FIELD CROPS. 779 



Data are also tabulated for percentage compositiou of fresh i)lants 

 and water-free substance, and nutrients per acre and per ton are com- 

 pared with other fodders. 



The author gives the following summary: 



"So far as is indicated by this experiment it would seem that sunflowers are not 

 nearly as profitable a cro]) to raise as corn. With the same (iiltivation corn pro- 

 duces a third more ])rotcin and nearly twice as much carbohydrate material as sun- 

 llov »r heads. 



"When compared with our common red clover an average crop of the hitter plant 

 produces nearly twice as much ])rotein and more carboliydrate matter per acre. 

 From this very limited exjierience we are not favorably impressed with the sun- 

 flower as a profitable silage crop. The peas are not considered, as a fair average 

 croj) was not secured." 



Autumn catch crops, P. P. Deherain {Ann. Agron., 23 (1896), iVb. 

 13, pp. 5I5-5.'j1). — The re(iuiremonts of a good autumn catch crop and 

 the adaptability of a number of plants to this purpose are discussed. 

 Experiments were made at Orignon in vegetation boxes containing 

 calcareous soils with white, blue, and yellow lupines, peas, vetches, 

 and mustard. Of the first three the white lupine alone survived. 

 Vetches gave by fiir the most satisfactory results as regards total yield 

 and proportion of nitrogen. During the experiments with catch crops 

 (October and the early part of IS^ovember) the bare soil lost 28 kg. of 

 nitric nitrogen per hectare and the soil covered with vetches 7 kg. 

 The difference (21 kg.) added to the amount of nitrogen furnished to 

 the soil by the crop of vetches (82 kg.) supplied the covered soil with 

 an excess of nitrogen over the bare soil of 103 kg., or an amount fur- 

 nished by 40 tons of barnyard manure, or 730 kg. of nitrate of soda. 



The influence of the rolling of crops upon their productiveness, 

 E. WoLLNY {Forsch. Geb. agr. rhys., 19 {1S96), ^^o. 5', 2>P' 331-253).— 

 The author states that the operation of rolling young crops is applied 

 for 3 purposes, (1) to check luxuriance of growth which causes lodg- 

 ing, (2) to induce tillering and consequent improvement of the stsind 

 of the crop, and (3) to promote formation of new roots by plants 

 which have been upheaved by freezing and thawing of the soil. He 

 discusses the physiological principles upon which these effects are 

 supposed to be based, reviews at some length the experiments of W. 

 Schumacher' and C. Kraus,^ and notes the work and conclusions of 

 other writers upon this subject. 



It has been assumed that the bending down or crushing of the stems 

 produced an advantageous effect by causing a thickening of walls of 

 the uninjured cells, thus making more stocky plants, and by inducing 

 develo])ment of side shoots. The checking of the luxuriance of growth 

 also admits more light and air to the remaining uninjured shoots, and 

 by thus stimulating assimilation it is thought exerts a favorable 

 influence upon the crop. Frequently new roots form at the nodes of 



'Korn und Peters, Landw. Jahrb., 3 (1872), p. 183. 



"Forsch. Gel), agr. Phys., 13 (1890), pp. 252-293; 14 (1891), pp. 77-96. 



15502— No. 9 4 



