Laboratory studies were conducted to investigate the effect of mineral phosphates upon the organic phosphorus content of eight organic soils. Soil types represented were Carlisle muck, Everglades peat, Houghton muck, Istopoka peat, and Rifle peat. Six of the samples were obtained in Michigan and two from Florida. Monocalcium phosphate was applied to each soil at the following rates; 12.5, 25, 50, 100 and 200 ppm. of phosphorus. Unphosphated samples were left as controls. To determine if mineralization was as extensive as shown by analyses for organic phosphorus, available soil phosphorus was determined before and after a 4-month incubation period. The effect of sterilization, temperature and moisture upon the mineralization of organic phosphorus in Houghton muck was also determined. Samples were incubated for a period of 4 months and the amount of organic phosphorus determined, at the end of 2, 3, and 4 months. No “fixation” of mineral phosphate as organic phosphorus occurred, but mineralization of the original organic phosphorus did occur. In general, the trend was toward more complete mineralization of the soil organic phosphorus, with increasing rates of added monocalcium phosphate, over a period of 4 months. Generally, the rate of mineralization was rapid the first 2 months and somewhat slower during the last 2 months of the incubation period. The percentage increase in available phosphorus after 4 months incubation ranged from 31.1 to 292.0%. Temperature and moisture were shown to be two factors affecting mineralization of organic phosphorus.

A number of field and vegetable crops were grown in the field and greenhouse on a peat soil very deficient in copper. Yield responses and copper contents of the plants were determined and copper deficiency symptoms photographed and described. In another series of tests the need for copper by oats on a number of upland soils was determined, and data concerning yield and copper content of the oats are presented. Significant increases in yields of straw were obtained in several cases. In the tests on the peat soil, oats showed the greatest need for copper among field crops and red beets among vegetable crops. Oat yields without copper were slightly over 1 bushel per acre, and with copper 64 bushels. Red beet yields were increased 5-fold by the application of copper to this soil. Copper contents of plants varied considerably and in general increased with copper fertilization.

The relation of the water content of soil to suction may be determined by use of suction control surfaces, ceramic or cellulosic, in pressure chambers. Advantage is gained for these measurements by placing the sample under test in a retainer having a porous ceramic bottom plate. Retainers for use with core and fragmented samples are described and procedures are given for their use.

Four years' data are reported for a 5-level NPK factorial experiment with 2 levels of dolomitic limestone. The experiment was conducted on Red Bay fine sandy loam in western Florida. Phosphorus showed the greatest yield response at the beginning of the experiment, but the amount of phosphorus required to give a maximum yield decreased as the experiment progressed. Nitrogen showed an excellent yield response in years when rainfall distribution was good. Potassium gave a positive response each year, with the degree of response increasing as the experiment progressed. The increase in the potash requirement was due to the depletion of soil potash on treatments which received small annual potash applications. Dolomitic limestone gave significant increases each year; these were greater at the 3-ton-per-acre rate than at lower rates. These data were fitted to general parabolic response surfaces, and equations were determined by multiple curvilinear regression techniques to describe each years results. The units of N, P₂O₅, and K₂O required to give a maximum yield and a maximum net return per acre were determined for each year reported.

Crop response to 7-14-14, 6-12-12, 10-20-20, and 11-22-22 fertilizers was determined on 5 soils in 2 greenhouse experiments in Tennessee and Virginia and in 21 field experiments in Georgia, Kentucky, Mississippi, North Carolina, Tennessee, and Washington. All soils were acid to neutral in reaction. The fertilizers, separately formulated from dicalcium phosphate, ammoniated ordinary superphosphate, ammoniated concentrated superphosphate, and diammonium phosphate, had 7, 27, 60, and 100%, respectively, of the phosphorus in a water-soluble form. Each fertilizer was granulated and screened into 6–14, 14–35, and −35 mesh sizes. Early growth response, as determined in the greenhouse with oats and Sudangrass, and in the field with wheat forage and other crops, increased with smaller granule sizes of the low water-soluble fertilizers but decreased with smaller granule sizes of the high water-soluble fertilizers. This pronounced interaction of water solubility and granule size found at early growth stages did not persist in final yields of corn or wheat grain and vegetables in most experiments. Where an early growth response is desired, results indicate that fertilizers having a low water-soluble phosphorus content should be granulated more finely than those having a high content of water-soluble phosphorus.

Carbohydrate materials, crop residues and proteinaceous materials were degraded by soil microflora in the presence and absence of clay minerals. The carbohydrates used included two cellulose dextrins differing in solubility and chain length, polysaccharides from sweet corn, starch dextrin, and hydroxyethylcellulose. The crop residues used were alfalfa meal, soybean leaf meal, soybean meal, and oat straw. Casein and gelatin were utilized as proteinaceous materials. A yeast nucleinic acid and a pectin (RX3) also were used in this study. A calcium bentonite, an illite, and a calcium kaolinite of pH 8.0 respectively, were added to the substrates in a mineral medium and phosphate buffer. Carbon dioxide was collected in standard Baryta's solution and determined by titration. The activity of the enzymes, cellulase and hemicellulase was determined in the presence and absence of two clay minerals using an Ostwald viscometer to measure the time of efflux. The association of the substrate with the bentonitic clays resulted in an attenuated breakdown of many of these substrates. Very little protective influence was noted with the illitic and the kaolinitic clays. However, the kind and complexity of the substrate influenced the amount of breakdown; the simpler compounds were broken down more completely than the complex. The cellulose dextrins, casein, gelatin, soybean leaf meal, alfalfa meal, soybean meal and oat straw all evolved less carbon dioxide in the presence of calcium bentonite than in its absence.

Exposure time required for the fast, efficient heat of infrared radiation to kill Lyctus powder-post beetles—in all stages of development—is governed by the thickness of the infested hardwood floor. Once the floor thickness has been determined and the exposure time known, 100% mortality of the Lyctus beetles can be expected under every square inch of area covered by a recently developed infrared unit.

A method which uses direct titration of ammonia as a measure of urease activity was modified for use in the assay of raw and of slightly denatured soybean meal. The modifications which were adopted were the use of glutathione, a presoaking of the sample for 30 min. at 40°C., and making of the assay at 40°C. Data on the urease activity of several varieties of soybeans, and for immature and frost-damaged soybeans were determined.

Soil profile studies were made along two traverses extending from the Wabash River in a southeasterly direction across southern Indiana for the purpose of determining the distribution of loess in this area. The variation in thickness of the loess mantle with distance from the Wabash River, the assumed source, was measured, and equations of the curves showing the relationship were calculated. X-ray diffraction studies were made of the medium and fine silt fractions of the A₂ horizon of 10 profiles along the southern traverse. The ratio of the quartz/feldspar intensities was determined using sodium fluoride as an internal standard. The calcium, sodium, and potassium content of the medium silt fractions of these 10 horizons was determined by flame photometry. The equation for the curve fitted to points plotted along the northern traverse was Y = 122 − 47 log X, where Y is the depth of the loess in inches and X is the distance from the Wabash River in miles. The equation for the southern traverse was Y = 125 − 53 log X. The X-ray diffraction studies indicate that the quartz/feldspar ratio may be used as an index of weathering. The correlation coefficients for the relationship between the quartz/feldspar ratio and distance from the Wabash River were 0.95 and 0.96 for the medium and fine silts, respectively. The results of the chemical determinations substantiated the findings of the X-ray diffraction studies. It is concluded that loess was transported across southern Indiana for a distance of about 90 miles.

Various methods of testing soils for antibiotics were compared using soils to which antibacterial substances (penicillin, streptomycin, chloramphenicol) or antifungal substances (cycloheximide, candicidin, nystatin) had been added. Chloramphenicol, penicillin, and cycloheximide could be tested by direct diffusion from soil through a cellulose film into assay agar. All of the antibiotics could be determined in soil-agar mixtures. Whith this method, some antibiotics were more active in nearly neutral media than in acid media. The antifungal antibiotics and streptomycin showed decreasing activity against certain test organisms with an increase in the amount of colloidal material in the soil. There was little or no such effect with chloramphenicol and penicillin.