Effect of Reflective Coatings on Soil Temperatures, Soil Moisture, and the Establishment of Fall Bell Peppers1Gerard, C. J.; Chambers, G.
doi: 10.2134/agronj1967.00021962005900040001xpmid: N/A
Reflective coatings when applied to modify the soil surface were effective in maintaining favorable soil temperatures and in suppressing evaporation for establishing plant stands. A high inverse relationship was obtained between soil temperatures at planting depth and stand establishment of fall bell peppers. Soil temperatures at 45 C to 47 C at planting depth prevented germination of peppers. Certain coatings were effective in suppressing soil temperatures below 43 C at planting depth and in providing a favorable environment for germination of fall peppers. The data suggest that the use of 41 to 61 liters/are (10 to 15 gal/1000 ft2) of better reflective coating materials adequately suppress evaporation and insure desired plant population of peppers. Pepper yields were a function of stand with the peppers growing under the better coatings producing about 5 metric tons per hectare or over five times the yield on the multi‐irrigated bare plots.
Accumulation of Sodium and Calcium by Seedlings of Some Cereal Crops Under Saline Conditions1George, Leon Y.
doi: 10.2134/agronj1967.00021962005900040002xpmid: N/A
Barley, wheat, and rice have widely differing abilities to tolerate saline conditions. In a study of the amounts of Na .and Ca accumulated by seedlings under progressively increasing saline conditions, seeds were allowed to germinate in glass dishes on filter paper saturated with distilled water. Eight days after germination started saline solutions having osmotic concentrations of 0, 2, 4, 6, 8, 10, and 12 atm were added to each germination flask. After 24 hours of the saline treatments, seedlings were washed with distilled water and dried in oven. Sodium and calcium contents of shoots and roots were then determined by flame photometer. During the period of investigation rice accumulated more Na and Ca in both shoots and roots than either barley or wheat. Wheat accumulated more Na and less Ca in shoots than barley whereas the roots have less Na and more Ca than barley. Rice roots were less selective between both cations than those of barley and wheat.
Flooding Tolerance of Ladino White, Intermediate White, Persian, and Strawberry Clovers1Hoveland, Carl S.; Mikkelsen, E. E.
doi: 10.2134/agronj1967.00021962005900040005xpmid: N/A
Intermediate white, ladino white, strawberry, and persian clovers were grown in the greenhouse during a 4‐month period and subjected to flooding 3 days in 10, 6 days in 10, and continuously. In another experiment, three varieties of ladino white and two varieties of intermediate white clover were compared when flooded 6 days in 10 during a 3‐month period.
Sustained Production of Blue Panicgrass, Panicum antidotale Retz., as Influenced by Management PracticesHolt, Ethan C.
doi: 10.2134/agronj1967.00021962005900040006xpmid: N/A
Blue panicgrass, Panicum antidotale Retz., frequently loses vigor following the year of establishment. The effect of cutting height, defoliation frequency, and nitrogen level on sustained production was studied at College Station and Iowa Park, Texas. Delaying harvest later than the boot stage had no advantage in yield in either the current or succeeding year and yield was less with greater stubble heights. Nitrogen increased yields but did not prevent a decline from one year to the next. Yields declined 38% at College Station and 56% at Iowa Park from the first to the second year of treatment. Uniform harvests in the third year indicated slightly favorable effects of some treatment combinations, but no combination prevented a decline in yield.
Milling, Baking, and Chemical Properties of Marquis and Kanred Wheat Grown in Colorado and Stored 35 to 43 Years1Fifield, Colburn C.; Robertson, D. W.
doi: 10.2134/agronj1967.00021962005900040009xpmid: N/A
Samples of ‘Marquis,’ a spring wheat grown under irrigation, and ‘Kanred,’ a winter wheat grown on fallow land without irrigation, were stored in bags in a dry, unheated room at Fort Collins, Colo., for periods up to 43 years. In 1964, all samples failed to germinate after 35 to 43 years storage. Kanred decreased somewhat faster in percentage of germination for the various testing periods than Marquis, when lots harvested in the same years were compared. The grain varied from 10.4 to 11.3% in moisture content during storage. Test weights of the grain were slightly, but, in general, consistently lower in 1964 than in 1938. During this same time flour yield increased for all the wheats. The ash content of the wheats did not change, but the flour ash averaged consistently higher in lots drawn since 1938. A definite and fairly regular increase in fat acidity indicated progressive deterioration. In 1964, gassing‐power determinations on the flour showed increases in 5 of the 8 Marquis samples and in 2 of the 3 Kanred wheats when compared with 1938 tests. Five of the eight long‐time stored Marquis samples and all of the Kanred samples decreased significantly in sedimentation values during the 10‐year period after the first tests were made. Determinations made in 1964 indicate that some thiamine probably was lost during storage under the test conditions. The diastatic activity, as a measure of the maltose content, showed significant3 increases during the 10 years from 1954 to 1964. The quality of the bread from all samples, as judged by loaf volume, was lower than from samples taken in 1938. None of the differences, which are small, seem to be greater than might be expected when tests are made 26 years apart. The breads made in 1964 were not considered to be objectionable for human consumption. Scores for bread grain, texture, and crumb color, however, were lower than in the initial tests. Absorption increased significantly3 in the 1964 tests as compared to the lots drawn in 1938.