30 FARMERS' BULLETIN 820. 



these regions many farms were so depleted in nitrogen and humus 

 by continuous cropping with nonleguminous crops that profitable 

 yields could be obtained no longer. Through the use of this crop 

 many of these farms have been brought back to a fair state of fer- 

 tility. Tests at the Alabama Agricultural Experiment Station show 

 that the increased yield of corn following sweet clover which had 

 occupied the land for two years was 6f bushels per acre. The cotton 

 grown on the land the second year showed an increase of 56 

 pounds per acre. The combined value of the increased yields of 

 corn and cotton for the two years was estimated at $9.75. The 

 total yield of hay for the two preceding years was 6.8 tons per acre. 

 In another experiment at this station cotton was planted on land 

 that had grown sweet clover the two previous years and on land 

 that had received an application of 18 tons of stable manure per 

 acre. The sweet-clover plat produced 280 pounds of seed cotton 

 the first year and 120 pounds of seed cotton the second year more 

 than the plat which received the heavy application of manure. 



Land on which sweet clover had been grown for four years at the 

 Ohio Agricultural Experiment Station yielded 26.9 bushels of wheat 

 per acre as compared with l.6 bushels on the check plat. Sweet clo- 

 ver was seeded at the Tennessee Agricultural Experiment Station in 

 the spring of 1912. One cutting of hay was removed that year and 

 the following spring the field was plowed and planted to corn. The 

 corn yielded 58.8 bushels per acre as compared with 41.1 bushels 

 per acre for an adjoining plat where rye was turned under. A num- 

 ber of tests have been conducted in southeastern Kansas which show 

 clearly the value of sweet clover as a soil-improving crop for that 

 section. The } 7 ield of wheat has been increased as much as 7 bushels 

 per acre and that of corn as much as 22 bushels per acre by plowing 

 under the second-year growth of clover. 



Annual yellow sweet clover is rapidly gaining in favor as a green- 

 manure crop for orchards in the Southwest. In Arizona two plats 

 seeded in October and plowed under in April yielded, respectively, 

 16 and 17 tons of green matter to the acre. At the Arizona Agricul- 

 tural Experiment Station annual yellow -sweet clover, lupines, and 

 alfalfa were tested as green-manure crops for orchards. In this ex- 

 periment the sweet clover clearly showed its superiority to lupines or 

 alfalfa for this purpose, as it yielded from 21 to 26 tons of green 

 matter per acre, whereas the highest yield for the lupines was 10 

 tons and for the alfalfa 15 tons per acre. 



The use of annual sweet clover as a green-manure crop in southern 

 California has increased very rapidly in recent years, and this in- 

 creased use apparently has been justified by the results obtained 

 with it. One of the most interesting green-manure tests thus far 

 noted was conducted at the California Citrus Experiment Station. 

 In this experiment nine legume plats and eight nonlegume plats 



