bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Types and Duration of Weeds on Yield Parameters of Cocoyam (Xanthosoma saghtifolium)
Authors: Sangakkara U. R. 
Published: April 2008

AbstractWeeds reduce yields of all tropical crops significantly, and these effects vary with different species. Thus, the influence of time of weed control and types of weeds on yield parameters of cocoyams (Xanthosoma sagittifolium), a tropical tuber crop, was determined by two experiments conducted simultaneously. In one experiment, weeds were removed at different times during crop growth. In the other, different weed types were removed selectively to leave either one or two of the identified categories, namely grasses, broadleaves and sedges. The presence of weeds throughout the growth cycle of the crop reduced yields of cocoyams by 60 %. Removal of weeds at early growth stages produced greater yields than weeds were present beyond 18–22 weeks after planting. The presence of weeds at the time of tuber initiation had the greatest adverse effect on yield parameters. Weeds had a delaying but not an inhibitory effect on cormel initiation. However, all other yield parameters were reduced by weeds. Broadleaved weeds, which have similar growth patterns as cocoyams reduced yields to a greater extent than grasses. Sedges had no significant impact on cocoyams. The presence of grasses and broadleaves together reduced growth and yields of this crop to a greater extent than any other combination.
Der Einsatz von Reststoffen der Altpapieraufbereitung auf landwirtschaftlich genutzten Flächen als Bodenverbesserungsmittel
Authors: Beyer L. , Blume H.‐P. , Mueller K. , Schleich‐Saidfar C. 
Published: April 2008

Abstract The application of secondary paper mill sludges on arable soils to improve soil fertility In field investigations the application of secondary paper mill sludges on arable soils was tested. No deterioration could be verified with regard to soil and plant growth. However an improvement was not significant.Accumulation of heavy metals in soils or plants was not observed. There was no risk of soils and plants, because the contents of organic halogen compounds were much lower than the common administrative threshold values. The carbonate content of the sludges was variing very much. This is why a prognosis of the pH‐effect was difficult. Nitrogen was fixed in the soil during decomposition of the sludge, which was poor in nitrogen.An application of secondary paper mill sludge on arable soils have to be connected with a fertilization to equalize nitrogen supply. Industrial process should guarantee always a similar carbonate content in the sludge to avoid micronutrients deficiency.
Narbon Vetch (Vicia narbonensis L.): A Potential Feed Legume Crop for Dry Areas in West Asia
Authors: Abd El Moneim A. M. 
Published: April 2008

AbstractProvision of feed supplies for the rapidly growing livestock population is essential in West Asia. Shortages can be alleviated by growing forage crops in the existing fallow lands.Narbon vetch (Vicia narbonensis L.) is a leguminous species with high yield potential, drought tolerance and cold resistance. It could be used for grain and straw production as source for animal feed in dry areas. It is good source of protein with seeds contain 28 % protein yielding 364 kg per hectare protein, whilst straw contains 9 % protein and yields a similar amounts of digestible protein per hectare.Nine promising lines of Narbon vetch developed at ICARDA were tested at two sites over four years under rainfed conditions. Since climatic conditions were considered to be of considerable importance, each site in each year was treated as a separate environment to give eight environments with annual rainfall varied from 195 to 504 mm.Narbon vetch possessed high seedling vigour with rapid winter growth and negligible cold damage. Grain yield varied form 0.47 to 1.90 t/ha, with a harvest index varying from 30 to 40 %. The data indicated that below 300 mm rainfall the grain yield varied from 0.47 t/ha when rain fall was 195 mm to 1.4 t/ha when rainfall was 245 mm. Most of the lines had wide adaptation to dry areas in terms of both grain yield and stability. Climate, except early spring rains had little effect on biological and grain yields.
Antibiosis to Corn Earworm [Helicoverpa zea (Boddie)] by Vegetable Soybean Cultivars
Authors: Joshi J. M. , Javaid I. , Dadson R. B. , Nobakht M. 
Published: April 2008

AbstractSix cultivars of vegetable sovbean (Glycine max [L.] Merr.) were evaluated in the laboratory for relative levels of antibiosis to corn earworm (Helicoverpa zea [Boddie]). The cultivars evaluated were Fuji, Kim, Oakland, Peking, Sanga, and Toano. One plant introduction (PI 229.358) having known resistance to corn earworm and Essex, a commercial cultivar, were used as check plants. The biological data for antibiosis in a series of tests included larval weights. The results showed that cultivars Sanga, Peking, and Oakland were comparatively more susceptible while cultivars Fuji, Kim, and Toano exhibited a moderate level of leaf feeding resistance to corn earworm. The cultivars with moderate resistance can be useful in reducing corn earworm damage and cost of chemical control in vegetable soybean insect pest management systems.
Effect of Nitrogen Fertilization on Grain Yield and Accumulation of Nitrogen, Phosphorus and Potassium in the Grains of Tropical Maize*
Authors: Thiraporn R. , Feil B. , Stamp P. 
Published: April 2008

AbstractTo investigate the effect of increasing rates of N on grain yield and the accumulation of N, P and K in the grains of maize, three experiments were conducted at Farm Suwan (Kasetsart University), Thailand (latitude 14.5°N). Grain yields and biomass increased considerably up to 80 kg N ha‐1. Higher doses (160 kg N) did not enhance the biomass and improved the grain yield only slightly. The harvest index did not respond uniformly to increasing rates of N. Nitrogen fertilization increased yields of grain N, P and K. The concentration of N in the grains generally increased with increasing N fertilization. The effect of increasing rates of N on P and K concentrations in the grains was different in the experiments. The total uptake of N and P increased up to 160 kg N, that of K up to 80 kg N. The N harvest index was only slightly affected by N fertilization whereas the K harvest index tended to increase and the P harvest index increased strongly with increasing rates of N. Kernel weights were higher at high levels of N. The weights of kernel N, P and K remained either almost stable or increased slightly with increasing rates of N fertilizer.ZusammenfassungEffekt der Stickstoff‐Düngung auf den Kornertrag und die Akkumulation von Stickstoff, Phosphor und Kalium in den Körnern von tropischem MaisUm den Effekt von steigenden Stickstoffgaben auf den Kornertrag und die Akkumulation von Stickstoff, Phosphor und Kalium in den Körnern von Mais zu untersuchen, wurden drei Versuche auf Farm Suwan (Kasetsart University), Thailand (14,5° nördlicher Breite), durchgeführt. Die Kornerträge stiegen bis zu einer Düngermenge von 80 kg N ha‐1 beträchtlich. Höhere N‐Gaben (160 kg N) führten zu etwas höheren Kornerträgen, vermochten jedoch die Biomasse nicht mehr zu steigern. Der Ernteindex reagierte auf steigende N‐Gaben uneinheitlich. Die N‐Düngung erhöhte die N, P und K‐Mengen in den Körnern. Die N‐Kon‐zentration in den Körnern stieg mit steigender N‐Versorgung. Der Effekt einer steigenden N‐Düngung auf die P und K‐Konzentration in den Körnern war in den Experimenten verschieden. Die gesamte Aufnahme von N und P stieg bis 160 kg N, die von K nur bis 80 kg N. Der N‐Ernteindex wurde von der N‐Düngung nur gering beeinflußt, der K‐Ernteindex tendierte zu einem Anstieg und der P‐Ernteindex zeigte einen deutlichen Anstieg mit sich erhöhendem N‐Angebot. Die N‐Düngung erhöhte das TKG. Die N, P und K‐Massen der Körner waren entweder fast unverändert oder stiegen geringfügig mit erhöhter N‐Zufuhr.
Distribution of Seed N and Soil N in Wheat Seedlings (Triticum aestivum L.)
Authors: Kullmann A. , Greef J. M. 
Published: April 2008

AbstractAn experiment was conducted to quantify the effect of a increasing N supply to the N uptake, translocation of seed N reserves and distribution of nitrogen within the plant of three wheat genotypes. The seedlings grow up under controlled conditions of a growth chamber in a period of 15 days. The main treatments were three N supply levels, namely, 0.5, 5.0 and 12.0 mM N given as labelled nitrate. For purposes of analyzing of dry matter, total nitrogen and nitrate concentration in different plant tissues plants were harvested in 3 days intervals beginning three days after germination. N uptake was calculated. With the use of labelled N it was possible to discriminate between the both N sources. Characteristic changes in the development were observed for the change from heterotroph to autotroph growth period. In the autotroph phase seed nitrogen was preferently translocated to the shoot tissue. A comparable situation existed for the uptake and distribution of soil nitrogen. With increasing N supply nitrate accumulated in root tissue. The three genotypes showed differences in the capacity of N uptake, N utilization and conversion into dry matter.Zusammenfassung Verteilung von Endosperm‐ und Bodenstickstoff in jungen Weizenpflanzen (Tri‐ticum aestivum L.) Bei drei Weizensorten wurden die Aufnahme von Stickstoff aus einem variierten N‐Angebot und die Verteilung von Stickstoff innerhalb der Pflanze unter Berücksichtigung der Endo‐spermreserven geprüft. Der Versuch wurde unter kontrollierten Bedingungen in einer Wachstumskammer in einer Zeitdauer von 15 Tagen durchgeführt. Markierter Stickstoff wurde in drei Konzentrationen (0,5, 5,0 und 12,0 mM) als Nitrat verabreicht. Die Keimpflanzen wurden in einem dreitägigen Intervall geerntet und fraktioniert. Von den einzelnen Pflanzenfraktionen wurde die Trockenmasse, die Gesamt‐N‐Konzentration und die Nitratkonzentration ermittelt. Aus diesen Werten wurde Stickstoffaufnahme berechnet. Die Verwendung von markiertem Stickstoff erlaubte eine Differenzierung der verschiedenen Stickstoffquellen. Charakteristische Veränderungen konnten für den Wechsel zwischen heterotro‐pher und autotropher Phase beobachtet werden. Während der autotrophen Phase wurde Stickstoff vorzugsweise in den Sproß transio‐ziert. Ähnliche Verhältnisse in der Verteilung konnten für aufgenommenen Stickstoff aus dem Nährmedium beschrieben werden. In Abhängigkeit von der N‐Konzentration wurde Nitrat vermehrt im Wurzelbereich akkumu‐liert. Die verwendeten Sorten unterschieden sich in ihrem Vermögen, Stickstoff aufzunehmen, umzusetzen und in Trockenmasse zu konvertieren.
Effect of Nitrate Application on Shoot and Root Development of Wheat Seedlings (Triticum aestivum L.)
Authors: Greef J. M. , Kullmann A. 
Published: April 2008

AbstractThe experiment was conducted to describe the effect of a varying nitrate level on shoot and root development of young wheat plants. The plants grew up under controlled condition of a growth chamber for a period of 15 days after germination. Nitrogen was applicated as nitrate in three levels of 0.5; 2.5 and 12.0 mM N. Seedlings were harvested in a three day interval beginning 72 d after germination. The plants were dissected into shoot and root. Root morphology is described by number, length and area of main and lateral root system. The shoot development is characterized by leaf area and chlorophyll concentration.Especially the shoot growth was effected by varying nitrate application. The reaction of the root system on the nitrogen nutrition showed an indifferent situation. With higher N level the N uptake of all genotypes increased. Genotypic differences exists between the efficiency of nitrate uptake determined as N absorption per unit root parameter. The shoot is an important factor for the utilization and conversion of nitrate into dry matter.Zusammenfassung Einfluß auf die Sproß‐ und Wurzelentwicklung verschiedener Weizengenotypen (Triti‐cum aestivum L.) in Abhängigkeit von der Nitratversorgung Der Versuch wurde durchgeführt, um den Effekt einer variierten Nitratversorgung auf die Sproß‐ und Wurzelentwicklung von verschiedenen Weizengenotypen zu erfassen. Die Keimpflanzen wuchsen unter kontrollierten Bedingungen 15 Tage nach der Keimung in einer Wachstumskammer auf. Stickstoff als Nitrat wurde in den drei Konzentrationen 0,5, 2,5 und 12,0 mM N verabreicht. Die Pflanzen wurden in einem dreitägigen Intervall geerntet, beginnend 72 Stunden nach der Keimung. Die Pflanzen wurden in Sproß und Wurzel getrennt. Die Wurzelmorphologie wurde mit Hilfe der Parameter Anzahl, Länge und Oberfläche des Haupt‐ und Seitenwurzelsystems erfaßt. Zusätzlich wurden die Blattflächenentwicklung und die Chlorophyllkonzentrationen der einzelnen Blattstufen beschrieben. Besonders das Sproßwachstum ist durch die Nitratbehandlung deutlich beeinflußt worden. Das Wurzelsystem zeigte ein uneinheitliches Reaktionsmuster auf. Die Nitrataufnahme steigerte sich mit zunehmender Stickstoffversorgung. Genotypische Differenzen bestanden in der Leistungsfähigkeit, Nitrat aufzunehmen, ausgedrückt als Nitrataufnahme per Einheit Wurzelmerkmal. Der Sproß spielte in der Verwertung und Umsetzung von Stickstoff in Trok‐kenmasse eine entscheidende Rolle.
Description and Application of a Screening Method to Determine Root Morphology Traits of Cereal Cultivars*
Authors: Léon J. , Schwarz K.‐U. 
Published: April 2008

AbstractGenotypic differences in root traits may be responsible for differences in yield especially under unfavourable growing conditions. This study was conducted to describe root morphology traits of oat and barley genotypes using a screening technique and to relate these root characteristics to the biomass accumulation of the genotypes in field tests. The described method permits the rapid quantification of morphological root parameters for large numbers of genotypes. Plants of oat and barley cukivars grew on filter‐paper which was soaked in a nutrient solution and was fixed on acryl‐glass plates. Genotypic differences in root morphology were measured periodically by counting the intersections between roots and horizontal lines of a grid. Oat and barley cultivar differences were detected for the sum of intersections (SIS) and for SIS of separated root zones. These cultivar differences showed no relationship to biomass and grain yield. However, regarding drought environments with low N fertilization supply the genotypic rank orders of grain yield and SIS were associated. Therefore it is stated that a selection for high SIS of deeper root zones may serve as an indirect selection for yield stability rather than for yield. Furthermore, the observed genotypic differences in SIS among high yielding cukivars provide the chance to select between actual breeding lines.ZusammenfassungBeschreibung und Anwendung einer Schnellmethode zur Bestimmung wurzelmorphologischer Merkmale bei GetreidesortenGenetische Unterschiede in Wurzeleigenschaften können insbesondere unter ungünstigen Wachstumsbedingungen für Ertragsunterschiede verantwortlich sein. Ziel dieser Studie war es, Merkmale der Wurzelmorphologie von Hafer‐ und Gerstengenotypen mittels einer Serienmethode zu untersuchen und diese Merkmale mit der Biomassenbildung zu verknüpfen. Bei der Bestimmungsmethode wuchsen die Getreidepflanzen auf einem mit Nährlösung getränkten Filterpapier, welches sich auf einer um 15 Grad von der Vertikalen geneigten Acrylglasscheibe befand. Die Genotypunterschiede in der Wurzelmorphologie wurden periodisch durch Zählung der Schnittpunkte zwischen den Wurzeln und einem horizontalenRaster gemessen. Sowohl die Hafer‐, als auch die Gerstensorten wiesen in der Summe der Schnittpunkte (SIS) Unterschiede auf. Diese Sortenunterschiede waren nicht mit Sortenunterschieden im Ertrag korreliert. Jedoch zeigte eine differenzierte Auswertung, daß für trok‐kene und schwach mit N‐Düngung versorgten Umwelten die Genotypenrangfolge zwischen Ertrag und SIS ähnlich waren. Eine Selektion auf hohe SIS der tieferen Wurzelschichten dürfte daher eher als Selektion auf höhere Ertragssicherheit als auf hohen Ertrag verstanden werden. Die Tatsache, daß auch zwischen hoch ertragreichen Sorten Unterschiede in der SIS gefunden wurden, bietet die Chance einer Selektion auf hohe SIS auch innerhalb des aktuellen Züchtungsmaterials.
Nitrogen Movement in an Arable Sandy Soil and Ways of Reducing Nitrogen Losses — Preliminary Results*
Authors: Herzog H. , Konrad R. 
Published: April 2008

AbstractIn order to reduce nitrogen leaching during the autumn‐winter period and to test methods for quantifying leaching processes, a field trial was performed on a sandy soil at the experimental station in Berlin‐Dahlem. Treatments comprised different tillage managements (10 cm rotary hoe vs. 25 cm plough), fallow vs. growing winter rape as a catch crop, and different nitrogen applications (0, 50, 100 kg/ha N). Effects were appraised by simple nitrogen balance, determination of Nmin and nitrate concentrations in the soil water. First attempts were made to assess water flows in the soil monitoring matric water potentials.The catch crop took up about 55 kg/ha N and was by far most efficient in reducing Nmin and nitrate concentrations of the soil; moreover, the beginning of water movement in the soil was considerably delayed. The addition of 50 or 100 kg/ha N stimulated growth and N‐uptake by the catch crop, but revealed no obvious advantage in N‐conservation in the soil, besides a 3‐day‐retardation of leaching. Nmin in May as well as plant data of the following spring wheat indicated a poor efficiency of autumn‐applied nitrogen. Reduced tillage on the fallow decreased Nmin and nitrate concentrations, but such effect was hardly detectable in combination with the catch crop (due to its impact on growth and N‐uptake).ZusammenfassungStickstoffverlagerung auf einem sandigen Ackerboden und Möglichkeiten zur Minderung von Verlusten — vorläufige ErgebnisseMit dem Ziel N‐Verlagerung im Herbst— Winter zu verringern und Methoden der Quantifizierung des Verlagerungsprozesses zu testen, wurde ein erster Feldversuch auf einem Sandboden der Versuchsstation in Dahlem angelegt. Die Maßnahmen umfaßten Bodenbearbeitung (10 cm flaches Fräsen und 25 cm tiefes Pflügen), Brache und Zwischenfruchtanbau mit Winterraps sowie 0, 50 und 100 kg/ha N‐Düngung. Die Wirkungen wurden anhand einer vereinfachten N‐Bilanz, Bestimmungen von Nmin sowie Nitrat der Bodenlösung überprüft. Einen ersten Ansatz, den Wasserfluß im Boden zu erfassen, bildete die Ermittlung der matrikalen Wasserpotentiale.Die Zwischenfrucht nahm ca. 55 kg/ha N auf und minderte die Nmin‐ und Nitratwerte im Boden am effektivsten, darüber hinaus verzögerte sie den Beginn der Wasserbewegung im Herbst erheblich. Eine Düngung mit 50 oder 100 kg/ha N förderte Wachstum und N‐Aufnahme der Zwischenfrucht, aber bedingte außer einer 3tägigen Verzögerung der Verlagerung keine Vorteile bei der N‐Konser‐vierung. Nmin im Mai und Pflanzendaten der Nachfrucht wiesen auf eine schlechte Effizienz dieser N‐Düngung. Reduzierte Bodenbearbeitung senkte die Nmin‐ und Nitratkonzentration unter Brache leicht, nicht jedoch bei Zwischenfruchtanbau.
Effect of Low Night Temperatures on Photosynthetic Activity of the Maize Seedlings (Zea mays L.)
Authors: Kościelniak J. 
Published: April 2008

AbstractNight chilling (5 °C) subsequently lowered photosynthetic intensity in the leaves of maize seedlings at 20 °C through an increase in leaf diffusive resistance brought on by lower tissue water content in morning hours. A more significant increase in leaf diffusion resistance was observed when soil temperature was lowered than in the case of lower air temperature.The unfavorable effect of soil and air cooling temperature on photosynthesis was limited by air saturated with water vapour. However, as a result of lowering the night temperature from 5 °C to 1 °C, the efficiency of the protective influence of higher atmospheric humidity was decreased. This demonstrates that the participation of factors unrelated to plant water status in inhibiting photosynthesis increases with lower night temperatures.An additional reason for inhibited photosynthesis following cool nights was a decrease in chlorophyll accumulation, below 50 μg per 1 cm2 of leaf area.
Weed Competition in Soybeans (Glycine max L.)
Authors: Abusteit E. O. 
Published: April 2008

AbstractThe present investigation was conducted to determine the critical period of weed competition in soybeans at Giza, Egypt. Weed flora in the experimental site at Giza contained a wide range of species during both seasons of study (1990 and 1991). Total weed dry weight increased progressively with time up to 12 WAE (182.0 g/m2). Weed‐free and weedy periods exhibited significant effects on soybeans height, number of pods per plant, stand at harvest, biological and seed yields. Optimum seed yields were produced by weed‐free durations for 6 WAF up to all season (3.229–3.545 t/ha). Whereas, weedy periods for 2, 4, 6, 8, 10 and 12 WAF reduced seed yield by 14.9, 28.0, 35.3, 45.1, 48.1 and 51.1 %, respectively. Weed competition for the entire season caused 56.1 % reduction in soybean seed yield. The obtained results indicate that weed competition during the early stages of growth, adversely affected soybeans. At least 6 WAE of weed‐free period was required to insure optimum soybean growth and yield. However, oil and protein contents were not affected by weed competition.
Stickstoffdüngung und chemischer Pflanzenschutz in einem Dauerfeldversuch und die Ertragsgesetze von Liebig, L.iebscher, WOLLNY und MITSCHERLICH
Authors: Claupein W. 
Published: April 2008

AbstractNitrogen fertilization and chemical plant protection in a long‐term field experiment and the yield response laws of Liebig, Liebscher, Wollny and MitscherlichAn interpretation of Liebig's “law of the minimum”, Liebscher's and Wollny's “law of the optimum” and Mitscherlich's “law of constant activity” for two growth factors is presented. With three‐quadrant diagrams (crop yield vs. N fertilization, crop yield vs. N uptake, N uptake vs. N fertilization) a long‐term field experiment in Göttingen (Ackerbau‐Systemversuch) is analyzed. This experiment started 1981 with the following treatments: 1. crop rotation (a: short rotation, sugar‐beet, winter‐wheat, winter‐barley/vetch‐green‐manure; b: long rotation, sugar‐beet, winter‐wheat, winter‐barley, lucerne, maize, faba beans); 2. chemical plant protection (a: with; b: without); 3. mineral nitrogen fertilization procedure (a: N‐fixed, cumulative effects; b: N‐rotating, one year's effects of different N fertilization); 4. mineral nitrogen fertilization (a: nil; b: suboptimal; c: optimal; d: hyper‐optimal doses).Without chemical plant protection resource use efficiency of applied nitrogen decreased according to Liebscher's and Wollny's “law of the optimum”. In most cases this “law of the optimum” was applicable to the empirical data. Liebig's “law of the minimum” and Mitscherlich's “law of constant activity” are exceptional cases, whereas Liebscher's and Wollny's “law of the optimum” has more general validity. For maximal resource use efficiency the growth factors have to be combined in optimal amounts.