INFLl'lOXCK OF ('l\LTL'KAL AlKTlloliS U>; GKUWTH 51 



inches. This difference of .7 of an inch is accounted for by the fact that 

 the cover crop checked the growth of the trees when sown, and the 

 wood was hardened up, while the clean cultivation kept the twigs from 

 that plat growing quite late in the fall. These twigs were not injured 

 by freezes as the cold weather held off quite late last fall, allowing the 

 previous season's growth ample time to mature. 



From 1,873 measurements taken from the trees of the weed plat, an 

 average length of 1.7 inches was obtained. This, as expected, gave the 

 shortest growth, which is accounted for by the fact that the weeds draw 

 heavily upon tlie soil moisture during the entire season and as last season 

 was a rather dry one, the effect was more noticeable. During seasons 

 of plenty of rain, thf re might not be a very noticeable difference between 

 this plat and the others. 



One thousand, seven hundred fifty-nine measurements were made in 

 the straw mulch plat, which gave an average of 2.2 inchesL This plat 

 would naturally be expected to show the largest growth during the past 

 season owing to the value of •<> mulch of this kind in retaining soil mois- 

 ture, but the average length of the branches of this plat are .4 of an inch 

 shorter than those of the clean cultivation plat. We are at a loss as to 

 how to account for as much difference. It is apparent that it must be 

 due to some factors other than soil moisture. However, we must re- 

 member that there are a number of purposes served by cultivation of the 

 soil, such as: 



1. Improving the physical condition of the soil. 



2i Promoting better soil drainage. 



3. Helps the soil to appropriate any fertilizer which may be used. 



4. Releasing new plant food in the soil. 



Then it conserves the soil moisture and keeps down the weeds but 

 these are also accomplished by the use of the straw mulch to a greater 

 or less extent. It might be stated here that the cultivation practiced in 

 the clean culture plat was very good. A fine soil mulch was kept on the 

 surface throughout the whole season, which would conserve a great 

 deal of the moisture, but from previous work in the horticultural as well 

 as the soils departments at the experiment station, we are convinced 

 that the straw mulch was more efficient in conserving this moisture. 



Three sod plats consisting of alfalfa, clover and mixed grasses, re- 

 spectively, have given comparatively the same results as regards the tree 

 development since the plats were started. Last spring a division was 

 made cutting each of these plats in halves. One-half was plowed early 

 in the spring, and the other half was allowed to continue as before. The 

 object of this was to see what results cultivation for two or three years 

 would have upon orchards that have been in sod for a number of years. 



Visual comparisons of these plats last summer, showed that the 

 foliage in the cultivated plats had a richer dark green color and was 

 larger than that in the part remaining in sod, which showed they were 

 making a more vigorous growth. The writer had intended to make 



