bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Mineral Nutrition on Chemical Composition and Early Reproductive Development of Virginia Type Peanuts (Arachis hypogaea L.)1
Authors: Nicholaides J. J. , Cox F. R.
Published: July 2010

Two nutrient solution studies, one involving levels of N, P, and S and the other involving levels of Ca, Mg, and K were conducted to determine the effect of mineral nutrition on the chemical composition and early reproductive development of a Virginia type peanut plant. None of the treatments significantly hastened time until flowering. Total flowers per plant were increased by increasing the N and Mg levels. Flowers per day per plant were affected similarly by the N treatments. Total pegs per plant were greatest with the medium P and low Ca treatments.

In order to determine whether present fertilization practices have been producing the nutrient concentrations in peanut plants that would result in the maximum rate of early reproductive development, nutrient concentrations in the plants which produced the maximum early flowering and peg development in the greenhouse were compared with those of field‐grown Virginia type peanut plants at a comparable stage of growth. The N and Ca concentrations in the peanut plants that had produced the maximum early reproductive development in the greenhouse were considerably lower than those of the field‐grown peanut plants, while the P and Mg concentrations were higher than those found in the field‐grown peanut plants.
Dry Matter Accumulation in Eight Soybean (Glycine max (L.) Merrill) Varieties1
Authors: Hanway J. J. , Weber C. R.
Published: July 2010

Dry matter accumulation in different plant parts of eight soybean (Glycine max (L.) Merrill) varieties was determined at developmental stages of growth during two growing seasons. Within varieties, rates of dry matter accumulation in different plant parts were similar in both years. From stages 5 to 9, daily rates of dry matter accumulation in the plant varied among varieties from 88 to 149 kg/ha/day. The rate of dry matter accumulation in seeds of all varieties, however, was similar at 99 kg/ha/day from 30 days after stage 5 to stage 10. Pods of all varieties increased in weight at a rate of 51 kg/ha/day from 20 days after stage 5 to stage 8. The rate of leaf fall was similar for all varieties, but time of leaf fall varied among varieties.
Effect of Branch Removal and Plant Populations at Equidistant Spacings on Yield and Light Use Efficiency of Soybean Canopies1
Authors: Beuerlein J. E. , Pendleton J. W. , Bauer M. E. , Ghorashy S. R.
Published: July 2010

The effects of branch removal and three equidistant plant spacings on yield and light penetration of canopies of ‘Wayne’ soybeans (Glycine max L. Merr.) were studied at Urbana, Illinois. Newly formed branches were removed from plants grown in equidistant spacings of 25, 30, and 35 cm. Plots were highly fertilized and irrigated throughout the growing season.

Seed yields increased with increased spacing of normal plants but decreased with increased spacing of plants without branches. A population (155,000 plants/ha) of plants without branches produced the greatest yield (4,397 kg/ha or 65.5 bu/acre). Plant height, lodging, stem weight and leaf area were greater in plants with branches than in plants without branches. Seed weight, leaf efficiency and leaf density were greater in plants without branches.
Field Measurement of Pan Evaporation1
Authors: Sims James R. , Jackson G. D.
Published: July 2010

An inexpensive method for measuring pan evaporation at off‐station sites was developed. Evaporation measured by the new method was significantly correlated (1% level) with evaporation measured with a standard U.S. Weather Bureau class A evaporation pan.
Turbulent Transport and Energy Balance as Affected by a Windbreak in an Irrigated Sugar Beet (Beta vulgaris) Field1
Authors: Brown K. W. , Rosenberg Norman J.
Published: July 2010

Turbulent exchange coefficients for sugar beets sheltered by corn windbreaks and unsheltered were calculated by means of an energy balance. Occasionally measurements were made within the boundary layer characteristic of the underlying surfaces at four locations in shelter and in the open field. At such times the coefficients were 25% lower on the average in the sheltered area. These results agree with the few available reports on this subject.

Decreased exchange coefficient in the sheltered area acts to suppress the transport of sensible heat. The suppression of upward sensible heat transport in a Great Plains irrigated valley during the morning results in an increase in energy available for consumption as latent heat. During the afternoon, however, when sensible heat is advected to the crop, latent heat flux is lower in the sheltered crop than in the open field. Thus the total daily latent heat flux may be the same in both plots. The sheltered crop is subjected to a reduced evaporative demand, however, during periods when water stress is most likely.
A Biological Method for Evaluating Soil Nitrogen Availability and Forecasting Nitrogen Fertilizer Needs of Wheat1
Authors: Amir J. , Ephrat J.
Published: July 2010

A biological method for evaluating N availability and forecasting N fertilizer needs of wheat (Triticum aestivum L.) is proposed.

Spring wheat plants were grown in containers with 8 kg of soil from the field under consideration. Total N uptake, as determined 60 days after sowing (at the beginning of heading), indicated the potential response of the wheat crop in the field. The test of the method's suitability for practical use was based on the response of the wheat crop to N application in the field.

The total N (in milligrams) taken up by the test plants was designated as the nitrogen index of the soil (NI). On the mineral loess soils of the semi‐arid Israeli Negev, wheat responded significantly to N fertilization only in fields with NI lower than 100.
Accumulation of N, P, and K by Soybean (Glycine max (L.) Merrill) Plants1
Authors: Hanway J. J. , Weber C. R.
Published: July 2010

Effects were studied of fertilizer applications for nodulating and non‐nodulating soybeans and of varieties on the amounts of N, P, and K accumulated in aboveground plant parts of soybeans at successive stages of plant development. Total accumulation of N, P, and K in the plants followed patterns similar to that of drymatter accumulation. Rates of accumulation were slow early in the season, but became rapid, and the nutrients accumulated at constant daily rates between stages 5 and 9. Approximately 79% of the total accumulation of these nutrients occurred during the 46‐day period between stages 5 and 9. Approximately half of the N, P, and K in the mature seeds were translocated from other plant parts, and the remaining half taken up from the soil and nodules during seed development. Fertilizer applications increased the amounts of N, P, and K accumulated by the plants. Nutrient accumulation was similar in 8 varieties.
Calcium Translocation in the Peanut (Arachis hypogaea L.)1
Authors: Skelton B. J. , Shear G. M.
Published: July 2010

Fruiting peanut plants (Arachis hypogaea L.) were grown in pots of soil with some roots extending through the drainage hole into jars of water. Supplying 45Ca to the water in these jars for 2 to 4 days resulted in calcium uptake and translocation primarily to the vegetative portions of the plants, as measured by autoradiographs. When fruit of plants, having 45Ca supplied as described above, were lifted from the fruiting medium and exposed to the atmosphere to promote water loss from transpiration, radioactive calcium moved readily into them, while only traces of 45Ca were detected in fruit remaining in the soil.

Peanut plants were grown so that the fruiting medium, consisting of nutrient free sand, was isolated from the rooting medium to study the effects on fruit development of varying water and calcium in the fruiting zone. Omission of water or intermittent watering of the fruiting medium resulted in an increased percentage of dead gynophores (pegs or fruiting stalks). Omission of calcium and/or water decreased the percentage of fruit containing seed, and also reduced the number of two‐segmented fruit. Calcium content of both pericarp and seed was decreased by omitting calcium and/water from the fruiting medium. Intermittent drying of a calcium‐free fruiting medium did not result in an increased movement of calcium into the fruit from the vegetative part of the plant, as compared with fruit in a continually moist calcium‐free medium.
Relationships between Tannin Content and Forage Digestibility in Sorghum1
Authors: Cummins D. G.
Published: July 2010

Two related sorghum [Sorghum bicolor (L.) Moench] hybrids, one bird‐resistant (high‐tannin grain, 10.5%) and one non‐bird‐resistant (low‐tannin grain, 4.2%), were harvested at the dough stage of grain maturity. In vitro dry matter digestibilities (IVDMD) and astringent tannin contents were determined on whole plant samples containing varying amounts of grain and on plant components from ensiled and non‐ensiled samples. IVDMD was correlated with percent grain in the non‐ensiled mixtures, but the rate of IVDMD increase was much less in the mixtures high in tannin (Y = 47.0 ‐f‐ 0.08X, r = 0.81) compared with the low‐tannin mixtures (Y = 43.7 + 0.21X, r = 0.99). Ensiling increased IVDMD, and this increase was greater in the high‐tannin hybrid (Y = 42.0 A + 0.23X, r = 0.98) than the low‐tannin hybrid (Y = 40.8 + 0.28X, r = 0.99). Loss of tannins from the grain of the high‐tannin hybrid on ensiling resulted in tannin contents equal to the low‐tannin hybrid. Tannin contents of the chaff, leaves, and stalks of the bird‐resistant hybrid were 9.7, 6.6, and 6.8%, respectively, and 7.8, 6.1, and 1.7% respectively in the non‐bird‐resistant hybrid. This tannin did not dissipate upon ensiling as did that in the grain of the high‐tannin hybrid. These results indicate that feed quality of silage made from bird‐resistant sorghums should be improved and closer to that of non‐bird‐resistant sorghum silage.
Comparative Yields and Composition of Eight Tropical Leafy Vegetables Grown at Two Soil Fertility Levels1
Authors: Schmidt D. R.
Published: July 2010

Tropical leafy vegetables including Amaranthus cruentus L., Basella alba L., Brassica chinensis L., Brassica aleracea var. acephala D.C., Corchorus olitorius L., Ipomoea aquatica Forsk, Solanum melanocerasum Allioni, and Talinum triangulare Willd. were grown on plots of medium and high soil fertility at Akure, Nigeria. Average dry matter yields of edible leaves from medium and highfertility soils, respectively, were 1,970 and 3,339 kg/ha from 70 days' growth in 1966, and 2,839 and 5,133 kg from 120 days' growth in 1967. Amaranthus cruentus was the highest‐yielding species, in 1966 producing 3,473 kg/ha, compared to an average of 2,383 kg from Brassica chinensis, Corchorus, Solatium, and Talinum. Amaranthus, Basella, and Solatium were most responsive to high fertility. The Brassica spp. and Ipomoea produced relatively high yields with medium fertility.

The dry matter of the leaves averaged approximately 5% total N, about three‐fourths of this being protein N. Solanum with 5.9% and Ipomoea with 5.4% had the highest total N contents. Leaves from the high‐fertility soil averaged 5.4% total N compared to 4.5% for leaves from medium fertility. Calcium contents ranged from 2,045 mg / 100 g dry matter in Amaranthus to 412 mg in Ipomoea. Basella had the highest iron content with 50 mg / 100 g dry matter compared to an average of 34 mg for the other seven species. Leaves from the medium‐ fertility plots contained an average of 22% more iron than those grown on high‐fertility plots.

Relationships of the nutrient contents of leafy vegetables to the diets of people in southern Nigeria are discussed.
Survival and Growth of Cotton Plants Damaged by Windblown Sand1
Authors: Fryreat D. W.
Published: July 2010

Cotton seedlings are easily damaged or destroyed by exposure to the abrasive action of windblown sand. The survival and recovery of damaged plants should be related to the moisture stress at the time of injury and the change in moisture stress following injury. Plants were grown in a greenhouse, exposed to windblown sand injury at 3 or 9 days of age, and returned to the greenhouse. The soil moisture content at exposure time was 7 (dry) or 11% (wet). The moisture content was constant or reversed at 3, 9, or 27 days after exposure.

Cotton plant leaf area, height, and dry matter production (at 50 days of age), were significantly reduced by exposure to abrasive injury. Plant growth was delayed from 8 to 25 days, and the plants that recovered were shorter but had more leaf area per unit of height than plants not exposed. Plant survival for 3‐day‐oId plants abraded with blowing sand was 62 and 65% for a soil at 7 (dry) and 11% (wet) moisture, respectively. Plant survival for 9‐day‐old plants exposed to abrasive injury was 78 and 63% for the dry and wet soil respectively. Decreasing the soil moisture content of a wet soil 9 or 27 days after 3‐day‐old plants were exposed significantly decreased survival. When 9‐day‐old plants in a dry soil were exposed, increasing the soil moisture 3 days after exposure significantly decreased survival, but decreasing :he soil moisture of a wet soil 9 or 27 days after exposure significantly increased plant survival.

Plant tissue destruction was observed as the leaves and hypocotyl became dark green or black. Thin sections of the tissue revealed a compression of the damaged cells rather than an actual abrading away of the plant material.
Soil Salinity Effects on Absorption of Nitrogen, Phosphorus, and Protein Synthesis by Coastal Bermudagrass1
Authors: Langdale G. W. , Thomas J. R.
Published: July 2010

The interaction of artificially salinized soil and N‐P fertilization on dry‐matter production and protein synthesis of coastal bermudagrass [Cynodon dactylon (L.) Pers.] was studied in a greenhouse environment. Saline solutions were prepared in concentration multiples with the same ionic ratios as the available irrigation water to develop four treatments with electrical conductivities (EC) of 0, 4.8, 9.6, and 14.4 mmhos/cm. After salinewater equilibration of a Brennan fine sandy loam soil (Typic Haplustalf), fertilizer treatments were applied in a factorial arrangement with N rates of 0, 67, 133, and 200 mg/kg of soil and P rates of 0, 20, 40, and 60 mg/kg of soil.

No response was obtained from P fertilization. Significant interactions occurred for both dry‐matter and protein‐N yields with soil salinity and N supply treatments. Soil salinities of 5.3 and 6.6 mmhos/cm yielded the most dry matter and protein N, respectively, in the presence of N fertilizer. Reduction in soluble N (nonprotein) occurred at the most efficient levels of protein‐N synthesis. Although N requirements decreased as soil salinity increased, N fertilization offset effects of salinity up to 9.6 mmhos/cm. Dry‐matter and protein syntheses were seriously restricted at the 14.4 mmhos/cm salinity level; however, salinity levels did not restrict N absorption by coastal bermudagrass.
Water Relations and Growth of Cotton as Influenced by Salinity and Relative Humidity1
Authors: Hoffman G. J. , Rawlins S. L. , Garber M. J. , Cullen E. M.
Published: July 2010

Soil salinity and atmospheric relative humidity influence plant growth, but few data are available showing the interaction between them. This interaction was studied with cotton (Gossypium hirsutum) in four sunlit climate chambers at temperatures cycling daily between 38 and 26 C. Relative humidity was controlled at 25, 40, 65, and 90%. The root medium was maintained at osmotic potentials of −0.4, −5, −10, and −15 bars.

Relative humidity significantly affected shoot growth only in the 90% relative humidity treatment, where growth was increased about 40%. The shoot‐to‐root ratio at high humidities was at least double the ratio at low humidities. The 50% yield decrement based on leaf area or plant dry weight occurred at an osmotic potential of –5 bars. Because the anthers of the cotton flowers in the 25 and 90% relative humidity treatments did not dehisce, seed cotton yields at these relative humidities were essentially zero. Seed cotton yields per plant at 40 and 65% relative humidities were comparable to or greater than field yields.

Transpiration per unit leaf area for the entire experiment increased an average of 80% for all salinity levels as the relative humidity decreased from 90 to 25% and decreased slightly with increasing salinity in all humidity treatments. Transpiration per unit leaf area decreased as the plants matured and tended to approach the same value for all treatments near the end of the experiment.

The relative yield of dry matter and leaf area as a function of salinity was the same at all relative humidities, indicating that no interaction between salinity and relative humidity occurred.
Salt Tolerance of Safflower Varieties (Carthamus Tinctorius L.) during Germination1
Authors: Ghorashy S. R. , Sionit N. , Kheradnam M.
Published: July 2010

Varietal differences with respect to salt tolerance have been observed in various crop species. Knowledge of such differences in safflower (Carthamus tinctorius L.) is of potential importance. Effects of seven salinity levels (0 to 2% NaCl) on germination of three safflower varieties were determined under controlled temperature (30 ± 2 C). The varieties were ‘Ute,’ Iranian local 3151, and Iranian local 2811. The three varieties showed a similar trend in germination reduction as salinity increased from 0 to 1% NaCl. However, Iranian local 3151 showed the least reduction in percent germination, as compared with the other two at NaCl concentrations greater than 1%.
Nitrogen Metabolism of Stargrass as Affected by Nitrogen and Soil Salinity1
Authors: Langdale G. W. , Thomas J. R. , Littleton T. G.
Published: July 2010

Interactive effects of soil salinity and N fertilizer on stargrass (Cynodon plectostachyus (K. Schum.) Pilger) growth and N metabolism were investigated. Nitrogen contents were partitioned to study the effects of substrate salinities on hydrolysis of protein‐N and the accumulation nonprotein‐N assimilates. Mixed chloride‐sulfate solutions of the same ionic ratios and electrical conductivities (EC) of 4.8, 9.6, and 14.4 mmhos/cm were equilibrated with Brennan fine sandy loam (Typic Haplustalf) soil, after which N was applied in a factorial arrangement at rates of 0, 67, 133, and 200 mg/kg of soil.

Nitrogen fertilizer interacted significantly with soil salinity to stimulate dry matter and protein‐N yields at the 4.8‐mmhos/cm level. No evidence of a toxic nonprotein‐N accumulation in plant tissue was observed even with high N fertilization at this salinity level. The 9.6‐mmhos/cm salinity treatment was considerably more deleterious to dry matter than to protein‐N production processes. Dry matter production and protein‐N synthesis were severely inhibited at the 14.4.mmhos/cm salinity level although NO3‐N appeared to be adequately absorbed and reduced.
Dispersal and Germination Dynamics of Broadleaf Filaree, Erodium botrys (Cav.) Bertol1
Authors: Young James A. , Evans Raymond A. , Kay Burgess L.
Published: July 2010

Erodium species are important forage plants in the western United States, Australia, and other areas with similar climate. Knowledge of the germination and seedbed ecology of Erodium species will aid in efficient management of rangelands where these annuals occur. Dispersal, self‐burying, and seed germination of the indehiscent fruits of broadleaf filaree (Erodium botrys (Cav.) Bertol.) were investigated. Field dispersal and laboratory germination in relation to temperature and germination enhancement experiments were conducted. The complex fruit consists of an indurate tipped corpusculum that contains the seed; the spirillium (coiled portion of the awn); and the flagellum (hairlike terminal of the awn). The three parts are a highly efficient mechanism for self‐burial. Indehiscent seeds are impermeable to water at first. This hard seed dormancy breaks during the summer in a natural seedbed condition, but persists if the fruits are stored under dry conditions. The natural mechanism of breaking dormancy involves mechanical action of the fruit breaking the hilum of the seed. The dormancy can be overcome artificially by soaking fruits in concentrated sulfuric acid or by exposing the seeds to diurnal fluctuations of temperature and relative humidity. Artificial hourly temperature fluctuation will accelerate the breaking of dormancy. Seeds that will imbibe water have an optimum germination at relatively cool temperatures, but considerable germination occurs with warm day temperatures and extreme diurnal fluctuations.
Potassium and Sodium Interrelations in Growth and Alkali Cation Content of Safflower1
Authors: Aslam M.
Published: July 2010

Application of Na often improves the growth of many crop plants resistant to Na. Part of this is due to “sparing” action of Na on K. Often Na improves the growth of some species regardless of K level. It has been suggested that safflower (Carthamus tinctorius L.) also responds to Na even in the presence of ample K. However, the information regarding the interactions of Na and K in this plant is scanty. This paper reports the effects of Na at different levels of K on the growth and accumulation of alkali cations in different parts of the plant.

The plants were grown for 24 days in nutrient solutions under controlled environments. The nutrient solutions contained six levels (0.1, 0.2, 0.4, 0.6, 0.8, and 1.0 meq/liter) of K and 2 levels (0 or 4 meq/liter) of Na. Other nutrients were supplied at their optimum concentrations.

Both growth and alkali cation content of the plants were affected by K and Na treatments. Sodium increased the plant growth by about 40 to 50% at all K treatments. Visual K deficiency symptoms were delayed and were less severe when Na was added to the treatment solutions as compared to the treatment where no Na was supplied.

Potassium concentrations in all above ground plant parts were directly related to K treatments. Potassium concentrations were lower in older blades than in younger blades when plants were K deficient, regardless of Na treatment. With more supplied, K concentrations were higher in the older leaves than in the younger. Addition of Na to the treatment solutions depressed the K concentration in all plant parts studied when K was deficient. However, in younger blades this effect was noticed even at higher K supply. Sodium concentrations in the above ground plant parts were strongly reduced by excess K in the solutions. Potassium and Na concentrations in the stem were higher as compared to other above ground plant parts.

Calcium and Mg concentrations in the stem and older blades decreased with increase in K regardless of Na treatments. The older blades had higher concentrations of Ca and Mg than the other above ground plant parts. Addition of Na to the treatment solutions did not affect the accumulation of Ca in any plant part, whereas the Mg concentrations in all above ground plant parts were significantly increased by Na treatment.

Information gained from these studies indicates that application of Na to safflower can give better growth and Na can also substitute for K especially when K supply is low.
Effect of Carrier, Rate, and Time of Application of S on the Yield, and S and N Content of Alfalfa1
Authors: Hoeft R. G. , Walsh L. M.
Published: July 2010

In view of the increased S deficiency in the North Central region of the United States and increased fertilizer prices, additional information was needed to develop more precise fertilizer recommendations. Accordingly, field experiments were conducted at nine locations in Wisconsin to evaluate the effect of carrier, rate, and time of application of S on yield, S and N content of alfalfa (Medicago sativa L.), and efficiency of S uptake. All fertilizer materials were broadcast on the soil surface in established stands of alfalfa. Significant forage yield, S concentration, and N concentration increases to S were obtained at five of the nine locations.

In the first year after application, SO4‐S carriers (K2SO4 and K2SO4 :2 MgSO4) were more effective than prilled elemental‐S (88% S and 12% bentonite) in correcting S‐deficiency of alfalfa. However, in the second year after application, the various S carriers were equally effective. The results of this study indicate that 28 and 112 kg S/ha as K2SO4 were adequate to correct S‐deficiency for a 1‐year and 2‐year period after application, respectively. In the second year after application, 56 kg S/ha as elemental S was required to significantly increase the yield for the first and second harvests and for the third harvest a significant response occurred only at the 112 kg S/ha rate.

Spring applied K2SO4 was more effective than a fall application, and K2SO4 applied at a rate of 28 kg S/ha each year over a 2‐year period was more effective than a single application of 56 kg S/ha made at the beginning of the 2‐year period. No significant difference between spring and fall application of elemental S was noted. During the second year after S application, a single treatment of elemental‐S made at the beginning of the experiment was more effective than the same amount split among two annual applications. Significant yield response was observed when the concentration of S in the tissue was ≤ 0.22% S.
Root and Rhizome Development of Some Kentucky Bluegrass and Red Fescue Cultivars1
Authors: Ensign R. D. , Weiser G. C.
Published: July 2010

Rapid and extensive root and rhizome development are desirable attributes for turfgrass sod production. Extensive rooting is also advantageous for plant development and seed maturation in the semiarid West during periods of drought stress. The purpose of this study was to determine if there were differences in the root and rhizome production among several cultivars of Kentucky bluegrass (Poa pratensis L.) and red fescue (festuca rubra L.) under mowed and unmowed management.

Mowed plots were cut weekly at 4 cm. Unmowed plots were allowed to produce seed. Sod samples were taken from unmowed plots at the soft dough stage of the caryopsis. Mowed plots produced significantly more roots and rhizomes than unmowed. Variation existed among cultivars with respect to root and rhizome production. ‘Adelphi,’ ‘Glade,’ ‘Nugget,’ ‘Fylking,’ and ‘Newport,’ produced high root weights. Adelphi, Nugget, and ‘P‐142,’ produced high rhizome numbers and weights. Some cultivars produced a high percentage of roots in the top 2.5‐cm layer of the rhizosphere, whereas others had rhizomes more equally distributed to the 7.5‐cm depth.

Total root and rhizome production in most bluegrasses exceeded the total production of the fescue cultivars. ‘Pennlawn’ red fescue was a prolific rhizome producer when compared to four other fescue cultivars. Several new bluegrass cultivars have relatively vigorous rhizosphere systems which may be significant for desirable sod production as well as their ability to compete for available moisture during periods of seed maturation.
Growth of Young Tobacco Plants as Affected by Carbon Dioxide and Nutrient Variables1
Authors: Thomas Judith F. , Raper C. David , Anderson C. E. , Downs R. J.
Published: July 2010

Tobacco (Nicotiana tabacum L.), essentially a nursery plant during seedling growth, is grown in a protected plant bed until it attains the size to be transplanted into the field. Enchancement of growth rates during seedling culture would have advantages in production of tobacco seedlings, as well as bedding plants. Enrichment of atmospheric CO2 is a generally recognized technique of increasing growth rates. Experiments were conducted in controlled‐environment chambers to evaluate the immediate effects of CO2 enrichment on seedling growth of tobacco, the carryover effects to post‐transplant growth, and nutritional requirements for maximum response to CO2 enrichment.

Tobacco seedlings were grown at two rates of nutrient application in atmospheres containing either ambient (400 ppm) or enriched (1,000 ppm) CO2 levels. At the time of transplanting half of the plants from each CO2 environment were reciprocally exchanged. During seedling culture, Relative Growth Rate (RGR) was enhanced CO2 enrichment but was depressed by the higher nutrient application rate. The RGR to CO2 enrichment was reversed during post‐transplant culture. For either CO2 environment, RGR during seedling growth was nearly three‐fold RGR during posttransplant culture. The reduction in RGR with CO2 enrichment occurred for both a 9‐hour and a 15‐hour light period of 450 hectolux intensity. The lower RGR for CO2 enrichment during post‐transplant culture was associated with increased starch in leaf tissues. These data support the hypothesis that, although growth response may temporarily be enhanced by CO2 enrichment, it must decline to a level similar to that of plants raised under ambient CO2.
Yield and Persistence of Several Legumes Growing in Tall Fescue
Authors: Dobson James W. , Fisher C. D. , Beaty E. R.
Published: July 2010

Despite two decades of use of nitrogen fertilizer to grass pastures, the rising cost of N and the introduction of new legumes and cultivars is cause for a reappraisal of grass‐legume mixtures for pastures in the South. The objective of this study was to evaluate new legume species and cultivars under two simulated grazing pressures. Information on production and clipping tolerance of these new legumes and cultivars is needed to plan management for production and persistence.

In the fall of 1970 tall fescue cultivar ‘Ky 31’ (Festuca arundinacea Schreb.) was seeded alone or with each of 10 legumes. During the summer of 1971 and 1972 plots were harvested monthly at heights of 5 and 10 cm. In 1973 only four harvests were made as compared to six for each of the first 2 years. Milkvetch (Astragalus cicer, L.) failed to persist in association with fescue and produced little more than fescue alone. Red clover (Trifolium pratense L.), produced high yields but persistence was short. Crownvetch (Coronilla varia L.), birdsfoot trefoil (Lotus corniculatus L.), and white clover (Trifolium repens L.) persisted well and significantly increased forage yields. The newer cultivars tended to be significantly higher yielding than the old ones. The crownvetches, red and white clovers, and birdsfoot trefoils were tolerant to heavy defoliation and increased forage yields. The use of these legumes in forage programs appeared to be highly desirable.
Soil Temperature Around the Crown Node Influences Early Growth, Nutrient Uptake, and Nutrient Translocation of Spring Wheat1
Authors: Boatwright G. O. , Ferguson Hayden , Sims J. R.
Published: July 2010

Farming practices such as stubble mulching are known to influence surface soil temperatures. This study was conducted to determine the effect of temperature variations in the shallow surface zone that normally contains the crown node on early growth, nutrient uptake, and nutrient translocation of spring wheat (Triticum aestivum L.).

Surface soil temperatures below optimum, about 19 C, significantly decreased top growth but not root growth. When surface soil temperature was increased, total nutrients accumulated in the tops increased. Under low surface soil temperature roots appeared to accumulate Cu and Zn. Translocation of 80Rb from the roots to the tops was significantly greater when the surface soil was warm than when it was cold. Thus, translocation of nutrients from the roots to the tops may be restricted by low soil surface temperatures.

Fertilization with N, P, and K appears to modify the detrimental effect of low surface soil temperatures. However, nutrients did not completely alleviate the detrimental effect of low surface soil temperatures.

The crown node (transition region) of the plant appears to be the plant component most sensitive to low surface soil temperatures. When the crown node was located above the cold zone, dry weight was nearly equal with cold and warm surface soil temperatures. Unlike the crown node, the shoot growing point (meristematic region) was not affected by low, surface‐soil temperatures.
Response of Sugarcane to Filter Press Mud and N, P, and K Fertilizers. I. Effect on Sugarcane Yield and Sucrose Content1
Authors: Prasad M.
Published: July 2010

Very little information is available regarding the plant nutrient value of filter press mud (FPM) for sugarcane. Yield increases of sugarcane as a result of FPM application have been inconsistent. Therefore eight field experiments were conducted to study the effect of FPM and NPK fertilizer, and their interaction on the yield and sucrose content of sugarcane (Saccharum officinarum L.). There were four plant cane and four ratoon experiments conducted over 2 years on seven sites. These included one experiment in which the residual effect of FPM after 1 year was studied. A split plot design was used with FPM on main plots (rates were 0, 20, and 40 metric tons/ha or 0 and 34 metric tons/ha dry wt with two or four replications), and N, P, and K fertilizer rates on subplots (two or four replications). The rates of fertilizers were as follows: N = 0, 94, and 188 kg/ha or 47, 94, and 141 kg/ha; P = 0, 45, and 90 kg/ha or 0 and 45 kg/ha; K = 0 and 112 kg/ha.

Filter press mud increased the yield of cane in six experiments including the residual FPM experiment. Yield increases were higher in plant than in ratoon cane. Nitrogen increased the yield of cane in all experiments and in five experiments, rates higher than 94 kg N/ha, the standard practice, gave higher yield. The response of sugarcane to N‐fertilizer was more related to the texture of the soil (r = −0.79) than N‐content of the soil. Phosphorus increased the yield in seven experiments. Potassium gave a response in two out of five experiments. FPM ✕ P was the most interesting interaction and occurred in six experiments. This interaction reflected the inter‐changeability of FPM at the rates studied with P‐fertilizer. Other significant interactions were FPM ✕ N ✕ K, FPM ✕ N ✕ P. Filter press mud also improved the quality of the cane in four experiments while P‐fertilizer improved it in three. On basis of these results, the following is recommended: 1) No P‐fertilizer need be applied where FPM has been applied in quantities as high as 20 metric tons/ha dry wt basis, 2) ratoons following the plant cane may need P‐fertilizer but possibly in much smaller amounts than normal, particularly if FPM rates are high, and 3) rates greater than 94 kg/ha are recommended particularly in the coarser textured soils.
Grass Tetany Hazard of Cereal Forages Based upon Chemical Composition1
Authors: Mayland H. F. , Grunes D. L. , Lazar V. A.
Published: July 2010

The occurrence of grass tetany in cattle grazing small grains pastures led us to examine the forage chemical composition and to suggest the relative risk of grass tetany to cattle grazing each forage.

Early spring vegetative growth of wheat (Triticum aestivum L.) and crested wheatgrass (Agropyron desertorum (Fisch.) Schult) was periodically sampled from 3 ✕ 20 m plots established on a fertile Portneuf silt loam (Durixerollic calciorthid). In addition, wheat, oats (Avena sativa L.), barley (Hordeum vulgare L.), and rye (Secale cereale L.) were grown in pots containing Portneuf silt loam in the greenhouse and were harvested once while still vegetative.

Forage samples were freeze‐dried and the following parameters determined: total N (Kjeldahl); NO‐3 (electrode); Na, K, Mg, and Ca (atomic absorption); S and Cl (x‐ray); P (vanadomolybdate); aconitic acid (polarography); higher fatty acids and ash alkalinity (both by titration). Estimated blood‐serum Mg values were calculated from a generally unavailable Dutch nomograph of forage N ✕ K and Mg values. The nomograph is included in this paper to enhance its availability.

Wheat forage seemed to pose a greater tetany hazard than the wheatgrass because wheat had lower values for Ca and higher values for K, K/(Ca + Mg), aconitic acid, ash alkalinity, and HFA. The estimated tetany hazard of the cereal forages was wheat > oats = barley > rye. This ranking corresponded to the other of blood‐serum Mg levels predicted from the Dutch nomograph. Wheat forage was lowest in Mg, while rye forage was highest in Mg and Ca, and lowest in K and N. Aconitic acid represented a large portion of the total organic acids in oats, rye, wheat, and wheatgrass, but only traces were found in barley.

The frequent occurrence of grass tetany in cattle grazing wheat forage may result because of lower Mg and Ca levels and higher K, N, ash alkalinity, and HFA levels in this forage compared to other cereal forages.
Manganese Deficiency and Toxicity Levels for ‘Bragg’ Soybeans1
Authors: Ohki K.
Published: July 2010

The lower and upper critical Mn levels in soybeans [Glycine max (L.) Merr.], which are not documented, were determined to provide guideline values for estimating the Mn status from deficiency through toxicity. Soybean (‘Bragg’) was grown in Hoagland nutrient solution with 14 Mn levels from 0 to 50,000 μg/liter. The plants were grown in the greenhouse for 33 days, harvested and analyzed for Mn.

The lower critical levels where Mn is required at minimum concentration for maximum growth ranged from 9 to 11 μg/g in blade 1 (young) and blade 5 (old), respectively. Blade 3 was the most recently matured leaf and is suggested as the tissue to sample for plant analysis. The lower critical Mn level for blade 3 is 10 μg/g. The upper critical level where maximum Mn concentration in blade tissue can be tolerated for maximum growth ranged from 100 to 250 μg/g in blade 1 to 5, respectively. The upper critical Mn level for blade 3 was 160 μg/g. For the ‘Bragg’ cultivar maximum growth was attained from 10 to 160 μ/g Mn in blade 3. The distribution of Mn was low (3 to 7 μg/g) and uniform when plants were under Mn stress. With adequate Mn, the Mn concentration in blade increased with tissue age.
Effects of Population Density upon Agronomic Traits Associated with Genetic Increases in Yield of Zea mays L.1
Authors: Moll R. H. , Kamprath E. J.
Published: July 2010

Several long term recurrent selection programs with strains of Zea mays L., which were initiated from one to three decades ago, are being carried out at plant densities considerably below those currently used in commercial production. The question arises whether responses realized at low plant densities will be maintained at higher plant densities. We chose to study strains from a selection program initiated three decades ago, in which 10 cycles of full‐sib family selection have been completed at a density of 24,000 plants per hectare. A study was conducted to characterize changes in agronomic traits of corn resulting from recurrent selection for yield when evaluated at 24,710, 38,300, and 49,420 plants per hectare. Comparisons were made among the original strain and strains resulting from the fifth (C6) and 10th (C10) selection cycles.

The improved strains, C5 and C10, averaged 27 and 42% more yield than the original strain. Important increases in prolificacy, ear corn/stover ratio, and total N accumulation in the grain were found to accompany the increases in yield due to selection. Increased population density resulted in greater yields per hectare in the improved strains. Interactions between strain and density were not statistically significant.

Both ear height and top height increased with selection, but leaf size and ear weight appeared to have decreased. Decreases were also noted in percent N in the grain and the stover.
Assessment of Water Loss Patterns with Microlysimeters1
Authors: Rogowski A. S. , Jacoby E. L.
Published: July 2010

It is difficult to measure the distribution of evapotranspiration(ET) in the field because of mixed soil types, moisture regime, and vegetation. Portable, cylindrical, grass‐growing lysimeters were constructed and used to obtain distribution patterns of evapotranspiration. The objective of the study was to develop a practical method of evaluating ET in the field. The microlysimeters were laboratory and field checked and the final study was carried out on a 58‐ha watershed. Laboratory check showed that at high soil water contents periodic removal of lysimeters for weighing did not destroy the continuity of flow. The field check demonstrated feasibility of field use and showed no significant diferences in ET between different segments of a small study area. The watershed study in addition to microlysimeter observations, included gamma‐probe measurements and ET predictions with an ET model. Except for a very stony and a wooded site ET estimates obtained by the three methods appeared satisfactory.
Field Measurements of Ammonia Volatilization from Surface Applications of Ammonium Salts to a Calcareous Soil1
Authors: Hargrove W. L. , Kissel D. E. , Fenn L. B.
Published: July 2010

Many laboratory experiments have been conducted to study ammonia volatilization from N fertilizers, but few experiments have been conducted under field conditions. The objective of this study was to evaluate ammonia volatilization in the field from ammonium sulfate and ammonium nitrate applied to the surface of a calcareous soil, Houston Black Clay, that belongs to the fine, montmorillonitic, thermic family of Udic Pellusterts. Volatilization was evaluated indirectly by measuring N uptake by Coastal bermudagrass (Cynodon dactylon L.) and directly by measuring ammonia as it volatilized. In the field plot study, estimated losses ranged from 3 to 10% of the applied N for ammonium nitrate, from 36 to 45% of the applied N for pelleted ammonium sulfate, and from 25 to 55% of the applied N for liquid ammonium sulfate at rates of 140 and 280 kg N/ha. Direct measurements of ammonia losses from pelleted ammonium sulfate were 47, 43, 59, and 50% of the applied N in late summer, 1975, and 39, 30, 27, and 35% of the applied N in spring, 1976, at rates of 33, 66, 140, and 280 kg N/ ha. The lower loss of ammonia in the spring was apparently in response to lower soil temperatures at that time. Consistent diurnal fluctuations in ammonia losses occurred at both times. These fluctuations corresponded closely with daily fluctuations in the atmospheric relative humidity. These results agree with earlier laboratory studies in that ammonium sulfate loses considerably more ammonia than ammonium nitrate when applied to the surface of a calcareous clay soil.
Effect of Acetic, Propionic, and Butyric Acids on Young Rice Seedlings' Growth1
Authors: Rao D. Niranjan , Mikkelsen D. S.
Published: July 2010

Anaerobic bacteria in flooded soils degrade various types of organic matter, including rice straw and green manure crops, with the production of low carbon, monobasic aliphatic acids. The major fermentation products are formic, acetic, propionic, butyric, and lactic acids. Organic acids produced in flooded soils may adversely affect the growth of rice seedlings.

Rice seedlings, Oryza sativa L. ‘Earlirose’, were grown in sterile nutrient solution containing 1, 5, and 10 mN concentrations of acetic, propionic, and butyric acid adjusted to variables of pH 3.0, 5.0, and 7.0. The seedlings were grown in treated nutrient solutions for 7 days before harvesting for plant growth measurements.

Root elongation, shoot height, and weight were retarded by all organic acids, the severity increasing with concentration and decreasing pH. Root elongation was affected most. Residual seed reserves were greater with higher acid concentrations, corresponding to decreased growth of the plant root and shoot suggesting that the translocation of stored seed reserves was inhibited. The magnitude of organic acid effects was in the order of butyric > propionic > acetic. At 1 mN concentration, all organic acids evaluated, reduced root length by 40 to 50%, but did not inhibit root initiation. At 5 mN concentration, root elongation was severely inhibited and most root tips showed severe root injury. At 10 mN concentration, both elongation and initiation of roots were completely inhibited. An increase in pH from 3 to 7 decreased the inhibiting effects of all organic acids at all concentrations, indicating that the concentration of undissociated acid was more critical than total acid concentration in inhibiting seedling growth. Anaerobic fermentation products, particularly organic acids, are potential problems in rice stand establishment in flooded soils. A proper time interval for their decomposition prior to planting rice must be observed to avoid seedling damage.
Relationship between Assimilate Source and Reproductive Sink in Maize Grown in a Short‐Season Environment1
Authors: Tollenaar M. , Daynard T. B.
Published: July 2010

Limitations to grain yield in maize (Zea mays L.) not explained by unfavorable factors such as disease, nutrient deficiency, or moisture stress may be analyzed in terms of assimilate supply to the grain (the source) and the potential of the grain to accommodate assimilate (the sink). In order to determine whether sink or source represented the first limitation to grain yield, an early‐maturing maize hybrid was grown in field tests at the Elora Research Station near Guelph, Ontario, Canada, during 1973, 1974, and 1975. Sink strength was manipulated by means of light enrichment or shading treatments applied from 2 weeks before until 2 weeks after mid silking. Light‐enrichment and shading treatments applied during the grain‐filling period (i.e., from 2 weeks after mid‐silking to maturity) served to provide information as to whether source capability during grain filling was a dominant limitation to grain yield. Grain yield was affected more by alterations in assimilate supply during the grain‐filling period than during the period which bracketed silking. The results indicate a predominant source limitation for grain yield in the maize hybrid, and others of related genetic composition grown in short growing‐season environments similar to Guelph. Where this occurs, grain yield may be improved by increasing leaf area per plant, or by extending leaf area duration after flowering.
Influence of Italian Ryegrass Density on Efficacy of Diuron Herbicide1
Authors: Burrill Larry C. , Appleby Arnold P.
Published: July 2010

Diuron [3‐(3,4‐dichlorohenyl‐l,l‐dimethylurea] has been used for many years to control Italian ryegrass (Lolium multiflorum Lam.) in winter wheat (Triticum aestivum L.) in western Oregon. Variable results cannot be attributed solely to soil and climatic factors. Studies were conducted to determine the effect of ryegrass density on diuron efficacy. Under both greenhouse and field conditions, control of ryegrass decreased as plant density was increased. One possible explanation for lower efficacy in dense stands is the reduced amount of herbicide in the soil solution available for each plant. The influence of density on herbicide performance may play an important role in commercial field practice as well as in the interpretation of bioassay results.