NURSERY PRACTICE FOR PRAIRIE-PLAINS PLANTING 51 



Any attempt to determine fertilizer treatment on the basis of analysis 

 of plant material and amount of such material removed per acre per 

 year will result in too light an application of fertilizer. Safe determi- 

 nants are tests for readily available nutrients or actual field tests to 

 determine the approximately correct treatment. 



The productivity of a soil is maintained by application of animal 

 manures or concentrated commercial fertilizers, or by the use of 

 legumes and other soiling crops. In some nurseries materials such as 

 peat. muck, and forest humus are used, especially in the form of 

 compost. Such composts are limited to use in areas where the above 

 materials are available close to the nursery; generally they are too 

 expensive to ship into the plains. 



Effectiveness of a fertilizer or combination of fertilizers will depend 

 on the availability of the various nutrients in the soil and on the de- 

 mands of the crop. Some clues as to which nutrients are lacking can 

 be obtained by making an analysis of the soil which would at least 

 include total nitrogen, available nitrogen (largely nitrate nitrogen + 

 ammonia nitrogen), available phosphorus, available potash, base- 

 exchange capacity, and soil reaction (pH), and then using the data in 

 table 11 to estimate their adequacy. 



Nursery soils on the prairie-plains are very liable to test low in 

 available phosphorus, and the deficiency can most readily be corrected 

 by addition of 20-percent superphosphate or 45-percent treble super- 

 phosphate. Bonemeal can also be used as a source of phosphorus. 

 The 20-percent superphosphate is generally most effective at rates of 

 application varying from 300 to 800 pounds per acre, and bonemeal 

 at somewhat higher rates because of its lower availability. If treble 

 superphosphate is used, quantities varying from 100 to 400 pounds 

 per acre are satisfactory, and 150 to 200 pounds is generally sufficient. 



Adequate nitrogen can be supplied to nursery stock by application 

 of animal manure at the rate of 10 to 30 tons per acre, the quantity 

 depending on present soil fertility and type of manure being applied. 

 Ordinarily 10 to 15 tons per acre is adequate. Where it is not feasible 

 to furnish nitrogen in this form, it can be supplied by using legumes in 

 the rotation, or it may be applied in the form of 20-percent ammonium 

 sulfate or 35-percent ammonium nitrate at the rate of 200 to 600 

 pounds per acre for the former and 100 to 300 pounds for the latter. 



Potash is nearly always present in adequate amounts in most plains 

 soils but any lack can be remedied by the use of animal manures which 

 contain some potash, or by applying 100 to 200 pounds per acre of 

 50-percent muriate of potash or 50-percent sulfate of potash. In 

 some cases it may be of advantage to apply combined fertilizers con- 

 taining two or more of the essential nutrients, as. for example, am- 

 monium phosphate and nitro-phoska. 



A low base-exchange capacity can be corrected by adding large 

 amounts of animal manure or compost or by the repeated plowing 

 under of soiling crops of legumes. Low base-exchange capacity is 

 usually associated with the sandier nursery soils which lack humus 

 and colloidal material. A low base-exchange capacity may also be 

 encountered on soils which have been overcropped and not fertilized 

 for many years, or, especially in the northern plains, where wind ero- 

 sion has removed a considerable part of the topsoil, rich in humus. 



