127 



that had received tillage alone, while those receiving cover- 

 crops and especially the one with an intercrop had been 

 reduced practically to an air-dry condition, from which 

 little or no more moisture could be extracted by the trees.. 

 This comparison may be hardly fair to tillage, since the 

 tests were made long after the regular tillage season was 

 over. But they do show exactly what is likely to occur in 

 the latter part of any season, with the result that the growth 

 is frequently curtailed, under the drier conditions. And 

 even the most active tillage has never yet proved equal in 

 moisture conserving to a definite vegetative mulch, so far 

 as the writer is aware. From this and other data now 

 available, we would say that orchard tillage is simply to be 

 regarded as preferable to sod or to the presence of other 

 untilled intercrops, but it is not equal to a definite mulch 

 either in moisture conservation or in promoting the growth 

 of young trees. 



Results from Covercrops alone. — The other experiment 

 at the College referred to above is concerned with tillage 

 and covercrops alone. This is because some form of annual 

 tillage and covercrops was generally considered best at the 

 time these experiments were started. Along with the 12 

 annual covers, however, we have one permanent cover, viz., 

 alfalfa in plat 13. It was sowed the first year, along with 

 the usual liming, manuring and inoculation necessary for 

 its proper growth, and was turned under and immediately 

 reseeded the following spring owing to a poor stand. Since 

 then it has remained as a permanent cover and has been cut 

 two or three times per season and placed around the trees 

 as a mulch so far as needed. It thus has developed and 

 maintained a very satisfactory mulch for five years without 

 the addition of any outside materials. The other crops are 

 seeded annually at the usual times and plowed under the 

 following spring. The results thus far are shown in Table 

 III. 



