AGRICULTURE 



avoids the risk of introducing new weed pests. He gets acclimated 

 seed, which is in many cases an advantage. By carefully selecting 

 seed from the best plants, he can grade up and improve a variety. 

 Planting. Depth. As you know, seeds differ much in size. 

 This naturally makes a difference in the depth that they should 



be planted. Each 

 seed contains a store 

 of food to nourish 

 the germ under or- 

 dinary conditions 

 until it can send 

 forth its root and 

 stem and begin 

 growth. If the seed 

 be planted too deep, 

 this store is used up 

 before the plant is 

 well established. Sometimes the deep-planted seed cannot get air 

 and warmth enough to enable it to germinate at all. 



Some seeds, such as wheat, come up with thin blades and slender 

 leaves. These can make their way through the soil more easily than 

 thick-leaved plants, such as beans, and so may be planted deeper. 

 Soil Conditions. Seeds require for germination a certain 

 amount of moisture, heat, and air. They grow best when the 

 soil around them is made fine and compact, not so close as to 

 exclude air, but close enough for the soil particles to touch 

 them and supply moisture. Gardeners often press small seed 

 down with a board and trample the beds in which larger ones 

 are planted, and farmers roll the land on which grain or grass seed 

 are sown. They know that firmly- planted seed come up in a shorter 

 time and produce stronger plants than those put in loose soil. 



A CONVENIENT SEED-TESTER 



It consists of a shallow box, filled with soil. It is di- 

 vided into sections by a wire netting with one-inch meshes. 



