37 



Fertilizers for Alfalfa. 



There can be no one combination of fertilizers or no one mixed 

 fertilizer which under all conditions will prove best. It will be gen- 

 erally admitted, however, by all qualified to judge, that on soils which 

 are in a fairly productive condition at the start the fertilizers applied 

 should furnish relatively large amounts of the mineral elements of 

 plant food, among which phosphoric acid, potash and lime are the 

 most important. Alfalfa, like other legumes, is capable of drawing 

 ujDon the air for most of the nitrogen which it needs, and applied 

 nitrogen in the form of a fertilizer in any large amounts is unneces- 

 sary. We may state the case even more strongly, — it is not only 

 unnecessary, it may positively prove harmful. If it exercises a harm- 

 ful effect, however, this will not usually be because the presence of 

 nitrogen in the soil is necessarily injurious to the alfalfa, but because 

 its presence increases the competition of the grasses for the possession 

 of the field. In a soil well stocked with lime, phosphoric acid and pot- 

 ash, but without available nitrogen in considerable amounts, the 

 grasses make only a feeble growth. If, in addition to the phosphoric 

 acid, potash and lime, we apply to such soil too large amounts of nitro- 

 gen, the grasses in our humid climate will gradually come in, with 

 the probability of crowding out the alfalfa with greater or less rapidity. 

 It is the belief of the writer that combinations of basic slag meal 

 and sulfates of potash are peculiarly adapted to alfalfa. The slag 

 meal furnishes not only phosphoric acid but lime, which will help 

 to bring the soil into condition for alfalfa and to maintain it in that 

 condition. The sulfate of potash, on all the heavier soils especially, 

 is superior to muriate. Many other suitable combinations of ma- 

 terials might be made up. Wood ashes should give good results. 

 Combinations of such grades of bone meal as contain relatively low 

 percentages of nitrogen and of either the low or high grade sulfate 

 of potash should do well. IVIixed fertilizers, containing not more 

 than IJ per cent of nitrogen but with 12 or more per cent of phos- 

 phoric acid and 8 to 10 per cent of potash, should generally give 

 good results. 



The Use of Manure. 



Whether manure should be applied either in preparation for alfalfa 

 or as a top dressing depends upon conditions. If a supply of fine 

 manure, free from weed seeds, is available, and if the soil is in a very 

 low state of fertility, a dressing of manure may be highly beneficial; 

 but on soils already in good condition the application of manure 

 is not called for, and from some points of view is undesirable. It 

 almost invariably carries weed seeds, and its use produces the condi- 

 tions already referred to under which, since it supphes an abundance 

 of quickly available nitrogen, the grasses thrive. If manure is used, 

 then it will usually mean that the grasses will tend to crowd out the 



