bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fractal Analysis for Morphological Description of Corn Roots under Nitrogen Stress
Authors: Eghball Bahman , Settimi John R. , Maranville Jerry W. , Parkhurst Anne M. 
Published: July 2010

AbstractA means of quantification of plant root branching, specifically under stress, is of importance for evaluating the contribution of plant roots to water and nutrient uptake and subsequently plant growth. An experiment was conducted to describe the morphology of corn (Zea mays L.) root systems using fractal analysis and also to determine if a root’s fractal dimension (D) is altered by N stress. Corn genotypes (B73 ✕ LH105 and N74 ✕ Mo17) were planted in peg boxes, 1.2 m long, 1.2 m deep, and 0.05 m wide filled with 20:80 soil to sand mixture and were grown with N rates of 0, 10, 20 and 30 mg kg−1. Thirtynine days after planting, the mixture was gently washed from the roots and the roots were divided into nine sections (squares of side 304.8 mm) and slide photographs were taken from each section. The slides were projected on grids made up of 122, 242, and 482 squares of sides (r) 25.4, 12.7, and 6.35 mm, respectively. Regression of log of number of squares intersected by roots vs. long of r levels was used to determine the slope (—D). Fractal dimension was significantly smaller for zero N compared to applied N with no detectable difference among applied N levels. Fractal dimension was highest for the section directly below the crown (D = 1.73) indicating high root branching and was lowest for the sections in deeper soil (D = 1.19, average of 3 sections in the 0.6 to 0.9‐m depth) indicating less branching. The intercept of the regression line (log K), which indicates root abundance, was lowest for zero N. Amount of roots in the section directly below the crown was 45% of total roots. Nitrogen stress changed the morphology of corn root system and caused less root branching. Fractal analysis was a useful method for describing the morphology of corn root systems, both quantitatively and qualitatively.
Crop Performance Trials under Irrigated and Dryland Conditions
Authors: Bowman Daryl , Raymer Paul , Dombeck Don 
Published: July 2010

AbstractCorn (Zea mays L.) and soybean [Glycine max (L.) Merr.] performance trials are sometimes conducted under both irrigated and dryland conditions in the southeastern USA. It is not known whether irrigated trials are better trials statistically or if irrigation causes relative rank changes in hybrid or cultivar performance. To answer these questions, corn data were examined from four different environments and three maturity groups, and soybean data were examined from five different environments and three maturity groups between 1987 and 1990. Water management × hybrid/cultivar interactions were evident in 8 of 12 corn data sets and 7 of 16 soybean data sets. Combining data across years eliminated the water management × hybrid/cultivar interactions in all soybean data sets and five of nine corn data sets. Irrigated corn trials produced year × hybrid interactions in seven of nine data sets while dryland trials produced year × hybrid interactions in four of nine data sets. Irrigated trials were only slightly better than dryland trials in accounting for variation; i.e., larger r2 values but produced smaller error variances in four of 12 data sets of corn. Irrigated trials separated entries better in nearly half of the soybean data sets. The data suggested that irrigated trials were not statistically better trials than dryland trials in all situations. Water management × hybrid/ cultivar interactions suggest that data for irrigated and dryland trials should be reported separately, and the year × hybrid/cultivar interactions indicated that multi‐year data should be examined during hybrid/ cultivar selection. Error variances, F probability values, and r2 values should be examined to determine level of precision when comparing trials of equal composition.
Radiation‐Use Efficiency among Grain Sorghum Cultivars and Plant Densities
Authors: Rosenthal W. D. , Gerik T. J. , Wade L. J. 
Published: July 2010

AbstractRadiation‐use efficiency (RUE, g MJ−1) has often been used in many crop model equations to estimate total biomass and yield based on cumulative absorbed photosynthetically active radiation. Management practice effects on radiation‐use efficiency have not been well documented for grain sorghum [Sorghum bicolor (L.) Moench]. A field study was conducted near Temple, TX to determine plant density and cultivar effects on RUE in grain sorghum. Early ‘Cargill 4462’ and late maturing ‘Cargill 6670’ cultivars were planted on a Houston Black clay (fine, montmorillonitic, thermic Udic Paleustert) on 16 Mar. and 1 Aug. 1989 at 5, 12, 19, and 26 plants per square meter. Incoming, reflected, and transmitted photosynthetically active radiation were measured weekly from 6 wk after emergence until full anthesis. Dry matter and leaf area index were determined from 0.5‐m2 areas immediately after the radiation measurements. The calculated extinction coefficient, 0.51, for PAR transmittance was significantly lower than in the crop growth model, SORKAM, documentation. This new value of extinction coefficient reduces total dry matter in and increases RUE in SORKAM. The average RUE for all treatments was 3.5 g MJ−1 as compared with 3.2 g MJ−1 in SORKAM. The new values will be incorporated into SORKAM. No significant radiation use efficiency differences were detected among density and maturity class treatments.
Response of Cotton to Varying COz, Irrigation, and Nitrogen: Yield and Growth
Authors: Kimball B. A. , Mauney J. R. 
Published: July 2010

AbstractThe CO2 concentration of the atmosphere is increasing and is expected to double sometime near the middle of the next century. To determine the effects of such a CO2 increase on cotton (Gossypium hirsutum L.) growth and productivity, a series of experiments from 1983 through 1987 were conducted with open‐top CO2‐enriched field chambers at ample as well as limiting levels of water and N at Phoenix, AZ. Comparisons with open‐field plots showed that there was a significant chamber effect, amounting to a 30% average increase in growth inside, but under dry conditions in 1985, the situation was reversed. No significant effects of CO2 on harvest index, root‐shoot ratio, or lint percentage were found, so the primary effect of elevated CO2 was to produce plants that were larger. Comparing the results of 500 and 650 µmol mol−1 CO2 treatments, the increments of growth from ambient (about 350 µmol mol −1) to 500 µmol mol−1 were not significantly different from increments from 500 to 650 µmol mol−1. No statistically significant interactions were detected between CO2 level and either irrigation or nitrogen level, even when these variables were sufficiently low enough to limit growth. However, under well‐maintained water stress conditions, the growth response to CO2 tended to he somewhat larger than under normal irrigation levels. Averaging over all the data available from these experiments, seed cotton yield (lint plus seed) and above‐ground biomass were increased by 60 and 63%, respectively, by CO2 enrichmen to 650 µmol mo1−1.
Carbohydrates in Alfalfa Seed Developed for Salt Tolerance during Germination
Authors: Dobrenz A. K. , Smith S. E. , Poteet D. , Miller William B. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) is an important forage crop in many areas of the world where salinity limits crop productivity. Alfalfa that is salt tolerant during the germination stage has been developed through eight cycles of recurrent selection starting with Mesa‐Sirsa. We investigated physiological attributes that may have been affected by selection, recognizing that understanding the basis of tolerance could facilitate more precise techniques for identifying salt‐tolerant plants in breeding programs. Free sugars in seed of Mesa‐Sirsa and in Cycle 5 and Cycle 8 (C5 and C8) from the selection program were extracted with 95% (v/v) ethanol and the residue hydrolyzed with 4 M H2SO4. All carbohydrates were quantified by HPLC. Percent galactomannan, glucose, and arabinose in the acid hydrolysate were not significantly different in Mesa‐Sirsa, C5, and C8 seeds. Percent stachyose and glucose were not different in the free sugar extraction of the seed; however, raffinose and sucrose were significantly higher in C8 seed. The increase in these free sugars was not sufficient to explain the increased salt tolerance of the selected populations.
Differentiating Chloride Susceptibility in Soybean Cultivars
Authors: Yang J. , Blanchar R. W. 
Published: July 2010

AbstractFertilization with KCl can induce a Cl toxicity that decreases the yield of soybean [Glycine max (L.) Merr.]. The objective of this study was to see if Cl toxicity can be avoided by selecting cultivars that take up less Cl from the soil. Sixty soybean cultivars, 12 each from Maturity Groups II, III, IV, V, and VI were grown on a Mexico silt loam (fine, montmorillonitic, mesic Udollic Ochraqualf) without added Cl or with 673 kg Cl ha−1 added as CaCl2. The addition of Cl increased the mean Cl concentration of all cultivars from 1.5 to 18.8 g Cl kg−1 at 15 d and from 0.4 to 1.3 g Cl kg−1 at 80 d. All 36 cultivars from MG II, III, and IV, along with 5 cultivars from MG V and VI, bad significantly higher concentrations of Cl in leaves than did 19 cultivars from MG V and VI. Cultivars with high Cl concentrations were referred to as accumulators and those with low concentrations as excluders. The occurrence of leaf scorch, a symptom of Cl toxicity, in Cl accumulator cultivars was significantly higher than in Cl excluder cultivars. Leaf scorch ratings were positively correlated with Cl concentrations of soybean leaves at 15 and 80 d. Chloride concentrations in the leaves were higher (accumulators, 24.3 g kg−1; excluders, 7.0 g kg−1) at the early growth stages than in the later stages (accumulators, 1.8 g kg−1; excluders, 0.3 g kg−1). Addition of CaCl2 increased Cl concentrations in seeds of Essex, an accumulator cultivar, but had no significant effect on oil and protein content. The average grain yields of Cl accumulator cultivars were significantly decreased by 16% due to Cl addition, while grain yields of excluder cultivars were not significantly reduced. Cultivar selection in MG V and VI may be a means of minimizing Cl effects associated with muriate of potash fertilization.
Response of Spikelet Number to Plant Nitrogen Concentration and Dry Weight in Paddy Rice
Authors: Hasegawa Toshihiro , Koroda Yasuo , Seligman No'am G. , Horie Takeshi 
Published: July 2010

AbstractSpikelet density, defined as number of spikelets per unit area of crop, is a major determinant of paddy rice (Oryza sativa L.) yield. Nitrogen accumulation at the panicle formation stage is closely associated with spikelet density, but regional variation has been observed in this relationship. Elucidating the reason for this interregional variation will improve our understanding of spikelet density response to N nutrition. A number of functions were tested to identify an appropriate relationship between N accumulation at the panicle formation stage and spikelet number in japonica rice. The data were collected from 157 field experiments conducted in widely different regions in Japan. The correlation with total N accumulated at the panicle formation stage was significant, but relatively low (r2 = 0.64). A considerably larger part of variation (r2 = 0.84) could be accounted for by a model based on a linear function of plant N concentration and an asymptotic function of aboveground biomass at the panicle formation stage. The standard error of the estimate was 3309 spikelets m−2 for the set of data that ranged from 10 500 to 46 400 spikelets m−2. This model can serve to give a fair estimate of potential grain number in japonica rice. The two distinct responses indicated that vigorous biomass growth with heavy dilution of plant N concentration up to the panicle formation stage could result in inefficient use of N for spikelet formation.
Intercrop Performance of Pearl Millet, Amaranth, Cowpea, Soybean, and Guar in Response to Planting Pattern and Nitrogen Fertilization
Authors: Clark Kerry M. , Myers Robert L. 
Published: July 2010

AbstractIntercropping is a common practice in developing countries because it may produce higher total yields than monocropping. The objective of this study was to apply intercropping principles to alternative and traditional crops in the USA under mechanized conditions. Although these crops have been examined in intercropping systems, in most cases studies were not conducted with improved varieties found in the USA or in strip widths that can accommodate machinery. A field study was conducted at two central Missouri locations in 1991 and 1992 to determine the effect of intercropping on grain yields of pearl millet [Pennisetum glaucum (L.) R. Br.], amaranth (Amaranthus hypochondriacus L. × A. hybridus L.), cowpea [Vigna unguiculata (L.) Walp.], guar [Cyamopsis tetragonoloba (L.) Taub.], and soybean [Glycine max (L.) Merrill]. Treatments were assigned in an incomplete factorial design and consisted of planting pattern (monocrops, narrow and wide row strips, and alternate row intercrops), N fertilizer (0, 56, or 112 kg N ha−1), and component crop combination. Each intercrop consisted of a legume (cowpea, soybean, or guar) and a nonlegume (pearl millet or amaranth). In the strip intercrops, only cowpea showed a consistent yield response to planting pattern, with the narrow strip arrangement with amaranth yielding 53 and 39% lower than its monocrop in two environments. Land equivalent ratios of amaranth and pearl millet grown in alternate rows with cowpea were not significantly different from their monocrops. At the Columbia site, yields of alternate row intercrops generally did not increase upon addition of N and in 1992, amaranth yield at 0 kg N ha−1 was 25% higher in the alternate row intercrop than it was at the same N rate in the monocrop. In general, grain yields were similar in the various intercrops compared with monocrops.
Nitrogen Utilization of Selected Cropping Systems in the U.S. Northeast: I. Dry Matter Yield, N Uptake, Apparent N Recovery, and N Use Efficiency
Authors: Guillard Karl , Griffin Gary F. , Allinson Derek W. , Rafey M. Moosa , Yamartino William R. , Pietrzyk Stephen W. 
Published: July 2010

AbstractExcessive application of N‐containing fertilizers may result in high concentrations of soil nitrate. Soil nitrate levels can be reduced with cropping systems that best utilize N. Split‐plot design experiments were conducted in Connecticut from 1987 through 1990 on a Paxton fine sandy loam soil (coarse‐loamy, mixed, mesic Typic Dystrochrept) to determine the effectiveness of various cropping systems in utilizing N. Orchardgrass (Dactylis glomerata L.), red clover (Trifolium pratense L.), a doublecrop system of oat (Avena sativa L.) followed by the forage brassica tyfon [Brassica rapa L. × B. pekinensis (Lour.) Rupr.], and maize (Zea mays L.) followed by a cover crop of winter rye (Secale cereale L.) received preplant N at 0, 112, 224, 336, and 448 kg ha−1. Cropping systems were tested three times for two consecutive growing seasons, with N applied only in the first season. Dry matter yield (DMY), N uptake (NUP), apparent N recovery (NREC), and N use efficiency (NUE) were determined. Maize‐rye produced the greatest DMY (18.3 to 22.8 Mg ha−1), followed by oat‐tyfon (9.8 to 16.5 Mg ha−1). Highest NUP (121 to 329 kg N ha−1) and NREC (46.5 to 81.7%) were obtained by oat‐tyfon. The greatest NUE was produced by maize‐rye and oat‐tyfon at 112 kg N ha−1. The oat‐tyfon double crop provides the most effective means for preventing N loss among the systems evaluated for N rates > 112 kg ha−1.
Regrowth of Bromegrass Species, a Bromegrass Interspecific Hybrid, and Meadow Foxtail in a Short‐Season Environment
Authors: Van Esbroeck George A. , Baron Vern S. , King Jane R. 
Published: July 2010

AbstractRegrowth in pastures is critical to economic production in short‐season areas. This study compared regrowth characteristics among three Bromus genotypes and meadow foxtail (Alopecurus pratensis L.) during late summer and fall. Growth analyses were conducted and yield components were determined in ‘Carlton’ smooth bromegrass (B. inermis Leyss.), ‘Regar’ meadow bromegrass (B. riparius Rhem.), an experimental strain (S9044) derived from F2 plants of a smooth ✕ meadow bromegrass cross, and common meadow foxtail. Seven weeks of plant regrowth after severe defoliation were characterized during 1985 and 1986 at Lacombe, AB, Canada (52° 28' N lat). The variation among the three grass species and the interspecific hybrid that was most critical to regrowth yield occurred during the first 21 to 28 d after defoliation. Smooth bromegrass consistently yielded less dry matter (DM) and had lower crop growth rates (CGR) than the other genotypes. Smooth bromegrass seemed limited most by a slowly developing leaf area index (LAI) as a result of a low and slowly developing tiller density. S9044 was improved over smooth bromegrass for regrowth yield and traits related to rapid regrowth. S9044 approached equilibrium tiller density quickly and had a large leaf area per tiller, which resulted in a higher leaf area expansion rate than in smooth bromegrass. Meadow bromegrass had CGR and DM yield similar to S9044, but the average LAI for meadow bromegrass was only 71% of that for S9044. Meadow bromegrass compensated for a small LAI with a specific leaf weight that was 1.4‐fold higher than S9044. When soil water was adequate, meadow foxtail produced regrowth equal to S9044 and meadow bromegrass through rapid development of leaf area of moderate specific leaf weight and a relatively large tiller size, given a high tiller density. As exhibited by meadow bromegrass, high specific leaf weight combined with rapid tiller development are traits associated with regrowth yield that may be worth exploiting in developing germplasm for short‐season areas where small LAI may be the norm.
Mean Squared Error of Yield Prediction by SOYGRO
Authors: Colson Josianne , Wallach Daniel , Bouniols Andrée , Denis Jean‐Baptiste , Jones James W. 
Published: July 2010

AbstractYield prediction is often one of the major intended uses of a crop simulation model. It is therefore important to evaluate how well a model performs as a predictor. The purpose of this study was to evaluate and analyze how well the SOYGRO model predicts soybean yield, using as a criterion the mean squared error of prediction (MSEP). The four target populations for prediction were irrigated or unirrigated plots at one location in France, for each of two varieties. The model parameters are estimated from the irrigated plots. The estimated MSEP values are on the order of 1(t ha−1)2 for all the target populations. For comparison, we defined an AVERAGE model. This model uses the average observed irrigated yield for each cultivar as the predictor of unobserved yields. AVERAGE was a better predictor than SOYGRO for the irrigated populations, while SOYGRO was better for the unirrigated populations. It seems that SOYGRO has sufficient built‐in biological realism to extrapolate more reasonably than the AVERAGE model from irrigated to unirrigated conditions; however, SOYGRO does not make as effective use of the data used for parameter estimation as does AVERAGE.
Economics of Growing Verticillium Wilt‐Resistant and Adapted Alfalfa Cultivars in Western Canada
Authors: Smith Elwin G. , Acharya Surya N. , Huang Henry C. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) production with cultivars susceptible to verticillium wilt (VW) (caused by Verticillium albo‐atrum Reinke & Berthier) or those poorly adapted to the region causes significant losses in forage productivity in western Canada. This study estimated the economic benefits that could be obtained by growing VW‐resistant and adapted cultivars in this region. The analysis used irrigated forage yield data from a 7‐yr trial conducted near Lethbridge, AB. The yearly benefit of high resistance to VW over moderately high resistance was $21 ha−1 and over low resistance was $44 ha−1. The potential yearly benefits to producers in western Canada from the development and adoption of high VW‐resistant cultivars were estimated at $2.2 million. The local benefits of growing adapted cultivars on irrigated land were $22 ha−1 yr−1. The regional benefits to western Canada from using adapted cultivars were $26.6 million yr−1. The greater potential benefit from growing adapted cultivars was attributed to benefits applied to all areas of western Canada, whereas benefits from VW applied to areas infested with VW.
Spectral Properties of Leaves Deficient in Iron, Sulfur, Magnesium, and Manganese
Authors: Masoni Alessandro , Ercoli Laura , Mariotti Marco 
Published: July 2010

AbstractIn crop plants, deficiency of an essential element may drastically reduce growth rate and yield. Research on the use of leaf spectral properties in the detection of crop mineral deficiency is needed. The objective of this study was to examine the effects of Fe, S, Mg, and Mn deficiency on reflectance (R), absorptance (A), and transmittance (T) spectra of barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), corn (Zea mays L.), and sunflower (Helianthus annuus L.) leaves. Plants were grown in the greenhouse in nutrient solution. Chlorophyll (Chl), Fe, S, Mg, and Mn concentrations and spectral properties were determined on the youngest fully expanded leaf when deficiency symptoms were clearly manifested. In all species, mineral deficiency affected leaf concentration of the deficient element and also of other elements. Nutrient deficiency reduced Chl concentration and A, and increased R and T. Iron deficiency severely affected all species, and corn was the species most sensitive to all deficiencies. Reflectance, A, and T spectra of leaves were correlated with leaf Chl concentration. Our results suggested that all nutritional deficiencies reduce leaf Chl concentration, and subsequently this reduction increases leaf R and T, decreases leaf A, and shortens the red‐edge position, defined as the inflection point that occurs in the rapid transition between red and near‐infrared. Modifications in leaf spectral properties were not characteristic of nutrient deficiency, but were always observed in the same wavelengths.