CHE REFERENCE LIBRARY - ZetaTalk

_---._---c____I_-CERTdliV ELEi\IENTS IN NURSERY PRACTICE 175The Iand shorlld ht strong enough t.o r&x a) good crop of wheat: r c:orn.\Vith fruit-t,rvc3, the age of the tree determines its salable-Iless ; therefore it is imperative that the growth within thegiven time he r;rpid and strong. N’ith orna,mentals, however,the value is tlctc-~rmi!!ecl by the size of the specimen, with littlereference to its age. It therefore follows t,hat lands not sufficientlxstrong to allow of the profitar i!e growing of fruit-treesma)* still be useful for growing ornaniekitals.111 consitleriug the question of t.hc fertility of nursery lands,it is first ncccssary to determine what are the proportions ofthe chief elements of plant,-food removed by the trees fromthe soil. The star&trd investigations of Roberts, at Cornell,still constitute a11 t3c4leut record :“ Amounts ad values of fertilizing constituents removedby a II acre of uurst’ry trees iu three years :PEAcH~~HPLUMRNitrogen . . . .Phosphoric acid .Potash . . . .Lbs.Value22.42 $3 365.42 3811.75 53$4 27Lb%____~Value19.75 $2 964.42 3111.50 52$3 79--___-~“The above resuks show conclusively that but a smallamount of plant-food is removed from the soil by the growthof nursery stock. They also show that more phosphoric acidis removed by the apples and pears than by the peaches andplums ; but. any orclinary soil, cultivated as nursery lands are,should easily furnish in three years ten times the plant-foodused by the trees. In order to compare the drafts made bynursery stock and some of the common crops raised in mixed