SOILS — FERTILIZERS. 129 



the first 5 years, but there was a marked decrease in the effectiveness of the 

 ammonium sulpluite, ospeciallj' when larger amounts were used. Witli a rotation 

 containing clover more than 24 lbs. of nitrogen per acre brought compara- 

 tively little increase in yield. 



Barnyard manure and a complete commercial fertilizer maintained the crop- 

 producing power of the soil about equally well. The excessive use of quick- 

 lime produced only a slight increase in crop yield. The soil receiving ground 

 limestone, with one exception, gave a higher annual crop yield than any soil 

 receiving no treatment. 



The influence of bacteria in manure on the decomposition of green manure 

 (legume and nonlegume), J. G. Lipman, A. W. Blaib, H. C. McLean, and 

 L. K. WiLKiNs (xVeiD Jersey Stas. Rpt. 1914, pp. 223-226). — This is an account 

 of a contimiation of experiments previously described (E. S. R., 32, p. 514), the 

 results of which indicate " that the bacteria conveyed in small quantities of 

 manure do have a beneficial effect in the decomposition of the green manure 

 crops. When the green manure crop is a legume, the additional nitrogen thus 

 secured tends to obscure the effects of the manure. The legume is more effective 

 in increasing the yield and also in maintaining the nitrogen supply of the soil 

 than the nonlegume, and there is good ground for believing that the nitrogen 

 in the former is more available than in the latter." 



Pot experiments on the availability of nitrogen in mineral and organic 

 compounds, J. G. Lipman, A. W. Blair, H. C. IMcLean, and L. K. Wilkins 

 {New Jersey Stas. Rpt. 1914, pp. 207-220). — The object of these experiments, 

 which supplement plat experiments previously noted (E. S. R., 31, p. 124), was 

 to determine the availability of a number of organic and inorganic nitrogenous 

 fertilizers as compared with that of sodium nitrate. In the first four experiments 

 pots containing 20 lbs. of sand were used. 



A comparison of sodium nitrate, ammonium sulphate, tankage, and cotton-seed 

 meal, when added to barley in sand, in amounts equivalent to 616 mg. of nitrogen 

 per pot, showed that the highest average yield of dry matter was with am- 

 monium sulphate and the next highest with cotton-seed meal, while the highest 

 content of nitrogen in the dry matter was obtained with sodium nitrate and the 

 next highest with ammonium sulphate. The amounts of dry matter of a second 

 crop grown in the same pots without further fertilizer treatment were much less 

 than those of the first crop in all cases, as was also the nitrogen content, except 

 where cotton-seed meal was used. The total recovery of nitrogen was greatest 

 with sodium nitrate and the next highest with ammonium sulphate. These re- 

 sults are taken to indicate that a comparison of sodium nitrate with equivalent 

 amounts of materials not so readily available is not fair if the application is 

 small or moderate and if only one crop is grown. 



A comparison of sodium nitrate, alfalfa meal, green rye, dried blood, and cot- 

 ton-seed meal, when added to buckwheat in sand at the rate of 462 mg. of 

 nitrogen per pot, showed that sodium nitrate gave the highest average yield and 

 dried blood was second. A residual crop of barley was largest on the nitrate 

 pots, but all the recoveries were low. 



A comparison of sodium nitrate alone and in combination with vegetable and 

 animal organic matter and with the organic matter alone, when added to buck- 

 wheat in sand in amounts equivalent to 616 mg. of nitrogen per pot, showed that 

 the residual effects from the use of sodium nitrate were small if the first crop 

 developed normally, but were considerably increased where an excessive amount 

 of the nitrate depressed the yield of the first crop. The residual effects from the 

 use of organic nitrogenous materials were greater than those from nitrate of 

 soda, but were small when considered from the standpoint of the amount of 



