27 



Iowa Studies on Transformations of Nutrient Elements In 



Decomposing Plant Materials and In Soils. Using Isotopes 

 fts Trf^cers* To (l) determine rate and quantity of nutrient 

 inmoblllzation in decomposing plant residues; (2) study 

 influence of nutrient concentration in residues on total 

 inmoblllzation and progress of decomposition; (3) evaluate 

 effect of various physical factors as moisture, temperature, 

 and aeration, (4) investigate sequence of biological and 

 chemical changes in mineralization; and (5) develop tech- 

 niques for wider use of Isotope tracer elements in 

 mineral nutrient transformations. 



Bact», Agron# 1070 Coop, Atomic Research Institute 



Kans. The Role of Surface Phenomena In the Uptake of Nutrients 

 By Soil Mlcro-Organisms> To learn mechanisms by which micro- 

 organisms abstract nutrients from their environment & to study 

 the physical & chemical factors effecting process. Investigate 

 the chemical groupings of the bacterial cell surface responsible 

 for ion exchange process. Determine homogeneity or heterogeneity 

 of adsorption sites by learning ratios of adsorbate & adsorbent. 

 Use of Ca^5 in exchange studies to detect small differences in 

 ion combining capacities of concentrated bacterial suspensions. 

 Bact. 465 



Minn. Microbiological Production of Organic Growth Substances 

 Within the Rhizosphere and Effects on Plant Growth . To study 

 microbiological production of organic plant growth substances 

 in the rhizosphere, and possible Influence of such growth 

 factors in growing plants. 

 Soils 2516 



Mo. The Protein Role of Nitrogen in Organic Matter. To (1) 



study cycles of organic compounds synthesized by alfalfa 

 according to the supply of boron and sulfur in the soil; (2) 

 study uptake of organic compounds by higher plants; and (3) 

 evaluate effects of some organic compounds on soil flora. 

 Soils 208 



Nebr. Microbiological Studies of Stubble Mulching in the Great 

 Plains . To learn influence of (l) stubble mulching on number & 

 kinds of microorganisms; total count, antinonycetes, fungi, bacteria, 

 anaerobes, denitrifiers, rhizobia, & nematodes; (2) stubble mulching 

 on nutrient element changes in soil by microorganisms; primarily 

 nitrate production & P availability; (3) stubble mulching on for- 

 Bttition of decomposition products bv microorganisms that affect 

 germination & growth of plants; (4) decomposition products of crop 

 residues in stubble mulch system on soil aggregate stability; & 

 (5) decomposition of crop residues under different methods of 

 management in stubble mulch systems. Find means of speeding up 

 or slowing down decomposition for disposing of heavy residue & 

 retaining light residue. 



Agron., Soils 279 Coop. ARS 



