ON THE ESSENTIAL CONSTITUENTS OF MANURES. 41 



The roots on this plot were for a long time decidedly inferior to the super- 

 phosphate turnips. But towards the middle of September the plants took 

 a start, and the guano turnips, so far as the tops were concerned, looked the 

 best in the field. When the crop was taken up, the guano turnips were at 

 least 3 inches higher in the tops, and promised, as far as appearance went, 

 the heaviest crop ; but the actual weight of the plots manured with dissolved 

 bone-ash and superphosphate not containing any nitrogenized matters, showed 

 that there was no advantage in using ammoniacal matters for producing good 

 bulbs on the experimental field. 



The whole tenor of the field trials in 1857 agrees well with the results of 

 the trials in 18,56. The experiments in 1859 afford a fresh proof that salts 

 of ammonia applied alone to root-crops have no beneficial effect, but rather 

 the reverse. They also show that phosphate of lime in a soluble state 

 favours more the production of good bulbs than any other manuring consti- 

 tuent, and that nitrogenized matters are not required in a manure for Swedish 

 turnips, grown on land similar to the experimental field, and under conditions 

 similar to those which prevailed in 1856 and 1857. 



In concluding this part of my Report, I may state that last year (1858) the 

 results of my field experiments were entirely spoiled by the ravages which 

 the fly and the black caterpillar committed. 



This year (1859) I have an extensive series of field experiments upon 

 Swedes. All the experimental plots look remarkably healthy, and I hope in 

 a future year to repeat the result of this year's trials, which were made like 

 those in 1856, 1857 5 and 1858, with a special view of determining the influ- 

 ence of nitrogenized substances and ammoniacal salts on root-crops. 



Before proceeding with another series of field experiments, I may state 

 that I have analysed at various times hundreds of turnips. It would be oc- 

 cupying too much space to give here tabulated abstracts of these analyses. 

 Although I am still occupied with following up this examination of turnips 

 grown under various conditions, and have not as yet arrived at any definite 

 conclusions respecting the influence of different manuring matters on this 

 crop, I may state a few general facts which my analyses have brought to 

 light. 



1. In the first place, I would observe that I do not find any striking differ- 

 ences in the composition of roots raised with different manures, provided 

 they are pulled up in an equally mature condition. 



2. Soluble phosphates appear to promote an early maturity of the roots, 

 and ammoniacal salts, on the contrary, to retard the maturity of roots. 

 However, on this point my experiments are not sufficiently numerous and 

 conclusive to establish satisfactorily this matter. 



3. Roots grown on poor soils and developed more gradually, contain less 

 water and more sugar, and are consequently more nutritious than roots of a 

 large size grown rapidly with much manure. 



4-. Contrary to a very prevalent opinion, I find that the best and most nu- 

 tritious roots invariably contain less nitrogen than inferior less nutritious 

 roots. Indeed I am of opinion that a high per-centage of nitrogen in turnips 

 is a sure sign that the roots have not reached full maturity, and are less 

 wholesome to cattle than well-ripened roots. In the latter I have found, in 

 some instances, fully one- third less of nitrogen than in the same roots at an 

 earlier stage of their growth. 



The examination of roots, taken once every fortnight from the same field 

 during several successive months, has shown that the pcr-centage of nitrogen 

 in turnips steadily decreases in the measure in which they proceed towards 

 maturity. In the measure in which the per-centage of nitrogen decreases, 



