bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Use and Yield of Wheat under Unmulched and Mulched Conditions in Laterite Soil of the Indian Sub‐continent
Authors: Zaman A. , Choudhuri S. K. 
Published: April 2008

AbstractA held experiment was conducted during three winter seasons on West Bengal laterite soil to study the effect of irrigation and paddy straw mulch on water consumption. Water use efficiency and yield of wheat are reported. Both irrigation and mulch increased wheat yield significantly; there was also significant interaction between irrigation and straw mulch application: three irrigations combined with mulch resulted in 21.6 q ha‐1 wheat grain yield compared with 17.5 q ha‐1 for three irrigations without mulch. Mulch consistently increased irrigation response. Both irrigation and mulch increased water consumption and water use efficiency of the wheat crop. To compare the two irrigation treatments, irrigation at crown root initiation followed up by at flowering stage gave higher values of water use efficiency as well as higher grain yield than that of irrigation applied at panicle stage followed by at crown root initiation.
Indirect Determination of Leaf Area Index of Sugar Beet Canopies in Comparison to Direct Measurement
Authors: Röver A. , Koch H.‐J. 
Published: April 2008

AbstractThe determination of the leaf area index of sugar beet canopies by using direct measurement techniques is very laborious. Indirect measurement techniques based on the theory of gap fractions offer a non‐destructive and rapid determination of the leaf area index. In this study the performance of the LAI‐2000 instrument from LI‐COR1 which measures the gap fraction at five zenith angle classes with an upward looking sensor was compared to a direct determination.A thinning test and two measurement series in sugar beet with different population densities and varied nitrogen application were conducted in 1992 and 1993 at the site of Göttingen. The direct determination of leaf area index was based on a destructive sampling of leaves and measurements with a Delta‐T2 image analysis system (DIAS).The results of the thinning test and the measurement series in 1992 did not indicate a significant difference between the LAI‐2000 and the direct determination. With correlation coefficients of 0.98 and 0.95 respectively, the relation between the two techniques was very close. The measurement series of 1993 showed a worse correspondence. In general the values of the LAI‐2000 measurements tended to be a bit lower than those of the direct determination. The leaf area index of sugar beet can be determined with sufficient accuracy using the LAI‐2000 instrument if light conditions are favourable and if the measurement procedure is adapted correctly.
Water Sensitive Periods during the Reproductive Growth Phase of Glycine max L. II Establishing Water Stress Sensitivity
Authors: De Bruyn L. P. , Pretorius J. P. , Human J. J. 
Published: April 2008

AbstractThe water sensitivity of soybeans was determined on a day‐to‐day basis from the onset of flowering to physiological maturity by correlating daily leaf water potential values of 50 different soil water regimes with corresponding grain, vegetative and biomass yields. Days, and consecutive days forming periods, during which significant negative correlations were obtained were regarded as water sensitive periods during the reproductive growth phase of the soybean crop.Water deficits during flowering significantly inhibited vegetative and biomass production but inhibited grain yields only when occurring during early flowering. During pod elongation and seed development the sensitivity of the soybean plant to water stress was present but diminished in time with regard to vegetative and biomass yields. The effect on grain yields was restricted to pod elongation and to later seed development stages. Water stress affected grain yields to a far greater extent than vegetative growth during seed filling and physiological maturity.
The Effect of Chilling Temperature on the Permeability of Membranes to K+, Mg2+, Ca2+ ions and on the Electric Potential of Leaves in the Seedlings of Maize (Zea mays L.)
Authors: Filek M. , Kościelniak J. 
Published: April 2008

AbstractThe relations between the extent of injuries in seedlings caused by a few day‐long exposures to chill (5°C) and the leakage of K+, Mg2+ and Ca2+ ions from the leaves as well as the electric potential in seven maize hybrids, were investigated. The permeability of cells to ions was defined based on their absolute concentration in a water diffusate (Ct) and concentration expressed in relation to the total ion content in the leaves (IL index).At lowered temperature the hybrids of higher resistance to chilling temperature were characterized by a lower value of the IL index for K+ and Mg2+ ions than the chill‐sensitive hybrids. On the other hand, absolute concentration of the ions (Ct) Mg2+ and Ca2+ leaking from the leaves before chill exposure of the seedlings was positively and highly correlated with the extent of injuries in hybrids caused by 4 day‐long exposures to chill. This observation is evidence that the chill injuries were predetermined through increased cell permeability to the mentioned ions at room temperature.Changes in the electric potential of leaves in conditions of lowered temperature preceded the injuries of leaves, which became apparent after a longer period of exposure to chill. Thus, as the leakage of Mg2+ and Ca2+ ions occurs, changes in the electric potential may supply early information about the predisposition of the particular maize hybrids to chilling injuries. Leakage measurements of Mg2+ and Ca2+ ions from the leaves at room temperature may find application in the selection of chill‐tolerant maize genotypes.
Water‐Sensitive Periods during the Reproductive Growth Phase of Glycine max L. I. Regression Model for estimating daily leaf water potential
Authors: de Bruyn L. P. , Pretorius J. P. , Human J. J. 
Published: April 2008

AbstractTo establish the exact duration of critical periods for plant water stress during the reproductive growth stage of soybeans it is necessary to draw correlations between daily leaf water potential values and crop growth and yield. Different sets of daily leaf water potential values can be induced by different sets of irrigation applications. It is, however, imperative that water stress values are available for each day over the growing season of a large number of irrigation treatments. Since these values were not available, it was decided to calculate it by establishing a relationship between leaf water potential as determined by potential evapotranspiration and soil water content as well as soil water potential for various layers of the root zone. The most reliable regression formula was found to be:
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Effect of Different Preceding Crops and Crop Rotations on Yield of Winter Oil‐seed Rape (Brassica napus L.)
Authors: Christen O. , Sieling K. 
Published: April 2008

AbstractTo determine the effect of different preceding crops and crop rotations on the grain yield of oil‐seed rape, a long‐term rotation experiment was conducted at the Hohenschulen experimental station in Kiel, NW Germany. Additional factors included the nitrogen fertilization and the fungicide application. The results reported herein are based upon the harvest years 1988 to 1993.Averaged over the different rotations and husbandry treatments, the grain yields in the 6 experimental years varied between 2.71 t ha−1 and 3.99 t ha−1. In contrast, the effect of the different husbandry treatments was smaller and non significant. Averaged over 6 years, only the fungicide application caused small yield increase of 0.2 t ha−1.The highest grain yields of 3.77 t ha−1 or 3.65 t ha−1 occurred when oil‐seed rape was directly following peas. Low yields between 3.15 tha−1 and 3.33 tha−1 were obtained when oil‐seed rape was grown after oilseed rape. The lowest grain yield of 3.13 t ha−1 was produced with oil‐seed rape grown in monoculture only. In rotations with oil‐seed rape following a preceding cereal crop (wheat or barley), the grain yields averaged between 3.22 tha−1 in a two course rotation and up to 3.44 tha−1 in a four course rotation. In general, the yields of oil‐seed rape increase with the length of the rotation and the length of the break between two oilseed rape crops. The yield component number of seeds per m2 was affected by the previous cropping accordingly, whereas the thousand seed weight did not respond to the cropping history.Based upon disease assessments in the first years of this experiment, we argue that an increase in the incidence of fungal diseases has considerably contributed to the yield decrease of oil‐seed rape in short rotations.
Maize Grain Yield Response to Tillage and Fertilizer Nitrogen Rates on a Tara Silt Loam
Authors: Olness A. , Evans S. D. , Moncrief J. F. 
Published: April 2008

AbstractEffects of tillage on the appropriate fertilizer N applications needed to achieve maximal grain yield are poorly denned. The study objective was determination of relative corn grain yield response to N application rate for four tillage practices: no‐tillage (NT), ridge tillage (RT), fall chisel plowing (CP) and fall moldboard plowing (MP). Maize (Zea mays L.) grain yield and N accumulation were monitored over a 6 year period with the same tillage treatment and the same fertilizer N rate applied each year to each plot. Two hybrids, differing in relative maturity rating, were planted each year. Fertilizer N rates ranged from 10 to 190 kg ha−1 and consisted of 10 kg ha−1 of liquid starter N applied at planting with varying amounts of fall applied anhydrous ammonia. With only starter fertilizer, grain yields increased with tillage intensity in the order NT ≤ RT ≤ CP ≤ MP. With ≥ 55 kg total applied Nha−1, 6 year average grain yields were unaffected by tillage. Total N removed in grain annually with only starter fertilizer ranged from 25–85 kg ha−1 Maximal amounts of N removed, about 145 kg N ha−1, occurred with 100–145 kg applied N ha−1 for all tillage treatments under the more favorable climatic conditions. Several interactions affecting grain yield appear climatically sensitive with exception of tillage by fertilizer N interactions. Because of variability in climate, planting dates varied by almost 4 weeks. Relative yield loss due to planting delay were Fertilizer N (mean change ≅−124 –−275 kg ha−1 day−1) > Starter N only and MP (mean ≅− 259 kg ha−1 day−1) > other tillages in general. Yield loss due to delayed planting ranged from 0.0–275 kg ha−1 day−1. Grain yield gains due to early spring soil temperatures were 16.0–21.8 kg ha−1 index‐degree−1 with MP tillage and averaged 2.7– 16.7 kg ha−1 index‐degree−1 more than those of other tillage‐hybrid combinations.
Physiological Basis of Salinity Tolerance of Sorghum Seeds During Germination
Authors: Marambe B. , Ando T. 
Published: April 2008

AbstractEffects of salinity on the isozyme activities of α‐amylase in germinating sorghum seeds were studied under laboratory conditions. Seeds were imbibed in NaCl solutions at concentrations ranging from 0–500 nM (osmotic pressure: 0–2.28 MPa) for 0–24 h and the isozymes activities were estimated after disc‐gel electrophoresis.Seed germination of sorghum was not affected by NaCl concentrations less than 100 nM (0.46 MPa). Germination was reduced by 50% at 300 nM NaCl (1.31 MPa), and completely inhibited at 500 nM (2.28 MPa). The α‐amylase activity in the treated seeds followed a similar pattern to that of germination.At least five isozyme patterns of a‐amylase were observed in germinating sorghum seeds. The activities of the respective isozymes were enhanced with increasing duration of imbibition in distilled water. When treated with 100 nM NaCl, the activities of isozymes 2 and 5 decreased, but this was compensated by the increased activity of isozyme 1. The sensitivity of isozymes to the salinity treatments varied where isozyme 1 was the most tolerant. The isozyme activities were completely inhibited by 500 nM NaCl.The results indicate that sorghum seeds could germinate well in saline environments up to 0.46 MPa. Higher osmotic pressure or saline concentrations could be detrimental to the seed germination of sorghum. The salinity tolerance could be attributable to the compensation of loss of activities of certain isozymes of α‐amylase by the other types.
Time Course of Nitrogen in Soil Solution and Nitrogen Uptake in Maize Plants as affected by Form and Application Time of Fertilizer Nitrogen
Authors: Buerkert B. , Horlacher D. , Marschner H. 
Published: April 2008

AbstractField experiments with silage maize were conducted in 1987 and 1988 on a loess‐derived Luvisol in southwest Germany. Four nitrogen fertilizer treatments were compared: application of preplanting NH4 N (plus a nitrification inhibitor, dicyandiamide as Didin) and preplanting NO3‐N, split application of NO3‐N (preplanting and side dressed 45 days after planting) and a control without nitrogen fertilizer in 1987 and with 64 kg N ha−1 as calcium ammonium nitrate in 1988. The total amounts of soil mineral nitrogen (Nmin+ fertilizer N) were 200 kg N ha−1 in 1987 and 240 kg N ha−1 in 1988. Suction cups and tensiometer were installed at five depths and samples were taken in regular intervals.Nitrate concentrations in the suction solution steeply increased at 15 cm and 45 cm soil depth 3‐4 weeks after fertilizer application (1987 up to 160mgNl−1; 1988 up to 170mgN l−1) and steeply decreased up to 75 cm depth with the onset of intensive N uptake at shooting. Ammonium concentrations in the suction solution were very low (0‐0.16 mg N l−1). Compared to preplanting NCyN application, preplanting NH4‐N and split NO3‐N application decreased nitrate concentrations in the suction solution in spring 1987. In 1988, however, nitrate concentrations in the suction solution of preplanting NH4‐N and split NO3‐N application plots did not fall below 50mgNl−1 at 15 cm depth during the growing season. Nitrate concentrations of split NO3‐N application increased again in autumn 1988 and hence doubled the calculated N losses by leaching during the winter months compared to preplanting N applications. At shooting, plants of the preplanting NH4‐N treatment had lower nitrate concentrations in leaf sheaths compared to plants of preplanting NO3‐N application. Total N uptake of maize between shooting and early grain filling of preplanting NH4‐N and split NO3 ‐N application tended to be higher compared to preplanting NO3‐N application, reflecting the higher N availability in the soil later in the season. However, final dry matter yields and N uptake were not significantly affected by N form or time of N application. Since N losses by nitrate leaching between N application and onset of N uptake by plants were negligible on the experimental site, preplanting NH4‐N application and split NO3‐N application showed no agronomic advantages. High amounts of side dressed NO3‐N may increase nitrate leaching during the winter months, especially in years with delayed rainfall after application.
Variation in Salinity Tolerance in Sunflower (Helianthus annum L.)
Authors: Ashraf M. , Tufail M. 
Published: April 2008

AbstractForty‐five accessions of sunflower collected from different countries were screened for salinity tolerance after 2 weeks growth in sand culture salinized with 150 meq l−1 of NaCl2+ CaCl2 (1:1 ratio equivalent wt. basis) in half strength Hoagland's nutrient solution. The results for plant biomass of 45 accessions show that there was considerable variation in salinity tolerance.In a further greenhouse experiment, the salinity tolerance of three tolerant (HO‐1, Predovik, Euroflor) and two sensitive (SMH‐24, 9UO‐985) lines (selected on the basis of their performance in the seedling experiment) was assessed at the adult stage to evaluate the consistency of salinity tolerance at different growth stages. All three salt tolerant accessions produced significantly greater plant biomass, seed yield and seed oil content than the salt sensitive accessions. The tolerant accessions accumulated less Cl− and more K+ in the leaves under saline conditions compared with the salt sensitive accessions. The salt tolerant accessions also maintained relatively high leaf K:Na ratio and K+ versus Na+ selectivity. Although statistically nonsignificant, all three tolerant accessions had greater soluble carbohydrates, soluble proteins, total free amino acids and proline in the leaves than the sensitive accessions. A field trial conducted in a salt‐affected field confirmed the greenhouse results of the selected accessions.This study shows that salinity tolerance of sunflower does not vary with stage of plant cycle, so selection for increased salt tolerance can be carried out at the initial growth stage. Secondly, it is found that there is great variation of salt tolerance in sunflower. Low uptake of Cl−, high uptake of K+, and maintenance of high K:Na ratios and K+ versus Na+ selectivity in the leaves and possibly the accumulation of organic osmotica such as soluble carbohydrates, soluble proteins, proline and free amino acids seem to be the important components of salt tolerance in sunflower.
Impact of Different Weed Types on Growth and Yield of Mungbean (Vigna radiata L. Wilczek)
Authors: Sangakkara U. R. , Meylemans B. , van Damme P. 
Published: April 2008

AbstractThe influence of different weed types (grass, broadleaved and sedge species) on growth and yield parameters of mungbean (Vigna radiata L. Wilczek) was evaluated under field conditions. The presence of all types of weeks had the most significant effect on growth and yields of mungbean. Broadleaved species alone had a greater adverse effect than grasses, and the influence of sedges was the lowest. The adverse effect of weeds was most prominent on vegetative growth. The influence on yield components reduced with time. However, the adverse impact of weeds on yields was similar to that on vegetative growth. A significant correlation between weed biomass and yield loss was observed. The study indicated the critical competitive period to be in the vegetative phase. Some possible implications for selective weeding are presented.
Evaluation of N Fertilizer Rate and Timing and Wheat Cultivars on Soil Residual Nitrates
Authors: Ayoub Micheline , Mackenzie A. , Smith D. L. 
Published: April 2008

AbstractNitrogen (N) fertilizer management for production of bread quality wheat may increase nitrate residues in the soil. To assess soil nitrate levels associated with bread quality wheat (Triticum aestivum L.) production in Eastern Canada, an experiment was conducted for 2 years at each of two sites in Québec. Four cultivars (Columbus, Katepwa, Max and Hege 155‐85), four N levels (0, 60, 120 and 180 kg N ha−1) and two N timings (all at seeding time or 60 % at seeding and 40 % at anthesis) were combined in a factorial arrangement on a Bearbrook clay and a Ste‐Rosalie clay. Residual soil NO3‐N levels were measured in the 0–20 and 20– 60 cm soil layers. The cultivars used have potential as bread wheats. Cultivar effects on soil nitrate levels existed only in the Ste‐Rosalie soil, suggesting that the cultivars used were better adapted to the conditions on the Bearbrook soil. Changes in soil NC3N levels over winter indicated that mineralization had occurred. Calculated balance‐sheet values were larger than measured residual NO3‐N in the autumn of each year, indicating that NO3‐N was lost from the systems, possibly due to denitrification. Potential increases in, and thus potential pollution from, residual soil NO‐N existed only at the 180 kg N ha−1 level. Overwinter changes in soil NO3‐N levels were proportional to the inverse of the fall NC3N levels. Differences between sites were large for many of the variables measured.
Electrolyte Leakage, ATP Content in Leaves and Intensity of Net Photosynthesis in Maize Seedlings at Permanent or Different Daily Exposure to Low Temperatures
Authors: Markowski A. , Skrudlik G. 
Published: April 2008

AbstractChanges were determined in electrolyte leakage (EL), ATP content in leaves and intensity of net photosynthesis (FJ in maize seedlings as a result of continued exposure to low temperatures for several days or, after a cold night (5 °C, 9 h), alternating application of 5 °C and 20 °C temperatures during the lit phase of the day (h of chilling during day/night: 0/9, 5/9, 10/9, 15/9).At continuous exposure to low temperatures, permanent reduction of ATP content occurred between days 7 and 10, while EL increased significantly between days 4 to 7 (depending on experimental conditions). Of three leaves differing in age, most injuries were found in the oldest leaf. An increased intensity of irradiation from 150 to 500 μE. m−2.s−1 caused an earlier decrease in the ATP content and a further increase in electrolyte leakage. ATP content showed a 24 h rhythm, it increased at the end of the night and decreased at the end of the day. The rhythm was particularly noticeable in the control plants (20 °C), as well as, however to a lesser extent, in plants exposed to daily fluctuating chilling temperatures. It has also been observed that higher temperatures occurring in day time may diminish electrolyte leakage induced by previous low temperaturesThe intensity of Fn determined at 20 °C, 4 h after withdrawal of chilling, decreased with the prolongation of the chilling period during the day.Thus, it may be assumed that the EL and Fn values as indicators of the plants' sensitivity are in better agreement with the induced chill doses than the ATP content in leaves, which to a greater extent depends on the interaction between chilling and other experimental factors, such as irradiation intensity or the sequence of light and darkness.
Interactions of Azotobacter chroococcum, Azospirillum brasilense and Streptomyces mutabilis, in Relation to their Effect on Wheat Development
Authors: El‐Shanshoury A. R. 
Published: April 2008

AbstractSingle or dual inoculation of wheat seedlings (Triticum aestivum L. cv. Sakha 69) with Azotobacter chroococcum, Azospirillum brasilense or Streptomyces mutabilis in sterilized soil resulted in significant stimulation of their populations in the rhizosphere, compared with the initial values. Viable counts of Azospirillum and Azotobacter decreased in dual inoculations with Azotobacter or Streptomyces, and contrasted with those of Streptomyces, compared with the results of single inoculation. Single and dual inoculations stimulated plant growth, significantly increased the concentrations of indole‐3‐acetic acid (IAA), P, Mg, N and total soluble sugars (TSS) in wheat shoots. Soil content of N increased by single inoculation with Azotobacter and all dual inoculations. Soil‐IAA significantly increased by all inoculations. Growth of A. brasilense significantly inhibited by filtrates from 7‐day‐old cultures of S. mutabilis than from A. chroococcum, in vitro. The biosynthesis of antibacterial substance(s) by Azotobacter significantly decreased by supplementing their cultures with metabolic products from A. brasilense, but were stimulated by metabolic products from Streptomyces cultures. All metabolic products significantly decreased the growth of A, chroococcum, A. brasilense and S. mutabilis, nitrogen‐fixation and biosynthesis of IAA in A chroococcum, whereas biosynthesis of IAA stimulated in S. mutabilis. Most of the measured parameters after exposure to the tested bacteria or their metabolites were significantly correlated. The significance of IAA, nitrogen fixation and antibacterial substances, produced by such agronomically beneficial bacteria in early wheat growth is discussed.