An introduction to agriculture . n.— When lime andhumus in a soil are destroyed, and when soil acids ac-cumulate, the physical condition of the soil you compare some good soil with some poor soil youcan easily see what the changes have been. The poorsoil is one which has lost its light, crumbly condition. Itpacks easily, especially if it is a loam or clay soil. Itscolor, also, has become lighter and its power to holdwater less. It is less favorable to the growth of soilbacteria and in it less plant food is made available. Elements af Plant Food Removed by Crops.— Table2 in the Appen
An introduction to agriculture . n.— When lime andhumus in a soil are destroyed, and when soil acids ac-cumulate, the physical condition of the soil you compare some good soil with some poor soil youcan easily see what the changes have been. The poorsoil is one which has lost its light, crumbly condition. Itpacks easily, especially if it is a loam or clay soil. Itscolor, also, has become lighter and its power to holdwater less. It is less favorable to the growth of soilbacteria and in it less plant food is made available. Elements af Plant Food Removed by Crops.— Table2 in the Appendix shows the average amount of the 56 SOIL FEKTILITY 57 three essential elements of plant food in the variouscrops. If one knows the weight of the crop harvestedfrom an acre of land^ he can, from this table, determineapproximately the amounts of these elements removedfrom an acre. It has been calculated that a ton oftimothy hay removes from the soil about lbs. ofnitrogen; lbs. of phosphorus, and lbs. of potas-. A SOIL. FERTILITY BARREL The water level can rise no higher than the lowest stave. The fertilityof the soil is limited by the lowest amounts of its most indispensable ele-ments.— From Wisconsin Bulletin 265. slum; and 50 bushels of oats and 1% tons of oat strawremove lbs. of nitrogen; 6 lbs. of phosphorus, lbs. of potassium. These figures are here givenmerely to show that no two crops use the elements ofplant food in similar amounts or in similar The Use to a Plant of the Elements of PlantFood.— Potassium.— Most of the potassium goes into 58 AN INTRODUCTION TO AGEICULTURE the straw and stalks of the plants. It strengthens andstiffens these parts. Weak stalks and weak stems incommon farm crops are an indication that not enoughpotassium is available. Besides strengthening andstiffening plants, an ample supply-of potassium hastensthe maturing of plants. Phosphorus.—Much of the phosphorus found inplants is in their seed
Size: 1645px × 1518px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
