664 



have in pure phosphoric acid fertilization a means of decreasing the dangers 

 of a too large supply of nitrogen. At least, the results obtained by the 

 above-named authors with wheat and barley showed that a fertilization with 

 phosphoric acid alone (Baker guano with 18.97 P^r cent, soluble Pg Or.) 

 resulted in a reduction of the nitrogen content of the grain. 



But, aside from the composition of the grain, which is changed by an 

 increased nitrogen supply, the whole amount of the harvest must be taken 

 into consideration, which had suffered not a little from a too luxuriant and, 

 therefore, too thick and dark a growth of the plant. Experiments based 

 mostly on the conditions occurring in practice, since they show the influence 

 of shading from the sides, have been cited by Fittbogen'. Under otherwise 

 perfectly similar nutritive conditions, he shaded barley plants by means of 

 a cylinder of rye stalks, fastened side by side and placed around the barley 

 plants, and raised it in proportion to the growth in height of the experi- 

 mental plant, which was constantly illuminated at the tip. The plants, 

 therefore, had light for production but still in insufficient amounts. On 

 this account, they produced only about two-thirds as much dry substance as 

 plants illuminated on all sides, in spite of the 4 to 6 weeks longer growth 

 which were needed for complete ripening. The dry substance, however, 

 was also distributed much less favorably in the different harvest products. 

 While, with a normal illumination, 47 per cent, of the dry substance in 

 summer barley, as a whole, was found in the grain, and 53 per cent, in the 

 straw and chaff, from shaded plants, only 39 per cent, of grain was har- 

 vested for 61 per cent, of straw and chaff, and the kernels were also poorer 

 in cjuality. In regard to the water used, it v^^as found that plants shaded on 

 the sides, in spite of the at least 6 weeks longer growing time, had used only 

 one-tenth more water in the hottest months (July and August). Therefore, 

 in the same unit of time they absolutely transpired considerably less than 

 the normally illuminated specimens, corresponding to the lesser production 

 of dry substances. On the other hand, the plant will have evaporated rela- 

 tively a great deal of water for we find, in shaded .plants, that more than 

 500 g. of water were used per gram of dry substance, while normally lighted 

 specimens have respired only something over 300 g. for the same amount of 

 dry substance. Therefore, we find, in this vegetative factor, the same eft"ect 

 on transpiration as in others (soil solutions, carbon dioxid content in the 

 air, etc.) A supply of one vegetative factor kept below the optimum, in- 

 creases the relative use of water per gram dry substance produced. 



The loss due to lodging will be decreased in many cases by the fact 

 that grain possesses the ability to right itself. The process of righting 

 consists in the ability of the nodes to show phenomena of growth at a time 

 when the internodes have already lignified. According to de Vries' expla- 

 nation", a new formation of osmotically effective substances takes place in 



1 Vortrag aus dem Klub der Landwirte am 14. Dez. 1875. 



'■!■ De Vries, tJber die Aufrichtung des gelagerten Getreides. Landwirtschaftl. 

 .JahibiiL-her von Thiel. IX, 1880, Part 3. 



