bluuebunny/crossref_metadata_2025_split huggingface dataset:
Furrow Diking Effects on Yield of Dryland Grain Sorghum and Winter Wheat
Authors: Tewolde Haile , Mulkey J. R. , Elledge Robert E. 
Published: July 2010

AbstractDryland sorghum [Sorghum bicolor (L.) Moench] and wheat (Triticum aestivum L.) production in areas where a large fraction of the annual rainfall is received during the fallow period may be improved by rain‐conserving practices. Furrow diking mainly during the growing season has been shown to improve crop production by conserving rainfall in many parts of the Southern Great Plains. The objectives of this study were to determine whether seasonal or year‐round furrow diking increases dryland yields of sorghum and wheat, to test the yield advantage of planting sorghum and wheat on a flat seedbed or on beds, and to analyze the dependence of yield on rainfall. The treatments included nonbedded (FLAT), bedded–nondiked (BND), bedded–diked during the growing season (BDG), bedded—diked during the fallow period (BDF), and bedded–diked during the fallow period and the growing season (BDFG). Relative to BND, the BDFG treatment increased yield by up to 72% in sorghum and 23% in wheat. The BDF treatment increased yield by up to 62% in sorghum and 23% in wheat. Furrow diking during the growing season alone did not significantly increase yield in sorghum or wheat. When annual rainfall exceeded the average, the FLAT treatment in sorghum yielded less than the BND treatment by 39%. Planting wheat on beds was not an improvement over the conventional flat seedbed. Dryland sorghum and wheat production in areas where a significant fraction of the annual rainfall is received during the fallow period may be improved by fallow period or year‐round furrow diking.
‘Tifgreen’ Bermudagrass Response to Late‐Season Application of Nitrogen and Potassium
Authors: Goatley J. M. , Maddox V. , Lang D. J. , Crouse K. K. 
Published: July 2010

AbstractLate‐season application of N to bermudagrass (Cynodon dactylon × transvaalensis Burtt‐Davey) putting greens are often made in an attempt to extend turfgrass growth and color. Research was conducted to evaluate the physiological and morphological responses of bermudagrass to late‐season application of N and K. Application of 0, 4.9, and 9.8 g N m−2 in factorial combination with 0, 4.1, 8.2 g K m−2 were made in October of 1989, 1990, and 1991. Following fertilizer application, measurements of fall and spring turfgrass color, total nonstructural carbohydrate (TNC) concentrations, and leaf tissue concentrations of N, P, and K were made. No changes in turfgrass color or TNC levels were observed for any level of K fertilization. Application of 4.9 or 9.8 g N m−2, alone or in combination with K, improved fall turfgrass color through October for each trial, and gave significantly higher spring turfgrass color ratings. Rhizome TNC levels declined linearly in December 1989 as N levels increased from 0 to 9.8 g m−2. There was a quadratic response in TNC levels across N fertility levels in March 1990. No significant differences in TNC levels were measured for any N level for 1990 and 1991 in December or March, although N at 9.8 g m−2 tended to give lower rhizome TNC levels as compared with 0 or 4.9 g m−2 of N. Nitrogen applications provided a linear increase in N, P, and K concentrations in the leaves. Late‐season application of N improved fall and spring bermudagrass color, and generally had little effect on rhizome TNC levels when measured in December or March.
Field Response of Alfalfa to Harvest Frequency, Cultivar, Crown Pathogens, and Soil Fertility: I. Survival and Yield
Authors: Gossen B. D. , Horton P. R. , Wright S. B. M. , Duncan C .H. 
Published: July 2010

AbstractDeclining productivity in older alfalfa (Medicago sativa L.) stands is an important problem in the Canadian prairies. Field trials were established in 1985 at three locations in Saskatchewan to examine the interaction of (i) harvest frequency, (ii) two alfalfa cultivars, (iii) inoculation with one of three fungal pathogens (Coprinus psychromorbidus, Phoma sclerotioides, or Fusarium spp.), and (iv) K fertilization on survival and forage yield of alfalfa. Harvest and inoculation treatments were initiated in 1986 and continued each year until the tests were terminated in 1989–1990. Plants were dug in spring and fall each year, and total nonstructural carbohydrate levels in the crowns were assessed using near infrared spectroscopy. Differences in plant numbers, stand density, persistence, and vigor between ‘Nordica’ (selected for resistance to C. psychromorbidus) and ‘Beaver’ were small. Harvest at 10% bloom (2–3 cuts) did not result in consistent reductions in numbers of plants, stand density, or total nonstructural carbohydrates relative to a single‐cut treatment. Frequent harvest reduced vigor and first‐cut yield of both cultivars in the year following the treatment, but caused larger reductions for Beaver than for Nordica. Total yields for the frequent harvests over all locations and treatments were 43% higher than for the single‐cut treatment (5.3 vs. 3.7 Mg ha−1). Potassium fertility and inoculation with fungal pathogens had minimal impact on plant survival and yield. In conclusion, interactions among the factors which cause stand decline were minimal, and the reductions in plant vigor and first‐cut yield resulting from frequent harvest were more than offset by the yield from late‐season harvests.
Quadratic and Quadratic‐Plus‐Plateau Models for Predicting Optimal Nitrogen Rate of Corn: A Comparison
Authors: Bullock Donald G. , Bullock David S. 
Published: July 2010

AbstractBased on quadratic response models, the University of Illinois recommends 22 kg fertilizer N Mg−1 corn (Zea mays L.) grain yield, with adjustments for cropping history, manure, and planting date. Recent work suggests recommendations based on the quadratic model are excessive. This field study evaluated the quadratic‐plus‐plateau and quadratic models and the current recommendation for a 10‐ to 12‐yr, two‐location, two‐crop‐sequence data set with 5 N fertilizer rates in Illinois. For all location‐sequences, we detected a systematic bias with the quadratic model as compared with the quadratic‐plus‐plateau model. The quadratic response model predicted a maximum grain yield of 3 to 6% larger and an optimal N fertilizer rate 5 to 60% larger than that predicted by the quadratic‐plus plateau model and decreased profit from $0.61 to $17.12 ha−1 yr−1. Current University of Illinois recommendations differed by from − 6 to + 104 kg N ha−1 from the amount predicted by the quadratic‐plus‐plateau and resulted in a profit reduction of $0.01 to $31.42 ha−1 yr−1. These analyses indicate that the quadratic‐plus‐plateau is preferable to the quadratic model for predicting N fertilizer requirements of corn. Economic analysis indicates that the consequences of using the quadratic model rather than quadratic‐plus‐plateau model can be large, but not in all cases. Furthermore, the general recommendation of 22 kg N Mg−1 of expected grain yield minus rate adjustments is not appropriate in all cases. Site‐specificity plays a large role in determining optimal N rates.
Apparatus for Measuring Water Vapor Transport at the Soil Surface
Authors: Saeed Ibrahim A. M. , Tanner C. B. , Sauer Thomas J. 
Published: July 2010

AbstractTo fully characterize the water and energy balances of a field crop it is necessary to separate soil evaporation from total canopy evapotranspiration. An alternative to measuring soil evaporation directly is to measure the vapor exchange at the soil surface in order to assess mass transfer there. The objective of this research was to develop a method for measuring vapor exchange coefficients beneath plant canopies. The system consists of a Mariotte siphon water supply apparatus and a felt‐covered vapor source plate, both of which were tested under laboratory and field conditions. A detailed description of the devices, their construction and operation, and a sample data set are presented. The system is suitable for long‐term field installation and is capable of accurately measuring vapor transfer rates over short time intervals.
Root Volume Effects on Nitrogen Uptake and Partitioning in Peach Trees
Authors: Ran Y. , Habib R. , Bar‐Yosef B. , Erez A. 
Published: July 2010

AbstractAlthough soil root volume can be modified under field conditions by adjusting irrigation frequency and emitter geometry, little is known about the effect of root volume on tree growth, uptake, and yield. The objective of this work was to investigate effects of physical restriction of root systems on N absorption by peach trees [Prunus persica (L.) Batsch.] and N partitioning among tree organs, and to compare experimental data with simulated results. Cumulative NO3 uptake by 3‐ and 3.5‐yr‐old trees grown in containers increased linearly with increasing root volumes from 5 to 10, 20, 40, and 80 L tree−1. This effect was simulated better when assuming a constant ratio of N to dry matter weight in the tree than when assuming a Michaelis‐Menten uptake mechanism. Nitrogen partitioning among leaves, branches, fruits, trunk, and roots differed at fruit harvest and at the end of the season. Despite considerable differences in tree organ weights, N concentration in the tree parts was quite similar in the various root volumes and along the growing season. Simulation of N concentration in annual tree parts was less satisfactory than in perennial organs, where initial conditions could be defined accurately. It is suggested that the physical restriction of root growth reduced N uptake, root hormone synthesis rate, and N accumulation in the canopy. The trees have a N‐concentration‐stat mechanism, which maintains a constant N percentage in the tops by adjusting photosynthesis and growth in direct proportion to the N and cytokinin accumulations in the canopy.
Tracing Nitrogen Movement in Corn Production Systems in the North Carolina Piedmont: Analysis of Nitrogen Pool Size
Authors: Crozier Carl R. , King Larry D. , Hoyt Greg D. 
Published: July 2010

AbstractThe fate of N in North Carolina Piedmont corn (Zea mays L.) was traced using N pool size analysis. In 1989 and 1990, selected N pools [corn; weeds; surface residues; and soil NH+4 NO‐3, and potentially mineralizable N (No)] were sequentially sampled in four reduced chemical input systems: (i) crimson clover (Trifolium incarnatum L.) with conventional tillage (clover‐till), (ii) no cover crop with conventional tillage and 70 kg N ha−1 as NH4NO3 (fertilizer‐till), (iii) crimson clover with strip‐tillage (clover‐strip), and (iv) no cover crop with no tillage and 70 kg N ha−1 as NH4NO3 (fertilizer‐no‐till). The largest of the repeatedly measured N pools was soil No, which accounted for <10% of the total Kjeldahl soil N. Soil No was highest in the clover‐till treatment, and had large seasonal fluctuations: 170 to 255 kg N ha−1 in clover‐ till, and 117 to 210 kg N ha−1 in other treatments. Fertilizer treatments had higher inorganic N levels than did clover treatments only immediately after fertilizer application. Although clover shoots contained 97 to 134 kg N ha−1 yr−1, more than the N applied to fertilizer treatments, no significant differences among treatments in plant (corn + weed) aboveground N accumulation (38 to 132 kg N ha−1) were observed. Of these totals, weed N accounted for 5 to 30 kg N ha−1. Surface residue N content was highest in reduced tillage treatments. In reduced chemical input systems such as these, N transfers among soil No, weed, and residue pools may be as large or larger than N transfers among soil inorganic and crop pools.
Shoot and Root Growth Response of Perennial Ryegrass to Fertilizer Placement Depth
Authors: Murphy James A. , Zaurov David E. 
Published: July 2010

AbstractA better understanding of turfgrass growth responses to the vertical placement of nutrients in the soil is needed if growth responses are to be maximized. This greenhouse work examined the shoot and root growth responses of perennial ryegrass (Lolium perenne L.) to placement of N‐P‐K fertilizer at various depths in a sandy clay loam and in a sandpeat mixture. Fertilization at the 5‐, 10‐, and 15‐cm soil depths produced greater verdure and total root mass than fertilization at 0 cm in both the sandy clay loam and sand‐peat. Root mass increases occurred within the 5‐ to 35‐cm zone of the sandy clay loam and the 10‐ to 35‐cm zone of the sand‐peat with subsurface fertilization. Water use efficiency was increased 11% in the sandy clay loam with 10 and 15 cm deep fertilization and 21% in the sand‐peat with 5 cm deep fertilization compared with surface fertilization. Except for P, nutrient accumulation with subsurface fertilization matched or exceeded that achieved with surface fertilization. Management practices that position nutrients below the soil surface and as deep as 15 cm can improve turfgrass growth responses to fertilizer. Further research needs to relate irrigation, fertilization, cultivation, and soil modification practices to fertilizer placement, and subsequently shoot and root growth responses.
Basic Linz‐Donawitz Slag as a Liming Agent for Pastureland
Authors: Rodríguez Marta , López Félix A. , Pinto Miriam , Balcázar Natalia , Besga Gerardo 
Published: July 2010

AbstractLinz‐Donawitz (LD) slag, a by‐product of the iron and steelmaking industry (29% Ca, 5% Mg w/w) produced in large quantities in Europe, poses a substantial disposal challenge. A field assay was conducted to study whether LD slag could be used as a dolomitic liming agent for pastures. Six slag rates (0, 1000, 1500, 3000, 5000, and 7500 kg ha−1), with or without NPK fertilizer, were investigated for their effects on soil properties, mineral concentrations of forage, and forage yield at Bizkaia, Spain, on a Derio silty clay soil [fine silty, mixed (acid), mesic Typic Udorthent]. The 3‐yr study was done on a newly established pasture of perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), and white clover (Trifolium repens L.). Slag application increased soil pH linearly, especially where fertilizer was not applied. The 7500 kg rate, without NPK fertilization, increased soil pH from 5.3 to 6.5. When 3000 kg ha−1 of slag was applied, the increase in soil pH was accompanied by a decrease of AI saturation percentage in the cation exchange complex, to <10%. At this rate, exchangeable Ca and Mg increased in comparison with the control, by a factor of 1.8 and 2.3, with and without fertilization, respectively. Slag application resulted in higher Ca, Mg, and P, lower K and Mn plant concentrations, and increased herbage yield. LD slag appears to be a useful liming material for correcting soil acidity on pasture soils and for increasing Ca, Mg, and P concentrations in plants.
Imbibition Response of Winter Wheat to Water‐Filled Pore Space
Authors: Studdert Guillermo A. , Wilhelm Wallace W. , Power James F. 
Published: July 2010

AbstractReduced temperature and increased bulk density associated with conservation tillage systems cause lower seed germination, seedling emergence, and early growth rates resulting in reduced plant stands. Prediction of the influence of soil condition on seed imbibition through simple soil measurements would help make agronomic decisions such as planting date and/or density. Our objectives were to evaluate the influence of soil water‐filled pore space on winter wheat (Triticum aestivum L.) seed imbibition and to assess the possibility of describing the relationship through simple mathematical models. We measured the rate of water uptake by heat‐killed wheat seeds at three levels of water‐filled pore space (WFPS: 0.35, 0.60, and 0.85) and temperature (T: 278, 283, and 288 K) and two levels of bulk density (ρb: 1.25 and 1.40 Mg m−3) in a Sharpsburg silty clay loam topsoil. The model proposed in 1972 by Blacklow to estimate seed water content (θs) after imbibing water for time t, θs(t) = (m + ot) − (m − θs(0)) e−qt, was fitted to seed water content as a function of time and initial seed water content, θs(0). This equation adequately described the process of water absorption (for 18 treatment combinations, R2 > 0.963). The model parameter o was related (R2 = 0.88) to WFPS and ρb, and q was related (R2 = 0.78) to T and WFPS. The third parameter, m, was significantly but weakly related (P < 0.01, r2 = 0.26) to initial seed weight. We showed that easily measured soil properties and simple mathematical models can be used to predict wheat seed imbibition under a variety of soil conditions.
Evaluation of the SPUR Model for Grasslands of the Northeastern United States
Authors: Stout William L. 
Published: July 2010

AbstractComputer models that simulate grassland production must be valid for the ecosystem in which they are used. Our objective was to develop a grassland production data base and to use the data base to calibrate and validate a grassland production model for the northeastern United States. The SPUR (Simulation of Production and Utilization of Rangeland) model was evaluated for its ability to simulate aboveground biomass production in two physiographic provinces of northeastern USA. The model was calibrated for orchardgrass and switchgrass using one year of plant, soil, and weather data from four study sites. Calibrations mainly involved adjustment of photosynthetic rate, root‐to‐shoot ratio, temperature for root‐to‐shoot translocation, and rooting depth. Once calibrated, the model was validated by simulating aboveground biomass production for two ensuing years on the four sites. Two years of simulated biomass for the grasses agreed well with the observed biomass on all four study sites with r2 values of 0.48 for orchardgrass and 0.70 for switchgrass. The largest discrepancies between simulated and observed biomass occurred early in the spring at low levels of N fertilization. In its present form, SPUR can be used to develop production indices for cool‐ and warm‐season grasses on different soils.
Performance of Fall‐ and Spring‐Planted Durum Wheat in Western Colorado
Authors: Pearson Calvin H. 
Published: July 2010

AbstractSeveral years of fall planting of spring types (non‐vernalization requiring) of durum wheat (Triticum turgidum L., durum group) in smallgrain cultivar performance tests in western Colorado have resulted in high grain yields with no observed plant stand losses. Comparison studies between fall and spring plantings of durum wheat have not been conducted. Field studies were conducted during 1988, 1989, and 1990 at the Colorado State University Fruita Research Center near Grand Junction to determine plant response of durum wheat cultivars to planting dates, and to study grain yield and yield component relationships of durum wheat cultivars when planted in the fall, early spring, and late spring. Fall‐ and early spring‐planted durum wheat generally had higher grain yields, test weights, kernel mass, and were taller than late springplanted wheat. Fall‐planted durum had fewer kernels per spikelet than wheat in spring plantings and a lower seed N concentration than durum in the late spring planting. Kernels per spikelet and kernel mass had the most consistent and highest direct correlations with grain yield. Our findings indicate that the potential exists to increase the productivity and widen the adaptation of durum wheat by identifying favorable temperate locations and using appropriate planting dates. Winter durum (vernalization‐requiring) cultivars developed for the USA would be useful in widening the adaptation and increasing the productivity of this class of wheat.
Recovery of Sesame from Defoliation and Growth Terminal Clipping
Authors: Tewolde Haile , Mulkey J. R. , Fernandez Carlos J. 
Published: July 2010

AbstractCrop loss assessment charts and loss adjustments related to hail damage are based on studies that determine the degree of plant recovery from defoliation. Such information is lacking in sesame (Sesamum indicum L.). An irrigated study was conducted in 1989 and 1990 to determine the ability of a nonbranching sesame cultivar to recover from defoliation and growth terminal clipping applied to plants at different growth stages. The treatments included 0, 33, 66, and 100% defoliation levels and clipped vs. nonclipped growth terminals applied at vegetative (37 days after planting, DAP), flowering (48 DAP), and capsule filling (71 DAP in 1989 and 65 DAP in 1990) stages. Average seed yield of the nondefoliated nonclipped (control) treatment was 1523 kg ha−1 in 1989 and 1832 kg ha−1 in 1990. The magnitude of recovery from defoliation and growth terminal clipping was highly dependent on when the treatments were imposed. In the nonclipped treatment, the 33% defoliation treatment produced 90 to 102% as much seed as the control regardless of the growth stage. Seed yield of the 66% defoliation in the nonclipped treatment varied from 85 to 103% of the control when defoliation was imposed before heavy fruiting (54 DAP or earlier). When imposed after heavy fruiting, the 66% defoliation reduced yield by 20% in 1989 and 30% in 1990. The most severe defoliation (100%) in the nonclipped treatment yielded 93, 89, and 34% of the control in 1989 and 77, 72, and 16% of the control in 1990 when applied at the vegetative, flowering, and capsule filling stages, respectively. The magnitude of recovery from defoliation in the clipped treatments also decreased with more advanced growth stage; however, this response was more pronounced in the clipped than the nonclipped treatments. The greatest reduction in seed yield occurred when all leaves were defoliated and the growth terminal removed after heavy fruiting.
Dinitrogen Fixation by Seven Legume Crops in Alaska
Authors: Sparrow Stephen D. , Cochran Verlan L. , Sparrow Elena B. 
Published: July 2010

AbstractInformation on amounts of N2 fixed by legumes in subarctic regions is lacking. We determined the N2‐fixation potential of seven legume species under field conditions in subarctic Alaska. Seasonal N2 fixation was estimated for alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), yellow sweetclover (Melilotus officinalis Lam.), fababean (Vicia faba L.), lentil (Lens culinaris Medik.), pea (Pisum sativum L.), and white lupin (Lupinus alba L.) on a neutral (pH 7.2) and an acid (pH 5.4) soil during two field seasons. A lime variable was included at the acid soil location. Dinitrogen fixation was estimated by the 15N isotope dilution method and by the total‐plant N difference method. Three non–N2‐fixing crops and uninoculated analogs at one location were used as reference crops. Agreement among reference crops and between methods of estimating N2 fixation was adequate for most applications, but differences of >50 kg ha−1 were sometimes observed. Maximum N2 fixation estimates by the isotope dilution method were 58 kg ha−1 for alfalfa, 121 for red clover, 109 for sweetclover, 204 for fababean, 72 for lentil, 121 for pea, and 162 for white lupin. Liming usually did not significantly affect N2 fixation. Nitrogenase activity, as measured by the acetylene reduction assay, peaked at or soon after flowering in some legumes; in others, it either plateaued or continued to increase after flowering until the end of the growing season.