bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field Response of Maize to a VAM Fungus and Water Management
Authors: Sylvia D. M. , Hammond L. C. , Bennett J. M. , Haas J. H. , Linda S. B. 
Published: July 2010

AbstractMycorrhizae improve plant nutrient uptake and are known to affect the water relations of plants grown in growth chambers and greenhouses. This paper summarizes a 3‐yr field study that tested the effects of mycorrhizae and water management on the growth and grain yield of maize (Zea mays L.). In each year, two inoculation treatments (inoculated or not with Glomus etunicatum Becker and Gerdemann) and three water‐management treatments (fully irrigated, moderate stress, and severe stress) were applied to fumigated and fertilized Millhopper fine sand (loamy, siliceous, hyperthermic Grossarenic Paleudult). Inoculum was placed in a furrow 10 cm deep at an average rate of 1500 propagules per meter of row. Six to 7 wk after planting, colonization ranged from 0 to 6% of total root length on noninoculated plants and from 10 to 61% on inoculated plants. Twelve to 13 wk after planting, colonization ranged from 2 to 30% on noninoculated plants and from 21 to 56% on inoculated plants. Water stress had little effect on root colonization. By 52 d after planting, one more leaf had appeared and one additional leaf had formed a collar on inoculated plants. Inoculation increased the concentrations of P and Cu in both shoots and grain on all measurement dates. Overall, grain yields (0.306) and total above‐ground biomass yields (0.458 Mg ha‐1 cm‐1 of water) increased linearly with irrigation. A positive response to mycorrhizal inoculation was constant across irrigation levels (0.802 for grain and 1.170 Mg ha−1 for biomass). Therefore, the proportional response of maize to inoculation with G. etunicatum increased with increasing drought stress.
Corn–Soybean Rotation Effects on Soil Water Depletion
Authors: Copeland P. J. , Allmaras R. R. , Crookston R. K. , Nelson W. W. 
Published: July 2010

AbstractThe positive yield effect of crop rotation may be linked to enhanced water uptake and associated efficient use. We hypothesized that a crop grown in rotation might deplete soil water more than the same crop grown under monoculture because some negative factor associated with monoculture was alleviated. Water use efficiency (WUE) might also be improved by rotation. The objective of our study was to determine whether altered water uptake or altered WUE was associated with the yield increase observed when corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] are rotated. A long‐term corn‐soybean rotation experiment was monitored in 1987 and 1988 to determine seasonal soil water status to 1.50m. Corn and soybean sequences monitored were: monoculture, first‐year crop following 5 yrs of the other crop, second‐year crop following 5 yrs of the other crop, and an annual alteration of the two crops. Compared with monoculture, yield was increased up to 30% when corn followed soybean and up to 11% when soybean followed corn. Average soil water depletion during the season by first‐year corn was 16 mm greater than by continuous corn. The WUE in corn was related to cropping sequence at a moderate level of significance (p = 0.14). Seasonal soil water depletion by soybean was not changed by cropping sequence but overall WUE by first‐year soybean was higher than by continuous soybean (p = 0.05). When there was a period with only sparse rainfall in 1988, corn had a greater water depletion than soybean and also a deeper zone of depletion. Both crops exhibited a greater water depletion when rotated. Frequent rainfall in 1987 sufficient to wet the soil below 0.30 m obliterated patterns of depleted soil water. Increased water use observed in first‐year corn and increased WUE observed in first‐year soybean (compared to monoculture) in both years suggest that rotation allows these crops to increase root surface or root activity and hence to improve grain yield.
Compatibility of Kentucky Bluegrass and Perennial Ryegrass with Tall Fescue in Transition Zone Turfgrass Mixtures
Authors: Hunt K. L. , Dunn J. H. 
Published: July 2010

AbstractUse of turf‐type tall fescue (TF), Festuca arundinacea Schreb., in mixture with Kentucky bluegrass (KB), Poa pratensis L., and, or perennial ryegrass (PR), Lolium perenne L., for sports turf may be advantageous because of genetic diversity and improved tolerance to pests and environmental stresses compared to TF in monoculture. The compatibility of TF in mixture with KB and PR, and TF in monoculture was evaluated over a 5‐yr period. Cultural treatments studied were 16 and 22‐mm mowing heights and 75 and 150 kg N ha‐1yr‐1 fall‐applied and 175 kg N ha−1yr‐1 spring‐fall applied N. Botanical composition and turfgrass cover were measured annually in June, 1985 to 1989, with an optical point quadrat. Visual quality ratings were taken monthly during the growing season. In the TF‐PR mixture, TF lacked competitiveness and had decreased from 51% the first year to 11% of the plant population 5 yr after planting. Tall fescue declined from 42% the first year to comprise 9% of the TF‐KB‐PR mixture after 5 yr. In the TF‐KB mixture, TF had an initial 1 yr decline of 60 to 44%, then remained competitive with KB and at 5 yr comprised 44% of the turf compared with 47% KB. The TF‐KB mixture and TF monoculture generally received higher quality ratings compared to the TF‐PR and TF‐KB‐PR mixtures starting in August 1988 and through completion of the study. Nitrogen and cutting height had little effect on botanical composition, and had occasional minor effects on turfgrass quality. These results show that selected, blended TF cultivars under non‐irrigated conditions can adapt to close mowing and remain competitive in mixture with selected blended KB cultivars over several years.
Skip‐Row and Equidistant‐Row Barley with Nitrogen Placement: Yield, Nitrogen Uptake, and Root Density
Authors: Sharratt B. S. , Cochran V. L. 
Published: July 2010

AbstractSmall grain management strategies are sought in the subarctic that improve the plant growing environment and maximize production. This study assessed whether seed‐row configuration and N fertilizer placement could alter growth and yield of barley (Hordeum vulgare L.) in the subarctic. Row spacing and N placement treatments established at Fairbanks, AK, during 1987 through 1989 consisted of equidistant‐row planting (0.18‐m equidistant seed rows) with N banded between alternate rows or broadcast and incorporated, and skip‐row planting (skipping every third row of equidistant rows) with N banded between the two closely spaced rows or broadcast and incorporated. Plant characteristics evaluated included tiller and head density, straw and grain yield, N uptake, leaf area, and root length density. Soil core samples were extracted to approximately 1 m in the mid‐interrow position near anthesis to determine root length density by the line intersect method. Tiller density was the primary yield component differing among treatments. Equidistant‐row barley had more tillers which resulted in a higher head density, 40% higher leaf area, and higher grain and straw yields than skip‐row barley. Rooting in the top 0.1 m of soil was more proliferous where N fertilizer was banded rather than broadcast, but total N uptake was not different among treatments. This study indicated that growth and yield of barley in the subarctic were favored by equidistant‐row planting with either banded or broadcast N applications.
The Effect of Citrate and pH on Zinc Uptake by Wheat
Authors: Chairidchai P. , Ritchie G. S. P. 
Published: July 2010

AbstractZinc uptake by plants may be influenced by its reaction with organic ligands in the rhizosphere. Therefore, four experiments were conducted to examine the effects of an organic ligand (citrate) and pH on the uptake of Zn by wheat (Triticum aestivum L. emend. Theil). Plants were grown for 21 to 28 d in a nutrient solution (containing 0–0.05 μmol L−1 Zn) in a temperature controlled tank, either in the absence or presence of citrate and at constant or variable pH (3.7–7.1). Dry matter weights of plant parts and Zn content in the shoots were determined. The activities of Zn in the nutrient solution were estimated. Shoot dry matter of the wheat plants in each experiment correlated well with either ZnT/[H+] or Σ(moles Zn1charge)/[H+] (ZnT = total Zn, Zn1 = each zinc species). Both parameters could explain the relative shoot dry matter of the plants from all experiments in one equation (y = A + BE−cx; r2 = 0.79 and 0.77, respectively). In the absence of citrate, shoot dry matter as well as Zn content increased with increasing pH and increasing total Zn concentrations in solution. In the presence of citrate, the shoot dry matter of wheat plants that were grown in nutrient solution with constant pH increased with the total Zn concentrations. However, the effect of the total Zn concentrations in the solution containing citrate with variable pH were less important than the effect of pH.
Parameterized Model of Gramineous Crop Growth: II. Within‐Season Simulation Calibration
Authors: Maas Stephan J. 
Published: July 2010

AbstractThe accuracy of parameterized crop growth models is dependent on obtaining the proper parameter values that control the response of the model to environmental conditions. In this study, a method is described for objectively evaluating model parameters based on observations of crop growth obtained during the growing season. An iterative numerical procedure is used to systematically manipulate the values of selected parameters and initial conditions until the model simulation matches the observations of growth. Examples involving a previously‐developed growth model indicate that reasonably accurate simulations can be made for three gramineous crops (grain sorghum, corn, and spring wheat) by calibrating a set of parameters and initial conditions that affect leaf area appearance and senescence. It is proposed that the effectiveness of this procedure in using infrequent growth observations and the ability to obtain these observations using nondestructive measurement techniques make this modelling procedure feasible for use in practical agricultural applications.
Reverse Water Flow in Sorghum Roots
Authors: Xu Xudan , Bland William L. 
Published: July 2010

AbstractEfflux of water from plant roots has implications for nutrient uptake in dry soil, the effectiveness of collection of water from deep in the soil, water parasitism among plants, and the ability of roots to resume water uptake after exposure to dry soil. We measured the minimum soil water potential required for reverse flow in sorghum [Sorghum bicolor (L.) Moench], the diurnal time‐course of the efflux, and differences between sorghum genotypes in reverse flow. A split‐root system was used in which near‐surface roots were subjected to drying and deeper roots were in free water. Efflux of water to the dry soil could first be detected at a soil water potential of about ‐0.55 MPa, or across a soil water potential gradient of 0.55 MPa, a smaller value than previously reported to induce reverse flow. Outflow was 5 to 6% of daily transpiration during the periods of highest water use. Differences between the genotypes in the amount of water emitted and recaptured and the mean water content of the soil were mimicked by a computer simulation of water uptake and release by plant roots. Plant parameters contributing to simulation of the observed behavior were the relationship of leaf water potential to stomatal closure and root length density. Water efflux from roots into the pot soil began at 1430 h, with the peak rate occurring near the end of the daytime period (1900 h) and cessation of outflow by 2400 h. Initiation of outflow during daytime is both physically reasonable and simulated in computer models. The time‐course of outflow, however, was not correctly simulated. Measurements should be made at 1 hour time resolution to capture all reverse flow.
A Crop‐Specific Drought Index for Corn: II. Application in Drought Monitoring and Assessment
Authors: Meyer Steven J. , Hubbard Kenneth G. , Wilhite Donald A. 
Published: July 2010

AbstractHow drought is perceived, and defined, determines the likely response of decision makers to a drought event. Since drought response is usually based on some type of assessment of the severity and duration of the event, a critical element of a drought response strategy lies in the incorporation of objective and reliable impact assessment techniques. However, a long‐standing problem in responding to past droughts has been the lack of reliable techniques for monitoring the drought event and assessing probable impacts. This paper describes a new method to reliably monitor and assess weather's probable impact on corn (Zea mays L.) yields, on a crop reporting district (CRD) level, any time during the growing season. The 1990 growing season was used to demonstrate the ability of the crop‐specific drought index (CSDI) to monitor and assess the condition of East Central Nebraska's corn crop every 10 days, starting 17 June, until a definitive projected CSDI value became established. A 3‐wk hot and dry spell (24 mm of rainfall during the 3‐wk period 28 June‐17 July) that immediately preceded silking resulted in a 17 July CSDI assessment, based on the climatological record of the CRD, that projected yields to be only 63% of the maximum yield previously attained in this CRD. However, a substantial rainfall event during the week of silking alleviated the stressful conditions, and by the beginning of the early grain fill period (blister stage), a 6 August CSDI assessment projected the final CSDI value to within 3% of the actual CSDI (projected and actual yields were 86 and 83%, respectively, of the maximum yield previously attained in Nebraska's East Central CRD). The results of this study demonstrate that the CSDI can monitor and assess weather's impact on corn yields on a CRD level.
Soil Tillage and Windbreak Effects on Millet and Cowpea: II. Dry Matter and Grain Yield
Authors: Leihner D. E. , Buerkert A. , Banzhaf J. , Serafini P. G. 
Published: July 2010

AbstractIn the West Africa Sahel, sand storms occurring early in the growing season may severely damage emerging crops. This study was conducted to determine the Influence of ridges and windbreaks on growth, water use and grain yield of millet, Pennisetum glaucum (L.), and cowpea, Vigna unguiculata (L.) Walp. A field trial was carried out from 1985 to 1987 on a Psammentic Paleustalf in southern Niger using 12 ha of land fallowed over the previous 5 yr. Treatments for millet and cowpea were flat and ridged soil preparation and windbreaks spaced at 6, 20, 40, and 90 m. Total annual rainfall was 558, 641, and 363 mm in the 3 yr of the experiment; onset and distribution of the rains varied. Millet total dry matter (TDM) increased as total water use Increased from 250 to 400 mm. Ridging did not change total dry matter or grain yield in millet but increased cowpea grain yield by 90 and 300 kg ha−1 in 2 of the 3 yr. Protection by windbreaks spaced 6 and 20 m apart resulted in a 48 to 90% Increase in early millet TDM and a 74 to 89% improvement of cowpea ground cover. However, these early effects were not sustained throughout the growing period. Average TDM at maturity and grain yields were similar in all windbreak spacings for millet and cowpea. Although windbreaks may not increase yields of two important Sahelian crops, they may help to stabilize longterm crop production by conserving the soil and providing additional marketable commodities if an appropriate selection is made of type of windbreak and species planted.
Inter‐Seasonal Variation in Soybean and Maize Yields under Global Environmental Change
Authors: Sinclair Thomas R. , Rawlins Stephen L. 
Published: July 2010

AbstractProjected global environment changes will have major influences on crop yields. A very important aspects of crop yields, and societal adjustments to environmental changes, may well be altered year‐to‐year stability in yields. Simulations for three locations in the Midwest with mechanistic growth models for maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] showed important species differences in projected yield stability. Maize yields under global environment changes were approximately equal to current levels and the year‐to‐year yield variability was unchanged. Soybean, however, had higher mean yields under changed global environments as compared to the current environment, and there was substantially greater year‐to‐year variability under possible future environments. This disparity among maize and soybean in mean yield changes and stability across years may have important consequences on crop management and stabilization of food and feed supplies.
Yield Components of Five Kenaf Cultivars
Authors: Webber Charles L. 
Published: July 2010

AbstractAs the USA approaches commercial production of kenaf (Hibiscus cannabinus L.) as an alternative fiber source for paper pulp and other uses, additional information is needed concerning the relationship among kenaf yield components. Kenaf yield components can be important parameters in the selection of the cultivars best suited for specific uses, and in maximizing the production and processing efficiency of a selected kenaf crop. The objective of this research was to examine the yield components of five kenaf cultivars. A 2‐yr study was conducted at Lane, OK, on a Bernow fine sandy loam, 0 to 3% slope, (fine‐loamy, siliceous, thermic Glossic Paleudalf). Kenaf cultivars Tainung #2, Everglades 71, Everglades 41, Cuba 108, and Guatemala 51 were planted on 8 May 1989 and 23 May 1990. In each year plots were arranged in a randomized complete block design with four replications. Plots were hand harvested on 24 Oct. 1989 and 1990. Data collected included stalk and leaf yield, stalk and leaf percentage, bark and core percentage, bark to core ratio, stalk diameter, plant height, and plant population. Everglades 41 had the greatest percentage of stalk by weight (78.5%). Cuba 108 had the least percentage core material (62%), and the greatest bark to core ratio (0.61), while Tainung #2 had the greatest percentage core material (69%) and greatest plant height (299 cm). Tainung #2 also had greater stalk yields (13.8 Mg ha−1) than either Guatemala 51 (11.4 Mg ha−1) or Cuba 108 (10.8 Mg ha−1).
Sub‐Root Zone Layering Effects on Water Retention in Sports Turf Soil Profiles
Authors: Taylor D. H. , Nelson S. D. , Williams C. F. 
Published: July 2010

AbstractSports turf areas are often constructed by placing a root zone soil mixture over coarse‐textured layers such as sand or gravel. The objective of this research was to determine the degree to which drainage from and water retention in soil mixtures were affected by properties of the underlying layers. In a laboratory experiment, soil water matric potential energies (Ψm) and mass water contents (θm) were measured to characterize the water relations during and after 48 h of drainage for four soil mixtures when placed over the following subsurface layering treatments: 50 mm of sand over 100 mm of gravel., 150 mm of gravel, 150 mm of sand, and loam soil. For the three treatments composed of coarse‐textured subsurface layers, soil water matric potential energies at the soil mixture/coarse‐textured layer interface after 48 hours of drainage were controlled by the coarse‐textured sublayer and varied from about −0.9 kPa for the gravel sublayer to about −2.4 kPa for the sand sublayer. Water retention in the soil mixture layer was greatest for the gravel sublayer, followed by sand over gravel, while sand and soil sublayers resulted in the least water retained. Generally, the increased water retention from gravel and sand over gravel sublayers resulted from creating a wet zone at the bottom of the soil mixture layer rather than increasing water retention throughout the soil mixture. Where coarse‐textured materials are used as sublayers in sports turf soils, choice of a soil mixture that drains at the matric potential established at the soil mixture/coarse layer interface is critical to avoid extended periods of saturated soil conditions in the root zone soil layer.
Carbon and Phosphorus Losses from Decomposing Crop Residues in No‐Till and Conventional Till Agroecosystems
Authors: Buchanan Marc , King Larry D. 
Published: July 2010

AbstractAn increased knowledge of crop residue decomposition characteristics is a critical component for nutrient cycling studies in agroecosystems. Carbon and P losses from shoot residues of maize (Zea mays L.), wheat [Triticum estivum (L.), emend. Thell], soybean [Glycine max (L.) Merr.], and shoot and root residues of crimson clover (Trifolium incarnatum L.) were compared in no‐till and conventional till systems. Grain crop residues were generally collected from senescent plants following harvest and placed in fiberglass mesh litter bags. Soybean leaf residues, however, were sampled following preharvest abscission, while crimson clover residues were collected at spring anthesis and buried only in a conventional till system. Generally, the changes in C and P content of residues were best described by exponential and/or logarithmic functions. Losses of C and P from crop residues were consistently greater, and more rapid when residues were buried vs. left on the soil surface. Crimson clover shoots lost C and P more rapidly than root residues. Generally, greater initial losses of P than of C occurred in most residues. The lack of correlation between C and P losses is believed to be due to an inital and probably variable inorganic P content that is readily leached prior to the decomposition and mineralization losses of C. Differences in the rate and magnitude of C losses were related to seasonal effects, the initial N and P content, and/or the proportional amount of lignin in the plant residues. Tillage is clearly an important regulator or driving variable for element cycling in agroecosystems.
Resumption of Water Uptake by Sorghum after Water Stress
Authors: Xu X. , Bland W. L. 
Published: July 2010

AbstractExposure of roots to dry soil may reduce their ability to absorb water when the soil is rewet. We sought to quantify the effects of the duration of exposure to dry soil and the availability of water in deeper soil layers on resumption of water uptake by roots of Sorghum bicolor (L.) Moench following rewetting of the soil. Plants were grown in a greenhouse in pots, half of which were fitted with a water‐filled reservoir below the pot bottom. Soil was allowed to dry for either 26 or 39 d before rewetting. Reservoir roots were excised at rewatering to limit uptake to roots previously exposed to soil drying. Time courses of plant transpiration and leaf water potential prior to and after rewatering were measured. Longer exposure to dry soil slowed resumption of uptake. After 26 d of drying, plants without reservoirs transpired 63.5% of that of well‐watered controls without reservoirs on the first day following rewatering, compared to 29.4% following 39 d of drying. Water available below the dry soil enabled roots to resume water absorption immediately after rewatering. On the first day after rewatering following 39 d of drying, transpiration relative to well‐watered controls (with and without reservoirs) was 2.6‐fold greater in plants with access to a reservoir than those without. Water‐stressed sorghum showed larger root/shoot and root weight/length ratios than controls.