70 The Bulletin. 



The question frequently arises as to whether or not it is best to cut 

 and use the vines for hay or allow them to remain on the soil for its 

 improvement. The feeding value of the hay needs to be considered in 

 this connection, as the feeding value can be obtained and under the 

 most favorable conditions 70 to 80 per cent of the fertilizing value 

 be returned to the soil in the manure. This is seldom accomplished, 

 however, with the methods followed for saving and handling manure. 

 In most cases likely not over 50 per cent and generally much less 

 than this finds its Avay back to the land. If the improvement of the 

 land is the sole or main question, there can be but one answer, and 

 that is to leave the entire crop on the soil. In addition to the 47 

 pounds of nitrogen, there are in a ton of pea-vine hay 10 pounds phos- 

 phoric acid and 29 pounds potash, which would be worth, at the pres- 

 ent prices for these three constituents in fertilizers, namely, 18 cents 

 per pound for nitrogen, 5 cents per pound each for phosphoric acid and 

 potash, $10.56 per ton. These constituents average around 85 per 

 cent of the entire fertilizing value of the pea crop, which is made up 

 of hay, roots, and stubble, the roots and stubble containing on an av- 

 erage about 15 per cent of the fertilizer constituents of the cowpea 

 crop. Good crops of co^vpeas grown on land and left there will im- 

 prove it rapidly, but if the hay is removed and exhausting crops are 

 planted in rotation the productiveness of the soil will be but slightly 

 increased or not at all, unless judicious fertilization is followed. 



Turning under large crops of cowpeas in the fall, to be followed by 

 small gi-ain, frequently results in disappointment because of reduced 

 yield in comparison with land which did not have the peas. This is 

 due to the habits of growth of the small grain, which require a com- 

 pact soil. The peas leave the soil too open and porous. This inter- 

 feres with root development and water-holding capacity. If the crop 

 is handled properly this difficulty will not be encountered. On heavy 

 land small crops of peas may be turned under green and greatly im- 

 prove the texture of the soil, besides the addition of the fertilizer 

 constituents of the pea. The safest way with moderate size and large 

 crops is to cut them with a disk harrow or some other implement, 

 allow them to wilt or even dry on the soil, and then turn them under. 

 On light soils the trouble is likely to be more serious, and here it is 

 especially necessary to either cut up large crops or else allow them 

 to remain on the soil until after frost and even into the winter or 

 early spring. On heavy, as well as light land, this practice is good, 

 as the vines will then become at least partially decomposed and can be 

 turned under during the winter or before planting in the spring. 

 There may be some loss from remaining on the surface, but this will 

 in all likelihood be overcome if not exceeded by j)revention from 

 washing. 



The large hay-yielding varieties, as the Iron, Clay, Unknown, and 

 Whippoorwill, are best suited for soil improvement. 



