Netherlands Journal of Agricultural Science最新文献

{"title":"Effects of gamma-irradiation of seed potatoes on numbers of stems and tubers.","authors":"A. Haverkort, D. Langerak, M. D. Waart","doi":"10.18174/njas.v39i2.16543","DOIUrl":"https://doi.org/10.18174/njas.v39i2.16543","url":null,"abstract":"In field trials with the cultivars Bintje, Jaerla and Spunta, whose seed potatoes were treated with gamma-rays from a ^Co source with doses varying from 0.5 to 27 Gy, tuber yield, har­ vest index, and number of stems and tubers were determined. A dose of 3 Gy increased the number of tubers by 30 % in Spunta in two out of three trials and by 17 % in one trial in Jaer­ la, but it did not increase number of tubers in Bintje. Doses of 9 or 10 Gy did not influence the number of tubers nor stems, and decreased harvest index. A dose of 27 Gy yielded off-type plants with reduced yield and number of tubers. Gamma-radiation affected the growth of the apex of the sprout allowing lateral buds or divisions of the affected apex to develop into stems. To achieve larger numbers of tuber-bearing stems, tubers should preferably be irra­ diated at the start of sprout growth, about 5 months before planting.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124329831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cadmium uptake by lettuce varieties.","authors":"P. J. Florijn, J. Nelemans, M. L. Beusichem","doi":"10.18174/NJAS.V39I2.16545","DOIUrl":"https://doi.org/10.18174/NJAS.V39I2.16545","url":null,"abstract":"The uptake of Cd by lettuce cultivars was studied in soil and water culture experiments (16 and 8 cultivars, respectively). In the soil experiment, sandy soils from both a Cd-contaminated and a non-contaminated area of the Netherlands were used; the water culture experiment included 3 Cd levels (0, 0.03 and 0.1 mg/litre). Fresh and dry yields of shoots and roots were hardly affected by Cd in either of the experiments. The lettuce cultivars showed a close similarity in shoot Cd concentration, ranging from 8.23 to 10.72 micro g/g DW for the Cd-contaminated soil and from 3.96 to 8.83 micro g/g DW in the water culture at the highest Cd level tested. These results contradict published data on a large genotypic variation in Cd concentration in lettuce [see John, M. K. et al, Environmental Pollution (1976) 10, 163-173]. Based on the narrow range in shoot (and root) Cd concentration between cultivars, it is concluded that it is unwarranted to use lettuce as a pilot plant in comparative physiological investigations on Cd uptake and distribution. (Abstract retrieved from CAB Abstracts by CABI’s permission)","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116628695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sodium chloride salinity in fruit vegetable crops in soilless culture.","authors":"C. Sonneveld, A. V. D. Burg","doi":"10.18174/NJAS.V39I2.16546","DOIUrl":"https://doi.org/10.18174/NJAS.V39I2.16546","url":null,"abstract":"Tomatoes, cucumbers and sweet peppers (capsicums) were grown in hydroponic systems in which the nutrient solutions were recirculated. The EC of the nutrient solution was maintained at values of 2.5, 3.7 or 5.2 dS m-1 (25 degrees C) in the different treatments. In some of the treatments, the EC values mentioned were achieved by addition of nutrients, and in others by addition of a combination of nutrients and NaCl. Yields of all 3 crops were adversely affected by increased EC values. Most fruit quality characteristics, on the contrary, were favourably affected. However, the incidence of blossom-end rot in tomatoes and capsicums increased at higher EC values. For capsicums, this was especially the case with NaCl addition. Apart from that, only slight specific NaCl effects were noticed. Salinity threshold values for the different crops lay between 2.3 and 3.5 dS m-1 and salinity yield decrease values ranged from 2.3 to 7.6% for each dS m-1. The absorption of Na and Cl differed with crop and with the Na and Cl concentration. (Abstract retrieved from CAB Abstracts by CABI’s permission)","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128072720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A simple model of crop loss by weed competition from early observations on relative leaf area of the weeds","authors":"M. Kropff, C. Spitters","doi":"10.1111/J.1365-3180.1991.TB01748.X","DOIUrl":"https://doi.org/10.1111/J.1365-3180.1991.TB01748.X","url":null,"abstract":"Summary: \u0000 \u0000A new simple empirical model for early prediction of crop losses by weed competition was introduced. This model relates yield loss to relative leaf area of the weeds shortly after crop emergence using the relative damage coefficient q as the single model parameter. The model is derived from the hyperbolic yield density relationship and therefore accounts for the effects of weed density. It is shown that the model also accounts for the effect of different relative times of weed emergence. A strong advantage of the approach is that it can be used when weeds emerge in separate flushes. \u0000 \u0000 \u0000 \u0000The regression model described experimental data on sugar-beet – lambsquarters (Beta vulgaris L. –Chenopodium album L.) and maize-barnyard grass (Zea mays L. –Echinochloa crus-galli L.) competition precisely. The model describes a single relationship between crop yield loss and relative leaf area of the weeds over a wide range of weed densities and relative times of weed emergence. Possibilities for scientific and practical application of the model are discussed. \u0000 \u0000Resume: \u0000 \u0000Un nouveau modele empirique simple pour la prevision precoce des pertes de recolte dues aux adventices a eteetabli. Ce modele relie les pertes de rendement a la surface relative des adventices peu apres la levee de la culture en utilisant le coefficient de degut relatif q comme seul parametre du modele. Le modele provenait de la relation hyperbolique entre rendement et densite et de ce fait prend en compte les effets de la densite des adventices. Ceci montre que le modele prend en compte egalement les differentes epoques de levee des adventices. Un grand avantage de l'approche est que l'utilisation est possible quand les adventices levent en vagues separees. \u0000 \u0000 \u0000 \u0000Le modele de regression a decrit avec precision les donnees experimentales de la competition des chenopodes (Chenopodium album L.) vis a vis des betteraves (Beta vulgaris L.), et des panics pied de coq (Echinochloa crus galli L.) vis a vis du mais (Zea mays L.). Le modele decrit une relation simple entre la perte de rendement et la surface foliaire relative des feuilles sur un grand nombre de densities d'adventices et d'epoqucs relatives de levee d'adventices. \u0000 \u0000 \u0000 \u0000Les possibilities pour des applications scientifiques et pratiques de modele sont discutees. \u0000 \u0000Zusammenfassung: \u0000 \u0000Es wurde ein einfaches Modell zur fruhen Vorhersage von Ertragsverlusten durch Unkrautkonkurrenz entwickelt. Dieses Modell stellt den Bezug von Ertragsverlusten zur relativen Blattflache der Unkrauter kurz nach dem Auflaufen der Kulturpflanzen her, wobei als einziger Modellparameter der Schadens-Koeffizient q benutzt wird. Das Modell wurde aus der hyperbolischen Ertrag/Dichte-Beziehung entwickelt und tragt deshalb dem Einflus der Unkrautdichte Rechnung. Es wurde gezeigt, das das Modell auch die von verschiedenen Keimzeiten der Unkrauter ausgehenden Wirkungen beriicksichtigt, so das es selbst bei schubweisem Auflaufen von Unkrautem benutzt ","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116610720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fine root density and root biomass of two Douglas-fir stands on sandy soils in The Netherlands. 1. Root biomass in early summer.","authors":"A. Olsthoorn","doi":"10.18174/njas.v39i1.16552","DOIUrl":"https://doi.org/10.18174/njas.v39i1.16552","url":null,"abstract":"In two fully stocked, fast growing Douglas-fir plantations of the Dutch ACIFORN project, detailed studies were carried out on fine root biomass and fine root length to obtain information on fine root densities. For three consecutive years, fine roots were sampled with a root corer in the early part of the growing season. The coarse root biomass was calculated from aboveground stand parameters. The vertical distribution of fine roots in these sites was similar. In the stand with less aboveground biomass the dry weight and density of the fine roots were higher. The fine root biomass agreed with values found in Douglas-fir stands in the Pacific northwest of the USA. Up to 80 em depth the fine root biomass varied from 3900 kg ha1 in moist conditions to 900 kg ha1 after dry periods. The fine root length varied accordingly, with a maximum of27.10 m ha1 and a minimum of 3.106 m ha1• The fine root density in the mineral topsoil varied between 0.6 and 0.05 em cm; in the subsoil it varied between 0.3 and 0.04 em cm-. In 1989 there was some sudden root death during a dry period.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1991-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122399905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling weed competition and yield losses to study the effect of omission of herbicides in winter wheat.","authors":"L. Lotz, M. Kropff, R. Groeneveld","doi":"10.18174/njas.v38i4.16559","DOIUrl":"https://doi.org/10.18174/njas.v38i4.16559","url":null,"abstract":"Omission of application of various herbicides to winter wheat cv. Arminda, cv. Citadel, cv. Okapi, cv. Granada, cv. Sarino and cv. Tombola on clay and sandy soil in 1982-86 caused a significantly lower crop yield only when the densities of certain weed species were extremely high in spring. A dynamic model simulating the competition for light and water between broadleaved weeds and winter wheat was used to assess the observed small effects of weeds on yield in terms of the relative emergence time, physiological and morphological characteristics of weeds. Like the experiments, the simulations indicated that in the Netherlands weeds emerging in spring hardly affect crop yield. Weeds emerging in autumn, however, reduced crop yield considerably if they grew as tall as winter wheat (20% loss at a density of 100 plants/msuperscript 2). The results are discussed in relation to characteristics of crop rotation systems that include root and tuber crops. (Abstract retrieved from CAB Abstracts by CABI’s permission)","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121938744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A weather-based yield-forcasting model for sugar beet.","authors":"C. Spitters, B. Kiewiet, T. Schiphouwer","doi":"10.18174/NJAS.V38I4.16562","DOIUrl":"https://doi.org/10.18174/NJAS.V38I4.16562","url":null,"abstract":"A simple model to predict seasonal growth in sugar beet yield is presented. Time from sowing to the so called 'growth point date' (the date on which a plant contains 4 g sugar) is character­ ized by a temperature sum. The increase in sugar yield after this date is calculated from in­ coming solar radiation using an average radiation use efficiency. Temperature sums and radi­ ation use efficiencies were estimated for each of the 11 Dutch sugar beet regions.","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121890530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ammonia volatilization from arable land after application of cattle slurry. 2. Derivation of a transfer model.","authors":"J. van der Molen, A. Beljaars, W.J. Chardon, W.A. Jury, H. V. Faassen","doi":"10.18174/njas.v38i3a.16586","DOIUrl":"https://doi.org/10.18174/njas.v38i3a.16586","url":null,"abstract":"A model for the transfer of ammonia from arable land to the atmosphere after surface application or incorporation of cattle slurry is presented. The model can be used to study the interactions of the chemical, physical and environmental factors influencing volatilization losses and their combined influence on NH3 volatilization under field conditions. The model employs the following flux equation: R = k (Cs-Ca) where k is a transfer function, Cs is the NH3(g) surface concentration and Ca is the atmospheric NH3(g) background concentration. The rate of volatilization R can be calculated at any moment after application, provided k, Cs and Ca are known at that moment. The model therefore basically consists of modules which yield these variables. (Abstract retrieved from CAB Abstracts by CABI’s permission)","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129956016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contribution of atmospheric deposition to heavy-metal concentrations in field crops.","authors":"J. Dalenberg, W. V. Driel","doi":"10.18174/njas.v38i3a.16594","DOIUrl":"https://doi.org/10.18174/njas.v38i3a.16594","url":null,"abstract":"Lolium multiflorum, spring wheat cv. Adonis, carrots and spinach were grown in the field and in a dust-free growth chamber in pots containing soil labelled with 109Cd and 210Pb. The contribution of atmospheric Cd and Pb deposition to plant concn was examined by isotope dilution. Atmospheric deposition contributed 73-95% to the Pb concn of leafy material of L. multiflorum, carrots, spinach, wheat grain and wheat straw. Cd deposition was only significant in wheat grain and straw (21-48%). (Abstract retrieved from CAB Abstracts by CABI’s permission)","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125010153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of different application rates of nitrogen to soil on rhizosphere bacteria","authors":"E. Liljeroth, G. Schelling, J. A. Veen","doi":"10.18174/njas.v38i3a.16587","DOIUrl":"https://doi.org/10.18174/njas.v38i3a.16587","url":null,"abstract":"Onderzoek naar de bacterieele populaties in de rhizosfeer van tarwe bij verschillende stikstofregimes. De stikstofgift (250 mg N en 50 mg ␛ per plant) werd gegeven in een eenmalige of gesplitste gift, waarbij steeds kleinere hoeveelheden werden gegeven. De verschillende giften maken het mogelijk om de bacterieele populaties te bestuderen in relatie tot de stikstofconcentraties in de wortels en in de bodem bij overeenkomstige biomassaproduktie","PeriodicalId":324908,"journal":{"name":"Netherlands Journal of Agricultural Science","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134388154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}