bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rice Ratoon Response to Main Crop Harvest Cutting Height
Authors: Jones David B. 
Published: July 2010

AbstractAlthough main crop rice (Oryza sativa L.) cultural practices are known to influence the subsequent ratoon crop, little specific information is available on the effect of many main crop management practices on ratoon crop performance. The objective of this study was to evaluate the effect of main crop harvest cutting height on ratoon crop agronomic performance, yield, and yield components. The ratoons of both a semidwarf and non‐semidwarf southern U.S. long‐grain rice cultivars were evaluated in the field for two growing seasons for response to main crop harvest cutting height. Main crop plants were harvested at a cutting height of 0.1, 0.2, 0.3, 0.4, and 0.5 m above the soil surface. The semidwarf cultivar had 7 and 40% higher grain yields than the taller cultivar in the main and ratoon crops, respectively. Ratoon plant height and days to 50% heading were numerically different for the two cultivars, but the same in proportion to their main crop traits. Reduced cutting heights delayed ratoon maturity by up to 4 d, but had minimal effects on ratoon plant height. No interactions between cutting height, cultivar, and/or year were found for ratoon yield or yield components. Highest ratoon yields were obtained at cutting heights of 0.2 to 0.3 m. Increasing cutting heights had little effect on ratoon panicle number per meter squared, but significantly decreased filled grain number per panicle, which led to decreased ratoon yields at the highest two cutting heights. The results show that proper main crop harvest cutting height can increase ratoon yields, but selecting a cultivar with inherent ratooning ability is also essential to successful rice ratooning.
Higher‐Order Analysis of Nutrient Accumulation Data
Authors: Sadler E. John , Karlen Douglas L. 
Published: July 2010

AbstractBiomass and nutrient accumulation data have often been obtained to determine rates of nutrient uptake. Traditionally calculated as the difference in accumulation divided by elapsed time, rate values thus obtained are slopes of linear interpolations between points on the accumulation curve. That implies an assumption of constant uptake rate during the observation period. Our objective was to illustrate a higherorder interpolant that is not subject to such assumptions. With it, one obtains smooth curves consistent with the assumption that daily uptake rates are somewhat related. The abrupt changes in rates determined with linear interpolation are consistent with daily rates that are unrelated. Analyses of historical and recent data showed that additional information may be obtained from higher‐order analysis methods. Cubic interpolation methods were applied to the accumulation curve to obtain continuous, smooth nutrient uptake curves. The programs used are described, and two sample data sets of corn (Zea mays L.) growth and N accumulation illustrate the strengths, weaknesses, and inherent assumptions of this analytical technique. In general, this technique can be used if the objective is to analyze intraseasonal variation in growth or uptake rates determined from sparse data.
Tillage Effects on Dryland Wheat and Sorghum Production in the Southern Great Plains
Authors: Unger Paul W. 
Published: July 2010

AbstractWinter wheat (Triticum aestivum L.) and grain sorghum [Sorghum bicolor (L.) Moench] are important, well‐adapted grain crops for the semiarid southern Great Plains. They often are grown in rotation on dryland to reduce the risk of failure associated with annual cropping and to overcome the low precipitation‐use efficiencies associated with crop‐fallow systems. This study on Pullman soil (Torrertic Paieustoli) determined the effects of 12 tillage systems ranging from no‐tillage (herbicides only) to sweep tillage (no herbicides) on water storage and use, crop growth, yields, and yield components for dryland wheat and sorghum grown in rotation. Tillage systems did not affect mean water storage during fallow nor mean water use by either crop. All yield, growth, and yield component factors differed among growing seasons. Wheat grain and straw yields were not affected by tillage. Mean wheat grain yield was 2.92 Mg ha−1. Mean sorghum grain yield was greatest (3.91 Mg ha−1) for the system of reduced tillage after sorghum and no‐tillage after wheat, and least (3.48 Mg ha−1) for the system of reduced tillage after each crop. Sorghum stover yields were not affected by tillage. Number of panicles harvested was greatest (233 000 ha−1) and least (212 000 ha−1) for the same treatments that resulted in the greatest and least grain yields. Sorghum seed weights and test weights were not affected by tillage. This study showed that a wide range of tillage systems is adaptable for a dryland wheat‐grain sorghum cropping system for the semiarid southern Great Plains.
Evaluation of Resistances for Bermudagrass Turf Crop Water Stress Index Models
Authors: Jalali‐Farahani H. R. , Slack D. C. , Kopec D. M. , Matthias A. D. , Brown P. W. 
Published: July 2010

AbstractEvaluation of the Penman‐Monteith‐based crop water stress index (CWSI), as a potential indicator of turf irrigation timing, requires reliable estimates of potential (minimum) canopy resistance, rcp, and aerodynamic resistance, ra. This paper compares various methods of estimating rcp and ra for evaluation of water stress of bermudagrass turfgrass (Cynodon dactylon cv. Midiron) in the desert Southwest of the USA. First, two empirical CWSI models were developed using field data collected from well‐watered and severely water‐stressed turf plots during the 1986 growing season in Tucson, AZ. Second, the regression constants in the empirical lower limits of CWSI (canopy temperature minus air temperature, Tc − Ta, of nonwater‐stressed turf) and the parameters associated with similar terms (net radiation and vapor pressure deficit) in the Penman‐Monteith equation were equated, thus solving for rcp and ra. This yielded mean rcp and ra values of 79 and 13 s m−1, respectively. Using these estimates, the predicted lower limits of Tc − Ta from the Penman‐Monteith equation were in good agreement with values measured over well‐watered turf. However, the predicted Tc − Ta for severely water‐stressed turf agreed very poorly with the measured values. The use of the log‐law equation yielded independent estimates of ra generally greater than 45 s m−1 and resulted in erroneous estimates of Tc − Ta by the Penman‐Monteith equation. Using a crop‐based method and data from the turf plots, estimates of the resistances were made in which constant rcp and ra values of 62.5 and 20 s m−1, respectively, were found. The crop‐based method was found to be not only simple to use, but also performed satisfactorily in predicting Tc − Ta. A well‐defined curvilinear relationship between estimates of midday canopy resistance (rc) and CWSI was determined for a wide range of turf water stress, implying that these two estimates nearly equally reflect the state of turf water stress. Our findings also suggest threshold midday CWSI and rc values for short bermudagrass turf of 0.16 and 125 s m−1, respectively, to indicate the need for irrigation.
Influence of Residue Removal Method and Herbicides on Perennial Ryegrass Seed Production: II. Crop Tolerance
Authors: Mueller‐Warrant George W. , Young William C. , Mellbye Mark E. 
Published: July 2010

AbstractInherent in the ongoing transition from open‐field burning to nonburn systems for grass seed production in the Pacific Northwest is an increased reliance on herbicides for weed control. However, herbicide treatments able to control volunteer crop seedlings, the most abundant weed in certified grass seed fields, may pose severe hazards to the established crop itself. Fourteen herbicide treatment sequences plus an untreated check were examined in five residue removal systems at two sites during two consecutive growing seasons to determine their impact on perennial ryegrass (Lolium perenne L.) seed yield. Seed yield was reduced by weed competition in nonburned, untreated checks, and by herbicide injury in some of the 14 herbicide treatment sequences. When compared across 13 promising herbicide treatments, seed yield did not differ between burned and nonburned plots in the first year, although burning was slightly superior in the second. However, the cumulative yield advantage to burning was only 84 kg ha−1, or 2.6%, over the 2‐yr period. Although differences in yield among four herbicides applied preemergence (PRE) to seedling grasses in mid‐October were relatively small, pendimethalin [N‐(1‐ethylpropyl)‐3,4‐dimethyl‐2,6‐dinitrobenzenamine] and oxyfluorfen [2‐chloro‐1‐(3‐ethoxy‐4‐nitrophenoxy)‐4‐(trifluoromethyl) benzene] were superior to either metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl)acetamide] or trifluralin [2,6‐dinitro‐N,N‐dipropyl‐4‐(trifluoromethyl)benzenamine] in specific instances. When applied following PRE herbicides, early December post‐emergence (POST) applications of 1.8 kg ha−1 diuron [N'‐(3,4‐dichlorophenyl)‐N,N‐dimethylurea] or 0.14 kg ha−1 oxyfluorfen plus 1.3 kg ha−1 diuron generally did not differ in yield. While there was usually little net effect on seed yield of applying POST herbicides following pendimethalin, they did depress yield 129 kg ha−1 the first year in burned plots, while increasing it an average of 79 kg ha−1 the second year in all plots. With properly chosen herbicide treatments, the impact on perennial ryegrass seed yield of changing to nonburned methods of residue removal should be minimal. If such herbicide treatments are not available, however, the elimination of field burning may seriously disrupt perennial ryegrass seed production.
Peanut Acclimation to Simulated Shading by Weeds
Authors: Barbour James C. , Bridges David C. , NeSmith D. Scott 
Published: July 2010

AbstractResearch was conducted to assess the acclimation responses of ‘Florunner’ peanut (Arachis hypogaea L.) to shading and the possible role of this acclimation in determining pod yield loss due to shading by weeds. The PNUTGRO model is being used to develop a model of competition for light between peanut and broadleaf weeds. This research was undertaken to validate the treatment of peanut response to shading in PNUTGRO. Peanut plants were grown in two matched growth chambers. At 2 wk after planting, light in one chamber was reduced to 51% of total daily photosynthetic photon flux density (PPFD) received by the full‐light treatment (900 μmol m−2 s−1). Photosynthetic rates acclimated to shading within 3 d. Apparent photosynthesis (AP) rates of shaded vs. control plants were not different at 350, 500, or 1000 μmol photons m−2 s−1, but at 2000 μmol m−2 s−1 shaded plants had AP rates 76% of those of controls. Specific leaf area (SLA) of shaded plants was not statistically different from the controls. There were no observed differences in chlorophyll content or chlorophyll a:b ratios within 3 d after imposition of shading. Field studies were conducted in 1991 and 1992 with shading imposed by shade cloth attached to computer‐controlled shelters. Shading reduced total daily PPFD by 40%, from about 40 d after planting to harvest. Leaf photosynthesis measurements confirmed laboratory results, indicating that shade‐acclimated peanut plants had greater efficiency at low light levels. Shaded plants accumulated less dry weight and were taller than controls. Shaded plants produced fewer roots, with root length density remaining nearly constant after shade imposition. Over the two years, the shaded plants averaged 72% of the fulllight yield on 60% of the PPFD, even though they produced fewer pods. Shaded peanut plants maintain photosynthetic capacity at low light and change partitioning to optimize utilization of available assimilate. Reproductive changes included production of fewer pegs, but a larger proportion of pegs produced harvestable pods. PNUTGRO performed well in simulating dry matter accumulation, but consistently overestimated SLA. It predicted 30% yield loss in both 1991 and 1992. Observed yield losses were 33 and 26% in the 2 yr, respectively. PNUTGRO performed sufficiently well in simulating shade response by peanut to justify its use in a light competition model.
Dairy Manure Applications to Alfalfa: Crop Response, Soil Nitrate, and Nitrate in Soil Water
Authors: Daliparthy Jayaram , Herbert Stephen J. , Veneman Peter L. M. 
Published: July 2010

AbstractMany dairy farmers apply manure predominately to land cropped to corn (Zea mays L.), often in excess of crop N requirements, resulting in potential groundwater contamination. Our research objective was to study the impact of dairy manure applications to established alfalfa (Medicago sativa L.) on crop response and on soil and soil water NO‐3‐N concentrations. Field experiments were initiated in 1990 on an Occum fine sandy loam variant soil (coarse‐loamy, mixed, mesic Fluventic Dystrochrepts) at South Deerfield and on an Agawam fine sandy loam soil (coarse‐loamy over sandy or sandy‐skeletal, mixed, mesic Typic Dystrochrepts) at Sunderland in western Massachusetts. Treatments consisted of zero N, low manure N (112 kg N ha−1 yr−1), high manure (336 kg N ha−1 yr−1), low N fertilizer (112 kg N ha−1 yr−1 from NH4 NO3), and high N fertilizer (336 kg N−1 yr−1 from NH4NO3). Liquid dairy manure or NH4NO3 was spread on the surface immediately after the first cutting in June 1990 and again in June 1991. Porous ceramic cup suction samplers were placed at the 30‐, 60‐, 90‐, and 120‐cm depths. Soil water was monitored throughout the year except in winter, when the topsoil was frozen. Movement of NO‐3‐N was observed to be more rapid in the sandier Agawam soil than the Occum soil. Nitrate‐N concentrations in water collected under alfalfa during summer and fall were significantly higher than in the spring. High concentrations of NO‐3‐N coupled with increased soil saturation during the fall make this period critical for monitoring NO‐3‐N movement. High manure application to alfalfa resulted in high soil water NO‐3‐N levels in the fall of 1991 on the Occum soil at the South Deerfield site. Application of N fertilizer at the high rate resulted in significantly increased NO‐3‐N concentrations. Low manure application to alfalfa did not increase NO‐3‐N concentrations in soil water compared with alfalfa receiving no N fertilization. Application of manure to alfalfa at the low rate had no significant effect on dry matter (DM) yields, N accumulation in herbage, and soil NO‐3‐N at the 0‐ to 25‐cm, 25‐ to 50‐cm, and 50‐ to 100‐cm depths. Dry matter yields were significantly lower at the South Deerfield site in 1991–1992 than in 1990–1991 for the high manure application. At the Sunderland site, no significant difference in yield was observed. Dairy manure can be applied to established alfalfa at the low rate of 112 kg N ha−1 without any adverse impact on herbage production or nitrates in soil water.
Light Reflectance Compared with Other Nitrogen Stress Measurements in Corn Leaves
Authors: Blackmer Tracy M. , Schepers James S. , Varvel Gary E. 
Published: July 2010

AbstractNew tools that can rapidly quantify the N status of corn could be valuable in N fertilizer management practices. This study was conducted to compare light reflectance from corn leaves with other parameters used to detect N deficiencies. Light reflectance (400–700 nm) as measured from corn leaves in the laboratory with a Hunter tristimulus colorimeter was compared with Minolta SPAD 502 chlorophyll meter readings (light transmittance at 650 and 940 nm), leaf N concentrations, and specific leaf N (N content per unit area). Measurements were made on individual ear leaves collected from an irrigated corn N response trial with four hybrids and five N treatments. Light reflectance near 550 nm was the best wavelength to separate N treatment differences. Reflectance at 550 nm provided a stronger relationship with both leaf N concentration and chlorophyll meter readings than between chlorophyll meter readings and leaf N concentration. The measurement of light reflectance near 550 nm has promise as a technique to detect N deficiencies in corn leaves.
Tillage, Nitrogen Timing, and Planting Date Effects on Western Corn Rootworm Injury to Corn
Authors: Roth Gregory W. , Calvin Dennis D. , Lueloff Susan M. 
Published: July 2010

AbstractThe western corn rootworm (WCR) (Diabrotica virgifera virgifera Le‐Conte) has become a serious pest of continuous corn (Zea mays L.) in the northeastern USA. Several recommended crop production practices in this area, such as early planting, sidedressing N applications, and no‐till, often contribute to slow early‐season growth, which could affect the potential for damage from the WCR. The objective of this study was to determine if these practices affected root damage ratings or yield reductions associated with the WCR. Field experiments were conducted in 1991, 1992, and 1993 on well‐drained Hagerstown silt loam soils (fine, mixed, mesic Typic Hapludalfs). Treatments in each study were factorial combinations of two tillage treatments( nonea nd chisel‐disk), three timings of N fertilizer application (at planting, sidedressed, or split), two planting dates (early and late May), and two insecticide treatments (none and 1.12 kg ha−1 chlorpyrifos). Each treatment was replicated four times. Lodging, root damage ratings, root dry matter estimates, and grain and silage yields were measured for each treatment. Root damage ratings were not affected by the planting date, N timing, or the tillage system. Insecticide had a large and consistent effect on reducing root damage from the WCR. Root size estimates indicates that late planting reduced root size but did not affect root damage. These results indicate that reduced tillage, N sidedressing, and early planting can be included in an integrated pest management program with no risk of increasing the potential for root damage from the western corn rootworm.
Regional Maize Grain Yield Response to Applied Phosphorus in Central America
Authors: Raun William R. , Barreto Hector J. 
Published: July 2010

AbstractMaize (Zea mays L.) in Central America is commonly grown under continuous cultivation and on marginal lands where restricted use of conservation practices and fertilizers limit productivity. Maize grain yield response to P source, rate, and method of application was evaluated at 33 locations in Central America. Soil orders included Andisols, Inceptisols, and Ultisols. Treatments included rock phosphate (RP) applied broadcast preplant without incorporation at rates of 13 and 26 kg P ha−1, triple superphosphate (TSP) band‐applied at planting at rates of 13 and 26 kg P ha−1, TSP broadcast preplant at 26 kg P ha−1, and a check where no P was applied. All treatments received 100 kg of N ha−1 as urea applied in split applications and 30 kg S ha−1 as CaSO4·2H2O. Averaged over locations, maize grain yield increased 0.38 and 0.74 Mg ha−1 when 13 and 26 kg P ha−1 was band‐applied as TSP and increased 0.21 and 0.16 Mg ha−1 when RP was broadcast at the same rates. All P treatments had a probability (PR) >0.61 of outperforming the unfertilized check. Triple superphosphate band‐applied at 26 kg P ha−1 offered the greatest probability (0.69) of an economic response to P fertilizer across environments. Stability analyses and analyses of yield differences suggest that response to applied P was independent of environment for the sites evaluated. The consistent response to applied P across a wide range of environments demonstrates that P is a limiting element for maize production on marginal lands in Central America and that the probability for economic response to applied P is high.
Wind‐Protected Sprayer for Single‐ and Multiple‐Row Field Plot Nurseries
Authors: Jollife Gary D. , Seddigh Majid , Crane Jimmie M. 
Published: July 2010

AbstractResearch plot size and proximity limit postemergence application of nonselective herbicides close to single rows, between plots, and in alleys. We had a wind‐protected spray applicator built to fit a fourwheel all‐terrain vehicle. This equipment has proven versatile, practical, and economical for chemical control of weeds within 10 mm of plants spaced 0.15 m apart in 0.6‐ to 0.9‐m rows, and around research plots.
Integrating Mechanical Weeding with Reduced Herbicide Use in Conservation Tillage Corn Production Systems
Authors: Buhler Douglas D. , Doll Jerry D. , Proost Richard T. , Visocky Mark R. 
Published: July 2010

AbstractIntegrated weed management for conservation tillage systems is needed so producers can minimize the environmental impacts of crop production while maintaining effective weed control and profitability. Reduced levels of herbicides and rotary hoeing were evaluated in combination with interrow cultivation for weed control in corn (Zea mays L.) planted into chisel‐plowed or untilled seedbeds. Atrazine [6‐chloro‐N‐ethyl‐N'‐(1‐methylethyl)‐1,3,5‐triazine‐2,4‐diamine] at 1.1 kg a.i. ha−1 or cyanazine{2‐[[4‐chloro‐6‐(ethylamino)‐l,3,5‐triazin‐2‐yl]amino]‐2‐methylpropanenitrile} at 1.7 kg a.i. ha−1 applied within 2 d after corn planting greatly reduced weed growth compared with no herbicide use. These reduced herbicide treatments often controlled weeds as well as a standard full‐rate treatment (atrazine at 1.6 kg ha−1 plus 2.0 kg a.i. ha−1 metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐l‐methylethyl) acetamide]) prior to cultivation in both tillage systems. In the chisel‐plow experiment, rotary hoeing was not as effective as atrazine or cyanazine in reducing early‐season weed growth. In most cases, one or two interrow cultivations following atrazine or cyanazine increased weed control and corn grain yield to levels similar to the full‐rate treatment in both the chisel‐plow and no‐tillage systems. Integrating interrow cultivation with reduced levels of herbicide maintained weed control and corn yield compared with the full‐rate treatment and is an effective weed management option for corn planted in conservation tillage systems.
Residue Removal Method and Herbicides for Tall Fescue Seed Production: I. Weed Control
Authors: Mueller‐Warrant George W. , Young William C. , Mellbye Mark E. 
Published: July 2010

AbstractPacific Northwest grass seed production is in transition from reliance on open‐field burning to new systems integrating chemical weed control with mechanical removal of crop residues. Field tests were initiated in 1989 to ascertain if these systems can meet seed trade expectations for genetic purity while maintaining normal seed yields. Fourteen herbicide treatment sequences plus an untreated check were evaluated under five residue removal methods at two sites during two consecutive growing seasons. Residue removal included two methods of burning and three nonburn systems varying in thoroughness of removal. Acceptable control (>90% reduction in ground cover) of volunteer seedling tall fescue (Festuca arundinacea Schreb.), the most abundant weed in all tests, was achieved by nearly all herbicide treatments at one site. At the other site, however, thorough residue removal or aggressive herbicide treatments were required to achieve this same degree of control. Over sites and years, acceptable control without use of herbicides was achieved in one case out of four for the most thorough mechanical residue removal system (vacuum‐sweep, VS) and twice by open‐field burning (FB). Preemergence (PRE) application of pendimethalin [N‐(1‐ethylpropyl)‐3,4‐dimethyl‐2,6‐dinitrobenzenamine] provided acceptable control following VS, FB, and propane flaming (PP). Oxyfluorfen [2‐chloro‐1‐(3‐ethoxy‐4‐nitrophenoxy)‐4‐(trifluoromethyl)benzene] applied postemergence (POST) at 0.28 kg a.i. ha−1 plus diuron [N′‐(3,4‐dichlorophenyl)‐N,N‐dimethylurea] at 2.7 kg a.i. ha−1 controlled weeds in all residue removal methods at one site, and for VS, FB, and PP at the other site. Applied in sequence after each of four PRE herbicides, POST application of 0.14 kg ha−1 oxyfluorfen plus 1.8 kg ha−1 diuron controlled volunteer seedling tall fescue better than POST application of 2.7 kg ha−1 diuron without oxyfluorfen. With properly chosen herbicide treatments, seed trade standards for tall fescue can be met without field burning.