A 2-year study (1976-1977) was conducted at the Safford Experiment Station, Safford, Arizona to investigate the response of barley (Hordeum vulgare L.) genotypes to both non-saline and saline environments. The soil types was a Grabe Clay Loam. One environment had received only river irrigation water for the previous 10 years and throughout the experiment (non-saline environment) and the other environment had been irrigated with only well water for the previous 10 years and throughout the experiment (saline environment). Fifteen barley genotypes were grown in each environment each year. The following data were recorded for each genotype each year: (1) plant height, (2) lodging, (3) number of heads per hill, (4) number of seeds per head, (5) seed weight, (6) grain yield, (7) straw yield, (8) grain-to-straw ratio, (9) days from planting to flowering, and (10) days from flowering to maturity. The exchange capacity, soluble ions, and ESP of the soil irrigated with well water were all much higher than the exchange capacity, soluble ions, and ESP of the soil irrigated with river water. The soluble salts, calcium, magnesium, sodium, chloride, sulfate, bicarbonate, and sodium adsorption ratio were all much higher in well irrigation water than were the same chemical properties in river irrigation water. The foregoing soil and water chemical properties indicate that the non-saline environment should be much more conducive to optimum plant growth than the saline environment. Most of the barley genotypes germinated more uniformally, grew better, and produced more forage and grain in the non-saline environment than they did in the saline environment. It required a longer period for barley to reach maturity in the saline environment than it did in the non-saline environment. When the data from the two years were combined, there were positive correlations between grain yield and plant height, number of heads per unit area, and straw yield in both non-saline and saline environments. Since there were significant differences between barley genotypes in a number of growth and yield characteristics in both environments, it should be possible to develop improved barley cultivars for both non-saline and saline environments using plant breeding techniques.

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No description available.

Reclamation of four salt-affected soils collected from southern Arizona was studied in the greenhouse and laboratory. Two rates of four amendments (sulphuric acid, gypsum, ammonium polysulphide, and ammonium thiosulphate) were applied in triplicate. Results were evaluated in terms of changes in nutrient availability, ions removed by leaching, plant growth, and infiltration rates. In most cases the high rates of sulphuric acid and gypsum increased the solubility of the major cations (Na, K, Ca, and Mg) in the soil. If the required amount of leaching water were applied to the soil, a significant amount of these cations, especially Na, was leached from the soil. For the Gothard soil (saline-sodic) two pore volumes were sufficient to accomplish leaching, but were insuffcient for the Guest (nonsaline-slightly sodic) and Gilman (highly saline-sodic) soils. High rates of sulphuric acid and gypsum decreased the pH and increased the EC for all soils, although the EC was not significant at the 5% level for the Mohall (nonsaline-nonsodic, calcareous) soil. All treatments decreased the pH of the Gothard soil significantly; however, the greatest increase in EC and least pH were obtained from acid application. Regarding changes in phosphorus (P), all treatments increased the amount of soluble P in the leachates from the Gothard and Guest soils; whereas available soil P increased significantly only with the acid treatments. None of the treatments affected the amount of P in the Gilman soil leachates, but acid and gypsum increased the available soil P. Ammonium polysulphide and ammonium thiosulphate tended to increase available P but the increase was not significant at the 5% level. None of the treatments affected the P parameters for the Mohall soil. Sulphuric acid increased growth and P uptake of alfalfa plants on all soils except the Mohall. Gypsum and ammonium polysulphide increased P uptake on the Gothard and Guest soils whereas ammonium thiosulphate increased P uptake only for the Guest soil. Sulphuric acid and gypsum increased the infiltration rates for all four soils. Thiosulphate produced intermediate infiltration rates while the lowest rates were found with ammonium polysulphide and the untreated soils. Although amendment rates were based on equivalent amounts of sulphur and their effectiveness in supplying soluble calcium, and the exchangeable sodium status of each soil, results varied according to such factors as rate of oxidation of the amendment, lime content of the soil, soluble salts present in the soil, and soil texture.

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Two laboratory experiments were conducted to study the effects of salt and nitrogen-sulfur compounds on the transformations of nitrogen in three Arizona soils. In the first experiment the effect of NaCl in concentrations of 0 to 1 m (molal) at moisture levels of 1/3 and 15 bars was studied in the Gila and Laveen loam soils. At 1/3 moisture nitrification of urea-¹⁵N and native soil nitrogen was appreciably reduced only at 1 m salt level. At 15 bars moisture, nitrification was almost completely inhibited by the 1 m salt concentration. Mineralization of soil nitrogen was reduced more by decreasing moisture than by increasing salt concentrations. Ammonia volatilization was increased by both salt and moisture stress and was associated with inhibition of nitrification. Slight effects of salt were observed on ¹⁵N immobilization and ¹⁵N recovery (including volatilization). In the second experiment nitrogen-sulphur combinations (¹⁵N labelled) of KNO₃, KNO₃ + S, urea, urea + S, APS (ammonia polysulfide) and Thiosul (ammonium thiosulfate) were studied at field capacity (FC) and 1.5 FC moistures. In the calcareous Gila soil nitrification was suppressed by the presence of sulfur at 1.5 FC moisture. Volatilization losses were appreciable only from APS. Immobilization of ¹⁵N was greatest from treatments with the higher sulfur rate (elemental S). Denitrification was slightly increased by sulfur at FC, however, at 1.5 FC dramatic losses occurred by denitrification (autotrophic in the presence of sulfur, especially with elemental S. The nitrifying ability of the slightly acid and coarse textured Sonoita soil was low. Nitrification was suppressed more by the presence of sulfur at both moistures. Ammonia volatilization was appreciable from APS followed by urea. ¹⁵N immobilization was high from urea followed by APS. Appreciable losses by denitrification occurred only with APS. The Sonoita soil showed a lower sulfur oxidizing power than the Gila with the only appreciable rate of oxidation from Thiosul followed by APS.

No description available.