XVIII TALKS OX MANURES. 



deep as the water sinks. For trees, therefore, it would seem 

 desirable to apply the superhosphate before they are planted, 

 and plow it under. And the same is true of potash ; but 

 nitrate of soda would be better applied as a top-dressing every 

 year, early in the spring. 



The most discouraging fact, in Lawes' and Gilbert's experi- 

 ments, is J;he great loss of nitrogen. It would seem that, on an 

 average, during the last forty years, about one-half the ni- 

 trogen is washed out of the soil, or otherwise lost. I can not 

 but hope and believe that, at any rate in this country, there is 

 no such loss in practical agriculture. In Lawes' and Gilbert's 

 experiments on wheat, this grain is grown year after year, on 

 the same land. Forty annual crops have been removed. No 

 clover is sown with the wheat, and great pains are taken to 

 keep the land clean. The crop is hoed while growing, and the 

 weeds are pulled out by hand. The best wheat season during 

 the forty years, was the year 1863. The poorest, that of 1879 ; 

 and it so happened, that after an absence of thirty years, I was 

 at Rothamsted during this poor year of 1879. The first thing 

 that struck me, in looking at the experimental wheat, was the 

 ragged appearance of the crop. My own wheat crop was being 

 cut the day I laf t home, July 15. Several men and boys were 

 pulling weeds out of the experimental wheat, two weeks later. 

 Had the weeds been suffered to grow, Sir John Bennet Lawes 

 tells us, there would be less loss of nitrogen. The loss of ni- 

 trogen in 1863, was about twenty-four pounds per acre, and in 

 1879 fifty pounds per acre the amount of available nitrogen, 

 applied in each year, being eighty-seven pounds per acre. As I 

 said before, the wheat in 1879 had to me a ragged look. It was 

 thin on the ground. There were not plants enough to take up 

 and evaporate the large amount of water which fell during the 

 wet season. Such a condition of things rarely occurs in this 

 country. We sow timothy with our winter wheat, in the 

 autumn, and red clover in the spring. After the wheat is 

 harvested, we frequently have a heavy growth of clover in the 

 autumn. In such circumstances I believe there would be com- 

 paratively little loss of nitrogen. 



In the summer-fallow experiments, which have now been 

 continued for twenty-seven years, there has been a great loss of 

 nitrogen. The same remarks apply to this case. No one ever 

 advocates summer-fallowing land every other year, and sow- 

 ing nothing but wheat. When we summer-fallow a piece of 

 land for wheat, we seed it down with grass and clover. 



