310 MEADOWS AND PASTURES 



of greater natural fertility than I assume this field to 

 have had, we should reach that gain or more. Returns 

 from pastures in Great Britain are, in many cases, of eye- 

 opening character to an American. I have changed the 

 values into American terms : 



"Manures for pasture in Tree Field. This report deals with the 

 complete results of the Tree Field experiments for the nine years 

 1897-1905. A slightly modified scheme of treatment was begun in 

 1906. The field extends to about 34 acres, and is divided into 11 

 plots, each 3 1/20 acres in area. While experiments on crops admit 

 of testing the comparative results by the weight of crops produced, 

 this cannot be done with pasture. The results of these experiments 

 have, therefore, been gauged by the increases in fasted live-weight 

 of the sheep on the various plots. The average prices of several 

 years indicated that about 7 l / 2 c.. a Ib. was a fair figure at which to 

 value the increase in live weight of the sheep. Of course this must 

 have a higher value on the better than on the poorer plots, but 

 granted that this is so the results arrived at would simply be accen- 

 tuated. In arriving at the final results, the increase in live weight 

 on the untreated plot is deducted from the same on the other plots, 

 and the value of this per acre has deducted from it the average 

 annual cost of the dressing. The result is the net annual gain or 

 loss resulting from each of the dressings. Each plot has been 

 treated differently, and has been stocked each year with a suitable 

 number of sheep. These have always been carefully selected, and 

 graded at the beginning of each season so that each plot might have 

 sheep of the same average quality ; and they have been all regularly 

 weighed every four weeks during each season, having previously 

 been fasted. Cross-bred wethers were purchased in the spring for 

 the first three years, and half-bred wethers in the second three years, 

 while for the last three years the stock has been mainly half-bred 

 and three-parts-bred wethers. The grazing periods have been as fol- 

 lows: 1897, June 21-Oct. 11; 1898, May 16-Oct. 3; 1899, May 4-Sept. 

 21; 1900, May 23-Oct. 10; 1901, May 10-Sept. 27; 1902, May 20-Oct. 

 7; 1903, May 15-Oct 2; 1904, May 17-Sept. 6; 1905, June 5-Sept. 25. 

 The first and the last two periods extended to 16 weeks, and the re- 

 mainder to 20 weeks. As the last four weeks always gave very low 

 increases in the longer periods, a reversion was made to the shorter 



