bluuebunny/crossref_metadata_2025_split huggingface dataset:
Root Temperature and Calcium Level Effects on Winter Wheat Forage: II. Nutrient Composition and Tetany Potential
Authors: Miyasaka S. C. , Grunes D. L. 
Published: July 2010

AbstractWheat pasture poisoning is a metabolic deficiency of Ca, and sometimes Mg, in ruminants. It occurs particularly in the spring, when K and N concentrations in the shoots, and the equivalent ratio of K/(Ca+Mg) in the forages, increase suddenly. To determine the effects of an increased root temperature and four Ca levels on the forage quality of winter wheat (Triticum aestivum L. ‘Centurk’), seedlings were grown under three root temperature regimes (constant 8 °C, constant 16 °C, and increasing from 8–16 °C), in nutrient solutions with four Ca levels (0.2, 0.6, 2.0, and 5.0 mM). Plants grown at 8 °C root temperature had significantly lower Ca, Mg, K, and N concentrations in the shoots, and a significantly lower equivalent ratio of K/(Ca + Mg), compared to those grown at 16 °C. Plants transferred from 8 to 16 °C had significantly increased Ca, Mg, K, and N concentrations in the shoots over time, as levels changed from those characteristic of low root temperature plants to those characteristic of high root temperature plants. Plants transferred from 8 to 16 °C also had an equivalent ratio of K/(Ca + Mg) that increased 1 wk after the transfer, indicating a greater tetany hazard. The doubling in forage K and N concentrations, and the increase in the equivalent ratio of K/(Ca+Mg) as root temperatures increased from 8 to 16 °C, are similar to those found in field‐grown plants at the time of tetany for grazing beef cattle. Thus, root temperature could be a key environmental factor involved in tetany, modifying the nutritional quality of winter wheat.
Phosphorus Management for Continuous Corn‐Cowpea Production in a Brazilian Amazon Oxisol
Authors: Smyth T. J. , Cravo M. S. 
Published: July 2010

AbstractAlthough Oxisols occupy extensive areas in the Amazon, few studies have addressed their fertilizer P requirements for sustained, long‐term crop production. This field study was conducted to evaluate initial and long‐term responses to P rates and placement by corn (Zea mays L.) and cowpea (Vigna Unguiculata L.) when grown in annual rotation during five consecutive years in a Xanthic Hapludox (clayey, kaolinitic, isohyperthermic) near Manaus, Brazil. Effects on yields of sole broadcast P rates of 0, 22, 44, 88 and 176 kg ha−1 in split‐plot combination with subplot banded P rates of 0, 11, 22 and 44 kg ha−1 were evaluated over 11 total crops. Banded P at 11 kg ha−1 was applied to every crop and rates of 22 and 44 kg P ha−1 were only applied to the initial eight and four crops, respectively. Residual effect of broadcast P, as measured by both yields and Mehlich 1 soil P, were greater at high rates. Although cowpea yields were increased up to the highest band rate, no response in corn yields were observed beyond the rate of 22 kg P ha−1. At equal amounts of applied P, banded P provided greater yields than broadcast P during the initial crops. Total corn and/or cowpea yields, after 11 crops, were similar for all broadcast and band combinations at equal amounts of total applied P. The absence of a cumulative yield difference among placement methods indicated that banded placement of 22 and 44 kg P ha−1 to corn and cowpea, respectively, would be the best method of applying P to sustain long‐term crop production under the manual tillage practices used in the region.
Soil Aluminum Effects on the Growth and Aluminum Concentration of Sorghum
Authors: Shuman L. M. , Ramseur E. L. , Duncan R. R. 
Published: July 2010

AbstractAluminum toxicity, especially in the subsoil, is a major limiting factor in crop production on acid soils. A greenhouse experiment with sorghum [Sorghum bicolor (L.) Moench)] was conducted on topsoils and subsoils of four widely different acid southeastern soils [Congaree (Typic Udifluvent), Pacolet (Typic Hapludult), Norfolk (Typic Paleudult), Pelham (Arenic Paleaquult)] to determine relationships between plant growth and levels of Al and other major cations in the soil. Plants were grown for 6 wk after which plant height, weight, and root weight were recorded. Plant tissue was analyzed for Al, Mn, Ca, K, and P concentrations. Soils were analyzed for pH, 1 M KCl‐exchangeable Al, Al saturation of the CEC, and 0.01 M CaCl2‐extractable Al. Major soil solution ions were also determined and the activity of Al species was calculated using GEOCHEM. Reductions in plant growth were ascribed to Al toxicity and not to Mn toxicity or Ca deficiency. In general the correlations between plant growth and soil Al levels were significant for topsoils [r = −0.53* to −0.91** (P = 0.05 and 0.01, respectively)] but nonsignificant for subsoils. Topsoil data and subsoil data were markedly different; subsoil Al values were low compared to those for topsoil (exchangeable Al 49 vs. 58 mg kg−1), but the plants grew better in topsoils (51 vs. 29 cm). The best predictors of plant height and plant Al were soil solution Al3+ activity (r = −0.91**, 0.83**) and Al saturation of the exchange complex (r = −0.89**, 0.82**), but CaCl2,‐extractable Al was also correlated well (r = −0.78**, 0.94**).
Turf Growth and Performance Evaluation Based on Turf Biomass and Tiller Density
Authors: Lush W. M. 
Published: July 2010

AbstractVisual rating systems are often used for evaluating turfs because of the absence of biological criteria associated with growth and performance. The purpose of this paper is to examine whether describing turfs quantitatively in terms of their biomass and tiller density can contribute to our understanding of turf growth, and form the basis of an objective, quantitative system of turf assessment. Measurements of the aboveground biomass, and the corresponding tiller densities of turfs, were gathered mostly from published work. The data indicate that turfs, like many crowded populations of plants, are governed by a rule of population biology called the power, or thinning, rule. As applied to turfs, conformity to the power rule means that biomass is highest at the lowest tiller densities, with the consequence that very hard‐wearing turfs may inevitably be coarse textured. Estimates of the upper limits to biomass at tiller densities commonly found in turfs of different texture, suggest that there is more potential for the improvement of coarse turfs than fine ones. For turf assessment, biomass (alone or divided by tiller density to estimate mean tiller mass), is a useful guide to wear resistance. A measure of the fineness of turf texture is proposed. The use of biomass density (biomass divided by turf height) as a predictor of golf ball roll and lie is discussed. When turfs are at full cover, one of the parameters of the power rule, the biomass intercept log c, which can be derived from single measurements of biomass and tiller density, is proposed as a measure of the ability of turfs to accumulate biomass. Log c has the advantage of being independent of tiller density and of differences in nonlimiting management resources
Kernel Abortion and Distribution of Mineral Elements Along the Maize Ear
Authors: Mozafar A. 
Published: July 2010

AbstractKernel abortion, especially prevalent at apical ear positions, results in malformed (nubbin) ears and substantial yield reduction in maize (Zea mays L.). Although deficiencies of N, P, K, Mn, Zn, and B are reported to cause nubbin ears, it is not known whether the concentrations of these or other elements are different in the aborted and normal (fully developed) kernels. In this study, the concentrations of 12 mineral elements in the kernel and cob tissue from apical, middle, and basal positions in normal and nubbin maize ears having aborted kernels at their tips were compared. The concentrations of N, P, K, Mg, Ca, Na, B, Zn, Cu, and Mn in the kernels and P, Na, Ca, Fe, B, Zn, Cu, Mn, and Mo in the cobs were the same in nubbin and normal ears. Kernel concentration of Mo and cob concentrations of N, K, and Mg were significantly higher in nubbin than in normal ears. In the normal ears, concentrations of K and Zn in the kernels and N, P, K, and Zn in the cobs were higher in apical than in basal ear positions. In nubbin ears, concentrations of N and Zn were higher in apical (aborted) than in basal (normal) kernels. In cobs of nubbin ears, however, concentrations of N, P, K, Mg, Ca, Zn, and Mn were higher in apical positions adjacent to aborted kernels as compared with basal positions adjacent to fully developed normal kernels. Since the concentration of no element was lower in the nubbin ear than in the normal ear, an insufficient supply of the tested mineral elements was ruled out as a cause of kernel abortion. From this study, it is not certain whether accumulation of elements in the apical portion of the cob precedes or follows kernel abortion. A malfunction in the transport of mineral elements and carbohydrates from the leaves to the kernels via phloem or a disturbance in the transfer of mineral elements between cob and kernel tissues at their junction may be concomitant with (but not necessarily the cause of) kernel abortion.
No‐Till Proso Millet Production
Authors: Anderson R. L. 
Published: July 2010

AbstractProso millet (Panicum miliaceum L.) is well‐adapted for the Central Great Plains and is commonly grown with a mechanical tillage production system in a winter wheat (Triticum aestivum L.)‐milletfallow rotation. The use of tillage results in extensive wind and water erosion, however. Research was conducted on a mesic Aridic Paleustoll soil near Akron, CO, to determine proso millet response to a no‐till production system. Eliminating tillage increased proso millet grain yields from 2290 to 2730 kg/ha in 1985 and from 1200 to 1610 kg/ha in 1986, compared to tilled proso millet production. Water use efficiency (WUE) also increased in the no‐till system. Nitrogen fertilizer at 22 or 44 kg N/ha increased grain yield, N concentration of grain, and WUE of no‐till proso millet regardless of whether growing‐season precipitation was near normal or 33% below the long‐term site average of 212 mm. Atrazine [6‐chloro‐N‐ethyl‐N'‐(1‐methylethyl)‐l,3,5‐triazine‐2,4‐diamine] applied either in the previous fall or 60 d before planting provided effective in‐crop weed control for the no‐till production system. Atrazine applied in the spring required two paraquat (1,1'‐dimethyl‐4,4'‐bipyridinium ion) applications at 0.28 kg ai/ha to control weeds the previous fall. Nitrogen fertilizer did not affect the bioactivity or soil persistence of atrazine.
Nitrogen Fertilizer Recovery by Corn in Monoculture and Rotation Systems
Authors: Varvel G. E. , Peterson Todd Andrews 
Published: July 2010

AbstractCrop rotations including legumes have increased in importance because of their potential to reduce large inorganic N fertilizer needs for corn [Zea mays L.] and other crops. This study was conducted to determine N fertilizer recovery by corn in monoculture and rotational systems. Corn was grown under rainfed conditions on a Sharpsburg silty clay loam (fine, montmorillinitic, mesic, Typic Argiudoll) in four cropping systems: (i) continuous corn monoculture, (ii) a 2‐yr soybean [Glycine max (L.) Merr.]‐corn rotation, (iii) a 4‐yr rotation of oat [Avena sativa (L.)] + clover [80% Melilotus officinalis (L.) and 20% Trifolium pratense]‐grain sorghum [Sorghum bicolor (L.)]‐soybean‐corn, and (iv) a 4‐yr rotation of soybean‐grain sorghum‐oat + clover‐corn at Mead, NE. Broadcast applications of 15N‐depleted NH4NO3 were made at 90 and 180 kg N ha−1 in 1985 and 1986 to evaluate N fertilizer recovery by corn in each cropping system using isotopic methods. Nitrogen recovery determined by isotopic methods was significantly higher for corn in rotation vs. corn in monoculture, averaging 58.6 vs. 52.3% and 49.8 vs. 43.4% at the 90 and 180 kg N ha−1 rates, respectively. In contrast, fertilizer N recovery estimated by the difference method was much greater in continuous corn vs. N recovery in corn following oat + clover in the 4‐yr rotation. These differences indicated that N fertilizer applied to corn in each cropping system appeared to be entering different sizes and types of organic soil N pools, resulting in apparent differences in N immobilization. Our results demonstrate problems exist in estimating fertilizer N recovery with both methods (isotope or difference) and before accurate N recovery estimates by corn or any other crop can be made in complex soil and crop management systems, procedures must be developed to explicitly follow N fertilizer pathways (immobilization, denitrification, volatilization, leaching, etc.). Until that time, correct interpretations with either method can be obtained within a system if all available information is used regarding both soil and crop factors.
Sustaining Soil Nitrogen for Corn Using Hairy Vetch Cover Crop
Authors: Utomo M. , Frye W. W. , Blevins R. L. 
Published: July 2010

AbstractNitrogen fertility management is often complicated by inadequate supply, low efficiency, high losses, and the potential of polluting water resources. This study was conducted in 1984 and 1985 on a Maury soil (fine, mixed, mesic Typic Paleudalfs) in Kentucky to determine the role of a hairy vetch (Vicia villosa Roth) cover crop in sustaining soil N for corn (Zea mays L.) under no‐tillage and conventional tillage. Winter cover treatments of hairy vetch, rye (Secale cereal L.), and corn residue were combined factorially with N rates of 0, 85, and 170 kg ha−1 in the two tillage systems. Total soil C and N in the 0‐ to 7.5‐cm depth, averaged across treatments and sampling dates, were 21.8 and 2.07 g kg−1, respectively, in no‐tillage and 16.6 and 1.70 g kg−1 in conventional tillage. Values were 19.8 and 1.99 g kg−1, respectively, with hairy vetch and 18.8 and 1.80 g kg−1 with rye. Conventional tillage caused rapid mineralization of soil N, as indicated by greater inorganic N approximately 6 wk after plowing. Nitrate apparently leached deeper into the soil under no‐tillage than conventional tillage. Grain yield without N on the vetch treatment was essentially equal to yields with 170 kg N ha−1 on the rye or corn residue treatments—6.75, 6.75, and 6.65 Mg ha−1, respectively. Grain yield with vetch and 170 kg N ha−1 was 7.85 Mg ha−1. Although vetch provided a substantial amount of N, results suggested that to obtain optimum corn yields N fertilization should be reduced little, if any, with a vetch cover crop. Vetch appeared to add grain yield instead of reduce the need for N fertilizer.
Soybean Growth Responses and Intraspecific Competition from Simulated Seedcorn Maggot Injury
Authors: Higley Leon G. , Pedigo Larry P. 
Published: July 2010

AbstractThe consequences of early‐season insect injury on subsequent plant development often are obscure. Further, such injury may produce intraspecific competition between injured and uninjured plants. We examined these issues by studying the impact of simulated seedcorn maggot (SCM) [Delia platura (Meigen) (Diptera: Anthomyiidae)], injury to soybean [Glycine max (L.) Merr.], in field studies from 1983 to 1986 in Iowa. Simulated SCM injury includes plant density (simulating stand reductions) and normal to Y‐plant ratios (simulating various proportions of plumule injury). The Y‐plants are plants that have had the plumule destroyed and subsequently develop two main stems. Our objectives were to describe how simulated SCM injury affected: (i) development of soybean stands, individual normal plants, and individual Y‐plants, and (ii) intraspecific competition between normal and Y‐plants. Higher crop growth rates (CGRs) and leaf area indices (LAIs) were associated with higher plant densities. Generally, plumule‐injured plants were more affected by plant density than uninjured plants. Examinations of competition between uninjured and plumule‐injured plants indicated that uninjured plants were competitively superior to plumule‐injured plants. Competitive interactions were influenced by plant density, Phenological delay associated with plumule injury contributed to height differences between uninjured and injured plants, which led to substantial differences in leaf area, number of nodes, and other developmental parameters between injured and uninjured plants. Consequently, unequal competitive ability between uninjured and injured plants was identified as a major consequence of plumule injury.
Overview of Long‐Term Agronomic Research
Authors: Mitchell C. C. , Westerman R. L. , Brown J. R. , Peck T. R. 
Published: July 2010

AbstractRenewed interest in low‐input and sustainable crop production has rekindled interest in long‐term agronomic research. Research plots that have been monitored continuously since the late 19th Century exist in several states. Twenty‐five experiments have been identified that have been monitored for over 25 yr; 12 of these are more than 50 yr old. Yield and treatment records provide valuable information on the effects of cropping systems, tillage, manuring, and fertilization practices on yields and on soil physical and chemical properties, Most of these very early tests were non‐replicated studies using large plots and crop rotation systems. Four of America's oldest, continuous agronomic research tests were reviewed in more detail: (i) Illinois' “Morrow Plots” (c. 1876), (ii) Missouri's “Sanborn Field” (c. 1888), (iii) Oklahoma's “Magruder Plots” (c. 1892) and (iv) Alabama's “Old Rotation” (c. 1896). All of these are listed on the National Register of Historical Places. These studies document that long‐term crop production can be sustained and improved in different regions and on different soils of the USA. Long‐term studies have shown that crop rotations and attention to recognized and established soil fertility practices, which may or may not include legumes and manuring, are essential to maintaining high, sustained production.
Noninvasive Measurement of Internal Oxygen Concentration of Field‐Grown Soybean Nodules
Authors: Denison R. F. , Smith D. L. , Legros T. , Layzell D. B. 
Published: July 2010

AbstractRecent research suggests that decreased N2 fixation with drought, defoliation, or nitrate exposure is due to decreased nodule permeability to O2. Decreased O2 permeability would result in lower O2 concentration in the nodule interior and a decreased rate of bacteroid respiration in support of N2 fixation. To test this hypothesis under field conditions, a noninvasive method (based on spectrophotometry of leghemoglobin) was used to measure O2 concentration within intact, attached nodules of soybean [Glycine max (L.) Merr.]. A detopping (shoot removal) treatment, which interrupted phloem supply to nodules, resulted in lower internal O2 concentration relative to controls, suggesting that nodule respiration was directly limited by O2 rather than carbohydrate. When the gas stream around a nodule was switched from pure N2 to pure O2, internal O2 concentration increased more rapidly in control nodules than in nodules attached to detopped plants. This difference in reoxygenation rate is also consistent with reduced nodule gas permeability after detopping. The method described here, with modifications, should be useful for a variety of field studies.
Simulated Growing‐Season Precipitation and Nitrogen Effects on Winter Wheat Yield
Authors: Engel R. E. 
Published: July 2010

AbstractAvailable water (precipitation plus stored soil water) is the principal factor that determines wheat (Triticum aestivum L.) yield patential and response to N in the Northern Great Plains. Field studies were conducted in 1987 and 1988 to determine the interactive effect of water and available N on ‘Redwin’ and ‘Centurk’ winter wheat yield. Seven fertilizer N levels and a line‐source sprinkler system created a wide range of N and simulated growing‐season precipitation (SGSP) regimes on a Yegen sandy loam (fine‐loamy, mixed, Typic Argiboroll). Wheat yield‐N‐SGSP functions revealed that yield and response to water were much greater in 1987 than 1988, when return from N was maximized (maximum economic yield or MEY). At 100, 200, and 300 mm SGSP, predicted MEY in 1987 averaged 2350,4019, and 5434 kg ha−1, respectively. In 1988, MEY was 9, 17, and 24% lower, respectively. High available N reduced yield from the maximum across all SGSP regimes in 1988, but not in 1987. High temperatures during grain fill in 1988 (23.1 °C, 4.7 °C: warmer than 1987), were likely the reason for differing yield‐NSGSP relations. Though Centurk yielded more than Redwin for most SGSP conditions, the N required for MEY or optimum N level. (ONL) was not greatly affected by cultivar. Due to less favorable growing conditions, the ONL was approximately 27% lower in 1988 than 1987. An acceptable fertilizer N strategy might be to raise the ONL level to 100 kg ha at 100 mm growing‐season precipitation, then adjust N upward 1 kg ha−1 for every 3 mm rise in available water.
Chloride Fertilizer Effects on Winter Wheat Inoculated with Fusarium culmorum
Authors: Engel R. E. , Grey W. E. 
Published: July 2010

AbstractStudies in the Northern Great Plains indicate that Cl fertilizers sometimes increase yield and reduce the severity of root diseases in small grains. Little information exists from this region on the relationship between Cl and common root rot incited by Fusarium culmorum (W.C. Sm.) Sacc., or the effect of Cl on winter wheat (Trificum aestivum L.) yield. The objectives of this study were to address these issues. Field experiments were conducted in south central Montana during 1988 and 1989 on a Fort Collins soil (fine‐loamy, mixed, mesic Ustollic Haplargids) that contained 57 and 39) kg Cl ha−1 (0−120 cm), respectively. The experiment consisted or two cultivars of winter wheat (Redwin and Cree), three seed treatments (heat sterilized F. culmorum, live F. culmorum plus chemical protectant, and live F. culmorum, and four CI fertilizer levels (0, 22.5, 45, and 90 kg Cl ha−1) in complete factorial arrangement. In. spection of lower stems and subcrown internodes at the soft dough stage indicated no effect from Cl on disease severity. Chloride fertilizer significantly increased grain yield in 1988 (P < 0.001), but not in 1989. In 1988 grain yields at 22.5, 45, and 90 kg Cl ha−1 were not different and averaged 3306 kg ha−1, or 227 kg ha−1 more than plants not receiving Cl. Whole plant Cl concentrations at heading and indigenous soil Cl were not reliable predictors of yield response to C1 fertilizer. Seasonal factors may be important in defining the likelihood of a response to Cl fertilizer in addition to soil and plant Cl status.
Cottonseed Preparation for Hydraulic Planter
Authors: Bordovsky J. P. , Lyle W. M. , Onken A. B. 
Published: July 2010

AbstractThe operation of a newly developed mobile irrigator planting system required seed of upland cotton (Gossypium hirsutum L.) to be stored in an aqueous gel slurry for up to 24 h prior to planting. Prolonged anaerobic conditions in the slurry resulted in poor cottonseed germination. Tests were conducted to determine if H2O2 would react with small amounts of starch‐based material in the slurry mixture and produce sufficient O2 to maintain seed germination. A laboratory seed germination test was conducted with three seed treatment factors considered (i) seed soaking or priming vs. nonpriming prior to placement in the slurry; (ii) level of H2O2 in the water used to mix the slurry – 0.0, 0.02 and 0.04 M, and (iii) the level of starch‐based material in the dry gel concentrate – 0.0, 1.0 and 5.0%. Additional tests were conducted to determine if O2 was produced from H2O2 reacting to components of the seed/gel slurry other than the starch material. The level of starch‐based material had no effect on germination, 0.02 and 0.04 M H2O2 solutions significantly improved final cottonseed germination over treatments with no H2O2 and nonprimed seed had significantly higher final germination than the primed seed, Tests indicated the volume of O2 released by H2O2 reacting with cottonseed is far greater than that released by H2O2 reacting with the starch. Therefore, the starch material was not required in the slurry mixtures..