42 EXPERIMENT STATION RECOED. 



catiou of ammonium sulphate was followed by increases in the yield of rice 

 straw and grain but nitrate of soda appeared ineffective. Ammonium sulphate 

 applied before planting was followed by greater yields than when applied at 

 intervals during the growing of the crop. 



In pot experiments the application of nitrates to the soil produced no appar- 

 ent effect until near the heading period. Small increases resulted from applica- 

 tions made before planting and a somewhat greater y'eld was obtained after 

 applications at intervals during the growing period. Ammonium sulphate ap- 

 parently increased the height and tillering power and the organic ammonia 

 contained in soy-bean cake produced considerable increase in growth. 



The author finds that denitrification takes place in paddy soils and that 

 ammonia develops to a considerable extent during irrigation, while the nitrates 

 originally In the soil soon become reduced to a low minimum. The use of 

 nitrates was followed by a slight increase in the ammonia of the soil, while the 

 addition of soy-bean cake considerably increased ammonia formation and am- 

 monium sulphate produced still more marked quantities of recoverable ammonia. 

 At the end of one month's growth there was still a higher ammonia content 

 in the ammonium sulphate and organic ammonia pots, while at the end of two 

 months differences of the same sort but of unequal extent appeared in the field 

 plat experiments. 



Flask experiments indicate that denitrification is sufficient to account for the 

 loss of nitrates observed in pot experiments and that considerable ammonifica- 

 tion occurs in submerged rice soil. Sand cultures indicate that unhealthy and 

 stunted growth results if nitrates are used as the only source of combined 

 ammonia, while the use of ammonium salts resulted in vigorous and apparently 

 normal plants. 



The failure of rice to assimilate nitrates properly may be due to a lack of 

 nitrate-reducing enzyms because of long cultivation of the crop under condi- 

 tions unfavorable to their development. 



Work in 1909 at the Vercelli Rice Experiment Station, G. Alice (Ahs. in 

 Internat. Inst. Agr. [jRowe], Bui. Bur. Agr. Intel, and Plant Diseases, 2 {1911), 

 No 1, pp. 8-i, 85). — Practically no increased yield followed the use of 2 quintals 

 per hectare (178 lbs. per acre) of sulphate of potassium together with sulphate 

 and organic nitrogenous manures, but there was an apparent increase in the 

 value of the crop of 20 francs per hectare. Ground horn and ammonium sul- 

 phate gave better results used together than when applied separately. 



Giana pyrophosphate has been usetl with good results upon extensive rice 

 fields. The author gives a detailed physical, microchemical, and chemical 

 study of this material with special reference to its solubility in water charged 

 with carbon dioxid and in soil solution. 



The successful control of weeds in rice fields has been attained by sowing rice 

 to a depth of 4 to 5 cm. in an unwatered soil, and allowing it to germinate by 

 the natural soil moisture. Tests to determine whether the germination of rice 

 is lower on unflooded fields indicate that it will grow very well during the 

 first period of its growth with the Siime amount of moisture that is necessary 

 for all cereals, but that it grows more rapidly on fields that are very damp 

 even though unflooded. 



Seed roots in beet raising, H. Briem {Osterr. Ungar. Ztschr. Zuclcerindus. 

 u. Landw., 39 (1910), No. 6, pp. 901-918, figs. 9; ahs. in Internat. Inst. Agr. 

 [Rome], Bui. Bur. Agr. Intel, and Plant Diseases, 2 (1911), No. 1, pp. J/S, 46). — 

 The author outlines the selection and other methods necessary to prevent de- 

 ^^eneration and secure the really good seed which is increasingly demanded for 

 seed production, and states what he regards as the most practical and cou- 

 \ enlent rules for cultivating the beet and harvesting the seed. 



