191 1.] The Use of Manures in Forestry. 139 



one of the following ways : — (1) planting of leguminosae, 

 especially lupins and acacias, on sandy soil, and trefoil and 

 grey alder on chalky soils ; (2) dressings with turf and other 

 substances containing humus; (3) covering the soil with lupin- 

 haulm, potato tops, straw T , leaves, and small twigs ; and 

 (4) interplanting with a species having a heavy leaf fall, such 

 as Pinus rigida and Pinus montana. Lupins, which in many 

 cases have proved of great value, can be used in one of two 

 forms, either as a crop before the trees are planted, or between 

 the lines of trees. For the first purpose, the yellow lupin, 

 and for the second the blue lupin, is best suited. When the 

 whole area is cropped before planting trees, a dressing of 

 about 3J cwt. to 6J cwt. of basic slag and if cwt. to. si cwt. 

 of kainit per acre should be used. In addition inoculation 

 with nitragin may be recommended, although lupins gener- 

 ally grow well, even on poor heath lands, and on soils which 

 have not carried a leguminous crop. If the lupins develop 

 poorly in the first year, they must be sown again the second 

 year. It is necessary in every case to get a good crop of 

 lupins before planting. The cost of raising a crop of lupins 

 is said to be about £1 12s. per acre in Germany, but in 

 Belgium an intermediate crop of rye or oats is taken in 

 order to reduce the cost. The fact that phosphoric acid and 

 nitrogen are removed by rye and oats is not sufficient to 

 prevent an appreciable enrichment of the soil in these sub- 

 stances. In Germany, experiments are being made to test 

 the effect of substituting potatoes for rye as an intermediate 

 crop. This method has the advantage that the soil is worked 

 up in digging the potatoes, and the tops are left on the 

 ground. 



A cheap system is to interplant with blue lupins. By this 

 method the area is ploughed up in the late autumn in the 

 usual way, and during the winter manured in the drills with 

 basic slag and kainit. The pines are planted the next spring. 

 In this way only 25 to 30 per cent, of the area is manured. 

 In favourable seasons excellent results are obtained. On 

 chalky heathland, the place of the lupin can best be taken by 

 Trifolium hybridum, grown between the forest trees. 



There are also a number of trees which possess the property 

 of utilising the free nitrogen of the air, and making it avail- 



