bluuebunny/crossref_metadata_2025_split huggingface dataset:
Potato Yield Response and Nitrate Leaching as Influenced by Nitrogen Management
Authors: Errebhi Mohamed , Rosen Carl J. , Gupta Satish C. , Birong David E. 
Published: July 2010

AbstractNitrogen management for irrigated potato (Solanum tuberosum L.) is important from both a production and environmental standpoint. Nitrogen deficiency can limit yield, while excessive N can leach to groundwater. The objective of this study was to investigate the effects of early‐season N management on irrigated ‘Russet Burbank’ potato yield, N recovery, and NO3‐N leaching. A 2‐yr experiment was conducted on a Hubbard loamy sand (Udorthentic Haploborolls), using four N treatments and a 0 N control. Total N applied was 270 kg N ha−1; the portion applied at planting was 0, 45, 90, and 135 kg N ha−1, with the remainder applied in equal quantities at emergence and hilling. In 1991, increasing the amount of N applied at planting did not affect total yield, but significantly increased the yield of nonmarketable tubers. In 1992, total yield again was not affected, but the yield of smaller tubers significantly increased and the yield of larger tubers decreased as the proportion of N applied at planting increased. During 1991, when heavy leaching occurred, an average of only 33% of applied N was recovered by the crop. In contrast, during 1992, when fewer leaching events occurred, recovery of N averaged 56%. In both growing seasons, the amount of NO3‐N leached increased linearly as the proportion of N applied at planting increased. The strategy of reducing N application at planting for irrigated Russet Burbank potato can reduce the potential for NO3‐N leaching, increase N uptake, and improve marketable yield.
Previous‐Crop Effects on Sugarcane Responses to Nitrogen Fertilization
Authors: Wiedenfeld Robert P. 
Published: July 2010

AbstractNitrogen fertilizer recommendations have been developed for sugarcane (Saccharum officinarum L.) based on numerous fertility trials, with the primary variables affecting those recommendations being soil type and crop age. Cropping history influences subsequent crop responses to N fertilization, but such effects have not been determined for sugarcane. The objective of this research was to evaluate previous‐crop effects on sugarcane growth and response to N fertilization. Eight 2‐yr previous‐crop treatments consisted of N‐fertilized and unfertilized corn (Zea mays L.), sorghum [Sorghum bicolor (L.) Moench], and cotton (Gossypium hirsutum L.); unfertilized soybean [Glycine max (L.) Merr.]; and fallow. These treatments were followed by sugarcane grown for 3 yr at four different levels of N fertilizer application. Previous‐crop treatments containing corn and sorghum contributed more biomass back to the soil than cotton or soybean. None of the crops grown prior to sugarcane responded to N fertilization, resulting in 90% of the N fertilizer applied remaining in the soil. Sugarcane yield and quality in the plant‐cane crop were affected primarily by previous‐crop treatments, in the first ratoon by both previous crop and N fertilizer application, and in the second ratoon primarily by N fertilizer application. Sugarcane responses to N fertilization were generally lowest following those treatments which had the most N returned from plant residue, or the most measured residual N. Inorganic soil N measurements correlated better with sugarcane responses to N in the plant cane crop, while mineralizable soil N levels correlated better with sugarcane responses to N in the first ratoon crop. Soybean resulted in low inorganic and mineralizable soil N, yet sugarcane following soybean failed to respond to N fertilizer application, indicating that N following soybean is less readily released but does later become available.
Cyanogenesis Effect on Insect Damage to Seedling White Clover in a Bermudagrass Sod
Authors: Pederson Gary A. , Brink Geoffrey E. 
Published: July 2010

AbstractCyanogenesis in white clover (Trifolium repens L.) has been shown to confer resistance to a number of leaf‐feeding insects and molluscs in laboratory and field studies. Most cultivars grown in the USA, however, are acyanogenic. White clover seedlings may be damaged or killed by insect feeding during establishment into a grass sod. The objective of this study was to determine if white clover stand establishment in a grass sod is influenced by cyanogenesis. Two cyanogenic white clover populations, HCNpi and BLHplus, and two acyanogenic populations, ‘Regal’ and BLHminus, were sod‐seeded into common bermudagrass [Cynodon dactylon (L.) Pers.] at two locations in 1994 and one location in 1995. The 1994 test in Forage Unit A was planted on an Oktibbeha silty clay (very‐fine, smectitic, thermic Chromic Dystrudert). The 1994 and 1995 tests in Forage Unit B were planted on a Savannah fine sandy loam (fine‐loamy, siliceous, semiactive, thermic Typic Fragiudult). The studies were conducted in a randomized complete block design with four replicates at Mississippi State, MS. Cotyledons, unifoliate leaves, and trifoliate leaves were rated for insect damage and leaf area loss due to insect feeding at 2, 4, and 6 wk after seeding. No differences were noted among the populations for seedling survival at 2 wk after seeding. At 4 and 6 wk after seeding, the highly cyanogenic population, HCNpi, had fewer plants with trifoliate leaves damaged and lost less leaf area due to insect feeding than either acyanogenic population. Seedling survival at 6 wk was 88% for HCNpi, compared with 66% for acyanogenic Regal. Cyanogenesis in white clover reduced insect feeding damage and improved seedling survival in bermudagrass sod. The incorporation of limited levels of cyanogenesis into acyanogenic U.S. cultivars could improve seedling establishment without the animal toxicity concerns of highly cyanogenic types.
Is Soil Temperature Better than Air Temperature for Predicting Winter Wheat Phenology?
Authors: McMaster Gregory S. , Wilhelm Wallace W. 
Published: July 2010

AbstractIn predicting wheat (Triticum aestivum L.) phenology, logic suggests that basing thermal unit accumulation on near‐surface soil temperature should give a better representation of shoot apex thermal unit accumulation than air temperature until internode elongation raises the apex above the soil surface. A study was undertaken to determine if predictions of winter wheat phenology are improved when based on measured near‐surface soil temperature rather than air temperature. Air temperature 1.5 m above the soil surface and soil temperature at crown depth (the position of the shoot apex before stem elongation) were collected for 23 site‐years across the U.S. Central Great Plains representing a range of cultivars, soils, management practices, and climates. Seven site‐years from different sites were randomly selected to calculate the mean thermal units from both seeding and 1 January to specific growth stages based on both air and soil temperature. These means were used to predict occurrence of growth stages for the remaining 16 site‐years. In no instance did soil temperature significantly improve prediction of winter wheat phenology. From these results, we conclude that the additional effort and expense of using soil temperature in predicting winter wheat phenology are not justified.
Modeling Freezing Injury in Alfalfa to Calculate Forage Yield: II. Model Validation and Example Simulations
Authors: Kanneganti V. Rao , Bland William L. , Undersander Daniel J. 
Published: July 2010

AbstractFreezing injury can cause extensive yield loss in alfalfa (Medicago sativa L.) exposed to severe winters in cold climates. Alfalfa models must simulate freezing injury effects in a cumulative way, so that forage dry matter (DM) yield can be accurately calculated during multiple years of a crop. A companion paper presents ALFACOLD, an alfalfa simulation model developed by integrating functions of cold tolerance, fall dormancy, and freezing injury into the ALSIM 1 (Level 2) alfalfa model. The ALFACOLD model calculates forage yield on a daily basis, while simulating freezing injury across multiple years of the same crop. The objective of this study was to test the ALFACOLD model's ability to calculate field‐measured forage DM yield. The model was tested against measured forage yield from 39 cultivars seeded in two years and managed under a 4‐cut system for 3 yr after the seeding year at two sites in Wisconsin. Averaged across the sites, cultivars, and years, the ALFACOLD model calculated annual forage DM yield to within 12% of the measured yield, compared with an error of 35% with the ALSIM model. A regression of field‐measured yield of individual harvests (n = 874) on the corresponding ALFACOLD calculated yield indicated that 70% of the measured variability in forage yield was explained by the model. The average difference between measured and calculated DM yield for Harvests 1, 2, and 3 was <7%, but the model overcalculated fourth‐cut yield by 38%. Averaged across all sites, cultivars, years, and cuts, the ALFACOLD model calculated yield with an average SD of 600 kg ha−1 cut−1.
Rotational vs. Continuous Intensive Stocking Management of Bahiagrass Pasture for Cows and Calves
Authors: Williams M. J. , Hammond A. C. 
Published: July 2010

AbstractRapid growth of warm‐season grasses such as bahiagrass (Paspalum notatum Flügge) is associated with their rapid decline in nutritional value. Grazing management that better matches forage growth and animal intake may improve animal performance on warm‐season grass pastures. A 3‐yr study (1989‐1991) was conducted at the USDAARS Subtropical Agricultural Research Station, Brooksville, FL, to determine the effect of the same stocking rate with either rotational or continuous intensive stocking (CIS; temporary increase in stocking density during periods of rapid forage growth) management on herbage mass, forage crude protein and in vitro organic matter digestibility (IVOMD), and the performance of cows and calves (Bos taurus). Cow performance was judged on weight, body condition score (BCS), plasma urea nitrogen (PUN, mg dL−1), and pregnancy rate; calf performance was judged on average daily gain (ADG), adjusted 205‐d weaning weight, and BCS. Herbage mass of both grazing treatments was similar until the start of the rainy season (June‐July). Stocking density of CIS cattle increased by 75%, which resulted in an increase in herbage mass of 250 to 1150 kg ha−1 on rotationally grazed pastures, but this was not significant. Even at the increased stocking density, herbage mass of grazed CIS pastures continued to increase in 2 out of 3 yr, indicating that animal selectivity was not limited by grazing treatment. Crude protein and IVOMD concentrations were not affected by grazing. As a consequence, none of the animal performance variables measured was affected by grazing management. The main advantages of CIS are less labor and fencing, and reserving an area for production of winter feed. Herbage mass on ungrazed CIS pastures (3000–4200 kg ha−1) would have produced between 1700 and 2400 kg hay ha−1.
Soil Management and Supplemental Irrigation Effects on Potato: I. Soil Properties, Tuber Yield, and Quality
Authors: Porter Gregory A. , Bradbury W. Bart , Sisson Jonathan A. , Opena Geraldine B. , McBurnie Jeffrey C. 
Published: July 2010

AbstractRainfall in the northeastern United States can be erratic, causing fluctuations in the supply and quality of potato (Solanum tuberosum L.). To address these problems, yield and quality of potato were studied during three growing seasons to determine their response to soil management treatments designed to increase soil organic matter. The soil management treatments, consisting of rotation crop [oat (Avena sativa L. cv. Porter vs. green manure] and annual soil amendment applications [none vs. 22 t ha−1 compost and 45 t ha−1 manure from beef cattle (Bos taurus L.)], were tested in combination with supplemental irrigation treatments (none, reduced, and moderate) on a Caribou gravelly loam (fine‐loamy, mixed, frigid Typic Haplorthod). The green manure consisted of pea (Pisum sativum L. cv. Trapper), oat, and hairy vetch (Vicia villosa Roth) seeded at 168, 56, and 34 kg ha−1, respectively. After a single season, the amendments increased soil organic matter, K, Mg, Ca, cation exchange capacity, and aggregation. Modified‐Morgan soil‐test P increased and bulk density decreased after two amendment applications. Total yields were significantly increased by the amendment treatment [8.6 t ha−1 (23%), 1993; 8.1 t ha−1 (27%), 1994; and 4.0 t ha−1 (11%) for 1995], and U.S. No. 1 yields were similarly affected. The amendments increased tuber decay incidence during all 3 yr. Irrigation treatments significantly increased total yields by 10 t ha−1 (36%) in 1994 and 11.6 t ha−1 (37%) in 1995, while significantly reducing specific gravity and increasing tuber size. Irrigation also increased tuber decay incidence in 2 of 3 yr. During the time course and under the conditions of this study, the green manure rotation crop had no significant effect on yields or tuber quality compared with the oat rotation. In contrast, soil amendment and supplemental irrigation proved to be management tools that could rapidly affect productivity in this agricultural system.
Rice—A Step Toward Use of Allelopathy
Authors: Olofsdotter Maria 
Published: July 2010

Rice (Oryza sativa L.) allelopathy has been on the research agenda for a decade. Now it is important to step back and look at its progress to enable priority setting for future research. This paper aims to do so primarily using the following five‐step protocol for allelopathy research: (i) carrying out laboratory, greenhouse, and field studies to illustrate the effect of released allelochemicals; (ii) isolating, identifying, and characterizing allelochemicals; (iii) establishing a correlation between growth inhibition and allelochemicals; (iv) performing genetic mapping of quantitative trait loci (QTLs) correlated with allelopathy; and (v) breeding for allelopathic cultivars tested for competitive ability in greenhouse and field experiments. Recent research on rice allelopathy has resulted in the following research milestones:

There is large variation in allelopathy among rice cultivars.Allelopathy plays a role under field conditions.Allelopathic rice can suppress both mono‐ and dicot weed species.Progress has been made in identifying rice allelochemicals.Quantitative trait loci correlated with allelopathy have been identified.

This paper discusses the progress made in recent years and suggests some direction for future research.
Coppice Dunes and the Rotura Soil
Authors: Gile Leland H. 
Published: July 2010

AbstractEarly land survey notes and present conditions indicate that certain coppice dunes near Las Cruces, N. M. have formed since 1885. The Rotura soil, formed in mid‐Pleistocene sediments, occurs at the land surface between dunes but is buried beneath the dunes. The dunes overlie and preserve the pre‐dune surficial horizons, and the stratigraphic relationships thus preserved can be useful in genetic studies of thin upper horizons between dunes.Coppice dune materials are not presently recognized as individual soils but are designated by such terms as “hummocky phase”. Although no A or B horizon development is apparent in the dune materials, roots and fauna have locally mixed the sediments. Coppice dunes dominate the microrelief and occupy major portions of the land surface in many areas. In addition, most dunes are thickly covered with vegetation. An alternative interpretation, therefore, is that sediments of a coppice dune constitute a soil and thus should be classified and named.
Estimation of Isotopically Exchangeable Cadmium and Zinc in Soils
Authors: Fujii R. , Corey R. B. 
Published: July 2010

AbstractIsotopically exchangeable and chelate‐extractable Cd and Zn (16‐h equilibrations) were compared for a silt loam and a loamy sand with and without addition of 51 kg m−3 of sewage sludge. The chelating agents used were 5 mM DTPA (diethylenetriaminepentaacetic acid) at a soil to solution ratio of 1:5 and 5 and 1 mM EDTA (ethylenediaminetetraacetic acid) at soil to solution ratios of 1:5 and 1:2.5. The extractant best suited to estimate isotopically exchangeable Cd and Zn in the soils studied was 5 mM EDTA at a soil to solution ratio of 1:2.5. Extractions with this sulution ranged from 87 to 114% of the Cd isotopically exchangeable in 16 h and 91 to 113% of the Zn isotopically exchangeable in the two soils with and without sludge addition.
Fractal Theory Applied to Soil Aggregation
Authors: Perfect E. , Kay B. D. 
Published: July 2010

AbstractRecent advances in fractal theory may be applicable to the characterization of soil structure. This study explored two such applications. Aggregates were assumed to be approximated by cubes of constant dry density. Under this condition, the fractal dimension, D, provides a measure of fragmentation. The value of D increases with increasing fragmentation. The influence of energy input (wet sieving) on the D of aggregates from a Conestogo silt loam soil (finesilty, mixed, mesic Aquic Eutrocrept) was investigated. Aggregates were obtained from five cropping treatments, ranging from 15 yr of continuous corn (Zea mays L.) to 15 yr of continuous bromegrass (Bromus inermis Leyss.). The value of D was estimated from cumulative size‐frequency distribution data plotted on a log‐log scale. Computed values of D ranged from 2.51 to 3.52. Energy input, cropping history, and their interaction all had a significant effect on D. Fragmentation increased with energy input and time under corn production. Relations between D and the breakdown of individual aggregates were investigated. A scale‐invariant breakdown model was developed and tested. The model permits calculation of apparent probabilities of failure, P, as a function of aggregate size, x. Stepwise multiple regression analysis selected the rate of change in P with x as the best predictor of D following energy input. Fractal theory offers potential for modeling aggregate breakdown, as well as characterizing the degree of fragmentation.
Influence of Added Nitrogen Interactions in Estimating Recovery Efficiency of Labeled Nitrogen
Authors: Rao A. C. S. , Smith J. L. , Papendick R. I. , Parr J. F. 
Published: July 2010

AbstractThe addition of N fertilizer to soil has been shown to stimulate the uptake of native soil N via a priming effect recently termed added nitrogen interaction (ANI). This ANI, due to pool substitution, can substantially affect the N‐recovery efficiency (NRE) by plants as calculated by the 15N isotopic dilution technique. We evaluated NRE in a pot study using ‘Edwall’ spring wheat (Triticum aestivum L.) with three soils (Palouse, a fine‐silty, mixed, mesic Pachic Ultic Haploxeroll; Ritzville, a coarse‐silty, mixed, mesic Calciorthidic Haploxeroll; and Shano, a coarse‐silty, mixed mesic Xerollic Camborthid) of varying organic C (OC) levels and five levels of 15N‐labeled fertilizer. Data obtained at 60 d after emergence (DAE) showed that NRE generally increased with fertilizer additions, was lowest in the soil having the greatest OC, and ranged from 57 to 79%. The NRE values estimated by the isotopic method averaged 20% lower than those estimated by the difference method, although the two estimates were strongly related. Although the magnitude of ANI showed no direct relationship to OC levels, it was strongly related to N rates, OC, soil C/N ratio, and N lost, which together explained 73% of the relationship. The magnitude of occurrence of ANI appears to be influenced by several factors and thus may be soil specific. Regression of NRE with soil properties showed that NRE was influenced primarily by the same factors that influenced ANI. This study suggests that, for accurate comparisons of nitrogen recovery efficiency between soils or treatments using the isotopic method or for comparing methods of determining N‐recovery efficiency, the role of added N interaction must be considered.
Inverse Method to Determine Soil Hydraulic Functions from Multistep Outflow Experiments
Authors: van Dam J. C. , Stricker J. N. M. , Droogers P. 
Published: July 2010

AbstractOutflow experiments, in combination with inverse modeling techniques, offer a time‐efficient way to simultaneously determine retention and hydraulic conductivity functions. Using outflow data only in the objective function, and applying the optimization algorithm of Marquardt's maximum neighborhood, the multistep outflow method results in unique estimates of the retention and hydraulic conductivity functions. For the same experimental conditions the one‐step outflow method often yields nonunique solutions. For the Mualem‐van Genuchten expression of the soil hydraulic functions, four parameters (α, n, Ks and λ) were estimated for a medium‐textured soil. Fixation of λ negatively affects the estimation of K(h). The reference curve as derived by similar media scaling corresponded with curves derived by the direct averaging of soil hydraulic functions, and with those obtained by optimization of the mean outflow for a set of 20 soil samples.
Site Preparation and Fertilization Effects on Growth of Slash Pine for Two Rotations
Authors: Tiarks A. E. , Haywood J. D. 
Published: July 2010

AbstractTwo replicated site preparation studies were used to examine the effect of management on pine height and volume growth in the next rotation on Paleudults. Treatments included no tillage, flat disking, bedding, and fertilization. The first rotation of planted slash pine (Pinus elliottii Engelm. var. elliottii) was measured for 15 yr on one site and 20 yr at the other, harvested, and replanted without additional tillage. The second rotations were measured for 10 yr. At one site, 100 kg ha−1 P was applied to each rotation as a treatment variable. At one site, disking before the first rotation increased pine heights. Bedding before the first rotation increased pine heights at both sites. In the second rotation, the response was reversed, with pines planted on beds being the shortest. The P fertilization increased heights in both rotations but did not affect response to tillage. The P as well as N, applied only at age 7 in the second rotation, had a negative effect on the second rotation's volume, probably because of increased competition from shrubs and other understory plants. Across both sites and for all treatments, 10‐yr‐old slash pines averaged 7% less in height and 24% less in volume in the second rotation. These differences are statistically significant. Analysis at age 10 from both rotations indicates stable foliar concentrations of P and Ca, declining K, and increasing Mn and Al.
Effectiveness of a Computerized Insulin Order Template in General Medical Inpatients With Type 2 Diabetes
Authors: Wexler Deborah J. , Shrader Peter , Burns Sean M. , Cagliero Enrico 
Published: July 2010

OBJECTIVE
To determine whether an electronic order template for basal-bolus insulin ordering improves mean blood glucose in hospitalized general medical patients with hyperglycemia and type 2 diabetes.

RESEARCH DESIGN AND METHODS
We randomly assigned internal medicine resident teams on acute general medical floors to the use of an electronic insulin order template or usual insulin ordering. We measured diabetes care parameters for 1 month on all patients with type 2 diabetes and blood glucose &lt;60 mg/dl or &gt;180 mg/dl treated by these physicians.

RESULTS
Intervention group patients (n = 65) had mean glucose of 195 ± 66 mg/dl. Control group patients (n = 63) had mean glucose of 224 ± 57 mg/dl (P = 0.004). In the intervention group, there was no increase in hypoglycemia.

CONCLUSIONS
Access to a computer insulin order template was associated with improved mean glucose levels without increasing hypoglycemia in patients with type 2 diabetes.