bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensitivity Analysis of the Parameters of a Mechanistic Mathematical Model Affected by Changing Soil Moisture1
Authors: Barber S. A. , Mackay A. D. 
Published: July 2010

AbstractSensitivity analyses are useful for evaluating the effects of changes in soil and plant properties on plant nutrient uptake. The objective of this study with corn (Zea maysL.) was to determine the influence on P and K uptake of changes in root growth rate, k, mean root radius, ro, and effective diffusion coefficient, De, that resulted from changing the level of soil moisture (volumetric moisture contents of 0.22 (M0), 0.27 (M1), and 0.32 (M2)) of three soils differing in available P and K. The data used were obtained in a controlled‐climate chamber study. Increases in De, which resulted from raising soil moisture, only explained 27 to 32% and 11 to 27% of the total calculated increase in P and K uptake, respectively, across the three soils as moisture was raised from M0to M1. In contrast, the increase in k, which resulted from raising soil moisture, explained 50 to 56% and 46 to 69% of the total calculated increase in P and K uptake, respectively, as moisture was raised from M0to M1. This emphasized the importance of root growth in providing the plant with an adequate supply of nutrients. The results highlight the significance of soil moisture in plant growth and demonstrate the advantages of using the modeling approach to furnish data on the effects of moisture on each of the mechanisms involved in nutrient uptake.
Nitrogen Requirements of Potatoes1
Authors: Westermann D. T. , Kleinkopf G. E. 
Published: July 2010

AbstractNitrogen fertilizer applications, for maximum fertilizer efficiencies and crop yields, should be based on the N required by the crop during its various growth stages. The objectives of this paper were to identify the N requirements of the potato plant (Solanum tuberosumL.) during growth and to evaluate selected soil and plant tissue tests as indicators of the plant's N status. Growth analysis data and soil and petiole NO3‐N concentrations were obtained at predetermined time intervals from N fertilization treatments in replicated field studies on a coarse‐silty mixed, mesic Durixerollic Calciorthrid soil. Maximum early tuber growth occurred when leaf area index was between 2.5 and 3.2 and the tops contained between 79 and 100 kg N ha−1at the start of linear tuber growth. A preplant N fertilizer application between 67 and 134 kg ha−1gave these characteristics under the experimental conditions. The maximum dry matter production rate per day (approx. 250 kg ha−1) occurred when there was between 80 and 140 kg N ha−1in the plant tops and roots. An average tuber growth rate of 0.75 Mg ha−1day−1required a N uptake rate of 3.7 kg ha−1day−1to prevent the loss of N and dry matter from the tops and roots. Sufficient N was available for this rate when the soil NO3‐N concentration was > 7.5 mg kg−1(0.46‐m soil depth), corresponding to 15 000 mg kg−1NO3‐N in the fourth petiole. Soil and petiole NO3‐N concentrations may be used to adjust the N fertilization rates during the growing season. This practice has the potential of increasing the overall N fertilizer use efficiency and final tuber yields within the climatic, disease, and variety limitations.
Evaluation of Three Wetting Agents as Soil Additives for Improving Crop Yield and Nutrient Availability1
Authors: Wolkowski R. P. , Kelling K. A. , Oplinger E. S. 
Published: July 2010

AbstractThe effect of soil applications of WEX, Basic H, and Amway Spray Adjuvant was evaluated using corn (Zea maysL.), soybean [Glycine max(L.) Merr.], or potato (Solanum tuberosumL.) as test crops at three Wisconsin locations. Each wetting agent is a nonionic surfactant, and claims or has claimed to improve crop yield, quality, and nutrient availability. WEX was evaluated at recommended fertilization levels. Amway and Basic H, in the corn experiments, were evaluated at varying levels of applied N. Basic H was evaluated on potatoes at 30, 50, and 100% of the entire recommended fertilization program. Although crop yield was increased by fertilization in all cases, no yield improvements were observed from the use of any wetting agent at any fertilizer rate. No differences in nutrient availability as evidenced by foliar nutrient content of N, P, and K or crop protein levels were observed in association with the application of a wetting agent.
Root Damage by Western Corn Rootworm and Nutrient Content in Maize1
Authors: Kahler A. L. , Olness A. E , Sutter G. R. , Dybing C. D. , Devine O. J. 
Published: July 2010

AbstractLittle is known about the effects of root pruning by insects on nutrient content of maize (Zea maysL.). The objective of this study was to evaluate root damage effects caused by western corn rootworm (WCR, Diabrotica virgifera virgiferaLeConte) larval feeding on Fe, Na, K, Ca, Mg, and N contents in shoots and seeds of maize hybrid ‘Pioneer 3978’. The experimental design was a randomized complete block, and treatments included applications of 0, 1000, 2000,4000, and 8,000 WCR eggs per lineal meter of row in 1982 and 0,4000, and 12 000 WCR eggs per lineal meter of row in 1983. Maize seeds were planted ca. 23 cm apart in Brookings sicl (pachic Udic Haploborolls) soil. Aboveground plant samples were collected before intense larval feeding and after adult beetle emergence. These shoot samples and grain harvested at maturity were weighed and analyzed for their nutrient content. Severe root pruning decreased shoot dry weight and reduced grain yields at harvest by 13.5% in 1982 and by 9.7% in 1983. Contents of K, Mg, and Ca decreased and Fe and Na contents increased in shoots in 1982, but were not affected by root pruning in 1983. Accumulation of Na and Fe in shoots was attributed to compensatory branch root growth at critical stages of plant development. Root pruning may have caused new root development or branching into parts of the soil where Fe and Na could be obtained. Grain yield and grain Na content were related directly to the amount of root pruning in 1982. In 1983, grain yield was reduced and element content was altered by root pruning, but not in a simple linear manner. The results suggested that further studies of root pruning by WCR larvae of additional hybrids and their inbred parents may aid identification of elemental functions for maize.
Phosphorus Fertilization in No‐Tillage Corn Production1
Authors: Eckert D. J. , Johnson J. W. 
Published: July 2010

AbstractThe use of no‐tillage crop production as a water quality management practice may be complicated by a tendency for phosphorus (P) to accumulate at or near the soil surface under no‐tillage conditions. Little work has been published to define best management strategies for P in no‐tillage situations, either from fertilization or water quality standpoints. In this study, P was applied to no‐tillage corn (Zea maysL.) by surface broadcasting or subsurface banding, to a Wooster silt loam (fine‐loamy, mixed, mesic Typic Fragiudalf) in northeastern Ohio at rates of 0, 14.5, and 29 kg P ha−1, and to a Loudon silt loam (fine, illitic, mesic Aquic Hapludalf) in southwestern Ohio at rates of 0, 19, 39, 58, and 116 kg P ha−1. Soil test P levels were generally below sufficiency for maximum corn production at both sites. Over a 3‐yr period at the Wooster site, both fertilized and unfertilized plots showed significant accumulations of P near the soil surface; however, subsurface banding reduced surface accumulation at the highest P rate. At both sites, banding P generally produced higher yields than broadcasting at equivalent rates. When yields, soil test P levels and fertilizer rates were fit to the Bray‐Mitscherlich function, the resulting equations indicated greater fertilizer efficiency for band application. Comparison of equations derived from data in the present study with the equation used for making P fertilizer recommendations for conventional tillage in Ohio indicated the need for higher broadcast fertilizer rates in no‐tillage and also a higher soil test P level for P sufficiency in no‐tillage when compared with conventional. The advantages of banding and lower broadcast fertilizer use efficiency in no tillage seen in this study are contrary to conclusions drawn from previous studies dealing with no‐tillage fertilization.
Extraction of Apoplastic Water during Pressure‐Volume Dehydrations1
Authors: Cortes P. M. , Sinclair T. R. 
Published: July 2010

AbstractIn interpreting pressure‐volume (P‐V) curves, it would be helpful to know the effects of relaxing some of the assumptions generally made in their analysis. More specifically, the consequences of apoplastic water loss during dehydration are of interest. The fraction of water acting osmotically was determined from pressure‐volume curves generated for water and drought‐stressed leaves from field‐grown soybean plants [Glycine max(L.) Merr. ‘Wilkin’]. All plants showed a seasonal increase in the apparent fraction of water acting osmotically. Occasionally, particularly in the stressed leaves, the osmotic fraction was higher than previously reported and in some cases > 1. During the generation of P‐V curves, the volume of apoplastic water is generally assumed to remain constant as plant tissue dehydrates. A recent analysis of water release curves allowed the volume of apoplastic water to vary during dehydration, but the form of the resulting equation relating water potential to relative water content did not apply directly to P‐V curves. This equation was transformed into the form generally used to interpret the curves. In this form the equation suggests that the anomalously high observed osmotic fractions may be due to the loss of apoplastic water during dehydration.
Seed Yield of Austrian Winter Field Peas Intercropped with Winter Cereals1
Authors: Murray G. A. , Swensen J. B. 
Published: July 2010

AbstractIntercropping has improved the production of annual food grasses and legumes in several warm‐season areas of the world. Winter cereals intercropped with winter peas may improve winter pea yields in many cool‐season areas. The primary objective of this study was to compare seed yield of winter peas in mono‐ and intercropped culture in northern Idaho. Winter peas (Pisum sativumspp. arvenseL. Poir) were intercropped with either winter wheat (Triticum aestivumL.) or winter barley (Hordeum vulgareL.) on a Tilma silt loam (fine, mixed, mesic Xeric Argialboll) in 1980–1981 and on a Palouse silt loam (fine‐silty, mixed, mesic Pachic Ultic Haploxeroll) in 1981–1982. Winter peas and winter cereals were planted either alone or in mixtures containing 25, 50, or 75% winter peas. Seeding rates of 67 and 90 kg ha−1were used for both monocrops and intercrops. All trials were conducted in fields that had been fallowed for 1 yr prior to planting the intercropping studies. Winter peas in mixtures with 25% winter cereals produced seed yields equal to or 27% greater than (P< 0.05) monocropped winter peas. Winter cereal yields were reduced an average of 60% (P< 0.05) when mixed with 25% winter peas (20 winter pea plants m−2). Monocropped winter wheat and winter barley produced higher seed yields than intercrops and monocrop winter peas under adequate N conditions, but winter peas produced higher seed yields than intercrops or monocrop winter cereals when N was partially limiting in the spring due to water logging. Seeding rate had no influence on seed yield but did increase plant populations of each species. Winter peas were compatible with winter cereals in both planting and grain harvesting requirements and pea seed can be easily separated from harvested mixtures.
Forage and Nitrogen Contributions of Arrowleaf and Subterranean Clovers Overseeded on Bermudagrass and Bahiagrass1
Authors: Evers G. W. 
Published: July 2010

AbstractTropical perennial grasses are the foundation of the pasture systems in the southeastern USA. However, they are low quality and require N fertilizer. Forage production and distribution and N accumulation of clover‐grass mixtures were compared to that of the grass alone receiving various rates of N fertilizer on a Crowley soil (fine, mortmorillonitic, thermic Typic Albaqualf). ‘Coastal’ bermudagrass [Cynodon dactylon(L.) Pers.] and ‘Pensacola’ bahiagrass (Paspalum notutumFlugge) sods were (i) overseeded with ‘Yuchi’ arrowleaf (Trifolium vesiculosumSavi) or ‘Mt. Barker’ subterranean clovers (Trifolium subterraneumL.), (ii) fertilized with 0, 84, 168, 252, or 336 kg N ha−1, or (iii) overseeded with arrowleaf or subterranean clover plus 112 kg N ha−1. Dry matter production of clover‐Coastal bermudagrass and clover‐bahiagrass mixtures was not significantly different from the grass alone at the 168 and the 252 kg N ha−1rate, respectively. Overseeding clovers improved seasonal forage distribution by providing forage one to two months earlier and reduced the May–June forage peak exhibited by the N fertilizer‐grass treatment. Average annual N accumulations of clover‐grass mixtures ranged from 177 to 217 kg N ha−1, which equaled or exceeded the 336 kg N rate except for the arrowleaf–bermudagrass mixture. The amount of N fertilizer required by the grass to replace the clover dry matter contribution was 127, 211, 160, and 254 kg N ha−1for the arrowleaf‐bermudagrass, arrowleaf‐bahiagrass, subterranean‐bermudagrass, and subterranean‐bahiagrass mixtures, respectively. Applying 112 kg N ha−1to clover‐grass mixtures did not improve total yield, forage distribution, or N accumulation, but did decrease percentage clover in the stand 5 to 33%.
Salinity Tolerance of Winged Bean as Compared to that of Soybean1
Authors: Weil Ray R. , Khalil N. A. 
Published: July 2010

AbstractWinged bean [Psophocarpus tetragonolobus(L.) DC] has been called an underutilized crop with the potential to become a major protein crop for the tropics and subtropics. As with soybean [Glycine max(L.) Merr.] the introduction of winged bean to warm arid regions will be affected by tolerance to salinity. In this study a prolific Sri Lankan winged bean accession (‘SLS47’) and two soybean cultivars (‘Jackson’ and ‘Lee’) were grown in pots of sandy soil amended with NaCL to give saturated paste electrical conductivities (EC) of 0.5, 2.5, 4.5, 6.5 and 8.5 dS m−1. At 0.5 dS m−1, dry matter accumulation (0.84 g plant−1), nodule mass, (32 mg plant−1), and tissue N (24 mg Ng−1) of winged bean were similar to those of both soybean cultivars. At 65 d after planting, however, specific nitrogenase activity by acetylene reduction assay was much lower for the winged bean (60 μmol ethylene g−1h−1) than for the soybean (160 to 190 μmol ethylene g−1h−1). The results indicated that winged bean was at least as tolerant as Lee soybean and more tolerant than Jackson. Though stunted, at 8.5 dS m−1winged bean showed significantly less foliar injury than did either of the soybean cultivars. For the soybean, the tissue N content was unchanged, but for winged bean it increased significantly with increasing salinity, suggesting that dry matter accumulation,especially by winged bean, was more sensitive to salinity than to N2fixation.
Wheat and Forage Sorghum Response to Residual Phosphorus in Blackland Soils1
Authors: Hipp Billy W. 
Published: July 2010

AbstractPhosphorus fertilizers are generally applied for crops grown on Blackland Prairie soils of Texas, but the crop yield response due to residual P from single applications of P is unknown. Studies were conducted over a 5‐yr period (1977 to 1981) on Austin silty clay (fine‐silty, carbonatic, thermic Entic Haplustolls) and Dalco clay (fine, montmorillonitic, thermic Udic Pellusterts) soils to evaluate the residual effects of P on subsequent crops. Fertilizer rates of 0, 25, and 50 kg P ha−1were applied in 1977,1978, and 1979 at three sites with soil P levels of 6,10, and 13 mg kg−1NaHCO3‐extractable P (0 to 15 cm depth). Following the initial crop year, plots were split to include 25 kg P ha−1with the seed. The other half received no fertilizer P other than the initial P application. The test crops were wheat (Triticum aestivumL.), forage sorghum (Sorghum bicolorL. Moench), and sweet clover (Melilotus albusLam.). A significant yield increase due to initial P application was obtained at each site. Crop yield increases due to residual effects of the 50 kg P ha−1rate ranged from 0 to 20%, while yield increases due to 25 kg P ha−1at planting ranged from 19 to 43%. Percent yield increase from residual P was greater on soil with 6 mg kg−1soluble P than on soil with 13 mg kg−1soluble P. Phosphorus concentrations in wheat plants were increased by residual P, but were much higher in plants receiving P at planting. These data indicate that some yield increase can be expected from residual P from a single application of moderate amounts of P. For more efficient use of P and high yields, P should be applied to each crop if initial NaHCO3‐extractable P levels are between 6 and 13 mg kg−1.
Field Measurements of Ammonia Loss from Surface Applications of Urea Solution to Bare Soil1
Authors: McInnes K. J. , Ferguson R. B. , Kissel D. E. , Kanemasu E. T. 
Published: July 2010

AbstractFactors influencing ammonia (NH3) volatilization from surface‐applied urea have been studied extensively; however, almost all research has been done in a manner that modifies the environment compared to field conditions. Results from such studies, therefore, may incorrectly assess actual losses in the field. Our objective was to evaluate the magnitude of NH3volatilization and how soil temperature, soil water, and other environmental factors affected rates of loss. Three studies were conducted to assess the volatilization of NH3from surface‐applied urea, two on a silt loam and one on a very fine sandy loam soil. A mass‐balance micrometeorological method, which produces very minimal disturbance of the natural environment was used in all studies. Diurnal patterns of NH3loss, which coincided with the fluctuations in surface temperature and water content, were found in each study. In all studies, loss followed most closely the pattern of urea hydrolysis. Urea hydrolysis in the surface soil was slowed by dry conditions and approached zero when the soil was near “air dryness.” Rainfall of 0.86 cm did not prevent further NH3loss from Muir silt loam soil (fine‐silty, mixed, mesic Pachic Haplustolls). Three simulated rainfalls with 0.5 cm of irrigation separated by 3 and 4 days did not curtail loss from Haynie very fine sandy loam soil (coarse‐silty, mixed, mesic Typic Udifluvents), but rather enhanced the rate of volatilization, probably due in part to an increased rate of urea hydrolysis.
Timing of Weed Control in No‐Tillage Wheat Crops
Authors: Forcella F. 
Published: July 2010

AbstractTiming of successful weed control in no‐tillage wheat is not well known, yet weeds, especially annual grasses, may reduce yields considerably in such crops. To evaluate the effect of weed control on no‐tillage wheat production, a 2‐yr study of the timing of wheat/weed interference was initiated in southeastern Australia, a region that effectively has a winter‐wet/summer‐dry climate. In this study, weeds were controlled either manually or chemically at various stages of crop growth. Wheat yield or dry weights were determined at harvest. Additionally, soil temperature, soil water, and available soil N were monitored throughout the growing seasons. If autumnal rains commenced early and the crop was sown early (i.e., before May), then significant wheat/weed competition took place only in May. However, if the crop was sown late (i.e., after May), then wheat/weed competition occurred only in early September. In all cases, wheat/weed competition increased when soil temperature exceeded 10°C and resulted in rapid depletions of available soil N.
The Use of Nitrogen‐15‐Depleted Ammonium Sulfate for Estimating Nitrogen Fixation by Leguminous Trees1
Authors: van Kessel Christopher , Nakao Patty 
Published: July 2010

AbstractThe feasibility of using 15N‐depleted (NH4)2SO4for assessing biological N2fixation of leguminous trees was investigated. A slowgrowing species, lebbeck [Albizia lebbeck(L.) Benth], and a fastgrowing species, leucaena [Leucaena leucocephala(Lam.) de Wit] were inoculated with appropriate Rhizobiumstrains and grown under four different levels of N. Each week, 0, 5, 12.5, or 25 mg of 15N depleted (NH4)2SO4was applied to the upper chamber of the Leonard assembly. After 10 and 18 weeks growth for leucaena and lebbeck respectively, plants were separated into shoots, roots, and nodules for analysis. The atom% 15N in shoots and roots was linearly correlated to the amount of applied 15N‐depleted (NH4)2SO4. Significant differences in atom% 15N and percentage N derived from N2fixation were measured in lebbeck and leucaena when, respectively, more than 8.3 and 2.9% of the total N was derived from (NH4)2SO4. Nodules derived a larger portion of their total N from N2fixation than did the roots or shoots, indicating that most of the N present in the nodules was derived from N2fixation. Nodules of both species at the no N treatment showed slightly higher atom% 15N values than the 15N‐natural abundance level of atmospheric N2.
Combinations of Preplant‐Banded and Seed‐Banded Applications of Nitrogen and Phosphorus Fertilizer for Winter Wheat Production1
Authors: Cabrera M. L. , Kissel D. E. , Whitney D. A. 
Published: July 2010

AbstractThe application of N and P fertilizers together in deep, preplant bands is an effective method of fertilizer placement for winter wheat (Triticum aestivum L.). However, it produces uneven growth of wheat with the greatest growth directly over the preplant bands. Two field studies were conducted on a Crete series soil (fine, montmorillonitic, mesic Pachic Argiustoll) to determine if the addition of N and P fertilizer banded with the seed could eliminate this uneven growth and, in turn, increase grain yields. Wheat was planted in rows perpendicular to the preplant bands so that plant and spike samples could be taken from row sections located at different distances from the preplant band. In 1980‐1981, seed‐banded fertilizer increased tillering and early dry‐matter production in all row sections. However, these increases did not translate into higher spike densities or grain yields. In 1981‐1982, seed‐banded fertilizer increased tillering and early dry‐matter production in row sections between preplant bands, which reduced but did not eliminate the uneven growth caused by preplant bands. Although significant grain yield increases were obtained in row sections between preplant bands, no significant increases in overall grain yield were found. Results indicate that the addition of seed‐banded fertilizer can increase overall early dry‐matter production and may reduce, although not eliminate, the uneven growth caused by preplant bands.
Use of a Hydraulic Press for Estimation of Leaf Water Potential in Grain Sorghum1
Authors: Hicks S. K. , Lascano R. J. , Wendt C. W. , Onken A. B. 
Published: July 2010

AbstractThe hydraulic press (HP) is a highly portable instrument designed for rapid measurement of leaf water potential of plants. This study compared grain sorghum [Sorghum bicolor (L.) Moench] leaf water potentials measured with a pressure chamber (PC) and using two endpoints with a HP, under glasshouse conditions. The first endpoint is when water exudes from one vein and the second endpoint when water exudes from all veins on both sides of the leaf tissue. The results showed that the HP and PC measurements agreed well in the range of −0.5 to −3.5 MPa of leaf water potentials when the second endpoint was selected for the HP. The HP can be used to measure the leaf water potential of grain sorghum, provided it is calibrated using the second endpoint against a PC or another method.