14 BULLETINS OF THE BUREAU OF PLANT INDUSTRY. 



TEXT FIGURES. 



Page. 

 Bulletin No. 173. — Seasonal Nitrification as Influenced by Crops 



and Tillage. 



Fig. 1. Diagram showing the parts per million of water-soluble ni- 

 trates in dry soil in the fallow plat in each 6-inch soil 

 layer to a depth of 2 feet ; also precipitation curve 12 



2. Diagram showing the parts per million of water-soluble ni- 



trates in dry soil in the spring-wheat plat in each 6-inch 

 soil layer to a depth of 2 feet ; also weekly increase of 

 wheat plants 14 



3. Diagram showing the average parts per million of water- 



soluble nitrates in dry soil to a depth of 2 feet in the 

 summer-fallow, spring-wheat, and corn plats; also weekly , 

 increase of wheat plants and precipitation curve 16 



4. Diagram showing the parts per million of water-soluble ni- 



trates in dry soil in each 6-inch soil layer in the corn plat 



to a depth of 2 feet IT 



5. Diagram showing the average parts per million of water- 



soluble nitrates in dry soil in the fallow plat to a depth of 



2 feet : also soil-moisture curve and precipitation curve 19 



6. Diagram showing the average parts per million of water- 



soluble nitrates in dry soil to a depth of 2 feet in the 

 spring-wheat plat; also soil-moisture, precipitation, and 

 weekly crop-increase curves 20 



7. Diagram showing the time and location of the maximum 



amount of nitrates in the wheat and fallow plats 21 



Bulletin No. 174. — The Control of Peach Brown-Rot and Scab. 



Fig. 1. An old brown-rot mummy with the cup-shaped bodies (apo- 

 thecia) of the fungus, in which myriads of ascospores are 



produced 12 



Bulletin No. 175. — The History and Distribution of Sorghum. 



Fig. 1. Map of the world on Merca tor's projection 9 



2. Map of Africa 12 



3. Heads of four kafir varieties 14 



4. Plants of shallu, representing the variety roxburghii, 



Hackel 35 



5. Plants of an Abyssinian sorghum not yet headed l v 



6. Plants of white durra from different countries, showing 



varying characters 20 



7. Plants of different varieties of sorghum from India 22 



8. Plants of two varieties of kowliang from China 24 



9. Plant of Chinese sorgo 25 



10. Plant of sorghum, after Fuchs, 1542 26 



11. Plant of sorghum, after Dodoens, 1583 27 



12. Heads of Holcus sorghum, L., and Holcus saccharatus. L.. 



after Arduino. 17S6 28 



13. Head of Holcus cafer, after Arduino, 1786 29 



14. Head of Holcus niger, after Arduino, 17S8 ■"■' 



15. Plant and head of FIolcus cernuus, after Arduino. 17S6 31 



16. Plant of sorghum, after Mattioli. 1598 38 



17. Heads of three sorghum varieties figured in 1869 45 



