844 EXPERIMENT STATION EECORD. 



to 20 lbs. of seed per acre for peas and 30 to 60 lbs. for hay, ensilage, pasturage, or 

 green manuring. Heavy seeding gives a greater proportion of hay and light seeding 

 a greater proportion of peas and a heavier total yield. In 1900 and 1901 cowpeas 

 were planted the first week in May, June, July, and August. The results for the 

 May and Jane plantings were practically the same, and the July plantings gave 5.15 

 bu. of peas and 448 lbs. of hay per acre less than the plats planted in June. Less than 

 one-half the quantity of hay and less than one-third the yield of peas produced by 

 the early plantings was obtained from the crop planted in August. 



A number of experiments were made to test the value of the cowpea for soil 

 improvement. Cowpeas were drilled and broadcasted between the rows of corn at 

 the time of the last cultivation. The best yield of peas and hay was obtained from 

 the drilled seed. The cowpeas had no appreciable effect on the corn crop growing at 

 the time, but the next year's crop was increased by 3.2 bu. per acre. The results of 

 experiments showing the fertilizing effects of plowing under cowpea stubble or cowpea 

 vines upon crops of wheat and oats, and the yield and value of cowpeas and other 

 crops planted after oats were harvested, are republished from former bulletins ( E. S. 

 R., 12, p. 1034; 13, p. 545). The value of cowpea culture for eradicating weeds, such 

 as nut grass and Johnson grass, is briefly discussed. 



Breedingflax, W. M. Hays ( Furm Students' Rev., 6 {1901), No. 6, pj). 85, 86, fig. 1). 



Hemp (Cannabis sativa), a practical treatise on tlie culture of hemp for 

 seed and fiber, with a sketch of the history and nature of the hemp plant, 

 S. S. BovcE {Nrw York: Orange Judd Co., 1000, pp. 112, figs. 13). 



Assimilation in the oat plant as aflPected by different conditions of soil 

 moisture and fertilization, L.LANGEuand B. Tollens {Jour. Landir., 49 {1901), No. 

 3, pp. 209-229; ahs. in Dent. Landw. I'resse, 28 {1901), No. 82, pp. 688, 689, figs. 3) .— 

 For the purpose of experiments here reported oats were grown in 36 pots divided 

 into 9 groups of 4 pots each, receiving the elements of plant food in different combi- 

 nations, with the exception of the check group, which received no fertilizing elements. 

 Nitrogen and phosphoric acid were supplied at the rate of 1 gm. per pot, in the form 

 of nitrate of soda and calcium phosphate, respectively, and potash was given in the 

 form of potassium carbonate, the quantity being 1 gm. calculated as potassium oxid. 

 Lime was furnished in the form of marl, supplying 2.652 gm. of calcium oxid per jiot, 

 and magnesia was given as magnesium sulphate in solution, the quantity being 0.5 

 gm. of the sulphate per pot. In each group the plants from 2 of the pots were har- 

 vested when the grain was in the milk stage, and from the remaining 2 when it was 

 fully ripe. As regards plant food, the pots in each group were treated alike. Each 

 pot contained 15.475 gm. of dry soil, having a water-holding capacity of 22.8 per 

 cent. In 2 pots of each group the quantity of water in the soil from April 15 to May 

 15 was brought down from 59.43 and 47.19 per cent of saturation; from this time 

 until the 5th of June it remained stationary, and then was held at 53.29 percent until 

 the plants were harvested. The soil in the other 2 pots of each group containe<l from 

 the 15th to the 26th of April about 59.43 per cent of the quantity of water held at 

 complete saturation, and from this time until harvest, 83.90 per cent. The results are 

 given in tables and discussed. 



The increase in the water content of the soil caused an increase in the plant sub- 

 stance, affecting the quantity of grain as well as the quantity of straw and chaff. The 

 percentage of phosphoric acid in the grain, straw, and chaff was increased by an 

 increase in soil moisture, while the percentage of nitrogen was decreased. The quan- 

 tity of potash in the plants was subject to greater fluctuations than the quantity of 

 phosphoric acid. An application of phosphoric acid alone, when no nitrogen had 

 been given, increased the yield of grain, straw, and chaff in the pots which had 

 received the larger quantity of water. The percentage of potash in these same parts 

 of the plant increased with the moisture supplied to the soil, but only Avhen this 

 element was present in considerable quantity; otherwise the percentage of potash in 



