48 MINNESOTA STATE HORTICULTURAL SOCIETY. 



DISCUSSION. 



Mr. Plants: I would like to ask Prof. Green what degree of 

 moisture is best adapted to growth. 



Prof. Green: The soil about half saturated. About from 

 one-half to one- third. 



Dr. Prisselle: I would ask Prof, Green what about the sur 

 face of the soil being stirred and being made fine so as to make 

 a mulch. How would that answer instead of hay or straw? 



Prof. Green: We did not carry on experiments in that line 

 this summer, but they were carried on at the farm. I had a 

 talk recently with the state chemist, and the results were sur- 

 prising in that so little difference was shown between cultiva- 

 tion and non-cultivation. Sometimes, it seems that results are 

 very great in cultivated soil and, sometimes, the results do not 

 show the effects of it at all. 



Mr. Sampson: Does not the checking of the wind hinder the 

 evaporation of the moisture, and is not that evaporation nec- 

 essary to the growth of the products; does not increased 

 evaporation give an increased growth? 



Prof. Green: To some extent that is possibly true. There must 

 be a large amount of material taken through the plant, but 

 there is this about it, where we suffer most is from those fear- 

 ful southwest winds. Where they sweep over a field of clover 

 or a lake the effects are not so bad; they take the moisture out 

 of the material over which they blow. A field of clover on the 

 windward side undoubtedly prevents the evaporation of mois- 

 ture on the leeward. Now, the point that you make is, whether 

 evaporation is necessary in order to have good plant growth. 

 Some is necessary, but I do not want evaporation beyond a 

 certain limit. The point I wish to make is that wind-breaks 

 may increase the amount of moisture in the soil by preventing 

 excessive evaporation. 



