bluuebunny/crossref_metadata_2025_split huggingface dataset:
Forage Quality and Harvest Index of Corn Hybrids under Different Growing Conditions
Authors: Cox W. J. , Cherney J. H. , Pardee W. D. , Cherney D. J. R. 
Published: July 2010

AbstractRecent studies suggest that grain content may not necessarily predict corn (Zea mays L.) forage quality. Field studies were conducted at two New York locations in 1991 and 1992 to evaluate forage quality differences among commercial corn hybrids across different growing conditions and the relationship between the harvest index (HI) value and forage quality. Twelve hybrids, which ranged in relative maturity from 95 to 116 d, were evaluated in two experiments according to maturity differences. Each hybrid was hand‐harvested at the 1/2‐milk‐line stage or 350 g kg−1 dry matter (DM) concentration to determine DM yield, HI, whole‐plant N, neutral‐detergent fiber (NDF), acid‐detergent fiber (ADF), lignin, and in vitro true digestibility (IVTD). Although the relationship among hybrids for NDF was consistent across three of four site‐year comparisons, year × hybrid and location × hybrid interactions existed in one experiment because some hybrids received a killing frost at one location before attaining the 1/2‐milk‐line stage. In contrast, hybrid interactions for IVTD did not exist, which suggests a consistent relationship among hybrids for digestibility, even if hybrids received a killing frost between the dent and 1/2‐milk‐line stage. The HI correlated closely with NDF (−084 and ‐0.82) and IVTD (0.79 and 0.63) in both experiments. Likewise, lignin correlated closely with NDF (0.84 and 0.88) and IVTD (−0.76 and −0.79). The data suggest that livestock producers can continue to choose hybrids with high grain content if relatively low fiber and high digestibility are of prime interest.
WeatherMan: A Utility for Managing and Generating Daily Weather Data
Authors: Pickering N. B. , Hansen J. W. , Jones J. W. , Wells C. M. , Chan V. K. , Godwin D. C. 
Published: July 2010

AbstractDaily weather data commonly used in simulation models of agricultural or ecological systems are sometimes incomplete, frequently contain errors, and are often in an inconvenient format. The WeatherMan is a user‐oriented software package designed to assist in preparing daily weather data for use with simulation models. The software can import or export daily weather files with any column format (including the Decision Support System for Agrotechnology Transfer ver. 2.1 and ver. 3.0 files) and convert the data to desirable units. Data are checked and flagged for possible errors on import. Several techniques are available for filling in missing values and erroneous data on export. WeatherMan also contains two methods (WGEN and SIMMETEO) for stochastically generating sequences of daily weather data. Both methods can be parameterized from the daily data and the second method uses monthly means from any secondary data source. Summary statistics of raw and generated data can be graphed or presented in tables.
Arbuscular Mycorrhizal Fungus Spore Populations Respond to Conversions between Low‐Input and Conventional Management Practices in a Corn‐Soybean Rotation
Authors: Kurle J. E. , Pfleger F. L. 
Published: July 2010

AbstractArbuscular mycorrhizal fungi (AMF), ubiquitous symbiotic fungi colonizing plant roots, can contribute to plant growth by improving nutrient uptake and stress tolerance. The influence of management practices and crop species on AMF spore populations and percent root colonization was examined during conversion from conventional to low‐input and low‐input to conventional management systems in 2‐yr crop rotations planted to alternating corn (Zea mays L.)‐soybean [Glycine max (L.) Merr.] sequences established in two adjacent areas with different management histories. During the previous 25 yr, the low‐input area had received no fertilizer or herbicide inputs, while the conventionally managed area had received recommended fertilizer and herbicide inputs. No input (NI), organic input (OI), minimum input (MI), and conventional input (CI) management systems were established within each crop sequence. Weeds were the dominant vegetation in both years in the low‐input area. Average AMF spore population in this area was 292 spores g−1 soil. In the conventionally managed area, only crop plants were present during the first year, while small weed populations had developed by the end of the second year in NI and OI. Average AMF spore population in the conventionally managed area was 175 spores g−1 soil. Average AMF colonization percentage in the low‐input area was 27.5%, while in the conventionally managed area it was 24.5%. AMF colonization percentages were not correlated with AMF spore populations and did not appear to be influenced by the management systems established within each area. Management systems appeared to influence AMF spore populations by their effect on weed populations.
Surface Residue and In‐Row Treatment Effects on Long‐Term No‐Tillage Continuous Corn
Authors: Swan James B. , Higgs Roger L. , Bailey Theodore B. , Wollenhaupt Nyle C. , Paulson William H. , Peterson Arthur E. 
Published: July 2010

AbstractMany farmers in the northern Corn Belt are reluctant to adopt notillage practices with continuous corn (Zea mays L.) because they fear that phenological development, stand establishment, and grain yield will be reduced compared with moldboard or chisel plowing. Mechanical removal of in‐row residue at planting may reduce or eliminate these problems. The objectives of this research were to determine the effects of surface crop residue and planter attachments on in‐row cover, seed placement, plant density, grain yield, and grain moisture content of notillage corn, and to determine if these effects changed with time. Three postharvest residue levels, residue removed, normal, and double, were compared from 1984 through 1990 on Rozetta and Palsgrove silt loam soils in southwestern Wisconsin. Average grain yields over the 7‐yr period ranged from 3.7 to 10.8 Mg ha−1. Seasonal effects, presumably due to weather conditions, accounted for >90% of the variability in grain yield. For the period 1984 to 1990, yield differences due to crop residue levels and in‐row residue removal techniques could not be declared statistically significant at the 5% level, given the limited size of the study. However, average yields with normal residue were 0.44 Mg ha−1 greater than where residues were removed. Because such a difference can be agronomically important, additional research seems warranted. In‐row residue affected planting depth and stand density emphasizing that uniform seeding depth is particularly important for successful no‐till corn production.
Source‐to‐Sink Manipulation Effects on Cotton Lint Yield and Yield Components
Authors: Pettigrew William T. 
Published: July 2010

AbstractCotton (Gossypium hirsutum L.) yields can vary considerably among years and locations, even under levels of water and nutrients considered adequate. Since photosynthesis is one of the principal components in determining reproductive yield, the objectives of this study were to determine how manipulations of the ratio of photosynthetic source to reproductive sink affect cotton lint yield and yield components (boll mass, seed mass, seed per boll, lint percentage, and bolls per square meter). Field studies were conducted in 1991 and 1992 on a Bosket fine sandy loam with six source‐to‐sink ratio manipulations (partial fruit pruned, partial leaf pruned, reflectors, open canopy, shaded plots, and an untreated control) imposed on three cotton genotypes: ‘DES 119’, ‘DPL 5690’, and ‘Prema’. White blooms were tagged twice in both years, and fruit were subsequently harvested after bolls had opened. These bolls were ginned and boll mass, lint percentage, and seed mass were determined. Overall lint yield and yield components were determined for the reflector, open canopy, shaded plot, and control treatments. The partial fruit pruned treatment had a 16% greater boll mass and a 10% greater seed mass than the control. Percentage lint was not affected by any of the treatments. In 1992, bolls at the first sympodial position (fruit at all other positions were pruned from the sympodial branches) had a 25% greater boll mass and 8% greater seed mass than bolls at the second sympodial position (fruit at all other positions were pruned from the sympodial branches) and control treatment bolls from the first tagging. Position 1 and Position 2 bolls did not differ in boll or seed mass during the second tagging period (both greater than the control) or in percent fruit abortion during either tagging period (both lower than the control). Lint yields from the open canopy and reflector treatments were 17% and 6% greater than the control, respectively, and the shaded plot yielded 20% less than the control. Boll number was the component of yield that accounted for these differences. Cotton canopies bred for increased light penetration to lower leaves or for better utilization of the intercepted light may lead to lint yield increases.
Straw Quality of 10 Wheat Cultivars under Conventional and No‐Till Systems
Authors: Rao Srinivas C. , Dao Thanh H. 
Published: July 2010

AbstractStraw of small‐grain cereal is an important source of feed for maintenance of ruminant livestock. Information on the nutritional quality of wheat (Triticum aestivum L.) straw under conservation tillage system is limited. Grain and straw (leaves and stem) samples were obtained from a previous tillage by cultivar field study conducted on a Bethany silt loam (fine, mixed, thermic Pachic Paleustoll) from 1984 to 1987 near El Reno, OK, to determine the straw quality of 10 hard red winter wheat cultivars grown under conventional (moldboard plow) and no‐till systems. Straw was analyzed for neutral‐detergent fiber (NDF), aciddetergent fiber (ADF), lignin (LIG), crude protein (CP), and in vitro dry matter digestibility (IVDMD). Fiber (ADF and NDF) and LIG concentrations of straw from the early‐maturity cultivars were higher (P ≤ 0.05) than medium and late maturity cultivars. Crude protein (5 to 12 g kg−1) and IVDMD(25 to 39 g kg−1) concentrations were lower in early‐maturing than in medium‐ and late‐maturing cultivars among years. Neutral‐detergent fiber and ADF concentrations of all cultivars were not affected by tillage system; however, LIG of early‐maturing cultivars (Chisholm and Vona) grown under a no‐till system was 9 to 24 g kg−1 lower in 1985 and 1986 than in conventionally tilled plots. In vitro dry matter digestibility of all cultivars was not consistently affected by tillage system: no significant difference in 1984, while straw IVDMD from no‐till plots of all cultivars averaged 9 g kg−1 lower in 1985 and 13 g kg−1 lower in 1986, compared with conventionally tilled plots. Straw quality of the 10 wheat cultivars varied among maturity groups, but the effect of tillage system on straw quality was minimal.
Soil and Plant Water Evaporation from Strip‐Tilled Cotton: Measurement and Simulation
Authors: Lascano Robert J. , Baumhardt R. Louis , Hicks Stanley K. , Heilman James L. 
Published: July 2010

AbstractIt is estimated that 20% of cotton producers in the Texas High Plains use the strip tillage practice of planting cotton (Gossypium hirsutum L.) in residues of chemically terminated winter wheat (Triticum aestivum L.). The effect of the residue on water use partitioning between soil (Es) and crop (Ec) evaporation has not been reported. This study tested the hypothesis that the cumulative evapotranspiration (Et), of crop ina strip tillage system and in conventional tillage are similar, and that the residue modifies the components of total Et by reducing Es and increasing Ec. Winter wheat was planted in the fall of 1990 and was chemically terminated in the spring of 1991 in an Olton soil (fine, mixed, thermic Aridic Paleustoll) at Lubbock, TX. The plot was divided into a wheat‐stubble and a conventional treatment. Residue on half of the plot was left as stubble and residue on the other half was shredded and incorporated. Both plots were planted with cotton on 20 May 1991. Measurements included soil water and temperature profiles, soil evaporation, weather, and crop phenology and lint yield. Input values obtained from these data were used in the energy and water balance model (ENWATBAL) to calculate the daily and seasonal water lost to Es and Ec for 100 d. Calculated daily Es varied <1 SD from measured values. Measured mean total Et were similar, i.e., 305 ± 20 mm for conventional and 304 ± 41 mm for cotton in the wheat stubble. Simulated Et was within 10% of the measured value. The ratio of total Ec to Et was 0.50 in the conventional and 0.69 in the wheat stubble cotton. The more efficient use of Et in the wheat stubble increased lint yield by 35%. The Ec water use efficiency was not modified by the wheat stubble and was 3.8 g lint kg−1 of transpired water. The modified version of ENWATBAL was adequate to calculate the daily and seasonal water use of a cotton crop in a terminated wheat stubble, and the results support our hypothesis. The Et water use efficiency was increased by the wheat residue without additional input of water.
Effect of Nitrogen Supply on Maize Yield: I. Modeling Physiological Responses
Authors: Sinclair Thomas R. , Muchow Russell C. 
Published: July 2010

AbstractMuch of the increase in maize (Zea mays L.) yields in recent decades has been closely associated with increased levels of N fertilizer application. Although many studies have documented yield responses to increased N levels in the soil, a mechanistic description of the physiological responses that influence crop growth under various levels of N has not been fully elucidated. The objective of this work was to develop a relatively simple, mechanistic model of maize growth and development to account for the influence of soil and crop N budgets. The soil N budget was simulated for two soil layers that incorporated fertilization, mineralization, denitrification, and leaching. Crop uptake rate of N was simulated by a supply function that depends on cumulative and daily thermal units, soil water content, and soil N availability. Comparison of simulated and experimental crop N uptake through the season showed especially good agreement for 0 to 12 g N m−2 fertilizer treatments. At 24 and 42 g N m−2, the simulated crop N uptake was greater than observed. Nevertheless, comparable seasonal patterns between simulations and observations at all fertility levels were obtained for accumulated total biomass and grain. Final grain yields for all fertility treatments were simulated to be within 8% of the observed. A sensitivity test was performed with the model to investigate the importance of various physiological parameters on biomass accumulation and yield. Yield estimates under low soil N levels tended to be most sensitive to minimum grain N concentration.
Crop and Soil Response to Long‐Term Tillage Practices in the Northern Great Plains
Authors: Aase J. Kristian , Pikul Joseph L. 
Published: July 2010

AbstractSummer fallow is the most common cultural practice in the northern Great Plains. With proper cultural management, however, annual cropping may be feasible and economical. Our objective was to determine crop and soil response to nontraditional annual cropping practices (till and no‐till) in lieu of conventional fallow‐crop rotation for the production of spring wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) in the in the northern Great Plains. The study, initiated in 1983, was on a Dooley sandy loam (fine‐loamy, mixed Typic Argiboroll) 11 km north of Culbertson, MT. Tillage practices on annually cropped treatments included sweep tillage in autumn and disk tillage in spring; sweep tillage in spring; and no‐tillage. Conventional fallow‐spring wheat rotations were included as the control. With three exceptions, there were no statistical differences among treatments in soil P, soil nitrate N, and pH. Phosphorus and N were nonlimiting in all years; pH decreased about 0.06 units per year in the 0‐ to 8‐cm layer because of N fertilization. Bulk density differences in the 0‐ to 10‐cm layer appeared after 7 yr, with the lowest bulk density for the no‐tillage annual crop treatment. Grain and straw yields with the no‐tillage treatment were both 80% of yields with the fallow‐crop treatment. Total water use efficiency, based on soil water differences between harvest of one crop and harvest of the next, was significantly greater with no‐tillage than with the fallow‐crop treatment. Soil organic C decreased nearly 0.4 g kg−1 per year with the fallow‐crop treatment; there was a negligible decline with the notillage annual crop treatment. No‐tillage annual spring wheat crop production was the most efficient crop and soil management practice from the standpoint of yield, water use efficiency, soil organic C, and bulk density.
Sap Flow in a Dicotyledon (Sunflower) and a Monocotyledon (Sorghum) by the Heat‐Balance Method
Authors: Zhang Jingxian , Kirkham M. B. 
Published: July 2010

AbstractThe heat‐balance method is widely used to monitor sap flow in stems of herbaceous plants. Measurements of sap flow made on monocotyledons, with scattered vascular bundles in their stems, may not be as accurate as measurements on dicotyledons, with annular vascular systems located next to the heater of the gauge. Therefore, we measured the accuracy of sap flow measurements made by the heat‐balance method for sunflower (Helianthus annuus L. ‘Hysun 354’), a dicotyledon with C3 photosynthesis, and sorghum [Sorghum bicolor (L.) Moench, Funk's hybrid G‐522DR], a monocotyledon with C4 photosynthesis. Plants were grown in pots with a commercial potting medium under greenhouse conditions. Measurements were made during a cycle when the plants were well watered, drought stressed, or rewatered. A potted plant was placed on a scale and sap flow (SF) values (units of g h−1) were compared with weight lost during the same period of time (WL, g h−1). Accuracy of the sap flow measurements was determined by calculating error, defined as (SF – WL)/WL. The gauge had good accuracy (error = 8.8%) only with watered sunflower, which had high flow rates (maximum rate = 64.7 g h−1). (This sap flow rate, nevertheless, is less than those for woody plants under field conditions, which are often >100 g h−1.) Sap flow rates in watered sorghum were less than those in watered sunflower (maximum sap flow rate = 18.9 g h−1), and error for watered sorghum was high (72.6%). The gauge had good accuracy when sap flow rates were 20 g h−1 or more. Despite gauge errors, gauge measurements usually paralleled scale measurements and rapidly monitored changes in sap flow rate. The data suggest that sap flow rate is more important than stem anatomy in determining the accuracy of the gauge.
Evaluation of Nitrification Inhibitors and Urea Placement in No‐Tillage Winter Wheat
Authors: Rao Srinivas C. 
Published: July 2010

AbstractNitrification inhibitors (NIs) such as dicyandiamide (DCD) and nitrapyrin [2‐chloro‐6‐(trichloromethyl)pyridine] (NP) slow the nitrification process, thus reducing N losses from leaching and denitrification. In field studies (1990–1994) on a Renfrow silt loam (fine‐silty, mixed, thermic Udertic Paleustolls) near El Reno, OK, we evaluated these two NIs and their placement effects on nitrification of applied urea in soils and on wheat (Triticum aestivum L.) yields. Urea at 60 kg N ha−1 treated with or without NIs was placed 3 to 4 cm below the seed (BL) at seeding or was broadcast (BR) after seeding on the day of seeding, with no N as control. Mineral N forms were determined in the 0‐ to 30‐cm soil zone in fall and spring. Differences in soil mineral N concentration below the 10‐cm depth were minimal (but higher than the control) in all N treatments. In the 0‐ to 10‐cm depth, BL placement of NI‐treated urea significantly reduced nitrification in the fall compared with BR urea with or without NIs, except in 1994. Soil mineral N content in spring was similar with either placement of NI‐treated urea, but was significantly greater than untreated BR urea. Warm temperatures and dry soil in the fall tended to reduce the effectiveness of surface‐applied NIs. The highest NH4+ percentage in total soil mineral N was observed with DCD BL or NP BL, followed by NP BR and DCD BR. Urea treated with NIs increased grain yield from 7 to 31% above untreated urea. Grain yield was highest with DCD BL (31%), followed by DCD BR (26%) and NP BR (24%), compared with the broadcast untreated urea. Grain N yield was 140 g kg−1 greater with DCD‐N than with untreated urea. Deep placement of DCD under no‐till winter wheat in the southern Great Plains can reduce nitrification and increase N availability under varying year‐to‐year environmental conditions and can improve wheat grain yield and grain N compared with surface broadcast of urea with or without NI.
Alfalfa Yield and Stand Response to Irrigation Termination in an Arid Environment
Authors: Ottman Michael J. , Tickes Barry R. , Roth Robert L. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) irrigation is often withheld as a water conservation measure in arid regions. The objective of this research was to test the hypothesis that alfalfa yields and stands can be permanently damaged by withholding irrigation water in arid environments. Irrigation termination studies were conducted on a Superstition sand (sandy, mixed, hyperthermic Typic Calciorthid; 95% sand) in Yuma, AZ, and on a Casa Grande sandy loam [coarse‐loamy, mixed (calcareous), hyperthermic Typic Natrargid (reclaimed)] at Maricopa, AZ. Irrigations were terminated in the summer (July through October) and winter (November through February) in Yuma and in the summer (August through September) and summer, fall, and winter (August through mid‐March) in Maricopa. Summer irrigation termination at the Yuma site reduced stand from 43 to 16 plants m−2 and reduced hay yield from 1.50 to 0.52 Mg ha−1 per cutting after irrigation was resumed. Irrigation termination at the Maricopa site was not detrimental to stands, although hay yields per cutting were depressed from 2.90 to 2.52 Mg ha−1 following the second cycle of summer irrigation termination and from 3.10 to 2A3 Mg ha−1 following the second cycle of summer through winter irrigation termination. Winter irrigation termination at Yuma had no residual effect on yield or stand. Alfalfa water use was reduced by irrigation termination at Maricopa, even after irrigation was resumed. Total nonstructural carbohydrates in the roots were not consistently higher or lower than the control during irrigation termination. Termination of alfalfa irrigation as a water‐conserving measure is not always advisable in arid environments due to the possibility of permanent crop damage.