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Volume 55 Issue 2, March-April 1963
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There were significant reductions in yield for all crops with increasing salinity. With the exception of beet tops and broccoli tops, reductions in yields were significantly less when salinized at more mature growth stages. Tomato tops and pepper tops were the only crops tested which showed a significant interaction between growth stage and salinity.
The cation composition of the plant was dependent on the equilibrium composition of the soil solution and the physiological characteristics of each crop, while the stage of growth at which salinization occurred had a lesser effect.
Leaf-burn of tobacco was significantly related to the leaf constituents in the following order of importance: K(+) > Cl(−) > SO4−S(−) > Mg(−) > NO3−N(−) > total N(−). Magnesium was the only constituent that was significantly related (inversely) to quality.
Losses attributed to hessian fly in wheat grown at 3 levels of nitrogen in the presence or absence of 2 levels of phosphorus and potassium were evaluated. Infestation and losses due to hessian fly were highest at the highest levels of nitrogen.
Orchardgrass and bromegrass seed yields were too low to be profitable, but timothy showed promise of profitable yields. Management requirements varied considerably.
Maximum yields on low nitrogen soils resulted from the application of 20 pounds of N per acre for every 3 inches of available preplanting soil moisture. Flour of inferior protein quality was milled from wheat grown under high moisture stress. N recovery increased from 30 to 50% as available soil moisture at seeding time increased from O to 8 inches. Water use and water use efficiency increased as available soil moisture and rate of N fertilization increased.
Alfalfa and orchardgrass had the greatest influence on production of pasture seeding mixtures. Ladino clover fluctuated widely due to winterkilling and reseeding. Smooth bromegrass, perennial ryegrass, red clover, alsike clover, and birdsfoot trefoil declined after the first year of production. Initial stands of tall fescue and timothy were not adequate to evaluate these species. After disappearance of a shortlived species from a mixture, there was only temporary reduction in yield if either alfalfa or orchardgrass was present.
Legumes were unproductive and were severely invaded by other species after the first year. Reed canarygrass, Alta tall fescue, and orchardgrass were the most productive grasses. Northern bromegrass was more productive and persistent than southern bromegrass. Orchardgrass had high yield, persistence, and resistance to invasion by other species; its performance warrants its being tested for pasture in comparison to other species such as reed canarygrass and bromegrass.
Subterranean and rose clovers were fertilized with S35 labeled S at 3 rates and grown in growth chambers at 50, 60, and 70° F. Radio-analysis of tops and roots indicated an increase in S concentration in tops with increasing temperature but a decrease of S concentration in roots from 60 to 70° F. On a dry matter basis subterranean clover exceeded rose clover in the total uptake of S.
Fatty alcohols and acids supplied to the roots did not reduce water losses through transpiration without simultaneously reducing yields.
The effects of several freezing temperature durations on viability of sorghum seed of varying moisture content were evaluated using maturing seed of four sorghum genotypes. As moisture content of the grain increased and as temperature decreased, progressively shorter durations were necessary to effect reduced seed viability. Durations of as little as 1/2 to 1 hour at 20° and 14° F. caused marked loss of viability in high moisture grain.
Radial restraint of cotton taproots was studied using plastic clamps to simulate zones of high soil strength. All treatments affected plant vigor and appearance, plant height, stem diameter, and lint cotton yield. A root diameter of about 0.65 centimeter was necessary to bring plants to full maturity.
Leachable nitrogen was greatest in the first 3-week period and varied as follows: (NH4)2S04 = Urea > castor pomace > Milorganite > Uramite = Nitroform. In the 3- to 12-week period leachable nitrogen varied as: Uramite = Nitroform > castor pomace = Milorganite. Decreased soil acidity increased the leachable nitrogen from all materials in the first 3 weeks.
Freezing sprouted barley seed after a hardening period gave survival scores similar to those obtained in field trials.
First harvest yields of orchardgrass, perennial ryegrass, and tall fescue increased at nearly uniform rates up to full bloom and rose relatively little after that. Timothy had the same growth rate, but extended over a longer time. It outyielded other species at heading and flowering stages. Most uniform seasonal distribution of pasture yield was provided by ryegrass and timothy. Digestible dry matter of each species, predicted by the regressions of other investigators, was maximum at full bloom.
Molybdenum seed treatment on soybeans gave yield responses ranging from 0.7 to 7.6 bushels per acre. Molybdenum response was related to soil pH on the Chalmers-Odell soils. Yield increases occurred where the soybean seeds produced on the untreated plots contained 1.6 or less ppm molybdenum.
Nitrogen uptake distribution from sources containing up to 62% of the N as water-insoluble from ureaform was not appreciably improved over watersoluble sources of N. More favorable N uptake distribution was obtained when the water-insoluble N was used alone, especially a product made with U/F mole ratio of 1.50, when applied at 1,000 pounds N per acre. Total yield was approximately doubled and total N recovery tripled as compared to a 100-pound application of soluble N.
Moisture and nitrogen variables influenced sweet corn production at various growth stages-seedling establishment, internode elongation, and pollination and grain development in a 3-year investigation. Components contributing directly to yield were plant population, ears per plant, and weight per ear (including rows of kernels per ear, kernels per row, and weight per kernel). All were affected by irrigation and/or N fertilization.
Annual application of 200 pounds of N and 83 pounds of K per acre resulted in the highest orchardgrass yields and best recovery of N, P, and K by the plant. The K level in the plant at which yields fell below the maximum was positively related to the rate of N applied.
Advancing maturity of sorghums from the bloom to the hard-seed stage resulted in significant decreases in moisture, crude protein, and crude fiber hut in an increase in nitrogen-free extract in sorghum silages. Hybrids were higher in crude protein and crude fiber but lower in nitrogen-free extract than standard varieties. Sterile hybrids were higher in moisture and crude fiber and lower in nitrogen-free extract than open-pollinated hybrids.
A range of sorghum genotypes differed significantly in relative expression of seed dormancy when germinated at intervals of 2 weeks and 1 month after harvest. Seed dormancy was of little consequence 3 months after harvest. Seed scarification was the most effective of several treatments evaluated for their utility in overcoming dormancy.
The weekly accumulative yield increases following first bloom were: 27, 41, 59, 72,.76, 97, and W4%. Yields of sterile hybrids were 10 to 15% less than those which set seed, but the stover was higher in protein and soluble solids (sugars).
Ability to germinate under moisture tension was not related to ability to harden under tension. Significant differences among varieties in uptake of N, P, and K under moisture stress were noted, but they were not related to relative hardiness. Evidence of correlation of relative hardiness in embryo, seedling, and youngplant stages of development was found. Gibberellic acid stimulated seedling growth more at higher than at lower moisture tensions.
A statistical technique using multiple curvilinear regression to differentiate between the effects of technology and weather on trends in yields of grain sorghums is described.
Substantial concentrations of carbohydrates were evident in roots of Du Puits, Vernal, and African seedlings 6 weeks after seeding. Neither growth under reduced light intensity nor 3 potash fertilization rates affected root concentrations of total available carbohydrates (TAG), but total amounts increased as root growth was greater under the higher light intensities and higher potash rates. Varieties differed less in the amounts of TAG produced than in the concentration of TAG in the roots.
In a peach orchard subjected to equipment travel and 4 cover crop management systems the bulk density of the' surface soil was markedly increased by travel with the effect decreasing with soil depth. Soil organic matter levels were increased by all cropping treatments compared to those obtained on chemicallymaintained bare soil. Travel reduced water intake to approximately one-third that obtained on nontraveled areas. Infiltration rates were greater in nontraveled trashy furrows than in clean furrows.
Previous grasses had no effect on grain yields of corn and oats, but N fertility was a factor. No toxic or yield effect was observed after incorporating grasses or the extracts of their autoclaved roots into the soil.
Responses of a native bluegrass sod to topdressed applications of N, P and K fertilizer rates varying jointly were used to fit a forage yield equation and to calculate iso-yield curves and least cost fertilizer ratios. It was then shown how these data and equations may be used in determining levels of fertilizer for optimum beef production and estimating the price of beef needed to justify fertilization of this type of sod.
Optimum plot size was estimated from Smith's soil heterogeneity index and relative cost of experimental procedures. Estimates of optimum size of unguarded plots for measuring yield ranged from 19 to 39 plants when data from individual locations and years were considered separately. However, considering all trials for both size and shape, plots 1 row wide (3.5 feet) by 49.5 feet long (27 plants spaced 22 inches) were optimum.
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