1907.] 



PUBLIC DOCUMENT — No. 33. 



187 



or no attempt is made to grow this crop in soils of this nature. 

 Lettuce seed sown in a soil of fine texture will not germinate 

 nearly as well as in loose soil, and lettuce seedlings will reach 

 a certain stage of develoj)ment, remain stationary for weeks 

 and eventually die. The reason why a fine-texture soil pre- 

 vents seedlings from developing is lack of air. This may be 

 illustrated by the more vigorous growth which lettuce seed- 

 lings make in such a soil near the edge of a flower pot than 

 in the middle, and by various soil aeration experiments. 



The compactness of a soil, as might be expected, exerts an 

 influence upon germination and growth. The following table 

 shows the effect of loose and tamped loam and subsoil upon 

 the germination of seeds. In one case a good loam, containing 

 about 8 per cent, of organic matter, was employed, one box 

 being tamped very firmly with a heavy weight after the seeds 

 were sown, and the other left very loose. In the other case 

 two boxes of soil of fine texture (subsoil) were employed. 

 This soil was very deficient in organic matter. These two 

 boxes were treated in a similar way to those containing loam ; 

 that is, one was left very loose and the other tamped firmly 

 after the seeds were sown. In all the boxes very little soil 

 was placed over the seed. 



Result of Seed Oerniination in Loose and Tamped Soils. 



Lettuce, 200 seeds, . 

 Rattlebox, 200 seeds, 

 White clover, 400 seeds. 



Loose. Tamped. 



75 



146 



Loose. Tamped. 



1 The seedlings came up in cracks in the soil. 



No lettuce seed germinated in the tamped loam or sub- 

 soil, while white clover made its appearance in the tamped 

 loam. Rattlebox, which with us is qviite at home in fine- 

 texture soil lacking organic matter, did better than the lettuce 

 or white clover. None of the seed possessed a high percentage 

 of germination, and some allowance must be made for this. 

 All of the seed germinated better in the loose loam than in 



