24 EXPERIMENT STATION RECORD. [Vol. 43 



plK.rus from 10 dairy furuis on wliicli in addition to whole milk some small 

 grains were sold showe<l a loss of 15 per cent of phosphorus. 

 "^ The results are taken to indicate that the increase in yield brought about 

 through the growing of clover and the introduction of a rotative scheme of 

 farming tends to extract larger amounts of phosphorus from the soil than would 

 lie the case otherwise. On the basis of these results the importance of carefully 

 conserving the manure and of maintaining and, if possible, increasing the 

 phosphorus supply of the soil is emphasized. 



Soil fertility, K. H. Gurnky (Proc. Roy. Soc. Queensland, 30 (1918), pp. 4- 

 77)._Considerable data relative to the fertility of Queensland soils is sum- 

 marized from different sources. It is noted that 27 per cent of the Queensland 

 soils have been found to have a low humus content, and the increase and 

 maintenance of the organic matter in these soils is considered to be of the 

 greatest importance. 



Forest fertilization experiments in a heathered pine plantation, Ludwig 

 {Zt.schr. Forst u. Jagdw., 52 {1920), No. 1, pp. ^2-5i ) .—Experiments on the 

 treiitment of a clayey sand forest soil covered with heather are reported, tlie 

 purpose being to determine and correct the injurious influence of the heather 

 and to establish a soil condition favorable to the development of pine trees. 

 The experimental area, covering about 30 acres, was divided into 48 squares 

 of espial area and the soil submitted to different treatments, including clear- 

 ing and cultivation, clearing alone, cultivation alone, and different fertilizer 

 treatments. 



It was found that fertilization alone with mineral fertilizers neither favored 

 the growth of pine trees nor reduced the growth of the heather, especially where 

 the soil was uncultivated and the heather removed. A favorable action on the 

 growth of pine trees was only obtained where the addition of plant nutrients 

 was accompanied by an improvement of the physical condition of the soil. This 

 was accomplished in two ways. The first consisted in covering the soil with 

 a thick layer of humus-producing plant residues. In this case a mineral 

 fertilizer was not necessary. Better results were obtained by growing soil 

 improving plants on the experimental areas. 



Season most favorable for applying barnyard manure, S. Rhodin 

 {Meddel. Centralaust. Forsoksv. Jordhruksomradet, No. 183 {1919), pp. 32; also 

 in K. Landtbr. Akad. Mandl. och Tidskr., 58 {1919), No. 3, pp. 127-158; abs. in 

 Chem. Abs., 14 {1920), No. 3, p. 307). — Experiments with potatoes and beets 

 showed that in all cases spring applications of barnyard manure gave much 

 better results, both in total crop and dry matter, than fall or winter applica- 

 tions. The returns from fall applications averaged 50.4 per cent and those 

 from winter applications 53.4 per cent of the returns from spring applications. 

 Long exposure of the manure resulted in losses of ammonia and total nitrogen. 



Observations on the guano of Sardinia, M. Giua {Gaz. Chim. Ital., Ji9 

 {1919), II, No. 5-6, pp. 21,6-249) .—The results of analyses of samples of bat 

 guanos from caves in Sardinia are summarized. It is noted that within a 

 particular layer there is a variation in composition from prevailingly am- 

 moniacal to prevailingly phosphatic with a deficiency in nitrogen. Studies of 

 certain deposits of recent origin, white in color and greasy in appearance, 

 showed a considerable phosphatic content, accompanied by more or less calcium 

 carbonate, silica, iron, aluminum, and magnesium oxids, and a small percentage 

 of nitrate. 



The demand and supply of fixed inorganic nitrogen in the United States, 

 A. H. White {Chcm. and Metallurg. Enyin., 22 {1920), No. 8, pp. 369-371, fig. 

 1). — This paper, a contribution from the University of Michigan, presents a 



