bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen, Climate, and Previous Crop Effect on Corn Yield and Grain N1
Authors: Asghari M. , Hanson R. G.
Published: July 2010

Two N response experiments, previously cropped with alfalfa and small grain, were conducted for 4 years (1977 to 1980) on Mexico silt loam soil, (fine, montmorillonitic, mesic Udollic Ochraqualf). The study included the evaluation of temperature and precipitation effects upon corn (Zea mays L.) yield, predicting the N requirement for maximum yield, based on N content of corn grain. A fertilizer N gradient of 0, 45, 90, 135, 180, and 225 kg N ha−1 with four replications was established. By dividing the growing season into 3 monthly periods (June, July, and August) the monthly heat units and precipitation were included as independent variables. Regression analysis related relative yield to monthly precipitation, monthly heat units and their products of grain N and the square of grain N. There was a significant yield response to N fertilizer 3 of 4 years where corn followed a small grain, but corn yield was not increased by N fertilization following alfalfa. Corn grain N content was significantly increased by N fertilization with the N content always higher where corn followed alfalfa (Glycine max L.). Relative yield of 100% was obtained with grain N content of 1.09 mol kg−1. June precipitation did not significantly effect corn yield, while above average heat units in June showed a positive effect on corn yield. The models showed that above average precipitation in July will increase corn yield and above average heat units would decrease yield. The effect of above average July heat units could be offset with a higher quantity of precipitation. To reach 100% relative yield, 114.3 mm of precipitation would be required in July (36.9 mm above mean) with mean of 450 heat units. On this soil, this 114.3 mm precipitation predicted corn yield of 9.36 Mg ha−1 requiring 136 kg N ha−1 of fertilizer N.
Fertilizer Effects on Crop Removal of P and K in ‘Coastal’ Bermudagrass Forage1
Authors: Day J. L. , Parker M. B.
Published: July 2010

In 1959, an N‐P‐K ratio of 9.1‐1‐3.8 (4‐1‐2 N‐P2O5‐K2O ratio) was proposed as the proper nutrient balance for fertilizing ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] for forage, but nutrient removal in forage was not taken into consideration with this ratio. The purpose of the study was to determine fertilizer effects on removal of P and K in ‘Coastal’ bermudagrass forage using increments of a fixed N‐P‐K ratio and high rates of P and K over a range of N rates. An established sod which had not received fertilizer for at least 5 years was selected for the 3‐year study. The soil was a Fuquay loamy sand (loamy, siliceous, thermic arenic Plinthic Paleudult) which was medium in P and low in K. Annual treatments for the first 2 years were 84,168,336, and 672 kg N ha−1 applied with P and K in a 9.1‐1‐5.7 N‐P‐K ratio (4‐1‐3 N‐P2O5‐K2O ratio). In the 3rd year 73.6 kg P ha−1 and 420 kg K ha−1 were applied uniformly at all N rates. The 9.1‐1‐5.7 N‐P‐K ratio supplied inadequate amounts of P and K to compensate for crop removal at the lower fertilizer rates but were excessive at the higher fertilizer rates. The N‐P‐K ratio required the 3rd year to supply P and K equivalent to that removed in the forage ranged from 6.4‐1‐6.5 for the 84 kg N ha−1 treatment to 14.4‐1‐7.9 for the 672 kg N ha−1 treatment. This study indicates that the use of regression equations for determining P and K needs for Coastal bermudagrass is a more suitable method than the N‐P‐K ratio method.
Soybean Irrigation Serially Timed During Stages R1 to R6. II. Yield Component Responses1
Authors: Kadhem F. A. , Specht J. E. , Williams J. H.
Published: July 2010

Soybean [Glycine max (L.) Merr.] seed yield components are established and fixed in a temporally ordered sequence during stages R1 to R6. To determine the effect of irrigation timing during R1 to R6 on these traits, we examined the seed yield component responses of 16 soybean cultivars to nine irrigation treatments in a 3‐year experiment. Treatments T1 thru T7 consisted of only a single irrigation coinciding with the average R stages 1.1, 2.5, 3.7, 4.7, 5.6, 5.9, and 6.4, respectively. ‘Check’ treatments included T0, which was not irrigated, and T8 which received seven total irrigations coincident with those for T0 and T7. Averaged over cultivars and years, the mean number of seeds/plant were: T0: 87f, T1: 121a, T2: 111bc, T3: 115ab, T4: 105cd, T5: 99def, T6: 102de, T7: 95ef, and T8: 122a. T0 and T8 thus established the minimum and maximum ‘limits’ in the seeds/plant response, respectively, with declining responses as irrigation was delayed from T1 to T7. The 100‐seed weight (g) means were: T0: 19.1b, T1: 17.8c, T2: 17.8c, T3: 18.3c, T4: 20.3a, T5: 20.4a, T6: 19.8ab, T7: 20.3a, and T8: 18.3c. Seed size for T8 was thus smaller than T0. The T4 thru T7 responses were significantly greater than T0, while the T1 thru T3 responses were significantly less than T0. Average seed yields were greatest for the T3 and T4 treatments, although for determinate cultivars, T8 also resulted in high yields. Only minimal changes in seed number and size were affected by irrigation in the determinate cultivars (in contrast to indeterminates), which may have accounted for the greater yield responsiveness of determinate cultivars to irrigation. Based on both the seed yield and yield component data, it would appear that stage R3.5 to R4.5 represents the reproductive period in soybeans most responsive to irrigation.
Excess Soil Water and Phytophthora Root Rot Stresses of Phytophthora Root Rot Sensitive and Resistant Alfalfa Cultivars1
Authors: Alva A. K. , Lanyon L. E. , Leath K. T.
Published: July 2010

The adaptation of alfalfa (Medicago sativa L.) to well‐drained soil has limited its range of culture. The poor performance of this crop in wet soils has often been attributed to the effects of Phytophthora root rot (PRR). However, excess soil water itself may reduce alfalfa growth. The impact of continuous excess soil water stress (ESWS) and PRR stress (PRRS) and the growth potential after elimination of the excess soil water was studied on PRR‐resistant (Oneida) and PRR‐susceptible (Iroquois) alfalfa cultivars. The impact of ESWS on the two cultivars was similar. No visible root injury symptoms were apparent despite significantly reduced root growth when compared to stress‐free (SF) plants. Shoot growth was less consistently affected than root growth. For the plants subjected to continuous PRRS the severity of PRR was 4.7 for Iroquois and 3.5 for Oneida on a scale of 1 to 5 representing increasing damage. The PRR symptoms were 42 and 15% less for the Oneida and Iroquois cultivars, respectively, after a recovery period following the elimination of excess soil water. Shoot and root growth after the recovery period were significantly greater than that of continuously stressed plants of Oneida, but the growth of Iroquois was not significantly different. Manganeses concentration in the plants under continuous stress was twice that of SF plants or of stressed plants after the recovery period. The concentrations did not reach toxic levels for the plants. Alfalfa response to wet soil is not a simple phenomenon that may be attributed to the same single factor in each situation. It may best be described as a “wet‐soil syndrome” the cause and intensity of which will depend on the magnitude and balance of all the individual stresses that are involved.
Yields of Forages Irrigated with Wastewater and the Fate of Added Nitrogen‐15‐Labeled Fertilizer Nitrogen1
Authors: Bole J. B. , Gould W. D. , Carson J. A.
Published: July 2010

Irrigation of legume and nonlegume forage species with municipal waste water at rates designed to approximate and double the net evapotranspiration minus precipitation deficit was studied for 11 yr at Taber, Alberta, Canada. The soil was a Brown Chernozemic Cavendish loamy sand (Aridic Haploboroll). Reed canarygrass required additional N to give yields similar to those of the alfalfa (Medicago sativaL.). Alfalfa yields were not greatly affected by increasing levels of N and P fertilizer or by the application of excess wastewater. The N uptake by reed canarygrass (Phalaris arundinaceaL.) was considerably less than that of alfalfa when the N supply was limited, but about the same when the N supply was adequate. Reed canarygrass recovered nearly 50% of applied fertilizer 15N over 2 yr with about 80% of total uptake in the first cutting after N application. Alfalfa only recovered 24% of applied N at low irrigation rates and 14% at the higher rate. Estimates of fertilizer N uptake based on the increase in N yield of reed canarygrass due to fertilization would have been much higher. About 25% of the fertilizer N remained in the soil after two irrigation seasons, independent of forage species or irrigation rate. Sixty percent of that N remained in the surface 15 cm. Losses of N from alfalfa were nearly double those from reed canarygrass plots. Wastewater irrigation did not lead to levels of any element phytotoxic to plants or harmful to animals consuming the forage and probably increased the nutritional quality of the forage.
Supplemental Boron Effects on Yield and Quality of Seven Bermudagrasses1
Authors: Monson Warren G. , Gaines T. Powell
Published: July 2010

Boron (B) has been recognized for many years as an essential element for plant growth, but there is limited information available on its effects on forage grasses. This 4‐yr study was initiated to examine the effects of B rates of 0, 1.1, 2.2, or 4.4 kg ha−1on yield and quality of established stands of seven bermudagrasses [Cynodon dactylon (L.) Pers.] growing on a Tifton sandy loam soil (Plinthic Paleudult). The effect of the B treatments across all grasses was an increase in dry matter (DM) yield when 2.2 kg ha−1B was applied annually. However, the effect was significant (P = 0.05) only for ‘Tifton 44’ and ‘Midland’ bermudagrasses. ‘Coastal’ and ‘Coastcross‐1’ bermudagrasses showed no response to treatments while ‘Callie’ and ‘Tifton 67’ tended to yield more with added B and ‘Tifton 84’ tended to yield less. There was no effect of B treatments on digestibility or crude protein concentration of the grasses. The data would not support a general recommendation of supplemental B on bermudagrasses
Samples Needed for Estimation of Plant Height of Pima Cotton1
Authors: Kittock D. L. , Cain C. J. , Selley R. A. , Taylor B. B.
Published: July 2010

Plant populations giving the highest lint yield of American pima cotton (Gossypium burbdense L.) grown in 1‐m spaced rows change as plant heights change. Therefore, plant height should be considered in future plant population studies with pima cotton. This study was conducted to determine the number and type of plant height measurements needed to give a satisfactory estimate of mean plant height for a plot. Plant height uniformity data were obtained from 12 plots (four locations with three plots per location) in Arizona. Soils were Torrifluvents Haplostolls, Anthropic Torrifluvents, and Thermic Torrifluvents. Measurement of four to eight plants per plot, half of the number on each end, appeared to be adequate to characterize the plant height of a plot. Plant heights were normally distributd. A systematic selection produced lower variation (about onehalf as many plants needed to be measured) but over‐estimated mean plant height by an average of 12.5%.
Evaluating Ten Cropping Alternatives for the Midsouth1
Authors: Sanford J. O. , Eddleman B. R. , Spurlock S. R. , Hairston J. E.
Published: July 2010

Many crop production systems and cropping sequences are available in the Midsouth and each differs in its management and potential contribution to net farm income. This paper considers several of these variables using yields and costs of production data from a 3‐yr crop production study in Mississippi. A nonirrigated experiment was conducted on Leeper silty clay (fine montmorillonitic, nonacid, thermic Vertic Haplaquepts) from 1976 through 1980. The experiment contained 10 treatments of five monocrop and five doublecrop enterprises in randomized block design. Monocrops were commercial hybrid corn (Zea mays L.), soybean [Glycine max (L.) Merr.], grain sorghum [Sorghum bicolor (L.) Moench], sunflower (Helianthus annuus L.), and wheat (Triticum aestivum L.). Doublecrops were wheat followed by the first four monocrops plus an experimental, insect and disease resistant corn hybrid. Yield and production records were maintained and used to calculate net returns for the cropping alternatives. The five enterprises with highest net returns per hectare (in descending order) were monocrop corn ($495), doublecropped wheat‐soybean ($407), monocrop soybean ($326), doublecropped wheat‐resistant corn ($306), and doublecropped wheat‐sunflower ($285). The farming system that most fully utilized a complement of sixrow equipment and associated power units, and maximized net farm income above variable costs, machinery ownership costs, and land costs was calculated to be 279 ha of cropland as determined by linear programming techniques. This 279 ha would be partitioned as follows: monocrop corn (120 ha), monocrop wheat (13 ha), doublecropped wheat‐resistant corn (62 ha), and doublecropped wheat‐soybean (84 ha). Net return above specified expenses was computed to be $45 897 annually.
Titanium Determination for Correction of Plant Sample Contamination by Soil1
Authors: Cary E. E. , Grunes D. L. , Bohman V. R. , Sanchirico C. A.
Published: July 2010

An accurate method for determining Ti in plant material and soil was developed. Titanium concentrations in plant and soil were used to correct analytical data of plant materials for contamination by soil. Different digestion schemes were used in the analysis of National Bureau of Standards (NBS) reference materials for Ti. A satisfactory result was obtained when the sample was digested in a Teflon beaker containing HNO3 and HClO4, taken to dryness, baked at 185°C, and then dissolved overnight at room temperature in HF. The solution was made to volume with 3M HCl, in polyethylene, after addition of H3BO3 to complex excess F . Titanium was determined by inductively coupled argon plasma (ICP) spectrometry. Certified Ti values for NBS mineral samples 120b and 692 are 899 and 270 mg kg 1, respectively. This method gave values of 898 ± 14 and 264 ± 6 mg kg 1, respectively. Correction of elemental analysis for soil contamination of plant, rumen fistula, and feces samples using this method agreed well with corrections using Fe or Al as a reference element as well as with determination for Ti by x‐ray fluorescence. Using residual ash content (Si) as a reference element appeared to be less reliable. The assumptions needed to make this correction using Ti are less prone to error than the assumptions needed when Fe, Al, or residual ash are used. It was imperative to use HF in the digestion procedure for quantitative determination of Ti in some samples.
Cultivar Dependent Sugarcane Response to Nitrogen1
Authors: Gascho G. J. , Anderson D. L. , Ozaki H. Y.
Published: July 2010

Sugarcane (a complex trispecies of Saccharum) in Florida is moving from N‐rich Histosols to N‐deficient sands. Since little is known about the N‐use efficiency of cultivars grown in the continental United States, we conducted studies with four cultivars to compare N‐use efficiencies under varying N levels. Three of the cultivars were originally selected as commercial cultivars from the breeding program conducted on N‐rich Histosols of the Everglades while the fourth (CP 65‐357) was selected from N‐deficient soils in Louisiana. A greenhouse experiment, conducted in nutriculture solutions with three N concentrations (0.1, 1.0, and 10.0 mmol L−1) indicated that the highest dry weights were obtained at the second N level from CP 65‐357. However, CP 65‐357 did not accumulate more N than the other cultivars, suggesting more efficient utilization of accumulated N. The field study was conducted for 2 yr on a complex of Pompano (Typic Psammaquants) and Myakka (Aerie Haplaquod) fine sands of low‐N status. Nitrogen levels applied to the first crop were 0, 56, 112, and 224 kg ha−1. The cultivar CP 65‐357 gave the highest yields of cane and sucrose, had the highest external and internal N‐use efficiencies (kg yield kg−1 applied N and kg yield kg−1 N accumulated in above ground plant parts, respectively) regardless of N rate or year. In the ratoon crop, the external and internal N‐use efficiencies for sucrose yield were 24 and 110 kg kg−1, respectively, for CP 65‐357 over all N rates, and 7 and 44 kg kg−1, respectively, for CP 63‐588, the least N‐efficient but the most widely grown cultivar on Histosols in Florida during the period 1975 to 1981. The results suggest that N‐use efficiency of sugarcane can be enhanced by selection under low‐N conditions.
Isolated Plot Technique for Studying Seedling Growth of Turfgrasses1
Authors: Brede A. D.
Published: July 2010

Field research with turfgrass seedlings is frequently complicated by weather disruptions and sampling error. A technique was developed for affixing turf seeds to a seedbed in the field for the purpose of monitoring field survival and growth of seedlings over time. Isolated plots of turfgrass seeds, 25 mm in diam and spaced 75 mm apart on a seedbed, were held in place with a liquid latex‐based mulch and a non‐woven fabric mulch. Seed displacement from rainwashing was held below 0.1% with this technique. The latex/fabric mulches had the same effect on seedling growth as do conventional mulches of straw or wood fiber; therefore, use of the latex/fabric mulches in this technique did not seem to constitute a serious deviation from standard planting practices. Results from field evaluations revealed that field survival (percent germination) was accurately assessed using this technique without the added variance associated with subsampling of solid stands. Field survival of perennial ryegrass (Lolium perenne L.) seedlings sown at 59 200 seeds m−2 could be measured with 9% variability (CV), vs. 35 to 51% variability with traditional sampling‐probe methods. Values of field survival obtained using isolated plots corresponded closely with values found in solid stands but with lesser variability. Plant growth parameters (leaves, shoots, roots) in isolated plots and solid stands diverged over time; interspecific competition occurred sooner in solid stands than in isolated plots. Care should be taken when extrapolating seedling growth results found using this technique to solid stand conditions since the seedlings are essentially space planted.
Effect of Tillage on Residual Nitrogen Availability From Alfalfa to Succeeding Corn Crops1
Authors: Levin A. , Beegle D. B. , Fox R. H.
Published: July 2010

It has been shown that there are significant differences in the potential rate of mineralization and nitrification between conventional and no‐till soils. However, the practical effect of this difference on the availability of residual N from a legume and yield of a succeeding corn crop is unclear. Two field experiments in which corn (Zea mays L.) followed alfalfa (Medicago sativa L.) were conducted on a Hagerstown silt loam (fine, mixed, mesic Typic Hapludult) and on a Gilpin channery silt loam (fine‐loamy, mixed, mesic Typic Hapludult) to determine the effect of no‐tillage (NT) and conventional tillage (CT) methods on residual N availability from the legume as measured by yield and N uptake of the succeeding corn crop. Five rates of N (0, 45, 90, 135, and 180 kg ha−1) as ammonium nitrate were surface applied as either at‐planting or sidedress applications. The mean soil N‐supplying capability was 126 kg N ha−1 at both sites. There was no interaction between tillage method and N response, indicating that the fertilizer N recommendations for first‐year corn following alfalfa should be similar for NT and CT methods. Optimum economic grain yields for first‐year corn resulted with the application of 83 and 88 kg N ha−1 for the NT and CT treatments, respectively, at one site and with no added N at a second site, confirming this conclusion. The experiment was repeated for the second year at one site and the results for the second year also indicated that there was no difference in N fertilizer response due to tillage and no interaction between tillage and N response. Again this would indicate that N recommendations should be similar for the two tillage systems. There was no yield response to time of N application.
Enhancement of Field Hay Curing with Potassium Carbonate
Authors: Mullahey J. J. , Mueller J. P. , Green J. T.
Published: July 2010

Treating alfalfa (Medicago sativa L.) herbage with solutions of K2CO3 reduces curing time. However, there is a lack of information concerning the effectiveness of K2CO3 solutions as a hay drying agent in the humid environment of the southeastern USA. The objective of this research was to quantify the influence of several concentrations [3.5‐17.2 kg Mg−1 of dry matter (DM)] and solution volumes (25–166 L Mg−1 DM) of K2CO3 on the time required to dry first‐, second‐, and third‐cutting alfalfa to 800 g kg−1 DM under field conditions in the humid southeastern USA. Field experiments were conducted during 1984 and 1985 on a Typic Hapludult soil in the Piedmont region of North Carolina. In all trials, applying K2CO3 solutions to alfalfa significantly reduced field drying time compared with untreated forage. Treating alfalfa with K2CO3 at mowing reduced field drying time from 3 to 22 h compared with untreated forage. Relative to untreated forage, drying time was reduced by 29 to 72% due to K2CO3 treatment. In five of seven trials, the treated forage reached a DM concentration of 800 g kg−1 1 d before untreated forage. Increasing the K2CO3 concentration from 3.5 to 14 kg Mg−1 of DM resulted in a small but statistically significant reduction in drying time of the forage in three of seven trials. These differences were considered to be biologically insignificant. Increasing K2CO3 solution volume from 25 to 166 L Mg−1 of DM did not affect drying time of alfalfa forage. Potassium carbonate applied as low as 3.5 kg Mg−1 of the forage DM in a solution volume of 25 L Mg−1 of DM has the potential to significantly reduce the field drying time of alfalfa hay in the humid southeastern USA.
Planting System and Weed Control Effects on Soybean Grown on Clay Soil
Authors: Elmore C. Dennis , Heatherly L. G.
Published: July 2010

Dryland soybean [Glycine max (L.) Merr.] production on clay soils in the Mississippi River alluvial flood plain (Delta) is economically marginal, and production inputs must be minimized to achieve economic feasibility. One scheme for reduction of inputs is stale seedbed planting. Three chemical weed control options (none, preemergence only, and post‐emergence only) were compared in both stale and tilled seedbeds on a Sharkey clay (very‐fine, montmorillonitic, thermic Vertic Haplaquept) in 1981 and 1982. Four soybean cultivars representing Maturity Groups V, VI, and VII were used. Yields from the two seedbed treatments with preemergence weed control were equal, but seed yield from the tilled seedbed treatment with no herbicide averaged 225 kg ha−1 greater than the stale seedbed treatment with comparable weed control. Percent weed cover was lowest both years in the tilled seedbed with postemergence weed control. Weed species present in the greatest abundance were prickly sida (Sida spinosa L.), pitted morningglory (Ipomoea lacunosa L.), and slender aster (Aster exilis Ell.). An unfilled seedbed is a viable choice with effective weed management to enable producers to minimize tillage inputs and still maintain yield on clay soils.
Critical Stress Periods Affecting Productivity of No‐Till Winter Wheat in Western Canada
Authors: Entz M. H. , Fowler D. B.
Published: July 2010

The influence of prevailing environmental conditions on wheat (Triticum aestivum L.) yield, grain protein, and yield components is dependent on plant development stage. This study identified critical stress periods influencing the productivity of no‐till winter wheat produced on the Canadian prairies. Grain yield, grain protein, aerial dry matter, harvest index, and individual yield components were related to weather and soil water factors at 11 field locations between 1984 and 1986. Soil types included Typic Haploborolls, Udic Haploborolls, and Vertic Haploborolls. Pan evaporation, precipitation, and growing degree‐days were totalized for six 15‐d periods corresponding with Zadok growth scale stages 21 to 32, 32 to 46, 46 to 65, 65 to 74, 74 to 83, and 83 to 91, respectively. Extractable soil water to 1.3 m was measured at the stem elongation (stage 31), anthesis (stage 65), and soft dough (stage 85) development stages. Environmental stress between stages 21 and 65 most influenced grain yield, aerial dry matter production, harvest index, grain protein yield, spikes per square meter, kernels per spike, and kernels per square meter. Kernel weight was most dependent on prevailing conditions after anthesis. Grain protein concentration was influenced by environmental stresses both before and after anthesis. Evaporation, followed by root zone extractable soil water and precipitation, had the largest influence on crop performance of all the environmental‐water parameters considered. Prediction equations that included these variables explained 91% of grain yield, 82% of aerial dry matter, 84% of the harvest index, 73% of protein concentration, 82% of protein yield, 47% of spikes per square meter, 83% of kernels per spike, 83% of kernels per square meter, and 82% of kernel weight variability observed.
Forage Legume Effects on Soil Nitrogen and Grain Yield, and Nitrogen Nutrition of Wheat
Authors: Badaruddin M. , Meyer D. W.
Published: July 2010

Information on the effect of hayed legumes on soil fertility and subsequent crop productivity is needed to evaluate the use of legumes in place of summerfallow in the northern Great Plains. The objectives of these studies were to determine (i) the seeding‐year hay yield, and root and crown N content of five forage legumes, (ii) the spring soil NO−3‐N status following the forage legumes, and (iii) the forage legume effects on grain yield, grain yield components, and N nutrition of the subsequent hard red spring wheat (Triticum aestivum L.) crop at 0, 75, or 150 kg of fertilizer N ha‐1. Field experiments were conducted on a Fargo silty clay (fine, montmorillonitic, frigid Vertic Haplaquolls) soil at Fargo, ND and on a Perella‐Bearden silty clay loam (fine‐silty, mixed, frigid Typic Haplaquolls, fine‐silty, frigid Aeric Calciaquolls) soil at Prosper, ND from 1984 to 1986. The legume species were not significantly different in hay yields, and root and crown N content across environments, although alfalfa (Medicago sativa L.) and sweetclover [Melilotus officinalis (L.) Lam.] had 35 to 83% greater N contents than other species. Fall regrowth, crowns, and roots were incorporated into the soil in late fall. Soil NO−3‐N in the spring following legumes was greater than following fertilized wheat, but less than following fallow across environments. Grain yield and N uptake of wheat following forage legumes generally were equal to those following fallow, but greater than those following wheat. Nitrogen use efficiency of unfertilized wheat following forage legumes was greater than following fallow or wheat in 1986, but equal in 1985. Grain yield to total N uptake ratio and N partitioning to grain following legumes were greater than following fallow or wheat in two of four environments. These results suggest that including 1‐yr forage legumes in crop sequence would be a better option than fallow in the higher moisture areas of the northern Great Plains.
Stubble Height Effect on Winter Wheat in the Northern Great Plains: II. Plant Population and Yield Relations
Authors: Black A. L. , Bauer Armand
Published: July 2010

Partial winterkill of winter wheat (Triticum aestivum L.) is a potential problem each year in the northern Great Plains, reducing plant population and yield potential, and forcing a decision to retain or destroy the crop. The objective was to develop algorithms relating postwinter agronomic characters to potential grain yield. Field trials were conducted 4 yr on Williams loam (fine‐loamy, mixed Typic Argiborolls) to measure the effect of four stubble heights (0, 5, 20, and 36 cm) on postwinter plant populations and agronomic characteristics of three cultivars (Roughrider, Mironovskaya, and Centurk) planted with two drills (disk‐ and hoe‐opener) on an area without and with 50‐mm supplemental water applied 1 to 2 wk before planting. Postwinter, pretilllering plant population, spike population at harvest, and grain yield differed among stubble heights and cultivars each year. Plant populations ranged from < 10 to >220/m2. Average spike/seedling population ratio ranged from about 2.5 to 5.5 with the largest ratio associated with the smallest plant population. Curvilinear relationships of spikes/m2 to plants/m2, grain yield (kg/ha) to spikes/m2, and grain yield (kg/ha) to plants/m2, respectively, were associated with R2 of 0.94, 0.97, and 0.95. The curvilinear function, no intercept option, of grain yield kg/ha (Y) to plants/m2 (X) was Y = 41.04x − 0.18x2 + 0.00021x3. This algorithm is a definitive measure of grain yield potential when postwinter plant population is known.
Spring Nitrogen Fertilizer Recommendation Models for Dryland Hard Red Winter Wheat
Authors: Vaughan B. , Barbarick K. A. , Westfall D. G. , Chapman P. L.
Published: July 2010

Nitrogen fertilizer recommendations for dryland hard red winter wheat (Triticum aestivum L.) are more reliable when based on spring rather than fall soil and plant measurements. Objectives of this research were to develop spring N recommendations based on soil available N, plant tissue N, and/or climatic variables measured in the spring. Grain yield variation was described by simple and multiple regression analysis with various levels of complexity. Soil NH4‐N levels in the spring explained more grain yield variation than did NO3‐N. Spring soil sampling to depths >60 cm explained no additional grain yield variation. Percent sand in the soil surface (0‐30 cm) explained more grain yield variation between experimental sites than did other site variables. Simple Cate‐Nelson III models were more accurate than complex multiple regression equations. Cate‐Nelson III models, for available soil NH4‐N plus NO3‐N (0‐30 and 0‐60 cm) and Feekes 5 leaf N, predicted required N rates in the spring within ±22 kg N ha−1, 87 to 95% of the time. Spring N recommendations were improved when spring N rates were based on both available soil N and Feekes 5 leaf N. These results indicate (i) that analysis of available soil N in the spring must include soil NH4‐N to prevent over‐fertilization, and (ii) that simple Cate‐Nelson models are sufficient for calibration of spring N rates to available soil and plant N levels measured in the spring.
Inorganic Nitrogen Distribution and Soil Chemical Transformations Associated with Injected Liquid Beef Manure
Authors: Sawyer J. E. , Schmitt M. A. , Hoeft R. G.
Published: July 2010

Some producers have reported corn (Zea mays L.) production problems associated with injected liquid manure. These have included uneven corn growth, plant stunting, yellowing and chlorosis. Field studies were initiated in northwestern Illinois on a Derinda silt loam (fine, mixed, mesic Typic Hapludalf) soil where these problems had been reported. This research evaluated inorganic N distribution and soil chemical transformations associated with liquid beef manure (28 and 37 Mg ha−1) injected with and without nitrapyrin [2‐chloro‐6‐(trichloromethyl pyridine]. Injection methods included knife (vertical) and sweep (horizontal). Movement of NH4, or NO3, was limited to less than 12.7 cm from the point of knife injection. High concentrations of NH+4 were found within the knife injection zone compared to low concentrations within the sweep injection zone. Horizontally spreading the liquid manure under the soil surface by sweep injection produced a more uniform lateral distribution of manure and inorganic N (25 cm from the center of the injection point). Nitrapyrin was effective in slowing nitrification with sweep but not knife injection. Conditions known to adversely affect root growth; including incipient toxic levels of NH3(aq), high moisture content, and high levels of NO2, were present for approximately 7 to 8 wk within knife injected manure zones. Root observations indicated growth in soil adjacent to the knife injected manure, but no growth within the zone during this same period. Sweep injection reduced or eliminated the length of time that these conditions existed.
Growth Form and Yield Responses of Four Cotton Cultivars to Ozone
Authors: Temple Patrick J.
Published: July 2010

Cultivars of crop plants can differ widely in their susceptibilities to yield losses induced by the air pollutant ozone (O3), but relatively little is known of the physiological mechanisms that account for these differences. Cotton (Gossypium hirsutum L.) cultivars differ in degree of determinance, which may affect cultivar responses to O3 through effects on rates of maturation of the cultivars. Four cultivars of cotton grown in the field on a Hanford coarse sandy loam (coarseloamy, mixed, nonacid, Thermic Xerorthents) were exposed to three levels of O3 in open‐top chambers to determine their relative susceptibility to O3, and to relate differences in susceptibility to morphological and physiological characteristics of the cultivars. Susceptibility to O3,‐induced yield losses in these cultivars was directly correlated with degree of determinance so that cultivar rank in order of both increasing determinance and susceptibility to O3 was: SJ‐2 < C1 < GC510 < SS2086. Differences among the cultivars in susceptibility to O3, were not associated with differences in rates of stomatal conductance. Instead, determinate cultivars appeared to be more susceptible to O3 because periods of peak flowering and boll set coincided with periods of high O3 concentration. Also, indeterminate cultivars appeared to have greater flexibility in altering branching patterns in response to O3,‐induced leaf abscission than did determinate lines. Since most high‐yielding, short‐season cotton cultivars have a determinate growth habit, these results suggest that production from short‐season cotton cultivars may be limited by the prevalence of O3 air pollution in many cotton‐growing regions of the USA.
Sweet Potato Root and Biomass Production with and without Nitrogen Fertilization
Authors: Hill Walter A. , Hortense Dodo , Hahn S. K. , Mulongoy K. , Adeyeye S. O.
Published: July 2010

Previous work suggests that some sweet potato (Ipomoea batatas, L.) cultivars can produce high storage root yields on soils without fertilizer N addition. This study was conducted to compare storage root yields, total biomass, N uptake and fibrous root weights of sweet potato cultivars grown on low N level soils with and without N addition. In 1987 and 1988, improved sweet potato cultivars developed at International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria were grown with and without 50 kg N ha−1 in Oxic Paleustalfs with low N and C concentrations. Yields of 21 to 38 Mg ha−1 were produced for four of the five improved cultivars grown in soil without N addition. Total biomass, foliage, fibrous root and storage root weights and N concentration in leaves were not influenced by fertilizer N addition. Up to 158 and 89 kg N ha−1 uptake in total biomass occurred with the +N and −N treatments, respectively. Indigenous soil N levels and fibrous root weights for − N vs. +N treatments could not account for the total N uptake and biomass produced on soils without N addition.
Differences among Certified Wheat Seedlots in Response to Trifluralin
Authors: Morrison I.N. , Nawolsky K.M. , Entz M.H. , Smith A.E.
Published: July 2010

Injury to wheat from trifluralin [2,6‐Dinitro‐N,N‐dipropyl‐4‐(trifluoromethy1)benzenamine] residue occurs under a range of environmental and field conditions and may influence crop stand density, seed quality, and grain yield. The objective of this study was to determine the relationship between seed quality, stand density, and grain yield of wheat (Triticum aestivum L.) at trifluralin dosages typical of residue levels occurring under western Canadian conditions. Three certified seedlots of ‘Katepwa’ spring wheat designated S1, S2, and S3 were planted into trifluralin‐treated soil under field conditions at Portage la Prairie, Manitoba in 1988 and 1989. All three seedlots had high germination percentages (> 95), however, S1 was darker colored and had a higher thousand‐kernel weight and a greater proportion of large kernels than either S2 or S3. Both cold germination and cold growth tests indicated that S1 and S2 were more vigorous than S3, however no differences in physiological vigor between S1 and S2 were observed. Significant seedlot ✕ trifluralin interactions (P ≤ 0.05) occurred for crop emergence and seed yield in both years, with S1 being less affected than either S2 or S3 as trifluralin dosages increased. For example, in 1988 where 0.25 kg ha−1 trifluralin was present at seeding, emergence of S1 was reduced by 22% compared to 27% for S2 and 31% for S3 relative to the untreated controls. In 1989, the comparative percentage reductions were 9, 12, and l8%, respectively. Similarly, at 0.25 kg ha−1, seed yields in plots sown to S1, S2, and S3 were 3, 7, and 13% less than in the untreated plots in 1988; and 5, 7, and 11% less in 1989. Results of this study substantiate that wheat response to soil trifluralin level at seeding can be modified by qualitative and quantitative differences in seed quality.
Expert System for Planning the Establishment of Turfs
Authors: Liu H. , Fermanian T.W. , Carmer S.G.
Published: July 2010

Establishing or renovating sites are routine events in the management of turfgrasses. Advice from turf experts on the design of the new turf is not always readily available, due to limitations on information about design and utility parameters. Knowledge‐based advisory systems, commonly called expert systems, have shown great potential for planning tasks. TURFPLAN, an expert planning system, was constructed principally for turf managers, Extension staff, educators, contractors, etc. The major design tasks of TURFPLAN are the selection of turfgrass species and their cultivars, establishment procedures, and maintenance procedures during the post‐planting period. Expert System Environment (ESE) was selected as the development platform for TURFPLAN. A portion of the rules covering the selection of turfgrass cultivars was developed from examples using AURORA, an inductive learning system. An evaluation of TURFPLAN's performance was conducted by comparing a set of generated designs to comparable designs developed by turf experts. The TURFPLAN design for a medium maintenance turf (home lawn) was ranked significantly superior to human produced designs. TURFPLAN establishment designs for low maintenance turfs (i.e., highway rights of way) and high maintenance turfs (i.e., golf course greens) were ranked significantly poorer than designs developed by human experts. The TURFPLAN knowledge base currently does not have an adequate quantity of knowledge specifically related to the establishment of low or very high maintenance level turfs. This evaluation indicated that a knowledge‐based planning system may provide turf establishment designs of high quality for home lawns in Illinois. This method of evaluation also establishes a systematic procedure for evaluating knowledge‐based systems.
Interpretive Analysis for Forage Yield Trial Data
Authors: Pedersen J. F. , Moore K. J. , van Santen Edzard
Published: July 2010

Forage cultivar evaluation is often done in small plots with multiple harvests throughout the growing season. Data is often summarized by presenting a yearly total yield for each cultivar in addition to the mean for each harvest date. Data summarization often becomes burdensome and difficult to interpret. Regressing yield against a growth index associated with harvest dates can be utilized to describe forage perfomrmance in a concise and easily interpreted format. Subsets of data from tall fescue (Festuca arundinacea Schreb.) yield trials conducted in Alabama and Kentucky were used to demonstrate the technique. The analysis involves regressing yield of a cultivar against an index calculated as the mean of all entries at a harvest date minus the grand mean. The resulting regression coefficient (b) describes cultivar yield response over several harvest and is indicative of performance under variable growth conditions.
Productivity and Quality of Bermudagrass in a Cool Temperate Environment
Authors: Belesky D. P. , Perry H. D. , Windham W. R. , Mathias E. L. , Fedders J. M.
Published: July 2010

In temperate environments a warm‐season species is needed to provide forage during summer when the growth rate of cool‐season forages is low. Management data for warm‐season pasture is limited for the Appalachian region. A bermudagrass [Cynodon dactylon (L.) Pers.] selection RS1, has been identified which is capable of growth and persistence in areas where other cultivars of the species winterkill. A field study was conducted to determine RS1 bermudagrass productivity and quality as affected by a split application of 60, 120, 240, or 360 kg N ha−1 and a 2‐, 4‐, or 6‐wk delay of initial harvest on a fine‐loamy, mixed, mesic, Typic Hapludult (Gilpin) soil. Treatments were replicated four times in the field, and the study was conducted for 2 yr. Delaying initial harvest significantly increased yield in both years to more than 8 Mg ha−1 when 360 kg N ha−1 yr−1 was applied. Herbage yields typically ranged between 3 and 6 Mg ha−1 and would contribute substantially to forage requirements in mid‐summer in the region. Increased N resulted in higher herbage yield regardless of harvest delay regime. Herbage yields were about 25% less in 1989 than in 1988 and could be due in part to cool and wet conditions in 1989, compared to a hot, dry 1988 growing season. Bermudagrass in vitro dry matter digestibility and crude protein declined with delayed initial harvest (maturity), increased following the mid‐season N application, and continued to decline into late summer. Season average quality was not affected by initial harvest delay. Bermudagrass (RS1) will persist and respond to N fertilizer and defoliation management in cool, temperate environments and promises to be a useful component in forage‐based animal production systems in the region
Optimum Seeding Date for Winter Wheat in Southwestern Saskatchewan
Authors: McLeod J.G. , Campbell C.A. , Dyck F.B. , Vera C.L.
Published: July 2010

Winter wheat (Triticum aestivum L.) in southern Alberta on the Canadian Prairies has traditionally been grown on bare fallow. Recently, the improved winterhardy cultivar Norstar and improved management recommendations, such as seeding directly into stubble or into chemical fallow, have encouraged producers to adapt this crop to the colder climate of southern Saskatchewan. The objective of the experiments reported herein was to determine if the optimum time for seeding winter wheat on stubble and chemical fallow differed from that recommended for seeding on conventional fallow in southern Alberta. A 4‐yr study of stubble‐seeded wheat and 3‐yr study of wheat seeded on chemical fallow were carried out on a medium‐textured soil at Swift Current and on a coarse‐textured soil at Cantuar (only the stubble treatment). The results for stubble‐seeded wheat confirmed that both plant population and yields decreased sharply by 40 to 60% and 30 to 40%, respectively, as seeding was delayed after the first week of September until very late October. The decrease in plant population was less pronounced on the sandy loam soil (40%) than on the silt loam soil (56%). On chemical fallow, there was a gradual decrease in plant population but grain yield did not decrease until seeding was delayed to mid‐October. Test weight was reduced (about 8%) by delayed seeding, and plants took 10 to 13 d dlonger to mature, which facilitated disease (e.g., rust) infestation. Grain protein concentration was not affected by time of seeding. For optimum results in southwestern Saskatchewan, winter wheat can be seeded into chemical fallow until early October but should be seeded in stubble by mid‐September.
Creeping Bentgrass Rooting as Influenced by Dithiopyr
Authors: Dernoeden P. H. , Christians N. E. , Krouse J. M. , Roe R. G.
Published: July 2010

Dithiopyr [3,5‐pyridinedicarbothioic acid, 2‐(difluoromethyl)‐4(2‐methylpropyl)‐6‐trifluoromethyl)S,S‐dimethyl ester] is a new herbicide, but its foliar safety and potential rooting effects need to be documented before its use on creeping bentgrass (Agrostis palustris Huds.) can be recommended. Field studies were conducted at five separate sites in Iowa and in Maryland, where creeping bentgrass was grown on modified sandy soils and maintained at putting green height. Three dithiopyr formulations (1.0 emulsifiable concentrate, 0.10 granular, 0.25 granular) at rates ranging from 0.28 to 0.84 kg ha−1 were compared with label rates of either bensulide [O,O‐bis (1‐methylethyl) S‐(2‐[(phenylsulfonyl)amino] ethyl] phosphorodithioate] or bensulide + oxadiazon [3‐[2‐4‐dichloro‐5‐(1‐methylethoxy)phenyl]‐5‐(1,1‐dimethylethyl)‐1,3,4‐oxadiazol‐2‐(3H)‐one] or DCPA [dimethyl 2,3,5,6‐tetrachloro‐1, 4‐benzenedicarboxylate] for potential rooting and foliar discoloration effects. Root masses were obtained from washed soil plugs, which were combusted to determine root weight. In Iowa all herbicides reduced total root weight on one of four sampling dates in 2 yr. No rooting differences were observed among herbicide rates or formulations at soil depths partitioned at 0 to 5, 5 to 10, 10 to 15, or 15 to 20 cm. Reduced root weight was observed with all herbicides on at least one of nine sampling dates in Maryland. Root weight reduction in Maryland studies was observed primarily within 29 d of treatment (DAT) in 1990, but not within 57 DAT in 1990 or on six sampling dates in 1991. No foliar discoloration was elicited by dithiopyr applied in either April or May. Discoloration and cover reduction occurred where dithiopyr 1.0 EC (0.84 kg ha−1) and bensulide + oxadiazon (6.7 + 1.7 kg ha−1) were applied in mid‐June in Maryland. Overall, data indicate that dithiopyr (0.28‐0.84 kg ha−1) had an acceptable safety margin for creeping bentgrass foliage and rooting on putting greens when applied preemergence in spring.