bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potassium Fertilization of Alfalfa Grown on a Soil High in Potassium1
Authors: Barbarick K. A. 
Published: July 2010

AbstractMost Colorado soils contain adequate levels of plant‐available K. This study investigated the influence of up to 750 kg K ha−1 on four semidormant varieties of alfalfa (Medicago sativa L.) grown on a soil high in K (Nunn clay loam—Aridic Argiustoll) over 4 years. Fertilizer K significantly increased dry matter yield for the first 2 years and significantly increased the total alfalfa yields for the entire duration of the study. The overall yield response, however, was not cost efficient based on current K fertilizer costs. Along with the yield increases, K fertilizer consistently decreased Na plant concentrations, Na uptake, and soil levels of Na. It is postulated that the additional K suppressed Na uptake which possibly resulted in greater N2 fixation and dry matter production. A greenhouse study using four rates of K and Mg applied as K2SO4 and MgSO4, respectively, showed that both materials equally reduced Na uptake and increased yields of the ‘Baker’ cv. Consequently, the yield response to applied K in the field was not a nutritional response to K but resulted from the suppression of Na uptake. This K‐Na interaction produced significant yield responses in the field and the greenhouse even though the Nunn soil (a fine, montmorillonitic, mesic Aridic Argiustoll) is a non‐sodic soil.
Continuous Tillage and Rotation Combinations Effects on Corn, Soybean, and Oat Yields1
Authors: Dick W. A. , Van Doren D. M. 
Published: July 2010

AbstractFew studies report long‐term effects of various tillage and crop rotation practices. Studies were conducted to compare the relative ability of various tillage and crop rotation combinations (3 ✕ 3 factorial) to sustain corn (Zea mays L.), soybean (Glycine max L.), and oat (Avena sativa L.) yields. The tillage and rotation combinations were continuously applied for more than 20 years to a well‐drained Wooster silt loam (fine‐loamy, mixed, mesic Typic Fragiudalf), an imperfectly drained Crosby silt loam (fine, mixed, mesic Aeric Ochraqualf), and a very poorly drained Hoytville silty clay loam (fine, illitic, mesic Mollic Ochraqualf). Tillage treatments were no‐tillage; plow and then plant; and plow, disk, and plant. Rotation treatments on the Wooster and Hoytville soils included continuous corn, corn and soybean in a 2‐year rotation, and corn‐oats‐meadow in a 3‐year rotation. Only continuous corn was grown on the Crosby soil. Corn yields were always positively influenced by no‐tillage on the Wooster soil and negatively influenced on the Hoytville soil. The results obtained for the Crosby soil were mixed. The average yearly corn yield increase and decrease due to no‐tillage on the Wooster and the Hoytville soils were 1070 kg ha−1 and 503 kg ha−1, respectively. The negative response to no‐tillage on the Hoytville soil was primarily due to the large decrease in yield obtained as a result of the continuous corn rotation treatment (average annual yield decrease, 880 kg ha−1). Yield responses of soybean and oats on the Wooster and the Hoytville soils were similar to those observed for corn. When Phytophthora root rot resistant (tolerant) soybean cultivars were grown on the Hoytville soil with the standard cultivars which had been used during most of the experimental period, yield differences between the no‐tillage and plow treatments were essentially eliminated. This study suggests that yield reductions of corn and soybean associated with no‐tillage on heavy clay, very poorly drained soils may be reduced by rotating crops and/or by the use of disease resistant cultivars.
Cotton Response to Mepiquat Chloride1
Authors: Kerby T. A. 
Published: July 2010

AbstractThe potential for mepiquat chloride (1,1‐dimethylpiperidinium chloride) to control excess vegetative growth and increase yield of cotton (Gossypium hirsutumL.) was evaluated under a wide range of environmental conditions in 35 replicated experiments conducted in the San Joaquin Valley of California from 1979 to 1983. Predominant soils were thermic Xeric Torriorthent's and typic Torriorthents. Yield response to mepiquat chloride (MC) has varied in production fields as well as in these tests. The focus of this study was to identify those variables which have contributed to the variability observed. Plot size among experiments varied from 15 m2to 1.3 ha. Mepiquat chloride was applied at 49 g ha−1when bloom counts reached 0.7 white blooms m−1row and plant height was between 46 to 61 cm. Overall, MC treated plots yielded 1309 compared to 1299 kg ha−1lint for control plots and the yield response varied significantly among experiments. Forty‐six percent of this variability could be accounted for by number of heat units for the growing season and by the final plant height of control plants. Yield increases occurred when the growing season was short or when final height of control plants was either shorter or taller than normal. Yield decreases occurred when heat units ranged between 2600 to 3000 and final control plant height ranged from 90 to 110 cm. Height reduction due to MC treatment varied according to plant height (r=0.57 for n= 17) and was maximal at 105 cm. Mepiquat chloride reduced main stem nodes by 1.0, gin turnout by 0.4%, and lint proportion by 0.3%; increased percent of final yield harvestable on 19 September by 5%, fiber strength by 3 kN m kg−1, micronaire by 0.06 units, and petiole NO3‐N at first open boll by 0.5 g kg−1; and had no effect on fiber length, fiber elongation, petiole PO4‐P and K, or NO3‐N at first bloom. Typical seasonal heat units and control plant heights in the San Joaquin Valley fall within the range where a favorable yield response to MC is not predicted.
Hybrid and Irrigation Effects on Conservation Tillage Corn in the Coastal Plain1
Authors: Karlen D. L. , Sojka R. E. 
Published: July 2010

AbstractConservation tillage (CT) can reduce soil erosion loss, but to be voluntarily implemented, corn (Zea maysL.) yield must not be reduced when compared with conventional tillage practices such as disking periodically (DP). We compared CT and DP treatments with and without irrigation on Norfolk (fine‐loamy, siliceous, thermic Typic Paleudults) sandy loam for 4 yr to determine if hybrid selection, water management, or soil temperature caused CT corn yields to be lower than where DP was used for seedbed preparation. Plant emergence and early season growth were consistently more rapid and uniform with DP than with CT. Water was conserved in CT treatments, but this increased grain yield only under nonirrigated conditions in 1981. Average daily soil temperature for 14 days after planting was 19 °C for both tillage systems and 22 or 24 °C for CT and DP treatments for days 15 to 28. When averaged for 28 days after planting, soil temperatures in CT treatments were 0.5 °C less at 0800 h and 1.1 °C less at 1500 h. Those soil temperature differences do not appear to be sufficient to cause slower, nonuniform emergence, growth, and generally lower corn grain yield when CT practices are used in this region, although maximum yield potential for corn appears to be physiologically initiated very early during the growing season. Therefore, a successful conservation tillage system must promote rapid, uniform germination, and emergence of all plants.
Fluxes of Ammonia Over an Alfalfa Field1
Authors: Dabney Seth M. , Bouldin David R. 
Published: July 2010

AbstractThe cycling of atmospheric ammonia has significance to both agricultural and global N balances. Field data concerning the magnitude of ammonia exchange is not available for many crops and ecosystems. The vertical flux of gaseous plus particulate ammonia above an extensive alfalfa (Medicago sativaL.) canopy was measured periodically over a one‐yr period. The gradients of mean wind speed, mean temperature, and mean ammonia concentration were simultaneously determined during one‐h runs and were combined to estimate average ammonia flux. Total ammonia was determined using a treated filter paper sampling technique. A diurnal pattern of ammonia evolution during the day and deposition at night was observed. At least a portion of the deposition at night was due to the influence of a local ammonia source. The magnitude of the fluxes was small. The nighttime observations yielded an estimated yearly gain of 1.6 kg N ha−1. The daytime observations, excluding periods of 10 days for each of three hay harvests yielded an estimated annual loss of 1.2 kg N ha−1. During the three periods of hay harvesting an additional 2.3 kg N ha−1was estimated to have been lost. The data indicate ammonia exchange over the alfalfa field was of little importance to the agricultural N balance, but has relevance to understanding global N cycling.
Diurnal and Seasonal Variation in Dinitrogen Fixation (Acetylene Reduction) Rates by Field–Grown Soybeans1
Authors: Denison R. F. , Sinclair T. R. 
Published: July 2010

AbstractNo data exist that represents in situ, continuous observations under field conditions of changes in dinitrogen fixation potential through diurnal cycles. Acetylene reduction responses of soybean [Glycine max(L.) Merr.] plants to changes during the diurnal cycle and during seasonal developmental changes were monitored using a continuous flow system with very low acetylene concentration. These data were used to assess the relative effects on acetylene reduction rates of environmental and plant ontogeny variables. During the diurnal cycle, acetylene reduction rates generally peaked late in the afternoon and then declined through the night. However, the night rates did not fall below half of the daily maximum. Within individual days, rates were more closely correlated with soil temperature than with photosynthetically active radiation. A consistent link was not observed between acetylene reduction rates and any particular stage of ontogeny. These results, and a reexamination of published reports, suggest that dinitrogen fixation rate in soybeans is not closely coupled to current photosynthetic rates under field conditions.
Grain Sorghum Yield and Yield Component Response to Timing and Number of Irrigations1
Authors: Hooker M. L. 
Published: July 2010

AbstractEfficient use of irrigation water becomes more essential as the availability of this resource declines. Research evaluating the effect of timing and number of irrigation water applications on yield and yield components of grain sorghum [Sorghum bicolor(L.) Moench] was initiated in 1976. The experiment was conducted on a Richfield silty clay loam (fine, montmorillonitic, mesic, Aridic Argiustoll). Irrigation water treatments were applied at preplant (PP), PP + growth differentiation (GD), PP + boot (B), PP + GD + B growth stages, and PP + initiation of irrigation at 50% available soil moisture. Maximum grain yields were consistently achieved when three or more irrigations were applied. Two irrigation water applications reduced grain yields, but the timing of the in‐season water application (GD or B) had no effect on yields. Yield components were evaluated in 1982 and 1983 to determine what effect timing of water application had on these parameters. Irrigation at GD resulted in a greater number of kernels per head and per unit area, whereas applications at B increased seed weight. Head weight showed no response to the timing of water applications, suggesting that the same amount of dry matter was accumulated in the head whether water was applied at GD or B. Therefore, producers of grain sorghum have a broader time period over which to apply limited quantities of irrigation water without reducing grain yield than is reported in most literature. However, if maximum yield potential is desired, it is necessary to have adequate water available to the plant at GD to set the maximum number of kernels.
Responses of Sugarbeet to Deficit, High‐Frequency Sprinkler Irrigation. II. Sugarbeet Development and Partitioning to Root Growth1
Authors: Hang An N. , Miller D. E. 
Published: July 2010

AbstractThe water requirement of sugarbeet (Beta vulgarisL.) has been studied extensively throughout the western states. However, there is limited information about the response to prolonged deficit irrigation, particularly on sandy soils with low water‐holding capacity. The present study was conducted to determine the effect of deficit, daily sprinkler irrigation on rates and growth characteristics of sugarbeet grown on loam and sandy soils (Xerollic Camborthids and Xeric Torripsamments, respectively). On loam soil, irrigation rates less than estimated evapotranspiration (Et) did not significantly affect the leaf blade petiole or top/root ratio until 4 to 8 weeks after they were initiated. Afternoon wilting of leaves was observed at the 15, 17, 39, and 41% Et irrigation rates, but they regained turgor during the night. After about 8 weeks of 15 and 17% Et irrigation rates specific leaf weight increased significantly. Top and root growth rates increased as the amount of water applied increased. Partitioning to root growth was maximum (75.8%) at irrigation rates equivalent to about 58% estimated Et. On sandy soil, irrigation rates less than estimated Et depressed growth, and shortened leaf life cycle. Leaf blade petiole and top/root ratio were not affected until after 6 weeks of deficit irrigation. Low irrigation rates depressed leaf expansion and resulted in very high specific leaf weights. Top and root growth rates increased with water application up to rates equivalent to 100% estimated Et. Maximum partitioning to root growth of 74.4% occurred at 100% irrigation rate. Increasing irrigation to 115% estimated Et gave no increased benefits. In both soil types, leaf blade petiole and top/root ratios were generally affected later and much less by drought than were leaf area, specific leaf weight and crop growth rate.
Alfalfa Dry Matter and Nitrogen Production, and Fertilizer Nitrogen Response in Legume‐Corn Rotations1
Authors: Hesterman O. B. , Sheaffer C. C. , Barnes D. K. , Lueschen W. E. , Ford J. H. 
Published: July 2010

AbstractNondormant alfalfa (Medicago sativaL.) germplasms have been selected for increased storage of reduced N in roots and crowns. It is important to learn how this improved germplasm will affect yield of a subsequent nonlegume crop in a cropping sequence. Our objectives were to (i) compare effects of two harvest systems on the forage yield, quality, and N incorporated for the nondormant experimental ‘MN ROOT N’ population and the moderately dormant cultivar ‘Saranac AR’; and (ii) evaluate effects of previous cropping and fallow treatments on grain yield and N response of a subsequent corn crop. Field studies were conducted in 1982 and 1983 at four Minnesota locations on a Hubbard loamy sand (Udorthentic Haploboroll), Webster silt loam (Typic Haplaquoll), Normania clay loam (Aquic Haplustoll), and Webster clay loam (Typic Haplaquoll). First‐year rotation components included seeding year alfalfa, corn (Zea maysL.), soybean [Glycine max(L.) Merr.], and fallow. The second‐year component was corn. Alfalfas were subjected to two harvest systems. The two alfalfas did not differ in total forage production, but Saranac AR tended to have higher crude protein and digestible dry matter concentrations than MN ROOT N. MN ROOT N had greater root dry matter yield and N concentration than Saranac AR. Total N incorporated was 14% greater for MN ROOT N than Saranac AR under the one‐cut system and 41% greater under the three‐cut system. Total N incorporation was 84% greater for the one‐cut (157 kg ha−1) than for the three‐cut (85 kg ha−1) system. Differences in second‐phase corn yields were correlated with differences in first‐phase alfalfa N incorporation at one of four locations. Alfalfa was a more effective first‐phase rotation crop for corn than corn, soybean, or fallow. With no N applied, second‐phase corn grain yields were 84% greater after first‐phase alfalfa (6.8 M g ha−1), 33% greater after soybean (5.1 Mg ha−1), and 61% greater after fallow (6.1 Mg ha−1) than after corn (3.7 Mg ha−1). Alfalfa cultivars and harvest systems affected the yield of a subsequent corn crop; however, harvest system effects were greater.
Winter Legumes as a Nitrogen Source for No‐Till Grain Sorghum1
Authors: Hargrove W. L. 
Published: July 2010

AbstractBecause winter legume cover crops may provide significant quantities of N while conserving soil and water resources, the role of legumes in conservation tillage production systems warrants renewed attention. The objectives of this study were (i) to determine the N contribution of several legumes to a subsequent crop of grain sorghum [Sorghum bicolor(L.) Moench] under no‐tillage management and (ii) to determine the influence of legume cover crops on soil fertility status. A field experiment was conducted in which four winter legumes, one nonlegume, and a no cover crop treatment were studied over a 3‐yr period. In addition, four fertilizer N rates (0, 28, 56, and 112 kg N ha−1) were applied to no‐till grain sorghum. Grain sorghum did not respond to fertilizer N when following a legume cover crop but responded to as much as 99 kg N ha−1when following a nonlegume cover crop or no cover crop. A mean estimate of 72 kg N ha−1was obtained for the fertilizer N replaced by the legume. The effects of the legume cover crops on soil fertility status included: (i) a lower pH, (ii) a redistribution of K+to the soil surface from deeper in the soil profile, and (iii) a lower C/N ratio in soil organic matter. Since fertilizer N represents a sizeable portion of the fossil fuel energy required for nonleguminous row crop production, the estimated N contribution of legume cover crops represents a significant energy savings, enhancing the conservation value of a no‐tillage production system.
A Nitrogen and Water Response Surface for Sprinkler‐Irrigated Broccoli1
Authors: Beverly R. B. , Jarrell W. M. , Letey John 
Published: July 2010

AbstractFarmers typically apply large amounts of both N and water in commercial vegetable production. As costs of both inputs increase, and with mounting concern over nitrate leaching and non‐point source water pollution, the need for information on optimal management of both resources grows. We investigated the combined effects of five N application rates (0, 87, 190, 255, and 331 kg ha−1) and a continuous irrigation variable (1.14 to 32.9 cm of water, or 0.05 to 1.52 times net pan evaporation) applied by a line‐source sprinkler system on broccoli (Brassica oleraceaL., Botrytis group) growth rates and yield. Growth rates generally increased with both water and N treatments, although some interactions emerged. Harvested fresh weights continued to increase throughout the range of treatments, applied, with maximum yields in excess of 20 Mg ha−1. Yield (Mg ha−1) responded to N (kg ha−1) and water applied following seedling establishment (cm) according to the equation Y−1.03 + 0.0498 N− 8.73 × 10−5N2+ 1.23 × l0−3NW+ 0.272 W− 8.20 × 10−3W2, where Yis yield, Nis nitrogen, and Wis water applied after seedling establishment. Analysis of the resulting response surface indicated that under these conditions of frequent sprinkler irrigation (approximately twice weekly), relatively low N rates (140 kg ha−1) provided the lowest combined N and water cost for 10 Mg ha−1) yield. Further, yields increased with higher N and water rates, although quality must also be considered
Carbon Dioxide Partial Pressure in Lysimeter Soils1
Authors: Robbins Charles W. 
Published: July 2010

AbstractThe carbonate chemistry portion of mechanistic salinity models is generally the weak link in describing salt reactions in soils. This is primarily due to a lack of available soil atmosphere CO2data. Carbon dioxide concentrations were measured at 0.25, 0.50, and 0.75 m depths in 0.30 m diam lysimeters containing 1.0 m of sodic soil. Four non‐cropped treatments included a check, gypsum, fresh manure, and chopped alfalfa irrigated weekly with 70 mm (5.0 1) of tap water (EC=0.7 and SAR=1.7). Six cropped treatments included barley (Hordeum vulgare), alfalfa (Medicago sativaL.), Sordan [Sordan is a trade name for a sorghum (Sorghum bicolor), sudangrass (Sorghum sudanesehybrid], Sordan + leaching, cotton (Gossypium hirsutumL.), and tall wheatgrass (Agropyron elongatum). The cropped lysimeters were irrigated at 1.25 times the consumptive use since the previous irrigation (0.20 leaching fraction). Soil PCO2values were decreased by the gypsum treatment and increased by all other treatments as compared to check. Cotton and barley had the lowest PCO2values for the cropped treatments and Sordan had the highest (frequently above 16 kPa). The PCO2levels were affected by applied organic matter source, crop, plant growth rate, irrigation water application and leaching.
Plant Interaction Among Poa Annua, Poa pratensis, and Lolium perenneTurfgrasses1
Authors: Brede A. D. , Duich J. M. 
Published: July 2010

AbstractAnnual bluegrass (Poa annuaL.) Kentucky bluegrass (Poa pratensisL.), and perennial ryegrass (Lolium perenneL.) differ in their competitive abilities. To properly maintain stands of these species, turfgrass managers need specific information on how these grasses interact with one another and what conditions favor the growth of one species over another. The purpose of this study was to determine the effects and locations (above vs. below ground) of plant interaction among these turfgrasses under field conditions. Furthermore, information was sought on the effects of environmental variables on the competitive potential of these grasses. Plant interaction was studied by means of partitioned boxes, installed within a mature sod environment in the field. Species pairs were established in alternating chambers within the apparatus and were evaluated after 1 yr of growth. Below‐ground partitions were used to confine the interaction to aboveground in one apparatus, and vice versa in another. Interspecific interaction was significant, both above and below ground, even though a relatively close mowing height (3.1 cm) and seemingly ample nutrients and water were supplied. All three species responded to interspecific interaction with reductions in root and shoot parameters. Competitive ability of perennial ryegrass was generally greatest below the ground, whereas Kentucky and annual bluegrass excelled above the ground. Tillering rate was used to assess the competitive potential of the three species under establishment conditions. Relative tillering rate, measured in the field via the growth of individual, transplanted shoots, generally increased with increasing temperature, daylength, and precipitation. Annual bluegrass had the highest rate of tillering of the three species during early autumn, whereas perennial ryegrass had the highest rate during early summer. Plant interaction among these species was characterized as the summation of their ability to proliferate tillers under establishment conditions and their ability to compete above and below ground under dense, solid‐stand conditions.