bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of N Fertilization on Yield, Growth, and Extraction of Water by Wheat Following Soybeans and Grain Sorghum1
Authors: Sanford J. O. , Hairston J. E.
Published: July 2010

Nitrogen fertilization is an important part of wheat (Triticum aestivum L.) production. It is especially important in double‐crop wheat production because the N system is influenced by previous crop residue. Our objective was to evaluate topdressed rates of 0, 34, 68, 102, and 136 kg N ha−1 as ammonium nitrate spring‐applied to soft red winter wheat (‘Arthur’) grown in double‐cropping sequence following soybeans [Glycine max (L.) Merr] or grain sorghum [Sorghum bicolor (L.) Moench]. The soil was Okolona silty clay (a fine montmorillonitic, thermic Typic Chromudert). We also evaluated a 34 kg ha−1 rate of fall‐applied N with topdressed rates in the spring bringing total N to the same levels as the single spring‐applied topdressed rates above. The effects of previous crop on grain yield, straw yield, plant height, and N uptake were pronounced. All of these were significantly higher following soybeans. We attributed this to greater availability of N following soybeans, but have not ruled out the possibility of a phytotoxic effect associated with grain sorghum residues. There was yellowing and stunting of early wheat growth following grain sorghum across all N rates, regardless of whether fall N was applied or not. This early depression may have led to yield differences that were not completely overcome by the conditions of this study. Depletion of soil water was related to N uptake and yield. Soil moisture from anthesis throughout grain filling decreased progressively faster under wheat that received high rates of N.
Steer Performance from Two Perennial PennisetumSpecies, Switchgrass, and a Fescue—‘Coastal’ Bermudagrass System1
Authors: Burns J. C. , Mochrie R. D. , Timothy D. H.
Published: July 2010

Subtropical perennial grasses make important contributions to productive, season‐long grazing systems in the USA. The perennial bermudagrasses, particularly ‘Coastal’ bermudagrass [Cynodon dactylon(L.) Pers.], are extremely productive, but high fiber allows only poor to moderate animal performance. Steer average daily gains (ADG) and productivity estimates of the subtropical perennials flaccidgrass (Pennisetum flaccidumGriseb.), P. orientaleRich., and switchgrass (Panicum virgatumL.) were obtained. Sequential grazing of tall fescue (Festuca arundinaceaSchreb.) and Coastal as a system (F + C) served as the standard for comparison. The grazing experiment with yearling steers was conducted on a Typic Hapludult soil for 3 years. Calendar days grazed, ADG (kg) and steers ha−1, respectively, from initiation of grazing until Coastal was stocked (period 1) averaged 53, 0.93, and 15.1 for tall fescue; 20, 1.35 and 11.1 for flaccidgrass and 40,1.07, and 8.9 for switchgrass. Number of steers ha−1was greatest on tall fescue and ADG lowest (P ≤ 0.06). Flaccidgrass supported significantly more animals than switchgrass. Summer (period 2) results (avg. 98 days) for AM; and steers ha−1, respectively, were 0.43 and 25.1 for Coastal; 0.78 and 9.1 for flaccidgrass (P. orientalewas similar), and 0.92 and 7.9 for switchgrass. Steer ADG was lowest and steers ha−1highest on Coastal, while the other grasses were similar for both. Tall fescue made little contribution because rainfall was below normal all 3 years. Seasonal results from the F + C showed most calendar days (160), lowest ADG (0.59) but similar numbers of steers ha−1(9.5) compared with respective values of 130,0.90, and 9.6 for flaccidgrass and 140, 0.96 and 8.2 for switchgrass. Flaccidgrass averaged significantly more steers ha−1than switchgrass. Gain ha−1from tall fescue in period 1 (792 kg) and Coastal in period 2 (1160 kg) was greater than the average for the other grasses, 349 and 559 kg, respectively. However, seasonal computations based on combined land areas for the F + C system yielded 1010 kg of gain ha−1. That gain did not differ from the 930 kg ha−1for the other grasses, even though the F + C system averaged 25 more calendar days. Flaccidgrass and switchgrass have quality attributes and a sufficiently long growing season to make an important contribution to an animal enterprise that values large daily animal responses. Coastal is more appropriately used in enterprises for an animal class, or portion of the season, where only moderate to low response animal−1is required.
Multiple Cropping Soybean with Oats and Barley1
Authors: Kaplan S. L. , Brinkman M. A.
Published: July 2010

Multiple cropping and relay intercropping of soybean [Glycine max(L.) Merr.] with small grains was studied as an alternative cropping system or areas that are traditionally oriented towards production of feed for dairy cattle (Bosspp.). The objective was to evaluate multiple cropping of small grains harvested as forage and soybean harvested as seed in a dairy forage area of the north central United States. One oat (Avena sativaL.) cultivar, two barleys (Hordeum vulgareL.), and the soybean cv. Hodgson were grown in relay intercropping, double cropping, and sole cropping systems on a Plano silt loam soil (fine‐silty, mixed, mesic Typic Argiudoll) at Arlington, WI in 1977 and 1978. Relay intercropping systems were established by planting soybean into unthinned stands of small grains or by removing rows of small grains shortly after emergence and later planting soybean in the gaps. Double‐cropped soybean was planted after barley and oats were harvested as forage. Early soybean checks (sole cropping) were planted on the same date that relay intercropped soybean was planted, and late soybean checks were planted on the same date that: double‐cropped soybean was planted. Soybean row widths in all systems were 0.41‐, 0.75‐, and 0.90‐m. Early soybean checks were more productive than soybean relay intercropped in both thinned and unthinned stands of oats and barley, but late soybean checks were not always more productive than double‐cropped soybean. Yields of soybean relay intercropped in 0.45‐m rows were higher in thinned stands of barley and oats than in unthinned stands. Differences were not as large in wider rows. Cultivar differences in forage yield were not associated with consistent differences in yields of relay intercropped and double‐cropped soybean. The most productive cropping sequence was a double‐cropping system that had a forage yield of 4.93 Mg ha‒1and a soybean yield of 2.21 Mg ha‒1.
Leaf Production and Growth Rates of Exotic Cottons1
Authors: McMichael B. L. , Jordan W. R. , Quisenberry J. E. , Dilbeck R. E.
Published: July 2010

An understanding of the growth and development of diverse nonflowering photoperiodic (long‐night) exotic cottons (Gossypium hirsutum L.) differing in traits associated with drought tolerance is needed before this material can be fully utilized in genetic selection programs. Therefore, glasshouse studies were conducted in 1980 to relate previously observed differences in dry matter production to differences in leaf morphology and development. Ten exotic and two commercial cotton lines were investigated at Lubbock; three of the exotic cottons were also grown in another study at Lubbock and at Temple, TX. Plants were grown in a commercial growing medium in the Lubbock experiments and in an Amarillo fine sandy loam soil (fine‐loamy, mixed, thermic, Aridic Paleustalfs) in the Temple experiment. The number of mainstem nodes was counted in the first experiment at Lubbock; in the second experiment the number of mainstem leaves was counted and harvested for dry weight, and total leaf number, total number of nodes, and total leaf area were recorded at 30,44,58,72, and 86 days after planting. Similar measurements were made at 44 and 56 days after planting at Temple. Leaf initiation rates varied significantly, from 0.35 to 0.29 leaves per day, among the exotic cottons in the first experiment, and significant differences occurred between the two locations. The development of leaf area, total dry matter accumulation, rate of dry matter production per unit leaf area, leaf size and total leaf number differed significantly among strains that had similar leaf initiation rates. Observed differences between greenhouse and field‐grown plants at Lubbock indicated a strong environmental influence on the relationships between the growth parameters. Leaf area was directly correlated with dry matter production for all strains. The development of and increase in leaf area, however, was strain‐specific and depended on either increased leaf numbers or increased leaf size.
Tillage for Control of Volunteer Proso Millet and for Production of Sorghum1
Authors: Robinson Robert G.
Published: July 2010

Production of proso millet (Panicum miliaceum L.) results in volunteer plants the following year. This research was conducted to determine if primary tillage influences the population density of volunteer proso and the persistence of the volunteer problem in five subsequent crops of sorghum [Sorghum bicolor (L.) Moench]. Following proso harvest, eight tillage treatments were repeated on the same plots for 5 years on Typic Hapludoll soil at Rosemount, MN. Treatments included moldboard or chisel plowing in the fall or spring, rototilling in the spring, moldboard or chisel plowing in the fall followed by rototilling in the spring, and zero tillage. Seed production of proso and other weeds was prevented for 5 and 3 years, respectively. Proso and annual weed numbers ha−1 were determined from repeated counts made shortly after emergence in permanent 1‐m2 quadrats. Most (80%) of the total proso emergence occurred the 1st year after proso harvest, but 17, 2, and 1% occurred in the next 3 years, respectively. Although moldboard plowing gave the most 1st year control, proso was a potential major weed for 4 years following annual moldboard plowing in the fall and for only 3 years following the other tillage treatments. Most proso plants emerged in May, 10% emerged in June, and only 3% later. Moldboard plowing gave the most control of annual weeds other than proso. Highest grain sorghum yields followed moldboard plowing or rototilling in March or April or moldboard plowing in the fall followed by rototilling in April or May.
Fungicide Effects on Thatch Depth, Thatch Decomposition Rate, and Growth of Kentucky Bluegrass1
Authors: Smiley R. W. , Fowler M. Craven , Kane R. T. , Petrovic A. M. , White R. A.
Published: July 2010

Development of improved management strategies for controlling thatch on tuifgrasses is limited by an incomplete understanding of thatch biology. Mechanisms whereby fungicides cause thatch to accumulate in turfgrass were investigated, by evaluating the influences of fungicides on rates of tissue production and thatch decomposition. Fourteen fungicides, one nematicide, and five mixed‐fungicide programs were applied repeatedly (up to nine times annually), over a 4‐yr period, to a field‐grown Kentucky bluegrass (Poa pratensisL.) turf on a soil of the fine, illitic mesic family of Glossoboric Hapludalfs. Measurements were made of thatch depths, root and leaf clipping weights, shear strength of sod, and decomposition rates for thatch implanted into the turfs. Compounds that caused thatch to become deeper (p= 0.05) than in the nontreated control included benomyl, cadmium succinate, fenamiphos, iprodione, and mancozeb. Treatments in which these pesticides were used were characterized by sod shear strengths greater (p= 0.05) than in the control. Thatch accumulations were related mostly to the amounts of roots in the surface 4 cm. None of the studied fungicides significantly (p= 0.10) reduced the apparent rate of thatch decomposition. Fungicides in this study therefore appeared to induce thatchiness in Kentucky bluegrass by increasing the rates of root and rhizome production and not by reducing the rate of litter decomposition.
Nitrogen Utilization of Corn Under Minimal Tillage and Moldboard Plow Tillage. I. Four‐Year Results Using Labeled N Fertilizer on an Atlantic Coastal Plain Soil1
Authors: Meisinger J. J. , Bandel V. A. , Stanford G. , Legg J. O.
Published: July 2010

Crop responses and N uptake of corn (Zea maysL.) grown with moldboard plow tillage (PT) and minimal tillage (MT) were measured in a 4‐yr field experiment on a Mattapex silt loam soil (finesilty, mixed, mesic, Aquic Hapludult) near Salisbury, MD (Atlantic Coastal Plain region). Labeled ammonium sulfate or ammonium nitrate (15N depleted) was applied annually to the entire area (74 m2) of each plot at five N rates ranging from 0 to 180 or 270 kg N ha−1. Corn dry matter yield, N content, and isotope composition were determined in the entire plant at the 11 to 12 leaf stage and at silage harvest, as well as in the corn grain at maturity. Below 135 kg N ha−1, dry matter yields, total N uptake, and fertilizer N (FN) uptake were greater with PT than with MT, but with 180 kg N ha1−1there was either no difference between the tillage systems or MT was greater than PT. Fertilizer N additions had no consistent or practically significant effect on soil N (SN) uptake. At 135 kg N ha−1, average crop FN recoveries were 62% for PT and 53% for MT, but this difference decreased with increasing N rate until both tillage systems averaged about 53% recovery at 180 kg N ha−1. Average SN uptake was greater with PT culture than with MT culture, averaging 76 kg N ha−1and 59 kg N ha−1, respectively. The crop N requirement of corn was about 17 kg N ha−1greater for MT corn than PT corn due to a 10% greater yield of total dry matter with MT. Corn grown with MT required about 68 kg more FN ha−1than PT, due to a lower uptake of SN and a greater crop N requirement. A lower uptake of N on MT plots during the second half of the growing season suggests (i) a greater net mineralization of N on PT plots and/or (ii) a greater loss of N via leaching and/or denitrification on MT plots. A nitrogen concentration of about 11 to 12 mg N g−1in the silage total dry matter, or about 15 mg N g−1in the grain, can be used as an approximate value for N sufficiency. However, these values should be considered broad guidelines since significant deviations were observed in individual years.
Tillage for Sunflower Control and for Annual Canarygrass and Fieldbean Production1
Authors: Robinson Robert G.
Published: July 2010

Sunflower (Helianthus annuusL.) is a major weed in crops that follow sunflower. This research measured the population density of volunteer sunflower and performance of annual canarygrass (Phalaris canariensisL.) and fieldbean (Phaseolus vulgarisL.) following tillage treatments of moldboard plowing, chisel plowing, rototilling, or zero tillage repeated on the same plots for 5 yr. Tillage plots, on Typic Hapludoll soil at Rosemount, MN, were divided into subplots of annual canarygrass planted between 26 March and 30 April and fieldbean planted between 21 and 25 May. Less than 1% of the volunteer sunflower achenes survived more than 1 yr in the soil, but tillage and planting date determined whether sunflower remained an important weed for 0,1, 2, or 3 yr. Sunflower was a major weed the first year after sunflower; however, the problem could be avoided by planting after mid‐June in soil not tilled in the fall. Moldboard plowing, which buried 82% of the achenes over 10 cm deep, gave the best but not adequate control the first year. Zero tillage or chisel plowing in the spring eliminated sunflower as an important weed after 1 yr, regardless of planting date. Chisel plowing in the fall or moldboard plowing in the spring tended to prolong the sunflower problem beyond 2 yr. Weed control in both crops was poorest following zero tillage. Moldboard or chisel plowing in the spring resulted in highest average yields of fieldbean. Highest yields of canarygrass followed moldboard plowing.
Nodulation of Dry Beans by Commercial and Indigenous Strains of Rhizobium phaseoli1
Authors: Weiser G. C. , Grafton K. F. , Berryhill D. L.
Published: July 2010

Successful nodulation and seed yield increase of dry bean (Phuseolus vulgarisL.) is not often observed after inoculation with Rhizobium phaseoliin the bean production region of North Dakota and Minnesota. A 2‐yr field study was conducted to assess nodulation by indigenous soil strains and commercial strains 127K12b, 127K44, and 127K81‐3 of R. phaseoliin the dry bean cultivars ‘Fleetwood’, ‘Pindak’, ‘UI‐114’, and ‘Upland’. Inoculation with the commercial strains, compared with uninoculated controls, did not increase seed yield; however, nodule number and nodule fresh weight were influenced. Strain 127K12b produced more nodules, more total nodule tissue, and larger nodules than other commercial or indigenous strains. The cultivar UI‐114 had more nodules, total nodule tissue, and larger nodules regardless of inoculum sources. The effect of individual inoculum strains did not vary between years, but was cultivar‐specific for nodule characteristics. Inoculation with commercial strains resulted in significantly greater nodule numbers, nodule tissue, and larger nodules relative to indigenous soil strains.
Uniform Travel Speed for Manually Propelled Sprayers and Spreaders1
Authors: Wolf D. D. , Edmisten K. L.
Published: July 2010

Accurate application of solutions from sprayers and of granules from spinner spreaders requires a known constant speed of travel. Use of a commercially available pocket‐size audio metronome is described to aid the operator in maintaining a desired speed. The metronome was powered by a 9‐V battery and was carried in a shirt pocket. The tempo of the metronome was adjusted so that the operator traversed a known course length in a specified time period. For example, 24 s to traverse 26.8 m would be equivalent to 4 km h−1. The tempo set by the metronome varied depending on the stride length of the operator. Coefficient of variation with metronome pacing was 1.7% and without the metronome was 3.7%. A method for calibrating walking speeds using a metronome is described.
Critical Evaporative Demands for Differential Stomatal Action in Peanut Grown in Narrow and Wide Row Spacings1
Authors: Erickson P. I. , Stone J. F. , Garton J. E.
Published: July 2010

Induced stomatal closure behavior of irrigated peanut (Arachis hypogeaeL. cv. Comet, a bunch type) as related to row spacing and evaporative demand has been previously demonstrated as real and repeatable. The objective of this research was to determine the magnitude of evaporative demand that induced stomatal closure in narrow‐row plantings. Stomates in wide rows tended to show far less closure on the same days. The differences were not noted on days with low evaporative demand. Concurrent measurements of net radiation, dry‐ and wet‐bulb temperature, and horizontal wind velocity were made every 15 min. Estimates of environmental evaporative demand were made. No distinct peak or cumulative evaporative demand levels were found that separated stomatal differential action days from nonaction days. However, analysis of the cumulative advective energy component of cumulative evaporative demand showed a threshold above which stomatal closure responses were noted. This threshold was 8.5 MJ m−2. Further detailed analysis of the factors involved in the cumulative advective energy component indicated stomatal closure was dominated by neither horizontal wind velocity, integrated over time, nor integrated vapor pressure deficit.
Planting Season and Harvest Date Effects on Dry Matter Production and Nutritional Value of Brassicaspp. in the Southern Great Plains1
Authors: Rao S. C. , Horn F. P.
Published: July 2010

Brassicaspp. may serve as high‐quality forage crops in parts of the Southern Great Plains when most warm‐ and cool‐season forages are unproductive. Field studies were conducted to assess the forage (shoot and/or root) yields, crude protein (CP), and digestibility (IVDMD) of turnip root crops (Brassica rapaL., ‘Purpletop’, ‘Cyclon’, ‘Frisia ’, and ‘Tyfon’; a Chinese cabbage × stubble turnip hybrid) and leafy‐stem crops [‘Winfred’ rape (B. napusL.) and ‘Merlin’ kale (B. oleruceaL.)] at different harvest dates. All six Brassicaswere established on a Dale silt loam soil (fine‐silty, mixed, thermic, Pachic Haplustoll) in September 1982 and 1983 (fall) and March 1983 and 1984 (spring) under dryland conditions. Shoot dry matter (DM) production for root crop cultivars was highest 85 and 95 days after planting in fall and spring, respectively. The greatest total plant DM yield was produced by Cyclon in the fall and Purpletop in the spring (7.4 and 7.6 Mg ha−1, respectively). Cyclon and Tyfon produced 0.7 Mg ha−1more shoot DM, whereas Purpletop and Frisia produced 0.4 to 0.9 Mg ha−1more root DM during their maximum DM production period. In early harvests, DM yields of kale were less than those of rape, but after 90 days growth, yields were similar (7.0 Mg ha−1). Shoot CP levels of root crops averaged 220 g kg−1and were about 25 to 60 g kg−1greater than root levels. The IVDMD of mots ranged from 670 to 840 g kg−1and were approximately 60 to 120 g kg−1higher than values for shoots. Levels of DM, CP, and IVDMD for all cultivars were similar or better in fall growing season and did not decline as rapidly compared with spring. Cyclon and Purpletop have the potential to provide high yields of high‐quality forage during the forage deficit periods of Southern Great Plains.
Experimental Test of a Model of Water Uptake by Soybean1
Authors: Radcliffe D. E. , Phillips R. E. , Egli D. B. , Meckel L.
Published: July 2010

Mechanistic models of soil water uptake have differed in the form of the water uptake term of Richard's equation. One of the most widely used uptake terms is that proposed by Hillel et al., although a detailed study comparing predicted soil water contents with those observed experimentally has been lacking. The purpose of this work was to develop a model that would test the accuracy of this water uptake term on a seasonal basis at various levels of water stress. Simulated soil water contents were compared with water contents observed biweekly in a 3‐yr field experiment that included three moisture treatments: irrigated, normal rainfall, and plastic covered. When a longitudinal resistance was included, 69 to 88% of the predicted soil water contents fell within the 95% confidence limits of the observed values from the irrigated and normal rainfall treatments in 3 yr. In the plastic‐covered treatment, however, only 17 to 49% of the predicted water contents were within the confidence limits. We conclude that the uptake term is accurate under normal and well watered conditions, but not under severe water‐stress conditions. Sensitivity analysis showed that the model was sensitive to net radiation, LAI, and rainfall and insensitive to hydraulic conductivity and root density.
A Compact Continuous Flow and Constant Level Solution Culture Renewal System1
Authors: Callahan L. M. , Engel R. E.
Published: July 2010

Researchers need a practical, compact, and versatile continuous flow and constantly renewed nutrient culture system. Therefore, such a system for plant growth in nutrient culture was developed and tested. Numerous individual culture jars can be supported by a single solution reservoir and distributor jar. Solution flow throughout the system is automatic with only the reservoir unit needing manual replacement or resupply. The level of solution in culture jars can be fixed easily and maintained rellably by adjustment of the air inlet tube in the reservoir jar. Each culture jar can be regulated for drainage and aeration. A compact aeration system adapts to the entire unit.
Mobilization of Nitrogen‐15 from Vegetative to Reproductive Tissue of Peanut1
Authors: Kvien C. S. , Weaver R. W. , Pallas J. E.
Published: July 2010

A field experiment was conducted to gain a greater understanding of vegetative N mobilization in the peanut (Arachis hypogaea L.) during the pod filling period. Vegetative tissue was labeled with foliarly applied 15NH4SO4 prior to initial pod set and mobilization of the incorporated 15N into various plant parts was then followed from initial pod set until harvest. We concluded from our analysis of individual plant parts that a portion of the 15N label moved out of all vegetative plant parts. Nitrogen concentration (g N kg−1 plant tissue) and 15N enrichment in the vegetative portion of both ‘Florunner’ and ‘Tamnut 74’ declined continuously until the optimum harvest date. The decline of 15N enrichment in the foliage over time was matched by a continuous increase in 15N by the developing fruit.
Photoperiod Effect before and after Flowering on Branch Development in Determinate Soybean1
Authors: Board J. E. , Settimi J. R.
Published: July 2010

Previous research indicated that restricted branch development was a factor associated with soybean [Glycine max (L.) Merr.] seed yield reductions at late planting dates in the southeastern United States. The present studies were conducted to outline the progress of branch development at different planting dates and to determine the role of photoperiod in branch restriction at late planting dates. In field studies, eight cultivars were planted at early April (nonoptimal), mid‐May (optimal), and mid‐June (nonoptimal) planting dates in 1982 and 1983 at Baton Rouge, LA (30°N Lat), on an Olivier silt loam (fine‐silty, mixed, thermic Aquic Fraguidalf) soil. Plants were sampled throughout the season for total branch length and number of branches. Photoperiod studies were conducted at the Phytotron, North Carolina State University, Raleigh, NC. Plants were subjected to combinations of preflowering and postflowering daylength simulations of optimal and late planting dates to determine photoperiod effects on branch development. Field results demonstrated that approximately two‐thirds of total branch length and number of branches were produced between growth stages R1 and R5 and that the period from R1 to R5 declined with each delay in planting. Reduced total branch length and number of branches at late planting dates were associated with fewer days from R1 to R5, while reduction at early planting dates occurred because of short plants. Data from the photoperiod study showed that shorter R1 to R5 period and the associated reduction in branch number, total branch length, and branch node number were photoperiodically induced phenomena. Both preflowering and postflowering daylength regimes at a late planting date were involved in these events.
Phaseolus vulgaris Growth in an Ammonium‐Based Nutrient Solution with Variable Calcium1
Authors: Fenn L. B. , Taylor R. M. , Horst G. L.
Published: July 2010

Field observations of tests where Ca was added with urea fertilizers have suggested a synergistic effect on plant growth beyond that expected from Ca control of NH3 volatilization and the nutritive effect of Ca. A study was designed to test the hypothesis that Ca stimulates NH4 absorption by plants. Greenhouse experiments were conducted with Phaseolus vulgaris (Great White Northern bean) in quartz sand with 5% CaCO3 to determine the effects of variable Ca concentration on plant growth in an NH4‐based nutrient solution. Ammonium absorption increased with increasing Ca to 13 mmol L−1, as indicated by decreasing NH4 concentration in the leachate, and increased plant growth. Tissue N was unchanged as solution Ca concentration increased. Potassium accumulation in the plant behaved much like N, whereas the Ca level increased with increasing solution Ca concentrations.
Seedling Vigor of Selected Alysicarpus Accessions1
Authors: Taylor S. G. , Baltensperger D. D.
Published: July 2010

Alyceclover [Alysicarpus vaginalis (L.) DC.] is a tropical legume considered to have poor seedling vigor. This characteristic often leads to difficulties in establishing new pastures. Ten Alysicarpus breeding lines were evaluated for early seedling growth and compared to common alyceclover. Field experiments in 1984 and 1985 at Gainesville, FL, on Arredondo fine sand (loamy, siliceous, hyperthermic Grossarenic Paleudult) detected a high degree of variation among genotypes for seedling vigor as measured by mean plant dry weights 3 and 6 weeks after planting. One line, FL‐3, was consistently more vigorous than common alyceclover. Several other lines (FL‐1, FL‐2, FL‐5, FL‐6, and FL‐11) were equal to or slightly less vigorous than the common type. Four lines (FL‐4, FL‐7, FL‐9, and FL‐10) had an unacceptable level of vigor. Within this collection of germplasm, there was a high correlation between seed weight and plant weight (r = 0.62 – 0.79). Visual ratings of seedling vigor taken 4 days after germination were also highly correlated with plant weights (r = 0.57 – 0.93). Seed weights and visual seedling vigor ratings may be useful characteristics for preliminary screening in future work. Broad‐sense heritabilities for plant dry weights were high (68–77%), indicating that seedling vigor may be under the control of genetic systems. It is suggested that improvement of alyceclover seedling vigor could be made via selection.
Electrical Conductivity as a Measure of Planting Seed Quality in Cotton1
Authors: Hopper N. W. , Hinton H. R.
Published: July 2010

Determining planting seed quality generally involves conducting a standard germination test or a tetrazolium test. The development of the Automatic Seed Analyzer (ASA‐610) has renewed interest in using electrical conductivity (EC) as a measure of seed viability. The purposes of this study were: (i) to evaluate the ASA‐610 in measuring the EC of various salt solutions, and (ii) to evaluate the ASA‐610 in assessing the planting seed quality of cottonseeds (Gossypium hirsutum L.). The EC of four sodium chloride solutions (10, 100, 500, and 1000 mg L−1) was measured at 10,20, and 30°C using the ASA‐610 and a Barnstead conductivity bridge (BCB). The BCB EC increased linearly as the salt concentration was increased at each of the temperatures. A linear increase in the EC was noted also with increased salt concentrations using the ASA‐610. In Exp. 1, the EC values, as indicated by the ASA‐610, of 15 cultivars increased as the seed soak time increased from 0.5 to 24 h. The best prediction of the planting seed quality resulted from soaking the seeds for 16 h and using 55 µA as the partition value (germination test values for 11 of the 15 cultivars predicted to within 10 percentage units). In Exp. 2, nine seed lots of marginal quality were evaluated using the ASA‐610 after soaking the seed for 16, 20, and 24 h. The best estimate of the standard germination resulted from soaking seeds for 20 h and using a partition value of 33 µA (germination predicted to within 10 percentage units for five of nine seed lots). The lack of consistency in selecting a unique partition value between the two studies would indicate difficulty in accurately assessing planting seed quality of cotton using the ASA‐610.
Relationship between Alkaline Mineral Concentration and Rate of pH Decline in Ensiled Greenhouse‐Grown Alfalfa1
Authors: Shockey W. L. , Barta A. L.
Published: July 2010

Alkaline minerals present in forage may form salts with fermentation end products during the ensiling process, thus slowing the rate of pH decline. For legumes, which have high concentrations of alkaline minerals, excessive degradation of plant protein might occur because of extended duration of proteolytic enzyme activity. This hypothesis was examined by fertilizing greenhouse‐grown alfalfa (Medicago sativa L.) so that the concentrations of the alkaline minerals, K, Mg, and Ca, varied. Stepwise regression techniques were used on data from 11 cuttings to relate mineral composition, lactic acid buffering capacity, initial pH, and percentage dry matter of green herbage to the rate of pH decline of the resulting silage. Results indicated that the rate of pH decline of alfalfa was significantly, but weakly, correlated to its alkaline mineral concentration. Unexpectedly, higher concentration of water soluble K and water soluble Ca resulted in increased rate of pH decline. The cause for this response is not known but may be related to specific effects of mineral concentration or content on microbial activity or mineral induced changes in levels of carbohydrates, soluble N, or other plant components that may strongly affect microbial activity and fermentation rate.
Cotton Response to Bud and Boll Removal1
Authors: Ungar E. D. , Wallach D. , Kletter E.
Published: July 2010

The compensation capacity of upland cotton (Gossypium hirsutum L.) for loss of fruiting bodies can be exploited in pest control management where environmental conditions permit some delay in yield. Three experiments were conducted on a clayey, montmorillonitic, calcareous, thermic Typic Chromoxerert, in a region with a growing season of 210 days. The first experiment investigated crop response to removal of different classes of fruiting bodies at different times. The second and third experiments tested the hypothesis that compensation for late‐season boll removal is enhanced when preceded by early season removal of squares. Removal of 120 squares/m2 over 2 weeks, 200 small squares/m2 over 4 weeks, or 60 small bolls/m2 over 2 weeks did not significantly reduce yield. Removal of 60 large bolls/m2 over 2 weeks or 30 large bolls/m2 on a single date significantly reduced final yield to between 56 and 85% of the control yield. Removal of 120 squares/m2 in combination with the late removal of 30 large bolls/m2 yielded 94% (NS) of the control yield when squares were removed early and 79% of the control yield when squares were removed late. The degree of compensation in the combination damage treatments was related to the extent to which the growth pattern of the crop was delayed by square removal. Early square removal delayed flowering cutout so that the plants were still producing flowers when the large bolls were removed. The effect of damage depended on the state of the crop, which then should be taken into account in determining pest control strategy.
Conservation and Aerobic Stability of Forage and Sweet Sorghum Silages Treated with Acrylic or Caproic Acid1
Authors: Hill N. S. , Posler G. L. , Bolsen K. K. , Ware G. O.
Published: July 2010

Application of formic acid to alfalfa (Medicago sativa L.) or corn (Zea mays L.) at harvest can increase fermentation and lactic acid production during ensiling. By increasing fermentation of the silage mass, potentially more energy can be lost from formic acid applications. Acrylic and caproic acids are effective microbial inhibitors and may be effective at lower concentrations than formic acid, this study was designed to determine the effectiveness of acrylic or caproic acids applied to ‘Rio’ and ‘Dale’ sweet sorghums [Sorghum bicolor (L.) Moench] and DeKalb ‘FS25A’ forage sorghum herbage to conserve sugars in silage and during aerobic exposure. Crops were harvested at black layer stage with a forage chopper and treated with 0, 0.5, 1.0,1.5, 2.0, 2.5, or 5.0 g kg−1 of acrylic or caproic acid. Sugar conservation was evaluated after 130‐days ensiling. Sugar conservation was greatest in Rio and FS25A silages. Caproic acid treatments resulted in lower sugar conservation in Dale and FS25A silages. Aerobic stability was measured by monitoring heat production from spoilage during 10‐days exposure following ensiling. Application of acrylic acid delayed heating in Rio but gave erratic responses in Dale and FS25A silages when exposed to air. Caproic acid treatments delayed heating at all rates in all silages. Silages that were thermally stable had greater sugar recovery at the end of the aerobic exposure.
Nitrogen Fixation Capacity of Field‐Grown Bean Compared to Other Grain Legumes1
Authors: Piha M. I. , Munns D. N.
Published: July 2010

The generally poor symbiotic performance of field‐grown bean (Phaseolus vulgaris L.) has been attributed to difficulty in establishing effective symbiosis and to genetic variability in N‐fixation capacity. The ontogeny of N accumulation by symbiotic and N‐fertilized common bean selected for high N‐fixation potential was compared to commercial bean varieties, cowpea [ Vigna unguiculata (L.) Walp.], and soybean [Glycine max, (L.) Merr.] in a N‐deficient field (Reiff sandy loam, Typic Xerorthent). Cowpea and Soybean accumulated N to higher levels and at faster rates than did common bean, whether symbiotic or N‐fertilized. Relative N accumulation (N accumulation in symbiotic plants relative to that in fertilized plants) during vegetative growth was highest for cowpea, intermediate for soybean and late maturing bean, and lowest for early maturing commercial bean varieties. Relative N accumulation during the late growth stages was always higher than in the early stages. Absolute rates of N accumulation declined after flowering in both symbiotic and N‐fertilized plants. Early maturing bean and cowpea reached physiological maturity at the same time, but bean accumulated more of its N during early development and had a shorter vegetative growth period. Despite weak vegetative N‐fixation capacity, some late maturing bean cultivars achieved similar final harvest N accumulation and seed yield whether they were N‐fertilized or not.
Nitrogen Fertilizer Effects on Uptake and Partitioning of Chloride in Sugarbeet Plants1
Authors: Moraghan J. T.
Published: July 2010

Knowledge of factors affecting availability of soil Cl− in cropping systems is needed. Sugarbeet (Beta vulgaris L.), a crop commonly treated with N fertilizer, can accumulate large quantities of Cl−. The influence of urea‐N (0, 56, 112, 168, and 224 kg N ha−1) on growth and Cl− accumulation by tops and storage roots of sugarbeet was studied at five dryland sites in the Red River Valley. The soils at all sites were Calciaquolls and contained from 59 to 329 kg Cl− ha−1 and 50 to 100 kg NO−3−N ha−1 in the top 1.20 m. Nitrogen fertilizer significantly increased yield of tops at all sites, and yields of roots and recoverable sugar at three sites. There was no tendency for N fertilizer to suppress uptake of plant Cl−, even though petiole analysis suggested that much of the added N entered the plant in the NO−3 form. The quantities of Cl− present in tops plus storage roots at the final harvest ranged from 54 to 246 kg Cl− ha−1 for sugarbeet grown with 224 kg N ha−1; the corresponding values for unfertilized sugarbeet were 35 to 167 kg Cl− ha−1. Most of this plant Cl−, 28 to 148 kg Cl− ha−1 and 46 to 226 kg Cl− ha−1 for the unfertilized and N‐fertilized (224 kg N ha−1) sugarbeet, respectively, was located in the tops, which are left in the fields. Consequently, a sugarbeet crop, especially when treated with N fertilizer, can result in considerable redistribution of Cl− within soil profiles, and through this redistribution possibly affect the growth of subsequent crops.
Yield Compensation for Stand Deficiencies by Determinate and Indeterminate Growth‐Habit Soybean
Authors: Pepper G. E. , Walker J. T.
Published: July 2010

Soybean [Glycine max (L.) Merr.] stands that emerge poorly are often replanted without taking into consideration the yield compensating ability of the plant in the field. This study was done to determine if compensation for yield in deficient soybean stands is influenced by the growth habit (determinate versus indeterminate). Gaps imposed at or before stage V2 were used to generate stand deficiencies. Compensation for yield in stands having gaps of fixed sizes was measured in the indeterminate cultivar Cumberland and the determinate cultivars Gnome, Sprite, and Pixie in 1981 and 1982. Three seeding dates were used in trials conducted on a Flanagan silt loam (Aquic Argiudoll) at Urbana, IL, and on a Cisne silt loam (Mollic Albaqualf) at Brownstown, IL. Compensation in yield for missing plants was found in both the rows with gaps and in adjacent full rows. Grain yields in gapped rows, having stand reductions equal to 63%, averaged 1614 kg/ha, or 55% of the control plot yield of 2923 kg/ha. Yields in adjacent full rows increased as much as 19% in response to the 63% stand reduction in gapped rows. In 1983, the determinate cultivar Sprite and the indeterminate, Asgrow A3127, were compared under farm field conditions where random gaps of various size were imposed as treatments. A single timely seeding was used. High levels of yield compensation for missing plants were again measured. Grain yields resulting from 60% stand reductions were only 25% less than those of full stands. Analysis of variance was used to evaluate gap x cultivar responses. The lack of a cultivar × gap interaction found in the analysis of variance suggested compensation for irregular or gap‐filled stands was not influenced by the growth habit of the soybean.
Effect of Calcium Source and Application Method on Potato Yield and Cation Composition
Authors: Simmons K. E. , Kelling K. A. , Wolkowski R. P. , Kelman A.
Published: July 2010

Calcium applications to low Ca, sandy soils can improve potato (Solanum tuberosum L.) grade and USlA size grade, and these improvements are significantly correlated with increased periderm Ca concentrations. This study evaluated the effectiveness of several Ca sources (pelleted CaSO4, granulated CaSO4, sieved CaSO4, dolomitic lime, triple superphosphate, or CaCl2), methods of application (broadcast, sidedress, and preplant strip), and rates (84–336 kg Ca ha−1) on increasing tuber Ca on two irrigated loamy sands (Typic Udipsamments) in Wisconsin from 1983 to 1985. The addition of Ca increased the percent of grade USlA tubers, the yield of prime size (<170–370 g) USlA tubers, and periderm Ca concentrations. It also reduced the percent of USlB or cull tubers, the yield of small (170 g) USlA tubers, and the concentration of periderm Mg. Improvements of grade USlA tubers ranged from 3 to l0%, and yield of USlA prime tubers was increased from 2 to 10 Mg ha−1. Dolomitic lime, triple superphosphate, and CaCl2 did not consistently improve tuber yield or grade, whereas CaSO4 in any of the forms applied was an effective Ca source. In 1985, a vertical cross‐section of the potato hill was sampled to determine the distribution of exchangeable Ca in the hill for each application method. The accumulation and uptake of Ca in the plant tops and in tuber periderm and medullar tissue for an untreated control and each application method were determined at several times during the season. The preplant strip method concentrated more material in the central portion of the potato hill where the tubers formed, and increased Ca uptake in both periderm and medullar tissue compared to the sidedress and broadcast treatments. Calcium concentration and uptake in the plant tops was not affected by any method of Ca application. Total Ca uptake averaged 8.5 and 32.9 kg Ca ha−1 in the tuber and plant tops, respectively.
Nitrogen Fertilization of Spring Wheat Genotypes: Influence on Root Growth and Soil Water Depletion
Authors: Comfort S. D. , Malzer G. L. , Busch R. H.
Published: July 2010

Root distribution within a soil profile affects the extent and depth of N and soil water utilization by a plant. We determined the effects of N fertilization on spring wheat (Triticum aestivum L.) root growth and soil water use, and determined if genotypic differences existed in root growth and soil water use in response to N fertilization. Eight genotypes (G) of hard red spring wheat were grown under three N fertilizer rates (0, 67, 134 kg N ha−1) at two locations in western Minnesota in 1982 and 1983. Major soil types were a Wheatville silt loam (coarse‐silty over clayey, frigid Aeric Calciaquoll) and a Forman clay loam (fine‐loamy, mixed Udic Argiboroll). Root sampies were obtained from all genotypes at the soft‐dough growth state in 15‐cm increments to a depth of 120 cm. Soil water use was determined weekly by neutron attenuation during the growing season on three genotypes in 1982 and five genotypes in 1983. Although a significant N × G interaction occurred for root length, certain similarities existed among genotypes. Root length was significantly (a = 0.05) increased in the top 30 cm by applying 67 kg N ha−1 but remained the same or decreased at 134 kg N ha−1. Below the 30‐cm depth, 134 kg N ha−1 generally suppressed root growth more than the 0 and 67 kg N ha−1 rates. Genotypes did not differ in total amount of available soil water (0 to 120 cm) used, but differences in depths from which soil water was extracted were observed in response to N fertilization. Depth of soil water use and root growth were influenced by N fertilization rates for some genotypes. We suggest that high rates of N fertilization may inhibit deeper root growth and hence decrease the potential use of deeper soil NO3 and water reserves.
Planting Date and Temperature Effects on Germination, Emergence, and Seed Yield of Chickpea
Authors: Auld D. L. , Bettis B. L. , Crock J. E. , Kephart K. D.
Published: July 2010

Commercial production of chickpea (Cicer arietinum L.) in the Palouse region of northern Idaho and eastern Washington was initiated in 1981. Since the cool springs and short growing season of this area limit the adaptation of chickpea, field and laboratory studies evaluating 10 chickpea lines were conducted to optimize the planting date of this new pulse crop. Laboratory germination and radicle elongation of the 10 lines at 5, 13, and 20 °C were compared to field emergence and seedling growth at Moscow, ID, on a Palouse silt loam (fine‐silty, mixed, mesic Pachic Ultic Haploxeroll) during 1982 and 1984. The 10 lines were also planted in late April, early May, and late May to determine the effect of planting date on yield components and seed yield. Greatest germination and radicle elongation of all 10 lines occurred at 20 °C. At 5 °C, less than half of the seed germinated within 7 d, and radicle elongation was less than 4% of that observed at 20 °C. The 10 lines did not differ in their ability to germinate under cold conditions in the laboratory. Under field conditions of 1984, the Desi lines with pigmented testa showed a higher percentage of emergence than the non‐pigmented Kabuli lines. Seedling dry weight accumulation was most rapid in the large seeded Kabuli seedlings and slowest in the smaller seeded Desi seedlings. Planting in late April produced higher seed yields than planting in late May (34 and 5% in 1982 and 1984, respectively). However, seedling emergence was slower at the early planting date. These results indicate that chickpea grown in areas with cool climates such as northern Idaho should be planted in the early spring when average soil temperatures exceed 13 °C to insure optimum seed yield.
Responses of Maize to Plant Population Density. II. Reproductive Development, Yield, and Yield Adjustments
Authors: Tetio‐Kagho F. , Gardner F. P.
Published: July 2010

Plant population density (PPD) exerts a strong influence on maize (Zea mays L.) growth and grain yield. Most PPD studies have usually confounded plant number with spatial arrangement, since row width remained constant and only spacing between plants in row was varied. This study used a systematic design (fan) to observe the effect of 15 PPD (0.8∓15.4 plants m−2) on maize reproductive growth in constant spatial arrangement on Lake fine sand (hyperthermic, coated Typic Quartzipsamments) at Gainesville, FL (29°38'N), in 1985 and 1986. All plants produced at least one ear over the 15 PPD range. Ear 2 and Ear 3 were lost at 4.3 and 2.8 plants m−2, respectively The kernel row number per ear (KRNE), kernel number per ear row (KNER), and kernel number per ear (KNE) were influenced by PPD and differed (P < 0.05) among ears (Ear 1 > Ear 2 > Ear 3). Mean kernel weight (WK) was unaffected by PPD. Yield component vulnerability due to PPD for three‐ear plants was: KNE and KNER > ear number per plant (ENP) > KRNE > WK. Kernel, stalk, and total dry matter yield per plant decreased reciprocally with increasing PPD. Kernel yield per land area increased parabolically up to a maximum yield of 1080 g m−2 at about 10.0 plants m−2, whereas stalk and total dry matter yield increased asymptotically up to 12.5 plants m−2. Shelling percentage was constant with inceasing PPD, but harvest index decerased, though not significantly. We conclude that as PPD pressure is gradually removed over a wide PPD range, yield is adjusted in prolific maize hybrids first by KNE and KNER, followed by ENP, KRNE, and WK, which remained relatively stable.