620 EXPERIMENT STATION RECORD. 



Soil fertility experiments, G. Robeets {Kcntucku Sta. Rpt. 191-i, pt. 1, pp. 

 36, 37). — Six years' experiments at tlie Burnside experimental field, Pulaski 

 County, witli different crops on an unproductive soil indicated " that potash 

 is not necessary on these soils, but that without phosphates no headway can be 

 made in restoring such soils to a productive state. The chief requirements of 

 these soils are phosphorus, organic matter, and nitrogen." 



At London, Laurel County, experiments on a very thin soil typical of the 

 base of the coal measures indicated that " the requirements for restoring this 

 land are tlie use of phosphate, limestone, and organic matter, although much 

 can be accomplished without the use of limestone." 



At the Greenville field, Muhlenberg County, phosphorus and nitrogen 

 markedly increased the yield on unproductive soil, while at the Lexington 

 field, Fayette County, neither phosphorus, potassium or lime, nor their combi- 

 nations gave any appreciable increase in the crops used in the rotation extend- 

 ing through four years and including four corn crops, three wheat crops, three 

 soy bean crops, and one clover crop. However, lime was found to give very 

 large increases on alfalfa and sweet clover on the same farm. 



[Soil fertility experiments]. J. H. Kastle (Kcntiiclnj Sta. Bicn. Rpt. 191-'/- 

 1915, pp. 7-12). — A review of results of field fertilizer experiments conducted 

 at different experimental fields in Kentucky " confirms the results of chemical 

 analysis as to the requirements of the soils represented in these particular 

 areas. The need for maintaining the supply of humus and available nitrogen 

 through the cultivation of leguminous crops and by the return to the .land of 

 the manurial equivalent of the crops removetl is emphasized, as is also the 

 need of all soils outside of the blue grass region for phosiihorus and the need 

 of many of the soils for lini(>." 



The influence on crop and soil of manures applied to pemianent meadow, 

 C. Crowtiier and A. G. lirsTON (Jour. Agr. Sci. [England], 7 {191,5), No. 2, 

 pp. 197-218, figs. 3). — Experiments conducted since 1899 on one-twentieth acre 

 plats of a dry light loam meadow soil poor in lime are reported. The purpose 

 was to determine the effect of annual and biennial dressings of manure, of 

 alternate annual dressings of manure and various artificial fertilizers, and of 

 complete an<l incomplete mixtures of artificial fertilizers, and the comparative 

 effects of sodium nitrate and ammonium sulphate on the soil and the hay crop. 

 Manure was added at the rate of 10 tons per acre, sodium nitrate at the rate 

 of 50 lbs., superphosphate at the rate of 200 lbs., kainit at the rate of 300 lbs., 

 and ammonium sulphate at the rate of 130 lbs. 



It was found that the crops obtained from annual applications of manure 

 were only slightly larger and more costly to obtain than those from the bi(Minial 

 treatment, especially if in the latter treatment a light dressing of artificial 

 fertilizers, including sodium nitrate, was given in the alternate year. Gootl 

 average crops were obtained with a complete artificial fertilizer including 

 sodium nitrate, but not equal to those obtained with biennial applications of 

 manure. Sodiun) nitrate was found to be generally better for hay on the soil 

 used than annnonium sulphate, as the continued use of the latter lerl to a 

 serious deterioration in the botanical composition of the crop. For equal 

 weights the hay grown with dung appeared to have a lower feeding value than 

 that grown with a good mixture of artificial fertilizers. The composition of 

 the ash of the hay did not indicate the character of the manuring, except with 

 regard to potash. 



The most marked change in the soil produced by the different treatments was 

 the removal of calcium carbonate by the prolonged use of ammonium salts. 

 Marked changes in the bacterial activity of the soil were also produced. " In 

 some cases the reduction in biological activity is so great that dead gi'asses 



