bluuebunny/crossref_metadata_2025 huggingface dataset:
Field Evaluation of Acid‐Base Fertilizers on Spring Wheat1
Authors: Varvel G. E. , Meredith H. L. , Severson R. K.
Published: July 2010

This study was initiated to evaluate acid‐base fertilizers on highly calcareous soils in the Red River Valley area of Minnesota and North Dakota. These soils represent an environment where acid‐base materials might provide additional flexibility in soil fertility programs because of their proposed ability to produce an acid environment in the zone of application. Two field experiments were conducted during the 1981,1982, and 1983 growing seasons to make this evaluation. One experiment utilized seed placements (band) and the other broadcast placements (surface). All experiments were conducted with spring wheat (Triticum aestivum L.) as the test crop on a Hegne silty clay soil (fine, frigid Typic Calciaquoll). Urea phosphate (UP), diammonium phosphate (DAP), UP combined with urea‐ammonium nitrate solution (UAN), and ammonium polyphosphate (AP) combined with UAN were utilized in the seed placement experiment, each at two rates (22 to 26 kg N ha−1 and 25 kg P ha−1 at the low rate and 44 to 52 kg N ha−1 and 50 kg P ha−1 at the high rate). A no fertilizer treatment (check) was also included. Cogranulated urea‐urea phosphate (UUP), urea‐ammonium polyphosphate (UAP), UP, and UP combined with UAN were utilized in the broadcast experiment at two rates (34 and 68 kg N ha−1). Triple superphosphate (0‐20‐0) was used to equalize applied P at 80 kg ha−1 in the broadcast experiment. A treatment with 80 kg P ha−1 applied (check) was also included. Evaluations of the treatments in each experiment were made utilizing plant population at emergence, nutrient concentrations in the plant at tillering and maturity, and final yields of aboveground dry matter and grain. These comparisons indicated all materials had little if any effect on plant population at emergence, were equally effective at supplying nutrients to the plant, and increased yields in both seed placement and broadcast experiments. Although acid‐base materials were not shown to be superior to current materials, they may provide additional alternatives in soil fertility programs in similar environments.
Effects of Pattern and Amount of Simulated Rainfall on Seedling Dynamics of Weeping Lovegrass and Kleingrass1
Authors: Wester David B. , Dahl Bill E. , Cotter Paul F.
Published: July 2010

Range seeding is a common improvement practice for revegetating abandoned cultivated land or following mechanical brush control. However, seeding failure is frequent because of unfavorable moisture and temperature conditions. The objective of this research was to study weeping lovegrass (Eragrostis curvula) and Kleingrass (Panicum coloratum) seedling emergence and survival in response to 16 different patterns and amounts of irrigation at 38, 30 and 24°C soil surface temperatures in a dry sand in a growth room. Watering treatments consisted of different sequences of wet and dry days; each watering day provided 5 mm. Pattern and amount of water affected seedling emergence and survival. Both species required 2 days of water to emerge at 30 and 24°C; there was no emergence at 38°C. Seedlings which emerged soonest within a treatment tended to survive longer than seedlings which emerged later. When treatment moisture was not sufficient to stimulate high emergence, seeds remained viable and emerged later when additional adequate moisture was provided. Field trails were established in a second phase of this research; growth‐room results were confirmed under natural and simulated rainfall. These results suggest that rainfall in specific patterns and amounts is important in determining seeding success.
Changes in Spring Wheat Tillering Patterns in Response to Delayed Irrigation1
Authors: Stark J. C. , Longley T. S.
Published: July 2010

Soil water availability can have a marked effect on the vegetative development of small cereal grains. However, few studies have examined the effects of soil water deficits on the appearance patterns of specific tillers. Field studies were conducted in 1983 and 1985 to evaluate the effects of early‐season irrigation timing on tillering patterns of spring wheat (Triticum aestivum L.). The studies were conducted on a Declo fine sandy loam and a Declo silt loam (coarseloamy, mixed, mesic Xerollic Calciorthids) in 1983 and 1985, respectively. In both studies, the first irrigation was applied by sprinkler when either 3, 5, or 7 leaves were present on the main stem. Subsequent irrigations were applied to provide more than 50% of available soil water for the remainder of the growing season. Main stem development was linearly related to cumulative degree‐days and was not affected by irrigation timing. Tillers which developed under optimal soil moisture conditions exhibited uniform appearance patterns and reached maximum populations over relatively short degree‐day intervals. Soil water deficits decreased the rate of appearance of all main stem tillers and caused appearance to occur over longer intervals. Dry soil conditions also severely reduced development of tillers at the coleoptilar node. When stressed plants were finally irrigated, the appearance rate of affected tillers frequently increased. This increase usually occurred 40 to 70 degree‐days (base 0°C) after irrigation. In some cases, the stimulation of tillering was sufficient to compensate for earlier tiller losses. However, periods of stress extending into the latter part of the vegetative period often reduced maximum tiller populations. Grain yields for wheat irrigated at the 3‐, 5‐, or 7‐leaf stage were 7.28, 6.34, and 5.66 Mg ha−1 in 1983 and 4.95,4.46, and 3.92 Mg ha−1 in 1985, respectively. The results of this study illustrate the importance of adequate early‐season soil water availability in developing uniform tillering patterns and high yield potential for spring wheat.
Incorporating Herbicides on Sandy Soil for Dryland Cotton1
Authors: Wiese A. F. , Chenault E. W.
Published: July 2010

Studies were conducted for 2 yr in the field, comparing the effectiveness of a spring‐toothed harrow and a tandem disk for incorporating preplant cotton (Gossypium hirsutum L.) herbicides under dryland cropping, on a Miles loamy fine sand soil (fine‐loamy, mixed, thermic Udic Palvestalf) that is subject to wind erosion. Herbicides3 used were trifluralin [2,6‐dinitro‐N,N‐dipropyl‐4‐(trifluoromenthyl)benzenamine], nitralin [4‐(methylsulfonyl)‐2,6‐dinitro‐N,N‐dipropylbenzenamine], butralin [4‐(1,1‐dimethylethyl)‐N‐(l‐methylpropyl)‐2,6‐dinitrobenzenamine], profluralin [N‐(cyclopropylmethyl)‐ 2,6‐dinitro‐N‐propyl‐4‐(trifluoromethyl) benzenamine], fluchloralin [N‐(2‐chloroethyl)‐2,6‐dinitro‐N‐propyl‐4‐(trifluoromethyl) benzenamine] and dinitramine (N3, N3‐diethyl‐2,4‐dinitro‐6‐ (trifluoromethyl)‐1,3‐benzenediamine]. Weeds encountered were redroot pigweed (Amaranthus retrofexus L.), green carpetweed (Mollugo verticillata L.), large crabgrass [Digitaria sanguinulis (L.) Scop.], and field sandbur (Cenchrus incertus M.A. Curtis). No appreciable difference in weed control was noted either year between the disk and spring‐toothed harrow. The first year, cotton yields were not affected by incorporation methods. The second year, incorporating the herbicides with a spring‐toothed harrow resulted in higher yield than incorporating with a tandem disk. Because the spring‐toothed harrow leaves the soil cloddy and less subject to wind erosion and gives equivalent weed control along with equal or better cotton yields, it is a better implement than a tandem disk for incorporating preplant cotton herbicides on sandy soil in dry areas.
Herbicides and Seeding Rate Effects on Sprinkler‐Irrigated Rice1
Authors: Akkari K. H. , Talbert R. E. , Ferguson J. A. , Gilmour J. T. , Khodayari K.
Published: July 2010

Two herbicide programs and four seeding rates were tested in 1981 and 1982 at Keiser, AR, to determine the optimum seeding rate that would be effective in maximizing yields in sprinkler‐irrigated rice (Oryza sativa L.). ‘Lebonnet’ rice was drill‐seeded into a Sharkey clay (Vertic Haplaquepts, 1.4% O.M.) at rates of 50, 100, 150, and 200 kg ha 1. The herbicide programs used were propanil [N−(3,4− dichloropheny1)propanamide] at 3.4 kg ha 1 or a tank mixture of propanil at 3.4 kg ha 1 + oxadiazon [3−[2,4−dichloro−5−(1−methylethoxy) phenyl]−5−(1,l−dimethylethyl)−1,3,4−oxadiazol−2−(3H)‐one] at 1.1 kg ha−1, each applied at the 2‐leaf stage of weeds. Each treatment was followed by 2,4,5−T [(2,4,5−trichlorophenoxy)acetic acid] at 1.1 kg ha 1 applied over‐the‐top at the onset of internode elongation of the rice stems. Both herbicide programs controlled barnyardgrass [Echinochloa crus‐galli (L.) Beauvois], broadleaf signalgrass [Brachiaria platyphylla (Grisebach) Nash], large crabgrass [Digitaria sanguinalis (L.) Scopoli], common cocklebur (Xanthium strumarium L.), and smooth pigweed (Amaranthus hybridus L.). Propanil + oxadiazon controlled pitted morningglory (Ipompoea lacunosa f. purpurata L.) and prickly sida (Sida spinosa L.), but propanil alone did not. A significant increase in rice plant population and panicle density with the increased seeding rates was offset by a corresponding decrease in number of seeds per panicle and rough rice yield, and an increase in tillering at the lower seeding rate. The results indicate that the present recommended seeding rate (140 kg ha 1) for sprinkler‐irrigated rice should be reduced to between 50 and 100 kg ha−1, but must be accompanied by timely and effective herbicide programs.
Lettuce Yield‐Irrigation Water Quality and Quantity Relationships in a Gypsiferous Desert Soil1
Authors: Russo David
Published: July 2010

Evaluation of the possibility of utilizing marginal soils and saline waters for agricultural production is essential for the development of arid zones. The effect of irrigation water quality (salinity) and quantity on the yield of lettuce (Lactuca saliva var. ‘Iceberg’) was studied in a gypsiferous desert soil (Typic Torrifluvent). Irrigation water volume (Q) ranging from 0.37 to 1.3, 0.6 to 1.6, and 0.7 to 2.4 times the Class A pan evaporation (Eo) for the irrigation water salinities of Ciw = 1.7, 3.1, and 4.7 dS/m, respectively, were applied via trickle irrigation. Root zone soil water pressure potential and salinity were monitored and lettuce yield was measured. Seasonal average soil water content (θ̅) was affected by irrigation water volume but not by quality (salinity) whereas seasonal average soil water salinity (E̅C̅) and lettuce yield (Y) were affected by both quality and quantity of the irrigation water. For the different ranges of Q associated with the different irrigation waters, θ̅ was increased by 30, 44, and 94%, EC was decreased by 20, 21, and 18%, and Y was increased by 120, 71, and 55% for Ciw = 1.7, 3.1, and 4.7 dS/m, respectively. Curvelinear salt tolerance functions were found to be dependent on the volume of irrigation water, approaching a piecewise linear function when relatively large volumes of irrigation water (Q/Eo > 1) were applied. The increase in irrigation volume compensated only in part for the adverse effect of the irrigation water salinity. Maximum yields obtained using the more saline waters are 6.5 and 20.7% smaller for Ciw = 3.1 and 4.7 dS/m, respectively, relative to yield obtained using Ciw =1.7 dS/m.
Morphological and Anatomical Characterization of Leaf Burn in Corn Induced from Foliar‐Applied Nitrogen1
Authors: Gamble P. E. , Emino E. R.
Published: July 2010

Foliar applied nutrients have been used to overcome nutrient deficiencies on a variety of crops; however, leaf burn is often a problem. Corn (Zea mays L.) Plants were treated with 120 g N L−1 from urea to study the leaf burn phenomenon. A 4‐µL drop applied to the adaxial leaf surface was observed at 2‐h intervals for 8 h. Leaf samples were studied with dissecting, compound, and scanning electron microscopes for changes resulting from the application of foliar applied fertilizer salts. Damage observed under the dissecting microscope after 2 h consisted of a darkening in the epidermal cells. After 8 h, the epidermis was desiccated, sunken, and discolored, forming a lesion on the leaf surface. Slides of leaf sections showed wrinkling and collapse of epidermal cells at 4, 6, and 8 h. Disorganization of mesophyll was observed after 8 h. Scanning electron microscope (SEM) micrographs revealed collapsed and wrinkled epidermal cells with sunken stomates after 2 h. Events associated with visual damage appear to be related to water loss since epidermal and mesophyll cells become desiccated.
Quality of Stockpiled Bigalta Limpograss Forage at Varying Fertility Levels1
Authors: Davis C. E. , Jolley V. D. , Mooso G. D. , Robison L. R. , Horrocks R. D.
Published: July 2010

Adequate quantity and quality of cool‐season forage are limiting factors in cattle (Bos taurus) producing areas of the subtropics. ‘Bigalta’ limpograss {Hemarthria altissima (Poir.) Stapf et C.E. Hubb.] has been proposed as a forage with potential to help overcome both problems. A 2‐yr study to determine the effect of increasing levels of fall‐applied fertilizer on the quality of stockpiled Bigalta limpograss was conducted in central Florida. Eight fertilizer treatments were applied on 10 October each year: (1) 0‐0‐0, (ii) 34‐4‐13, (iii) 68‐7‐26, (iv) 100‐11‐40, (v) 135‐15‐54, (vi) 168‐18‐67, (vii) 200‐22‐80, and (viii) 400‐45‐160 kg ha−1 of N‐P‐K. Forage quality variables were measured in whole plant samples at monthly intervals from 5 December through 5 April, inclusive, and were compared to established National Research Council (NRC) requirements for beef cattle. Yield increases entering into the stockpile period (December) of 285 to 610% (relative to the control) resulted from rates of 68‐7‐26 kg ha−1 of N‐P‐K and higher, and these yield increases were maintained through April. Addition of greater than 68‐7‐26 kg ha−1 of N‐P‐K consistently increased in vitro dry matter digestibility (IVDMD) crude protein (CP), P, K, and Mn, whereas Zn concentration was decreased by fertilizer application. Acid detergent fiber (ADF), neutral detergent fiber (NDF), and concentrations of Ca, Mg, Fe, and Cu were generally unaffected by fertilizer level. Crude protein, P, and K levels were raised into acceptable NRC ranges, while Zn dropped below the required range as a result of fertilization. Animals grazing stockpiled limpograss of this quality would require supplementation with Zn and Cu during the entire period, while supplementation with CP and P would be required only during February and April, respectively. Both Ca/P and K/(Ca+Mg) ratios were maintained at levels conducive to good beef cattle production throughout the stockpile period.
Quality Analysis of Summer‐Annual Forages. I. Sample Preparation Methods and Chemical Characterization of Forage Types and Cultivars1
Authors: Fisher D. S. , Burns J. C.
Published: July 2010

The effects of sample preparation on the chemical composition and the subsequent estimation of nutritive value of silage from different sorghum (Sorghum bicolor L.) cultivars and millet (Pennisetum americanum L.) may alter experimental results and conclusions. The objectives of this study were to determine the differential effects of oven‐drying, freeze‐drying, and ensiling on the concentrations of the Van Soest fiber fractions, total N, and several carbohydrate fractions of summer‐annual forages with major interest in cultivar rank. One millet, one corn (Zea mays L.), and eight sorghum cultivars, including one sudangrass [Sorghum sudanense (Piper) Stapf], one sorghum × sudangrass hybrid, two grain sorghums, two intermediate sorghums, and two forage sorghums, were ensiled. The study was conducted as a randomized complete block design with four replications and grown at two locations in two different years. The soil type was a fine‐loamy, siliceous, thermic Typic Paleudult (Norfolk loamy sand) at Location 1 and a clayey, kaolinitic, thermic Typic Hapludult (Cecil clay loam) at Location 2. Neutral detergent fiber (NDF), acid detergent fiber (ADF), and apparent cellulose showed significant cultivar × sample preparation method interactions from both locations. Cultivars partitioned total nonstructural carbohydrates (TNC) differently between sugars and starch, with significant cultivar × sample preparation interactions occurring for total sugar, starch, and TNC from both locations. The interaction of cultivar and sample preparation can affect the results of cultivar comparisons. Oven‐drying should not be used to prepare either fodder or silage samples for quality determinations.
Studies of Intact Shoot‐Root Systems of Field‐Grown Winter Wheat. II. Root and Shoot Developmental Patterns as Related to Nitrogen Fertilizer1
Authors: Belford R. K. , Klepper Betty , Rickman R. W.
Published: July 2010

Root development and growth for winter wheat (Triticum aestivum L. em. Thell.) influence seasonal water and nutrient uptake. Root location and function with time in the field are needed to understand the role of roots in plant growth and tiller survival. Fertilizer timing was used to modify root and tiller growth in a field experiment. Objectives were to observe appearance and measure distribution with depth and time of identified roots during the growing season. Field plots on a Walla Walla silt loam (mixed, mesic Typic Haploxeroll) were fertilized once with (NH4)2SO4 in October, February, or April or left unfertilized. Square metal tubes, forced into the soil after emergence, enclosed shoots and developing root systems of six to eight plants. Tubes were extracted at beginning and mid‐tillering, jointing, and anthesis. Roots were washed, separated, and identified. Length, condition, order of branching, and number and length of lateral roots was measured on each. Leaf development rates were the same in tubes and plots only for February‐applied fertilizer. Denitrification from transient waterlogging occurred in some tubes. Seminal roots remained intact and grew until anthesis. Crown roots explored the soil in order of their appearance with older axes branching more and penetrating deeper. Seminal root distribution with depth was more nearly linear than that of nodal and tiller roots, which were exponentially distributed. Magnitude of rooting at all depths was increased by N which increased branching. Leaf and root development were closely correlated, but root development or lack thereof on tillers did not appear to be the major factor controlling tiller survival.
Simulated Hail Research in Sunflower: Defoliation1
Authors: Schneiter A. , Jones J. M. , Hammond J. J.
Published: July 2010

Accurate loss procedure and compensation due to hail losses are a major concern to both the producer and the insurance company. Field experiments simulating leaf loss such as that which would occur as a result of a hail storm were conducted on hybrid sunflower (Helianthus annuus L.) at Carrington and Fargo, ND. The objective of this study was to investigate the agronomic response of sunflower to various levels of defoliation applied at different stages of plant development. Defoliation treatments (0, 25, 50, 75, and 100% of the leaves randomly removed with a knife) were applied at nine stages of plant development from V4 through R7. Fifty, 75, and 100% defoliation averaged across all developmental stages decreased seed yield significantly compared to the check. Seventy‐five and 100% defoliation decreased seed yield significantly compared to the check when treatments were applied at the R1 through R6 stages. Plant death often resulted when treatments of 100% defoliation were applied at stages R3 and R4. Oil percentage decreased significantly with 100% defoliation at the R4 through R7 stages. One‐hundred‐percent defoliation averaged over all stages of plant development decreased oil percentage an average of 11.9%. One‐hundred‐percent defoliation averaged across all stages of plant development decreased head diameter, plant height, percent stem breakage; days to R5.5, and achene weight. Complete removal of leaves at the reproductive (R) stages of plant development affected the variables measured to the greatest degree. As defoliation percentage decreased, values of variables measured were affected to a lesser degree.
Modeling Long‐Term Crop Response to Fertilizer Phosphorus. II. Comparison with Field Results1
Authors: Janssen B. H. , Lathwell D. J. , Wolf J.
Published: July 2010

Results obtained using a simple model for computing the residual effect of applied fertilizer P were compared with results of long‐term field trials with maize (Zea mays L.), sorghum [Sorghum bicolor (L.) Moench], and rice (Oryza sativa L.), carried out in Brazil, Australia, and Madagascar, respectively. The calculated and experimentally found residual effects of fertilizer P were in close agreement, provided the applications rates were not too high and seasonal effects not too strong. At all locations the same values for the time constants of P transfer between the labile and stable pools could be used, irrespective of the method of application and the type of fertilizer. As a consequence, the residual effect of fertilizer P is directly related to the first‐year recovery fraction. For given recovery fractions, the residual effects are calculated for different types of P fertilizers.
Tillage and Residue Management Effects on Properties of an Ultisol and Double‐Cropped Soybean Production1
Authors: NeSmith D. S. , Hargrove W. L. , Radcliffe D. E. , Tollner E. W. , Arioglu H. H.
Published: July 2010

Doublecropping soybean [Glycine max (L.) Merrill] and wheat (Triticum aestivum L.) has become widespread in the southeastern United States. This has encouraged use of reduced and no‐tillage systems, but burning of the wheat straw prior to planting soybean has also become common. A 2‐yr field study was initiated on a Greenville sandy clay loam (Rhodic Paleudult) in Georgia to evaluate effects of tillage and residue management practices on selected soil properties and plant growth parameters. Main experimental blocks were split into burned and nonburned wheat straw, and tillage treatments were randomly applied in strips. Tillage treatments were notillage, disk tillage (disk), and moldboard plow (plow). Soil temperature, water content, and bulk density, as well as plant population, height, dry weight, root mass, and seed yield were determined. Notillage with residue resulted in soil surface temperatures 5 to 8°C lower than temperatures measured on bare soil. Also, water content of the upper 0.10 m of soil in the no‐tillage nonburned treatment was as much as 30 to 40% higher than other treatments. Bulk densities in excess of 1.7 Mg/m3 occurred under disk and no‐tillage at a depth of 0.15 to 0.25 m. This compaction reduced water extraction and plant growth in those treatments as compared to the plowed soil. These results indicate that, for sandy Ultisols with poorly developed structure, tillage pan amelioration may be necessary in the fall to ensure better soil conditions for no‐tillage in the spring, as no‐tillage tends to preserve the initial soil physical condition. Burning residues did not significantly influence crop growth but did influence soil properties adversely. It is apparent that burning residues is a matter of convenience for ease of planting but is of no agronomic benefit.
Evaluation of the EPIC Simulation Model Using a Dryland Wheat‐Sorghum‐Fallow Crop Rotation1
Authors: Steiner J. L. , Williams J. R. , Jones O. R.
Published: July 2010

Dryland cropping is extremely variable, and stability over time is important. Analysis of soil‐crop‐climate interactions using simulation models can expand dryland cropping research through extrapolation of experimental results across a range of soils, climates, and management practices and over longer time periods. The Erosion‐Productivity Impact Calculator (EPIC) simulates evapotranspiration (ET), runoff, plant growth, and related processes; but validation was needed for semiarid regions. Predicted ET, runoff, soil water, and crop yield were compared to data collected from 1958 to 1984 at Bushland, TX. Wheat (Triticum aestivum L.) and sorghum [Sorghum bicolor (L.) Moench] were grown on a Pullman clay loam (fine, mixed, thermic Torrertic Paleustoll), with each crop grown each year. Predicted mean growing season ET, soil water depletion, and annual runoff were not significantly different from observed values. EPIC tended to underpredict high values of water balance components and overpredict low values, but predicted realistic distributions of values. Local calibration of the conversion factor of dry matter production from intercepted radiation was required for yield prediction of 1.3 and 2.7 Mg/ha for wheat and sorghum, respectively, which then did not significantly differ from observed values of 1.3 and 2.3 Mg/ha. EPIC was generally satisfactory in predicting the water balance over long periods of time, with means, standard errors, ranges, and probability distributions being similar for observed and predicted values. Satisfactory yield prediction required calibration to the location. Prediction of yield or water balance components for specific fields in specific years is not recommended.
Differences in Drought Resistance between Two Corn Hybrids. II. Component Analysis and Growth Rates1
Authors: Lorens G. F. , Bennett J. M. , Loggale L. B.
Published: July 2010

Relatively little research has been conducted to evaluate differing responses to water stress among genotypes of the same species. The objective of this study was to identify differences in growth and development of plant parts resulting from water stress imposed on two corn (Zea mays L.) hybrids that had been observed to differ in their sensitivity to water stress. During 1983 and 1984, two corn hybrids (Pioneer Brands 3192 and 3165) were subjected to three water management treatments: optimal irrigation, rainfed, and stress during vegetative (1983) or early reproductive (1984) growth. Growth analysis revealed few differences between hybrids for leaf area index, and crop and seed growth rates when well‐watered or stressed during vegetative growth, except that hybrid 3192 showed more rapid early growth. When well‐watered, grain yield of hybrid 3192 was the same (1983) or higher (1984) than grain yield of hybrid 3165. However, the two hybrids differed in their ability to resist severe water stress. The greater grain yield of hybrid 3165 in the rainfed treatment was associated with relatively smaller reductions in crop growth rate, total biomass accumulation, seed number, effective filling period, and harvest index with stress when compared to hybrid 3192. The greater crop growth rate and final biomass and grain yield of hybrid 3165 during severe stress most likely resulted from the maintenance of higher leaf water and turgor potentials and lower leaf diffusive resistances that were apparently mediated by higher root length densities in deeper zones of the soil profile as described in a companion paper.
Effects of Alfalfa Proportions and Clipping Frequencies on Timothy‐Alfalfa Mixtures. II. Nitrogen Fixation and Transfer1
Authors: Ta T. C. , Faris M. A.
Published: July 2010

The inclusion of legumes in grass pastures often increases grass yields due to the contribution of the N fixed by the legume to the associated grass. This benefit was evaluated in field experiments under different management conditions at Ottawa, Ontario, Canada, on a Manotick mixed sandy loam soil (Typic Dystrochrett) labeled with 15N. Timothy (Phleum pratense L.) and alfalfa (Medicago sativa L.) were grown in pure stands and in mixtures at two proportions (1:1 and 1:2) and harvested at three alfalfa maturity stages (early, mid‐, and late bloom). Nitrogen fixed by alfalfa and N transfer from alfalfa to timothy were calculated from the differences between the isotopic compositions of the two species in mixture and timothy in pure stand. The highest amounts of N in alfalfa shoots originating from N fixed were 192 and 215 kg N ha−1 yr−1 in the first and second year, respectively, when harvested at mid‐bloom (four cuts). The inclusion of timothy in alfalfa stands increased the proportion of N fixed by alfalfa. Nitrogen transfer from alfalfa to associated timothy contributed up to 22% (first year) and 30% (second year) of the total N yield of timothy and amounted to up to 13 kg N ha−1 yr −1. This transfer increased with progressive cuts and with an increased proportion of alfalfa in the mixture. Growing alfalfa in mixture with timothy at a high proportion to timothy is an ideal system for maximum N transfer and for reducing N fertilizer usage.
Cabbage Plant Responses to Residual Phosphorus and Potassium in the Soil and to Band‐Applied Concentrated Superphosphate and Potassium Chloride Fertilizers1
Authors: Peck N. H. , MacDonald G. E. , Hemmat M.
Published: July 2010

Fertilization with P and K should be adjusted to supplement the available residual P and K in the soil to supply sufficient nutrients for crops. The objective of this study was to determine the responses of cabbage (Brassica oleracea (L.) Capitata group, cv. King Cole) plants to levels of residual P and K in the soil from previous applications of concentrated superphosphate (CSP) and potassium chloride (KCl) and to banded CSP and KCl fertilizers at planting. Cabbage plants were grown in a Honeoye fine sandy loam soil (fine loamy, mixed, mesic Glossoboric Hapludalf). Main plots were arranged in a factorial combination of four levels of residual P in the soil from CSP times four levels of residual K in the soil from KCl applied during 1963 through 1972. Banded fertilizer treatments of (i) no CSP or KCl, (ii) CSP, (iii) KCl, and (iv) CSP plus KCI were applied at planting time in each main plot in 1973 and 1985. At harvest, the yields of whole heads and of burst heads were measured and the concentrations of P, K, Cl, Na, Mg, S, N, Zn, Mn, Fe, and Cu in the heads were determined. Increasing the level of residual P in the soil increased the concentration of P from 3.0 to 3.8 mg g−1 dry weight in the heads in 1973, and from 2.6 to 3.4 mg g−1 dry weight in the heads in 1985. Increasing the level of residual K in the soil increased the concentration of K from 24 to 32 mg g−1 dry weight in the heads in 1973, and from 22 to 26 mg g−1 dry weight in the heads in 1985. Applications of KCl during 1963 through 1972 increased the concentration of Cl from 2.0 to 3.4 mg g−1 dry weight in the heads in 1973, but did not affect Cl in the heads in 1985. Increasing the level of residual P in the soil up to 30 kg ha−1 in 1973 and to 21 kg ha−1 in 1985 increased the yield of heads. Banded CSP increased the yield of heads at the lower levels of soil P but not at the highest level. Increasing the level of residual K in the soil or banded KCl fertilizer, or both, increased the yield of heads but also increased the percentage of burst heads. Heads of cabbage plants with the highest yield had concentrations of P and K of 3.2 and 30 mg g−1 dry weight, respectively, in the heads; however, a concentration of K of over 26 mg g−1 dry weight caused excessive burst heads.
Infuence of Calcium, Nitrogen, and pH on Alfalfa Root Growth and Nitrogen Fixation Using the Implanted Soil Mass Technique1
Authors: Rechcigl J. E. , Edmisten K. L. , Wolf D. D. , Reneau R. B.
Published: July 2010

Soil acidity is a major growth‐limiting factor responsible for stunting roots, reducing forage yield, and limiting N2 fixation in alfalfa (Medicago saliva L.). The implanted soil mass technique was utilized to investigate the influence of subsurface amendments on root systems. It consisted of mixing a study soil with chemical treatments of interest, burying the mixture in mesh bags 15 cm below an existing alfalfa stand, removing the bags after 1 yr, and determining root mass and N2 fixation via acetylene reduction. A Tatum clay loam (clayey, mixed, thermic Typic Hapludult) soil with an initial pH of 4.4 and amended with either CaSO4, NH4NO3, CaSO4, + NH4NO3, KOH, or Ca(OH)2 was buried in the mesh bags, in an Ernest silt loam (fine‐loamy, mixed, mesic Aquic Fragidult) that had received either 0 or 6.7 Mg ha−1 of surface‐applied dolomitic limestone. After liming, the pH of the soil surface (0–5 cm) increased from 5.3 to 6.3. Surface liming increased the root mass in only the implanted soil mass receiving a Ca(OH)2 or KOH amendment and did so by 7.5‐ and fivefold, respectively. With the unlimed soil, only Ca(OH)2 increased root mass in the implanted soil mass. With the exception of Ca(OH)2, treatments had no influence on N2 fixation in the implanted soil mass. For the Ca(OH)2 amendment there was a fourfold increase in N2 fixation in the surface‐limed soil and a 20‐fold increase in the unlimed soil.
A Method for Evaluation of Salt Tolerance during Germination, Emergence, and Seedling Establishment1
Authors: McKimmie T. , Dobrenz A. K.
Published: July 2010

Salinity is an increasing problem for irrigated agriculture, but few well‐defined methods exist for providing uniform, repeatable conditions to select plants for salt tolerance. A floodable planter box (salt box) was designed and used as a screening method for salt tolerance in alfalfa (Medicago sariva L.). The Salt box was used to screen over 100 000 seedlings. Vigorous plants were selected after 6 weeks growth in −0.8 MPa salinity (NaCl). This system provides a method to identify salt tolerant plant, and to test selections against other populations.
Application of Phosphorus and Sulfur on Irrigated Alfalfa1
Authors: Rehm G. W.
Published: July 2010

Low nutrient supplies often limit crop production on irrigated sandy soils. Soils in the Sandhills region of Nebraska have a limited capacity to supply P and S to crops. This study was conducted to determine optimum application rates of P and S for intensive alfalfa (Medicago sativa L.) production and to determine the relationship between nutrient application rate and concentration of these nutrients in plant tissue. Seven rates of P were combined with seven rates of S in a central composite factorial design with three replications. Treatments were broadcast and incorporated into a Typic Ustipsamment prior to seeding in August 1978. Applications were repeated on the established stand in the early spring of 1980, 1981, and 1982. Dry matter yields were recorded in four cuttings each year. Whole plant samples were taken from each harvest and analyzed for P and S. Except for 1982, alfalfa yield increased curvilinearly with the application of both P and S, but there was no significant interaction between these nutrients. In 1982, there was no response to applied S, but the response to P was curvilinear. Rates of 44 kg P ha−1 and 56 kg S ha−1 were needed for maximum production. The P concentration in the tissue increased with the rate of applied P, while fertilizer S had no consistent effect. The S concentration in the tissue increased with the rate of applied S. Sulfur concentration decreased as the P rate increased. This reduction was attributed to plant dilution effects. Concentrations of both P and S were near reported critical values when rates of P and S needed for highest yield were applied.
Optimizing Row Spacing and Seeding Rate for Soft Red Winter Wheat
Authors: Johnson J. W. , Hargrove W. L. , Moss R. B.
Published: July 2010

Intensive management practices, such as high fertility, fungicides, and plant growth regulators, have substantially increased grain yield of soft red winter wheat (Triticum aestivum L.) in the northeastern and mid‐Atlantic USA. Our objective was to determine the effects of row spacing and seeding rate on grain yield and yield components of several cultivars in a high‐yield environment in the southeastern USA. Five cultivars, Coker 916, Coker 983, Hunter, Florida 301, and Florida 302, were grown during 1985 and 1986 on a Greenville sandy clay loam (clayey, kaolinitic, thermic Rhodic Paleudult) in row spacings of 0.10 and 0.20 m at seeding rates of 288 and 576 seeds m−2. Management practices included a high rate of fertilizer‐N (176 kg ha−1) in multiple applications, fungicide and plant growth regulator applications, irrigation, and adequate levels of P, K, S, and Mg. Grain yields ranged from 3.9 to 6.3 Mg ha−1 and averaged 5.0 Mg ha−1. Narrow row spacing (0.10 m) yielded 0.4 Mg ha−1 or about 8% greater than the 0.20‐m spacing. Grain yield was not influenced by seeding rates when averaged over years. Number of spikes per square meter was the yield component most affected by row spacing and seeding rate. Neither the cultivar × row spacing nor cultivar × seeding rate interaction for grain yield was significant. Therefore, new cultivars should react similarly to those studied here.
Corn Hybrid Responses to Reconstructed Mine Soils in Western Illinois
Authors: Dunker R. E. , Jansen I. J. , Pedersen W. L.
Published: July 2010

Federal law requires that surface‐mined prime farmland be reclaimed and restored to productivity for row crops equivalent to that present before mining (Surface Mining Control and Reclamation Act, 1977. Public Law 95‐87. U.S. Code Vol. 30, Sect. 1265). Success of reclamation of such cropland shall be determined on the basis of crop production from the mined area compared to an approved reference area or other technical guidance procedure (Surface Coal Mining Land Conservation Act, 1981. Illinois Public Act 81‐1015). The objective of this study was to evaluate a wide range of corn (Zea mays L.) genotypes grown on mined land compared to corn grown on an adjacent natural soil. Forty corn hybrids in 1984 and 38 hybrids in 1985, with 29 hybrids being common to both years, were planted on two reclaimed soils and an undisturbed tract. The two mine soils consisted of: (i) 45 cm of topsoil replaced over graded wheel spoil, and (ii) graded wheel spoil only. Both soils are Typic Udorthents. A nearby tract of Sable soil (fine‐silty, mixed, mesic Typic Haplaquoll) was used as the unmined comparison. Results indicate that hybrid yield variation is associated more with weather variation on mine soils than on the undisturbed Sable soil. Pollination dates were delayed, and yield potential varied among hybrids grown on these disturbed soils. Those hybrids with the highest yield potential on the Sable soil did not necessarily produce the highest yields on the disturbed soils. No significant yield response to topsoil replacement was observed for any hybrid in 1984, and only one hybrid had a significant positive response and two hybrids responded negatively to topsoil replacement in 1985.
Growth and Composition of Grain Sorghum with Limited Nitrogen
Authors: Lafitte H. R. , Loomis R. S.
Published: July 2010

A study of N fertilization of grain sorghum [Sorghum bicolor (L.) Moench] was conducted in two fields on a Typic Xerorthent with contrasting patterns of N availability, to extend our understanding of how the partitioning of N to vegetative parts and to structural biomass influences grain yield and N‐use efficiency. The study was supported by detailed analyses of N and dry matter distribution, and proximal analyses of biochemical composition. Nitrogen accumulation differed greatly, but the patterns of N partitioning and the structural carbohydrate content of vegetative parts at equivalent developmental stages were little affected. Changes in dry weight partitioning among vegetative parts were primarily a result of the parts' differential abilities to store nonstructural compounds. In contrast, the structural carbohydrate content of panicles was affected by N availability. Low N supply resulted in leaves with a smaller N content, and lower light conversion efficiency was observed. In addition, those canopies were not able to supply as much N to panicle growth. Roughly two‐thirds of the observed effects of N deficiency on grain yield were due to structural limitations to growth; the remaining effects were associated with reduced conversion efficiency per unit leaf area.
Switchgrass and Big Bluestem Responses to Amendments on Strongly Acid Soil
Authors: Jung G. A. , Shaffer J. A. , Stout W. L.
Published: July 2010

Native perennial warm‐season grasses are established and used in the northeastern United States for beef cattle (Bos taurus) production, wildlife habitat, and soil conservation. This research was conducted in Pennsylvania to study select plant growth responses and forage quality of switchgrass (SWG), Panicum virgatum L., and big bluestem (BBS), Andropogon gerardii Vitman, to dolomitic lime, and P and N fertilizers on strongly acid, fine‐loamy, mixed, mesic, Typic Fragiaqualfs. The soil amendments were applied after the first growing season. Growth of SWG and BBS was markedly improved by topdressings of lime and N fertilizer. In 1981 and 1982, untreated warm‐season grass yielded approximately 50%, and grass receiving the low rate of applied nutrients yielded 90%, of that with the high lime and fertilizer rate (8.76 Mg ha−1). Nitrogen fertilizer increased production of stems and leaf sheaths more than leaf laminae. Crude protein concentration (CPC) of both species generally was low, but N fertilizer increased CPC from 52 to 77 g kg−1. In vitro dry matter disappearance values were low, but significant species X N, lime X N, species X lime X N, and N X year interactions occurred. Lime effects were significant for concentrations of Ca, Mg, and Mn; P fertilizer for Ca, Mg, and P; and N fertilizer for Ca, Mg, P, and Mn. Aluminum concentrations in forage were low even with an exchangeable soil Al of 100 kg ha−1. Approximately 80% of the root mass of each species was within the top 10 cm of soil, but roots were observed growing along prism faces of the fragipan at 60 cm. The warm‐season grasses were productive on strongly acid (31 Mg lime ha−1 needed for neutralization), infertile soil, with low inputs of lime (4.5 Mg ha−1) and fertilizer.
Functional Boron Requirement for Leaf Expansion and Its Use as a Critical Value for Diagnosis of Boron Deficiency in Soybean
Authors: Kirk G. J. , Loneragan J. F.
Published: July 2010

The slow response of shoot dry matter to nutrient stress under many experimental conditions sometimes makes it an unsatisfactory criterion for defining critical concentrations of nutrients for deficiency diagnosis by plant analysis. This study was done to see if the relationship between the B concentration in young leaves and their rate of elongation could be used to define critical values for diagnosis of B deficiency in soybean [Glycine max (L.) Merr.] Soybean was grown in nonrenewed solution culture at two initial B concentrations chosen so that plants at the lower concentration became deficient during the growing period, while those at the higher B concentration remained healthy. Boron deficiency depressed dry matter (DM) of roots and young leaves but increased DM of older, expanded leaves, thus delaying the response of total shoot DM to B deficiency. As B supply became depleted, B concentrations in young leaves declined rapidly from 20 to 3 mg kg−1 DM, giving falsely low values for diagnosis of B deficiency when correlated with shoot DM. The rate of elongation of young expanding leaflet blades was depressed by B deficiency earlier than shoot DM. Correlation of B concentration in young leaves with their elongation rate suggests that they require 12 mg B kg−1 DM to achieve 90% of their maximal rate. It is suggested that this value represents the functional B requirement for leaf expansion and that it provides a more consistent and accurate critical value for diagnosis of B deficiency in soybean than that determined by correlation with shoot DM in the usual way.
Evaluation of Soil Fertility in Some Prehistoric Agricultural Terraces in New Mexico
Authors: Sandor J. A. , Gersper P. L.
Published: July 2010

A greenhouse study was conducted to evaluate the fertility of some prehistorically terraced soils in New Mexico that were cultivated sometime between 1000 and 1150 A.D. and then abandoned. The impetus for this study was a finding that these soils still show the effects of cultivation nearly 900 yr after farming ceased. Soil changes, inferred by comparison with nearby uncultivated but otherwise similar soils, were mainly degradative, including accelerated erosion, compaction, and losses of organic matter and nutrients such as N and P. A traditional crop (Chapalote corn, Zea mays L.) and a standard test plant (barley, Hordeum vulgare L.) were grown for 28 d in samples of prehistorically cultivated and uncultivated soil, using a check and up to five fertilizer treatments: NPKS, PKS, NKS, NPS, and NPK. Fertility was assessed with measurements of plant growth and by chemical analyses of soils and whole plants. Results indicated that differences in plant growth and composition were associated with soil differences. For example, corn dry weights were about 45% lower in cultivated soils for the check and PKS treatments, and cultivated soils averaged 39% lower in total N relative to uncultivated soils. However, the opposite trend occurred in the NKS treatment because of lower available P in the uncultivated soil. Manganese uptake was greater in corn grown in cultivated soil. Corn dry weights were not significantly different between soils with the NPKS treatment. The five to ten times increase in plant dry weights in the NPKS versus PKS treatment indicates that N is the main limiting nutrient in the cultivated soil. The strong response of barley to N fertilization and comparison of dry weights to those obtained from similarly tested modern cultivated soils suggest that the soils used for prehistoric agriculture are potentially productive by modern agricultural standards.
Frequency of Fertilizer Applications and Centipedegrass Performance
Authors: Johnson B. J. , Carrow R. N.
Published: July 2010

Centipedegrass [Eremochloa ophiuroides (Munro) Hack.] is a low maintenance grass widely used throughout the southeastern United States. Improper fertilization continues to be a major concern and results in Centipedegrass decline. With low fertilization, the grass has a pale green color that is often unacceptable to many turfgrass managers. This research was initiated to determine the influence of frequency of annual fertilizer treatments on turfgrass quality. Treatments were arranged in a split plot design with frequency of annual fertilization treatments as main plots and N rates as subplots. Soil type was a Cecil sandy loam (clayey, kaolinitic, thermic Typic Hapludult). The quality of Centipedegrass treated with 50 kg N ha−1 in April and repeated at the same rate in July for a total rate of 100 kg ha−1 was equal to or better than that from a single application of 100 kg N ha−1 in April. Centipedegrass quality from split applications (April + July) was also equal to or better than that when a total of 100 kg N ha−1 was split into three or four equal applications over the growing season. The exception occurred in September in 2 of 4 yr when the quality of Centipedegrass was better when N was applied in three and four annual applications. Centipedegrass decline measured by quality and stand density occurred in plots treated with 100 kg N ha−1 in April after 3 and 4 yr of consecutive applications. Decline was not evident when N was applied annually at 100 kg ha−1 in split applications. At 0 kg N ha−1 yr−1 Centipedegrass failed to provide sufficient growth to maintain an acceptable stand. Also, after two consecutive years without N applications, centipedegrass quality declined, which indicates that some N is necessary every year.