journal article
LitStream Collection
Home
Fuehring, H. D.; Finkner, M. D.
doi: 10.2134/agronj1983.00021962007500040003xpmid: N/A
Little has been done on the practical use of antitranspirants to increase the yield of field crops. The objective of this study was to determine the yield response of moisture‐stressed corn to the application of an antitranspirant. Folicote, a hydrocarbon film‐type antitranspirant, was foliarly applied on moisture‐stressed field corn (Zea mays L.) grown on Pullman silty clay loam (fine, mixed, thermic Torrertic Paleustoll) soil. Single seasonal applications (foliar spray with ground rig just prior to tasseling) resulted in average yield increases of 11 and 17 %. Fields where both the upper and lower leaf surfaces were sprayed required 1.93 L/ ha for maximum yield response, 42 % less than required where spraying was from the top only. The response was curvilinear with definite yield depression when rates were too great, indicating the need to determine optimum application rates according to the method of application. It was concluded that antitranspirant application is a feasible method of increasing corn yield under the conditions of this study.
doi: 10.2134/agronj1983.00021962007500040004xpmid: N/A
Clarification of relationships among species in mixed stands is essential to enlightened management of forage mixtures. During 1976–1979, we evaluated several grass‐legume mixtures in a field study in eastern Kansas. Grasses were: commercial smooth brome, Bromus inermis Leyss.; ‘Regar’ Turkish brome, B. biebersteinii Roem. &Schult.; ‘Kentucky 31’ tall fescue, Festuca arundinacea Scbreb.; and ‘Ioreed’ reed canarygrass, Phalaris arundinacea L. Legumes were: ‘Kanza’ alfalfa, Medicago sativa L.; ‘Kenstar’ red clover, Trifolium pratense L.; ‘Dawn’ birdsfoot trefoil, Lotus corniculatus L.; and ‘Emerald’ crownvetch, Coronilla varia L. Each grass was grown in a two‐species mixture with each legume, and in a pure stand with 0 and 90 kg N ha‐1 as NH4NO3. Mixtures were obtained by alternating all‐grass and all‐legume drill rows. Legumes were grown in pure stands in an adjacent planting. Both plantings were on a Woodson silt loam of the fine, mixed, thermic family in the Abruptic Argiaquolls subgroup of the Mollisols. Dry matter (DM) yields were obtained from all plots. Proportion of grass in mixtures was determined from hand‐harvested samples. Dry matter yield of the grass component of each mixture was computed as the product of the DM yield of the whole stand and the proportion of grass in the mixture. Crude protein (CP) contents of whole stands and grass components of mixtures were computed as 6.25 times N. Although comparisons varied across years, mixtures averaged as much grass DM (3.21 Mg ha‐1) as unfertilized all‐grass stands (3.07 Mg ha‐1) during the 4‐year period. Crude‐protein contents of grass components of mixtures consistently ranked above those of unfertilized all‐grass stands; differences usually were significant (P < 0.05) but varied in magnitude with year and type of stand. Legumes differed significantly (P < 0.05) every year in DM yield and every year except 1979 in CP content. Over the 4‐year period, however, no legume was clearly superior in either variable.
McLaren, J. B.; Carlisle, R. J.; Fribourg, H. A.; Bryan, J. M.
doi: 10.2134/agronj1983.00021962007500040005xpmid: N/A
Information on pasture productivity and forage quality of various adapted species and combinations that support rapid animal gains is needed for successfully backgrounding yearling steers in the humid southeastern USA prior to feedlot placement. To evaluate productivity and quality of pasture combinations for growing beef steers, a grazing experiment was conducted near Memphis, Tenn., in 1975 to 1977 on a Typic Hapludalf. The 1.2 ha pastures were Midland (Cynodon dactylon (L.) Pers.) + (Trifolium repens L.) clover, Midland + N, 1/3 Midland + N plus 2/3 fescue (Festuca arundinacea Schreb.) + N in separate pastures, Midland overseeded with fescue + N, common (C. dactylon var. dactylon) + N, fescue + clover, and orchardgrass (Dactylis glomerata L.) + clover (OG + clo). Nitrogen was applied at 224 kg ha−1 y−1 on bermudagrass and at 67 kg ha−1 y−1 on fescue. Pastures were grazed using a modified put−and−take system maintaining orchardgrass at 7 to 14 cm high and the other grasses at 5 to 8 cm. Forage growth and consumption were determined by the cage−and−strip method. Yearling steers weighing 230 kg in the spring grazed 123 to 150 days; they were weighed at 21−day intervals and visual estimates of species composition were made at that time. Forage yield was 8.3 t/ha for Midland + fescue and ranged between 4.0 and 5.7 t/ha for the other treatments. Estimated forage consumption was 80% or more of the forage growth. Forage crude protein (122 to 152 g/kg) was sufficient for meeting the minimum requirements for growing 250− to 300−kg steers. Stocking rates were between 4 and 6 steers/ha. Average daily gains were about 475 to 575 g for all treatments, except for OG + clo (825 g/day). Pasture productivity ranged between 520 animal grazing days/ha for OG + clo to 1190 for Midland + fescue. The productivity of the other pastures was between 730 and 880 grazing days/ha. Daily forage dry matter (DM) intake was 5 to 7 kg/steer. Steers grazing OG + clo, fescue + clover, and Midland + N pastures had feed efficiencies of about 9 kg DM/kg gain; steers on the other treatments required 11 to 13 kg DM/ kg gain. Beef production was 321, 339, 375, 400, 416, 424, and 593 kg/ha for fescue + clover, common + N, 1/3 Midland − 2/3 fescue, Midland + clover, OG + clo, Midland + N, and Midland + fescue, respectively.
Russelle, M. P.; Hauck, R. D.; Olson, R. A.
doi: 10.2134/agronj1983.00021962007500040006xpmid: N/A
Improved fertilizer nitrogen (N) use efficiency in irrigated maize (Zea mays L.) often results from delaying application of moderate N rates until the crop is rapidly growing. The objective of this experiment was to determine how N application time, N rate, and planting date influenced the pattern of N and fertilizer−derived N (FN) accumulation in irrigated maize grown on a deep, productive silty clay loam soil (Typic Argiudoll, fine, montmorillonitic, mesic). A factorial combination of early and late planting, N application at planting, or at the 4−, 8− or 16−leaf growth stage, and two N rates (90 and 180 kg N ha−1 as 15N−depleted ammonium sulfate) were applied to the same plots in 1979–1980. Above−ground plant samples were taken at the 8−leaf, l2−leaf, silking, soft dough, and physiological maturity stages of growth. Average net rates of N and FN accumulation were calculated using a temperature index as the divisor. Rates of N and FN accumulation per plant were greatest between the 12−leaf and silking growth stages in 1979, except when N application was made at the 16−leaf stage where maximum accumulation rates occurred during early grain fill. Effects of N application time on N accumulation rates were more pronounced in 1980 and followed patterns similar to those in 1979. Substantial amounts of residual FN from 1979 accumulated in above−ground tissue in 1980. Residual FN uptake was apparently greater, in comparison to newly applied FN, in the heavily−fertilized or late−planted crop. Time of maximum N accumulation was delayed as time of N application was delayed. Grain yield was reduced by early N deprivation only when active N uptake ceased during early grain fill. Excessive N application minimized the effect of application time on final grain FN content. Delayed planting reduced FN recovery at both levels of N fertilization. Relative recovery of FN in maize grain was maximized by applying the low N rate late in vegetative growth, irrespective of planting date.
Hofmann, L.; Ries, R. E.; Gilley, J. E.
doi: 10.2134/agronj1983.00021962007500040007xpmid: N/A
Vegetation cover is a dominant factor in controlling runoff and water erosion from agricultural land and an important criterion for determining adequate reclamation of strip−mined land. A simulated rainfall study was conducted near Center, N.D. to determine the relationship of ground cover factors to runoff and soil loss. The point frame technique was used to estimate vegetation cover as measured by either the first contact (first hit) of the sliding pins with live vegetation, litter, or bare soil and rock or by a similar contact of the sliding pins at the soil surface (surface hit). Artificial rainfall was applied at the rate of 46 mm/h to 4.0 × 22.1 m runoff plots located on 9 to 12% slopes within reclaimed and unmined pastures. Reclaimed treatments were ungrazed or grazed at light, moderate, or heavy intensity plus vegetation and litter removed by burning. Native range treatments were ungrazed, closely grazed, and burned. Native ungrazed plots had greater live surface cover than ungrazed or lightly grazed reclaimed plots but similar soil loss, runoff, and soil loss/runoff ratio (SL/RO). Best fit techniques revealed some cover factors linearly related to soil loss, runoff, and SL/RO; others logarithmically related. Live surface cover estimates were poorly related to runoff and soil loss. Adequacy of soil protection can be best estimated by percentage of bare soil. Runoff or soil loss estimates were similar whether total cover was estimated by surface hits or first hits; however, surface hits were easier to determine in tall vegetation under windy conditions. The point frame technique is satisfactory for estimating whether the cover is adequate to maintain soil stability on reclaimed land or native range. Its use can be extended to estimate ground cover in other erosion studies.
Thompson, D. C.; Smiley, R. W.; Fowler, M. Craven
doi: 10.2134/agronj1983.00021962007500040008xpmid: N/A
Excess thatch in turfgrasses is often associated with decreased plant vigor and increased disease susceptibility. Thatch is the primary rooting medium for many grasses, and is a substrate that possesses many prerequisites for anaerobiosis. The oxidation status and the gas composition in unsaturated thatch of mature Kentucky bluegrass (Poa pratensis L.) were measured to determine if anaerobiosis occurs under field and greenhouse conditions. Soils under the sods included a Hudson silty clay loam (fine, illitic, mesic Glossaquic Hapludolf), a Riverhead sandy loam (coarse−loamy, mixed, mesic Typic Dystrochrept), and an Arkport fine sandy loam (coarse−loamy, mixed, mesic Psammentic Hapludalf). Measurements of redox potentials (Eh) and concentrations of oxygen (O2), carbon dioxide (CO2) and ethylene (C2H4) were made. Conditions of poor oxidation, including low Eh and O2 and CO2 concentrations, and accumulations of C2H4, were measured in thatch on poorly drained soils in the field and in the greenhouse. Applications of lime and calcium arsenate amplified the extent of poor oxidation in thatch, whereas calcium nitrate improved the oxidation status. Thatch depth and a coring procedure did not influence thatch oxidation. The Eh varied diurnally and was lowest in wet thatches during warm, sunny days when thatch became warmer (by up to 7°C) than the air. Poorly oxidized conditions for periods over 7 h were measured in moist but unsaturated thatch in the field. The temperature of thatch appeared to be important in governing the oxidation status. Measurements of Eh were considered to provide rapid and useful insights into the gaseous composition of wet thatches. Our results imply that phytotoxic products of poorly oxidized environments may accumulate in wet thatch on warm sunny days. Such conditions may also be common in field−grown cores of mature turfgrass which are moved to the greenhouse for study. The relevance of these results to the occurrence of diseases such as Fusarium blight are discussed.
doi: 10.2134/agronj1983.00021962007500040009xpmid: N/A
Small grains have been used in various regions of the United States and Canada as a source of forage; however, forage yield and quality from spring seedings have not been evaluated adequately. A field study was conducted on a Palouse silt loam (fine‐silty, mixed, mesic pachic Ultic Haploxerolls) to compare the forage production of two spring seeded triticale (Triticale hexaploide Lart.) lines (VT75229 and CF76) to currently grown oats (Avena sativa L.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.) cultivars in eastern Washington. Forage yield, percent crude protein, and crude protein yield were determined at the heading and the soft‐dough stage of development from an early and a normal date of planting for the area. Forage yields were not significantly affected by planting date or any of the interactions containing planting date; however, there was a significant increase in percent crude protein with all species except barley when seeded at the normal compared to an early planting date. Triticale CF76 had a mean forage yield averaged over years and planting dates generally equal to the other spring grain species at the soft‐dough stage, but lower than barley and oats at the beading stage. Crude protein yield for the triticales was similar to the other spring grains under the majority of planting dates and harvest stages. These data indicate that triticale will have forage yields and crude protein yields equal to other spring grains in the Pacific Northwest; however, management factors, i.e., planting date and stage of harvest, need to be considered in making recommendations to producers in order to obtain maximum forage potential.
doi: 10.2134/agronj1983.00021962007500040010xpmid: N/A
Soil temperatures vary with depth and time within and among years. An experiment was conducted to quantitatively evaluate the effects of temperature on the development of the taproot and lateral roots of four soybean (Glycine max (L.) Merr.) cultivars at four temperatures. ‘Beeson’, ‘Hawkeye 63’, ‘Wayne’, and ‘Harosoy 63’ soybeans were grown at 17, 21, 25, and 29°C, using a specially designed, constant‐temperature, water bath system. The water bath was located in a temperature‐modified greenhouse where air temperature ranged from 20 to 35°C during the 12‐month experimental program. Serial measurements of taproot and lateral root tip location and number of primary nodes were recorded on alternate days until 19 days after emergence. A primary node was defined as the position at which one or more 1st order laterals emerge from the taproot. The rate of taproot extension increased with temperature, decreased with time at temperatures greater than 17°C, and was greater for the Beeson and Hawkeye 63 cultivars than for the Wayne and Harosoy 63 cultivars when averaged over time. The rate of lateral root extension increased with temperature, increased with time at temperatures less than 29°C, and was greater for the Beeson and Hawkeye 63 cultivars than for the Wayne and Harosoy 63 cultivars at temperature treatments greater than 17°C when averaged over time. The number of primary nodes varied with depth, time, and cultivar. The greatest number of nodes occurred 2.5 to 7.5 cm below the vermiculite surface. The Beeson and Hawkeye 63 cultivars had fewer primary nodes than the Wayne and Harosoy 63 cultivars. The results indicate that the depth of soybean root penetration can be altered to increase available water during periods of stress by cultivar selection and changes in soil temperature.
Showing 1 to 10 of 38 Articles