 



Other farmers do not leave their land out, but plough early, in some cases 

 as soon as the harvest is over, and work the land with the harrows or 

 cultivator to induce the oats to germinate. A quick-growing, early maturing 

 variety such as Canberra, Florence, or Clarendon is then sown. This method 

 is perhaps the most successful, but it does not altogether remove the evil, 

 for the simple reason that many of the wild oat seeds lie dormant and only 

 start into life after the wheat has been sown. 



How, then, is the wild oat to be controlled 1 If the seed which is lying 

 in the ground can be made to germinate, then its eradication becomes a 

 simple matter, as it is only necessary to kill the young plant. How is 

 germination to be brought about? The wild oat seed is accused of lying 

 dormant in the ground for years. Some men quote instances of paddocks, 

 which have been thrown out of cultivation and so closely grazed that no oat 

 seeds have been allowed to mature, but which have produced oats as thickly 

 as ever, five, seven, and even ten years later, when ploughed up. Even 

 allowing for seed which may have been produced unobserved, it is certain 

 that the seed does, under certain conditions, retain its vitality for long periods 

 when buried. 



Close observation and study lead to the opinion that the persistence of 

 the wild oat is not due to any peculiarity which causes some seeds to remain 

 dormant for one or more years, but is chiefly due to the fact that the seed 

 germinates slowly- and requires favourable temperatures. It is evident from 

 the observations of Dr. Darnell-Smith that the short velvety hairs on the 

 seed form a protective covering, preventing moisture coming in contact with 

 the germ, and so retarding germination. It is probable that this protective 

 covering is effective only for a time, and that when the soil immediately 

 surrounding the seed is kept moist long enough, germination does take place. 



If young wild oat plants are examined it will be found that in nearly every 

 case the seed has sprouted in the earth about 3 or 4 inches below the surface ; 

 and it is here the land remains moist for the longest period. The surface 

 soon dries out, and becomes unfavourable to germination. 



Experiments have proved that when the soil is kept moist only 2i per 

 cent, of the seed germinates after three weeks in February, when the tempera- 

 ture of the soil is comparatively high. Observation in the field indicates 

 that comparatively low temperatures encourage germination, and that the 

 oats come up most thickly in May, June, and July. This has led practical 

 farmers to sow wheat early so that it will start ahead of the oats. 



Experience shows that few of the seeds will germinate if the land is not 

 worked. It may be left out for a year, but when it is broken up the wild 

 oats will come almost if not quite as thickly as ever. This, of course, shows 

 that the cultivated soil provides the conditions which are favourable to 

 germination. 



If the seed be examined it will be noticed that the hairs are arranged in 

 such a way that it always moves forward when touched. The tough awn or 

 tail attached to the seed assists in the progressive movement, as with changes 

 in amount of moisture, &c, it alternately twists and straightens, and each time 

 forces the seed in a forward direction. The seed, therefore, works through 

 the soil, and is further distributed by cultivators, harrows, ploughs, Ac, 

 until it is ultimately mixed with the soil to at least the depth to which 

 cultivation is carried. 



