Alfalfa was grown on Superstition loamy fine sand on the Yuma Mesa for the 4‐year period, 1949–52, to evaluate the effects of moisture and phosphate variables on hay production and associated factors. The three moisture treatments were based on tension levels, tensiometers being installed at 9 depths from 6 to 120 inches. A total of about 125,000 tensiometer readings were recorded during the 4 years. Ten phosphate (superphosphate) rates and/or frequencies varying from 100 to 1,300 pounds P2O5 for the 4‐year period were employed as subplots in the split plot design. Average annual hay yields for the 4‐year period varied from 6.4 to 12.3 tons per acre, being greatly affected by either moisture or P level. Small frequent irrigations and an initial fertilizer application of more than 200 pounds P2O5 plus 100 pounds P2O5 annually appeared to be the goals to approach. Phosphorus movement was largely limited to the surface 18 inches, which was less than expected. As measured by tensiometers the depth for the greatest relative activity of roots decreased with decreasing moisture tension, increased with decreasing supplemental phosphate, and increased with increasing temperatures. Soil sampling during a 32‐month period revealed that for “dry”, “medium”, and “wet” treatments respectively, 80, 74, and 27% of the available moisture and 72, 82, and 85% of the total water utilized by the plant was removed from the surface 48 inches of soil. During a 3‐year period the mean water use per day varied from 0.21 to 0.25 inch, the greatest amount being used in the “wet” or low‐tension treatment. Water used per ton of hay produced varied from 7.1 to 16.5 inches, high rates of moisture and phosphate giving greatest efficiency. The alfalfa stand thinned rapidly, correlation analysis indicating a reduced stand was an important cause for declining yields. Root grading analyses at the termination of the experiment demonstrated that moisture and phosphate levels had no effect upon root shape and nematode infection. Moisture and/or phosphorus had significant effects on crown and root weight, root diameter, amount and distribution of feeder roots, and crown‐ and root‐rot. A barley crop was grown following the alfalfa to measure residual productivity levels due to previous moisture and phosphate variables. The only significant difference was caused by moisture, the “dry” treatment resulting in the greatest grain yields.
(7), who have studied artificial zeolites and the clay fraction from the soil and used them as a source of ions for plants. ALBRECHT and MCCALLA (1) give a very good account of this subject and references to previous work.
Ohio State University has desired a collection of soil profiles for class room and demonstration use. It seemed essential that such a collection be monoliths of the normal profile which could be easily handled and demonstrated and that they show: the various horizons in their natural relation to one another, the color and mottling as nearly as possible like that seen in the field, and the true structure of the different layers.With these criteria in mind, profile monoliths covering the chief Ohio soil types were collected in the summer of 1938 and mounted for exhibition at the University. This collection of profiles has created such a favorable impression upon students and others that the procedure for taking and mounting them is thought worth presenting. PROCEDUREThe site for taking each sample was selected -in an undisturbed area, preferably ungrazed woodland. Where such was not available, a pastured woods or unbroken sod served as a source for the sample.After the site had been selected by means of auger borings, a straight-sided pit about 2j4 feet wide by 3 feet long by 26 inches deep was dug. Then a box made of i8-gauge galvanized sheet steel 24 inches long, 2j4 inches deep, and 4 inches wide, open at the ends, was placed against the side of the pit where the profile was most satisfactorily exposed, with the upper end of the box just flush with the ground surface. A longer profile would have been preferable, but the length of the mount was limited by the display space available.The box was then forced into the side of the pit with a screw jack (a light hydraulic jack will do nearly as well). Two-by 6-inch oak planks were placed against the back of the metal box and against the opposite side of the pit beneath the base of the jack.After the box had been pressed flush with the wall of the pit, a small lid was pushed down over the open end to protect the ground surface from foreign material, and the side of the pit was carefully dug away along the length of the box. The cuts were started about 3 inches from each side of the box, and were made with a spade and a spud-bar. The two cuts were brought together back of the box, the jack was cautiously removed, a shovel was pushed under the buried end of the box, and the box and column of soil were loosened and tipped back into the open pit. The excess soil was then broken from the sides and the open face of the box, a completely enclosing metal lid was put over it, and the sample was marked with two tags, one inside and one outside, to indicate the type of soil and the location of the sample.Before the pit was filled, loose samples of each horizon were collected in heavy paper bags for laboratory study. The loose sample at the thirty-inch level was obtained with a posthole digger. The whole job of collecting, including excavating and filling the pit, required two men from 2 to 4 hours to complete.
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