Agricultural Research in New Hampshire 35 



primary aim was to discover just how yield, total air space, and moisture 

 supply were related. Knowing the optimum moisture should allow 

 various combinations of aggregates and textures to be compared more 

 readily. 



The yield data indicate that in general the more air space in the 

 soil, the better is the utilization of small amounts of water. Other inter- 

 esting conjectures might be made from these data, but it is desirable to 

 duplicate and otherwise substantiate the tests before definite conclusions 

 are attempted or any application to tillage practices is suggested. 



Parallel experiments were carried on with corn and cabbage plants 

 grown in sand and water cultures with nutrient solutions. The aim in 

 this cas2 was to eliminate, in so far as possible, the effects of every variable 

 except texture. The plants were grown with their roots in nutrient 

 solution alone, in nutrient solution with fine sand, and in nutrient solu- 

 tion with coarse sand. Aeration was supplied by pumping air through 

 porous carbon tubes buried in the medium. Yield as indicated by dry 

 weights of tops was greater in all treatments with aeration than without. 

 Whether with aeration or without, yield was. greatest in the nutrient 

 solution only, next largest in fine sand, and least in coarse sand. (Stuart 

 Dunn and W. H. Lyford, Jr.) 



FORESTRY 



During the eighteen months since the last report the Forestry De- 

 partment has had an opportunity to analyze the investigations carried on 

 under some of the older projects and to reorganize them somewhat. One 

 of the more immediate results will be a clearer understanding of our 

 objectives and a better program by which we can work toward them. 



Plantation Studies 



This project has been divided into a number of experiments which 

 may best be organized by grouping the plantations into series. As new 

 ideas develop, additional series may be set up so that each group will 

 present a more homogeneous nature. To date the following groups 

 have been recognized. 



Series A: Early Plantations, 1913-1917. These plots varied in size, 

 and only commercially valuable species were represented, including sev- 

 eral exotics. Some data were destroyed by fire in 1937. These planta- 

 tions are being examined and the records brought up to date. 



Series B: Forest Trees, 1938 to date. Here again the plots are 

 variable in size. Commercially valuable species predominate, although 

 a few others are included in certain smaller areas in the arboretum. They 

 are made primarily for the purpose of producing stands of timber, and 

 the trees will normally be allowed to reach maturity before they are cut. 



The plantations are examined periodically, and a staked row of 

 sample trees is measured for height and condition, 1, 2. 5, and 10 years 

 after planting. Usually about 10 per cent of the total number is in- 

 cluded in the sample, up to 100 trees. 



