bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drought Response of Grain Legumes Under Irrigation Gradient: II. Plant Water Status and Canopy Temperature1
Authors: Pandey R. K. , Herrera W. A. T. , Pendleton J. W. 
Published: July 2010

AbstractA great need exists in semiarid or tropical areas to include food legumes in rice (Oryza sativa L.) based cropping systems during the post monsoon or dry season. The seed of these legumes provide needed protein for the prevalent high starch diets. Mungbean (Vigna radiata L.), cowpea (Vigna unguiculata L.), soybean (Glycine max L.), and peanut (Arachis hypogeae L.) are four short‐season legumes receiving attention. The purpose of this research was to compare their drought responses on a medium‐deep Tropudalf soil by using a line‐source sprinkler irrigation system. This paper presents findings on plant water status and canopy temperature and their relationships to yield. Plant water status was determined with a pressure chamber and canopy temperature with an infrared thermometer. Plants exhibited leaf water potentials between 1300 to 1400 h of −1.20 MPa in mungbean, −1.40 MPa in cowpea, −1.41 MPa in soybean, and −0.67 MPa in peanut in the dry regimes 60 days after emergence. Seasonal leaf water potential was closely related to canopy temperature in all four legumes. Increasing water stress decreased leaf water potential and increased canopy‐air temperature differences (ΔT). The seasonal cumulative leaf water potential and ∆T during crop growth were negatively correlated with yield and may be useful for selecting crop species for drought prone areas. Peanut had a higher leaf water potential and maintained a lower canopy temperature than the other species.
Influence of Grass Species on Composition, Yield, and Quality of Birdsfoot Trefoil Mixtures1
Authors: Sheaffer C. C. , Marten G. C. , Rabas D. L. 
Published: July 2010

AbstractMixtures with noncompetitive perennial grasses have been recommended to reduce weed invasion which commonly occurs in pure stands of birdsfoot trefoil (Lotus corniculatus L.). Our objective was to determine the potential of competitive vs. noncompetitive grass species in mixtures with birdsfoot trefoil to prevent weed invasion while maintaining stands with maximum birdsfoot trefoil composition and forage quality. ‘Leo’ and ‘Viking’ birdsfoot trefoil were established in monoculture and in binary mixtures with nine grass species on a Waukegan silt loam (fine‐silty over sandy, mixed, mesic Typic Hapludolls) in southeastern Minnesota. The same treatments, except one, were also established on a Cowhorn sandy loam (coarseloamy, mixed nonacid sand, frigid Aeric Haploquepts) in northcentral Minnesota. Conventional (when Leo reached first flower) and stockpiled (when Leo reached full bloom) harvest managements were applied for 2 years. Mixtures with high yielding competitive grasses (Phalaris arundinacea L., Bromus inermis Leyss., or Dactylis glomerata L.) had the least weed infestation and greatest weed‐free forage yield, but had consistently lower forage quality than the birdsfoot trefoil monoculture or mixtures with noncompetitive grasses (Phleum pratense L., K2‐106; Lolium perenne L.; or Poa pratensis L.) at the southeastern location. Competitive grasses also maximized birdsfoot trefoil persistence in southeastern Minnesota, while noncompetitive grasses and the birdsfoot trefoil monoculture maximized birdsfoot trefoil persistence in northcentral Minnesota. Relative mixture differences in weed infestation, forage quality, and yield were generally not affected by harvest management (stockpiled vs conventional). Stockpiled forage had lower quality than did conventionally harvested forage at both locations, and greater yields at the southeastern location. Stockpiled mixtures containing Leo had a greater final birdsfoot trefoil composition than did mixtures containing Viking only at the southeastern location. Birdsfoot trefoil cultivar selection did not affect final composition when mixtures were conventionally managed at either location. Because competitive vs noncompetitive grasses led to differing birdsfoot trefoil persistence depending on location, noncompetitive companion grasses may maximize birdsfoot trefoil persistence in mixtures in some environments, whereas competitive grasses may ultimately maximize birdsfoot trefoil in others. If forage quality is the primary concern, noncompetitive grasses should be used; if total weed‐free forage yield is the primary concern, competitive grasses may be advisable.
Response of Sorghum and Wheat to Different K+/Na+ Ratios at Varying Osmotic Potentials1
Authors: Devitt D. , Stolzy L. H. , Jarrell W. M. 
Published: July 2010

AbstractPlants growing in saline‐sodic conditions must confront not only osmotic stress but the relative toxicity of the Na ion. The impact of these two factors on the physiology and morphology of the plant will often determine the plant growth in saline‐sodic soils. The objective of this experiment was to investigate the impact of low K+/Na+ ratios at given osmotic potentials in the solution phase on cation composition in the plant tissue, stomatal response, and root growth and development. The experiment was conducted in outdoor solution culture tanks. Wheat (Triticum aestivum) and sorghum [Sorghum bicolor (L.) Moench] were grown for 6 weeks in nutrient solution to which a range of polyethylene glycol 6000 and/or NaCl additions were made (MPa = −0.070, −0.076, −0.193, −0.340, −0.493 and K+ mmol L−1/Na+ mmol L−1 = 1/0,1/1,1/10,1/25,1/60,1/100). Porometry measurements were taken twice weekly at 830 and 1230 h. Leaf xylem water potentials were measured at 1230 h. Root length extension, root volume solution displacement and solution samples were taken weekly over the 6 week experimental periods. At harvest, fresh and dry weights were measured and the plants were subdivided into roots, shoots, stalks, and leaves for eventual analysis of Na, K, Ca, and Mg. Diffusive resistances generally increased with decreasing osmotic potential for both sorghum and wheat; however, measurement variability prevented clear separation between all osmotic and K+/Na+ treatments. The highest diffusive resistances were measured in plants grown in the −0.493 MPa, K+/Na+ = 1/100 solution. Interpolated Na+ concentrations in the plant tissue from estimated growth and Na uptake curves suggested translocation of Na to the upper leaves coincident with the stomatal response. The Ca concentration in the upper leaves decreased as Na increased. The combination of high Na and low Ca concentrations in the leaves, even when K concentrations appeared to be adequate, apparently decreased effective regulation of the stomata in the sorghum treatment. Root mass decreased as the osmotic potential of the solution decreased, while root elongation was primarily dictated by the Na concentration in solution. Sorghum root elongation decreased while wheat root elongation increased as the Na concentration increased within each osmotic level. Sodium was primarily confined to the root system in sorghum but translocation to the tops increased as the Na concentration increased. With wheat, Na was not restricted to the root system. An excellent exponential relationship for sorghum was found between the coefficient of root elongation and the concentration of Na in the plant. Root elongation of both wheat and sorghum under saline‐sodic conditions is controlled to a great extent by the degree of Na saturation of the root tissue.
Yield and Quality of a Warm‐Season Grass Mixture Treated with N, P, and Atrazine1
Authors: Rehm G. W. 
Published: July 2010

AbstractWarm‐season grasses can be important in pasture systems in the eastern Great Plains. Currently, production from the majority of pastures which contain these grasses is quite low and improvement is needed. In previous research with warm‐season prairie grasses, the effect of fertilization as well as the influence of atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine] has been investigatd in separate studies. Only limited research has been conducted to evaluate the combined effects. This study evaluated the rate and frequency of fertilizer N and P with and without use of atrazine on yield and protein content of warm‐season prairie grasses. Three management systems (annual fertilizer with no atrazine, annual fertilizer with atrazine, biennial fertilizer with atrazine) were randomized and replicated in the experimental area. The soil was a Crofton silt loam [fine‐silty, mixed (calcareous) mesic Typic Ustorthent]. Applications of N (0, 34, 67, 101, and 134 kg ha−1) and P (0, 6, 12, 18, and 24 kg ha−1) were applied to the systems involving annual fertilization. These rates were doubled when applied on alternate years (1974, 1976, 1978). Atrazine (1.12 kg ha−1) was applied in early April in 1974, 1976, and 1978. All fertilizer treatments were applied in late May. The response to P was linear in all situations. The response to N was linear where atrazine was not used and curvilinear where atrazine was applied. Atrazine effectively controlled weeds and encroachment of cool‐season species. Compared to the system where no herbicide was used, atrazine applied every 2 years resulted in higher forage production in 4 out of 6 years. Crude protein concentration of the forage increased by about 35 g kg−1with the use of fertilizer N. Neither applied P nor atrazine affected crude protein concentration.
Examination of Microorganisms and Deterioration Resistance Mechanisms Associated with Velvetleaf Seed1
Authors: Kremer R. J. , Hughes L. B. , Aldrich R. J. 
Published: July 2010

AbstractAnnual weed seeds persist in cultivated soils due to seed dormancy and possibly to resistance to microbial attack. The relationships between microorganisms and velvetleaf (Abutilon theophrastiMedic.) seeds were investigated to elucidate the deterioration resistance mechanisms in this species. Microorganisms were isolated from velvetleaf seeds matured on the plant and from seeds dispersed on the soil surface. An association of sporulating fungi comprised of Alternaria alternata, Cladosporium cladosporioides, Epicoccum purpurascens, and Fusariumspp. was consistently found on the seed surface. This association persisted on seeds after dispersal to the soil. Seed deterioration was infrequent despite abundant microbial growth on the seed surface. About 80% of the bacteria isolated from within seeds were antagonistic to externally seedborne fungi.The proportion of surface‐sterilized seeds with internal fungi was 10%, indicating the seed coat acts as a barrier to most fungal invasions. When the seed coat was punctured, however, seed deterioration by the seedborne microorganisms readily occurred. Seed coat extracts contained tannin‐like compounds that inhibited in vitro growth of several bacterial and fungal isolates. Histochemical examination of seed sections revealed localization of tannin‐like compounds in the palisade layer of the seed coat and the chalazal area of the embryo. It is suggested that deterioration of velvetleaf seeds by microorganisms is limited by the dense layer of palisade cells in the seed coat, chemical compounds within the seed coat that are inhibitory to certain microorganisms outside the seed, and antagonistic bacteria located within the seed. Resistances to microbial attack may act together with seed dormancy to maintain velvetleaf seed longevity in soil.
Night Temperature Effects on Morphology, Phenology, Yield and Yield Components of Indeterminate Field‐Grown Soybean1
Authors: Seddigh Majid , Jolliff Gary D. 
Published: July 2010

AbstractSmall changes in geography and topography can result in great differences in night temperature. Indeterminate soybeans [Glycine max(L.) Merr. ‘S09‐90’] of Maturity Group 0 were grown under field conditions in 1981 and 1982 to assess the effect of low night temperature on growth and seed yield. The soil was a Woodburn silt loam (fine‐silty, mixed, mesic Aquultic Argixerolls). Mean minimum night temperature treatments were: Check (uncontrolled, ca. 10°C), 16±1°C and 24±2°C. Elevated night temperatures were achieved by enclosing the plots at night in polyethylene‐covered chambers and increasing chamber temperature with electric heaters. The chamber covers were removed each morning to provide natural field conditions during the daylight hours. Treatments were applied from 2 weeks after crop emergence until physiological maturity. Higher night temperatures enhanced vegetative growth. However, morphological characteristics, e.g., plant height, number of nodes, and number of auxiliary branches were not significantly (P < 0.05) different among the treatments at maturity since the growth of these components also terminated earlier for plants receiving higher night temperatures. Warmer night temperatures considerably shortened the time period between plant emergence and appearance of first flower (R1) and appearance of flowers at the node immediately below the uppermost node (R2), while they had little additional effect on the subsequent reproductive development. Physiological maturity (R7), however, was hastened by higher night temperatures. Accumulated growing degree‐days appeared to be of value for the prediction of all developmental stages and were a good indicator of the time period between emergence and physiological maturity of plants within treatments. Plants with warmer nights, however, accumulated more heat units than the check for the onset of all developmental stages. Seed weight/plant increased above the check by 27 and 37% for 16°C, and 20 and 23% for the 24°C treatments in 1981 and 1982, respectively. The growth of individual seeds appeared to be most responsive to night temperatures, and increased seed size (1000‐seed weight) accounted for the seed yield increase of both treatments. Final numbers of seeds/plant and pods/plant were not significantly affected by the treatments. The number of seeds/pod for the 24°C treatment was, however, significantly greater than the check. The data indicate that the genetic potential for seed yield of indeterminate soybeans is not realized under low night temperatures. This study emphasizes the importance of night temperatures as a potential criterion for developing new soybean cultivars.
Canopy Target Dimensions for Infrared Thermometry1
Authors: O'Toole J. C. , Real J. 
Published: July 2010

AbstractThe increasing use of infrared thermometry in agricultural research and management obviates the necessity of users being cognizant of the instrument's target area characteristics. In this note, we illustrate the target dimensions when an infrared thermometer of specified field of view (4°, 8°, and 20°) is used to remotely sense surface temperature of a leaf, canopy, or crop surface. Knowledge of target dimensions and special characteristics related to the ellipse center and target point at various distances to and angles above the target surface should decrease error in surface temperature measurements and assist in standardization of techniques.
Increased N Efficiency from Nitrapyrin Added to Liquid Swine Manure Used as a Fertilizer for Corn1
Authors: McCormick R. A. , Nelson D. W. , Sutton A. L. , Huber D. M. 
Published: July 2010

AbstractIncreases in the price of N fertilizers encourage farmers to utilize alternative sources of nutrients such as sewage sludges and animal manure when the wastes are available. However, a portion of the applied N may be lost by leaching and/or denitrification after organic N and NH +4‐N in the waste is converted to NO ‐3 by ammonification and nitrification. One way to reduce leaching and denitrification losses is through the use of a nitrification inhibitor. Therefore, field experiments were conducted during three growing seasons to evaluate the effects on corn (Zea mays L.) grain yield and plant composition of mixing nitrapyrin [2‐chloro‐6(trichlormethyl)pyridine], a nitrification inhibitor, with liquid swine (Sus spp.) manure applied to a silty clay loam (fine‐silty, mixed, mesic, Typic Haplaquoll). Nitrapyrin was added to swine manure at rates of 0, 25, and 50 mg L−1, and the swine manure was soil injected in bands during the fall or spring prior to corn planting. Corn grain yields, ear leaf N levels, and grain N concentrations were measured. In 1978, the addition of nitrapyrin (at a rate of 50 mg L−1) to liquid swine manure springapplied at a rate of 49 Mg ha−1 (154 kg available N ha−1) significantly increased grain yield, but not tissue N levels when compared to plots receiving only manure. Yields obtained from plots treated with manure (49 Mg ha−1) plus nitrapyrin were similar to those from plots receiving swine manure at a rate of 110 Mg ha−1 (345 kg available N ha−1) without nitrapyrin or from 134 or 180 kg urea N ha−1. During the 1979 and 1980 growing seasons, the addition of 25 or 50 mg nitrapyrin L−1 of swine manure applied at rates of 31 to 60 and 38 to 60 Mg ha−1, respectively, in the fall significantly increased yields as compared to plots receiving waste without the inhibitor. In 1979 and 1980, addition of nitrapyrin to swine manure applied in the spring at rates of 63 and 78 Mg ha−1 (161 and 286 kg available N ha−1, respectively) had no effect upon corn yield. However, in 1980 the addition of 50 mg nitrapyrin L−1 to manure applied in the spring at a rate of 44 Mg ha−1 (159 kg available N ha−1) significantly increased yields as compared to plots receiving waste without the inhibitor. Large losses of applied N apparently occurred following fall applications of manure. Based upon yield results of manure treatments it is likely that nitrapyrin was effective in reducing losses of applied N and, thereby, increased corn yields by maintaining adequate levels of available N in the plant rooting zone throughout the growing season
Growth, Nutrition, and Water Uptake of Tomato Plants with Divided Roots Growing in Differentially Salinized Soil1
Authors: Papadopoulos I. , Rendig V. V. , Broadbent F. E 
Published: July 2010

AbstractTomato (Lycopersicon esculentum Mill. var. VF 145) plants were grown in the greenhouse to determine effects of uniform and nonuniform salinity distribution on root growth and on water and N uptake. The plants were grown in Reiff sandy loam (Coarse‐loamy, mixed, nonacid, thermic Mollic Xerofluvents) using a technique by which the root system was divided and each of four quadrants allowed to grow in separate compartments. Nutrient solutions differing in salinity levels (1, 4, 7, and 10 dS/m; nonuniform treatment) were applied to the four compartments, or all four received a nutrient solution otherwise similar but with a salinity of 5.5 dS/m (uniform treatment). The salinization was brought about by a mixture of NaCl and CaCI2 in a ratio of 1:1 by weight. To determine sources of N taken up, sufficient K15NO3 was added to provide 2% 15N in the solution. Yields of shoots and roots were lower for the plants grown with the uniform than the nonuniform salinization treatment. With nonuniform salt distribution, about 62 and 8% by weight of the total root system were found in the compartments irrigated with nutrient solutions having initial salinities of 1 and 10 dS/m, respectively. About 63% of the total water taken up per plant was drawn from the compartment with the lowest salinity. With the uniform salt distribution treatment, N uptake into the shoots was more severely affected than growth. With treatments in which salinity was nonuniformly distributed, the main source of N was the compartment with the lowest salinity. The contribution of this compartment, however, decreased during the growing period as its relatively greater salinity buildup favored uptake of N by roots in the other compartments, initially irrigated with the more saline solutions. Plants growing in the units with the nonuniform salinity treatment generally showed lower leaf concentrations of Ca, Na, K, and Cl, but higher leaf concentrations of Mg and P than the plants growing in the uniformly salinized units. Unlike the other elements, K and P concentrations decreased with time. Differences in S concentrations as related to salinization treatments were variable during the growth period. Higher concentrations of the “bound” organic anion fraction, but lower concentrations of the “diffusible” fraction, as determined from differences in amounts of inorganic cations and anion present, were found in leaves of plants grown with the higher salinity levels. In general, for nutrition of tomato plants grown under conditions in which different regions of the root system are exposed to differences in salinity, the least saline environment is dominant, but over time root activity shows some accommodation to the presence of salt.
Narrow Row Soybean Production in Untilled Oat Stubble1
Authors: Burnside O. C. , Moomaw R. S. 
Published: July 2010

AbstractBoth established and subsequently emerging weed species in ecofarming systems must be selectively controlled without tillage in order to better conserve soil and water in the semiarid region of the Great Plains. The objective of this research was to determine selective weed control methods for an oat (Avena sativa L.)‐soybean [Glycine max (L.) Merr.] ecofarming rotation in order to allow dryland soybean production to move further west in the Great Plains. Experiments were conducted at Concord, NE on a Colo silty clay loam (fine‐silty, mixed, mesic, Cumulic Haplaquoll) and at Lincoln, NE on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic, Typic Argiudoll) during 1976 through 1979. Weed control must be effective during the entire crop rotation. There are several herbicide treatments that provide ample length and spectrum of weed control after oat harvest. During the subsequent soybean year, glyphosate [N‐ (phosphonomethyl)glycine] at 0.8 kg ha−1 controlled established weeds prior to soybean planting, and there were several residual herbicide treatments that gave selective weed control in soybeans without cultivation. The low‐till farmer has several herbicide treatments available that will selectively and adequately control weeds without tillage in an oat‐soybean rotation. This low‐tillage method of growing crops in the Great Plains should improve soybean yields and yield stability while conserving soil, water, energy, and labor.