摘要:

AbstractIn a lysimeter trial the legumes faba bean (Vicia faba), red clover (Trifolium repens), and alfalfa (Medicago sativa) were grown for two years, followed by winter wheat on all plots in the third year. Plots fertilized with mineral nitrogen and a rye/maize – wheat cropping sequence were included for comparisons. These four cropping sequences were replicated twice in 1982–1984 and 1985–1987, respectively. Two soils, a loamy sand and a sandy loam were used.On average of both soils:– N fixation during two years was 461 kg N/ha, 803 kg N/ha, and 790 kg N/ha for faba bean, red clover, and alfalfa, respectively.– Leaching of nitrogen occurred mainly during the periods of winter fallow or, in case of the perennial legumes, after incorporation of residues into the soil and planting of wheat. Average leaching for all 6 years was 49, 28, and 29 kg ha−1year−1for faba bean, red clover, and alfalfa, respectively.– In the period of wheat growth and before planting the new crop (1.5 years) in 1984/85 51–64 kg N/ha and 1986/87 68–94 kg N/ha were leached after growing legumes. Leaching was less for rye/maize fertilized with mineral N, 41 kg N/ha in 1984/85, and 51 kg N/ha in 1986/87, respectively.– Winter wheat grown after legumes took up 18 kg N/ha<47 kg N/ha<65 kg N/ha on average of both soils and 2 years (1984, 1987) after faba bean, red clover, and alfalfa, respectively. This indicates a nitrogen recovery of 24–44% of the legume N potentially available, and consequently a loss by leaching from 56 to 76 %.On the sandy loam amount of drainage water and N leaching were lower, and faba bean and wheat yields higher than

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00681.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe relationship between seed corn vigor and some crop characters in uniform and reduced plant populations is poorly defined. This study, was designed to define the crop characters through which seed vigor is expressed in reduced and uniform populations of corn and to clarify which experimental technique should be used in seed vigor studies. Seeds of two corn hybrids, A632 x (H99 x H95) and B73 x (H99 x H95), were dried at two temperatures, 35 °C and 50oC, and planted near Ames, Iowa, in 1983. The two drying temperatures created differential vigor levels between the seed lots. There were 21 crop characters measured in two populations, reduced populations due to lack of seed vigor and uniform population (thinning to stand). Early vegetative growth was influenced by seed vigor, but as the plant aged, the influence of seed vigor decreased. Increased early plant height, up to 6 weeks old, small stem diameter, low shoot dry‐matter content, delay in days from sowing to 50 % tasseling and to 50 % silking, narrow penultimate and ear leaf, and reduction in the number of ears and tiller production were observed in the uniform population. The differences in population density due to seed vigor did not have a significant effect on final grain yield inasmuch as plants in the reduced populations were able to compensate completely for missing stan

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00682.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractField experiments were conducted during 1980‐82 at the Agronomy Farm of the University of California, Davis, to compare fermentable carbohydrate production and cost of potential ethanol from fodderbeet, sweet sorghum, sugarbeet, and corn in relation to the requirements of these crops for fertilizer nitrogen and irrigation. The response of hexose yields of these crops to fertilizer N varied in the two experiments. When all crops responded, sweet sorghum and sugarbeet required 36 % and fodderbeet 68 % of the fertilizer N needed for corn. Twelve weeks following a mid‐season irrigation cut off, hexose yield of sugarbeet was decreased by 18 % as compared to an adequately watered crop. Water stressed sweet sorghum extracted higher amounts of soil moisture, increased in hexose concentration and produced 29 % higher hexose yield than when adequately watered. Stressed sugarbeet, however, had a higher hexose yield due to its higher sugar concentration.When fertilized and irrigated adequately, fodderbeet produced 13.4, sugarbeet 11.9, sweet sorghum 10.0, and corn 8.15 Mg hexose ha−1. Comparative on‐farm ethanol production costs of these four crops were very close ($0.38 to 0.40 L−1). Thus, growing established crops like corn and sugarbeet for which processing facilities and alternative markets already exist would be

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00683.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractAn experiment with sixteen cropping systems (pure and intercroppings) was conducted during thekharifseason of 1985 and 1986. The sixteen cropping systems were: sole rice, sole mungbean, sole soybean, sole peanut, sole blackgram, rice + mungbean (2:1), rice + mungbean (4:1), rice + mungbean deferred (2:1), rice + soybean (2:1), rice + soybean (4 : 1), rice + soybean deferred (2 : 1), rice + peanut (2:1), rice + peanut (4 : 1), rice + blackgram (2:1), rice + blackgram (4:1) and rice + blackgram deferred (2:1). Sole crop of rice always recorded higher number of effective tillers/m2, however, it was observed that legumes had an influence on the number of filled grains per panicle and thousand grain weight of rice in rice + legume combinations. Among legumes, pure crops of soybean and peanut always gave rise to increased number of yield components than the other crops grown in association with rice. In case of mungbean, number of pods per plant and thousand seed weight was higher in pure crops though number of seeds per pod was more with rice + mungbean combination. Deferred sown blackgram in association with rice yielded greater number of seeds per pod and thousand seed weight though sole crop of blackgram significantly produced higher number of pods per plant.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00684.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractTwo varieties of triticale possessing differential tolerance to salinity were grown in a glass‐house in nutrient solution with or without the addition of 50, 100 and 150 mM NaCl. Plants were harvested after 20, 30, 37 and 44 days of vegetative growth. Relatively salt sensitive variety had slightly better growth in nutrient solution without salt throughout the study period but it could not survive at 150 mM NaCl treatment upto the final harvest. Better relative growth rates of the salt tolerant variety were observed at all salt levels during the four harvests. A significant negative correlation between Cl in shoot tissue water and the growth depression was observed for the salt sensitive variety. Better salt tolerance of the relatively salt tolerant variety seemed to be due to its ability to avoid salt build‐up in plant body which was confirmed by short term Na and Cl uptake from labelled solution of 100 mM N

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00685.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA proportion of the maize seed sold in the Netherlands is genetically impure. The most common form of genetic impurity in hybrid seed production is the accidental self‐pollination of the female parent. Varying quantities of selfed seeds were added to certified seedlots of three‐way cross hybrids. These mixtures were tested in nine field experiments, in 1985 and 1986.Whole plant dry matter yield decreased by 40 to 45 kg/ha per percent of selfed seed added. The effect of selfed seed on dry matter yield did not differ significantly in the hybrids stud

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00686.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractUptake and distribution of nitrogen in old and new German summer wheatsFive old German summer wheat varieties, bred in the first third of this century, were compared with five new varieties in an outdoor pot trial. The modern genotypes had taken up slightly more N, both at anthesis and at maturity. At anthesis, N percentage in all organs was considerably higher for modern cultivars. This resulted mainly from a dilution effect caused by superior dry masses of old varieties. Modern genotypes accumulated more N in the upper leaves and ears. As compared with the old varieties, less N was found in the stems of the new cultivars. At maturity, N concentration in vegetative organs was simular for both groups of varieties. N percentage of grains was higher for old cultivars. However, the new genotypes achieved higher N yields. This resulted in part from the slightly higher assimilation of N. Moreover, new genotypes were superior in N translocation which was reflected by higher nitrogen harvest indexes. The postfloral loss of N from the vegetative tissue depended on the organ and the age of the varieties.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00687.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractGenotypic differences in the translocation of temporarily stored14C from the stem to the grains in spring wheat (Triticum aestivum L.)In three field experiments with two spring wheat genotypes (Kolibri and breeding line93117), changes in the total nonstructural carbohydrates (TNC) of the stem were observed after anthesis. Maximum values were measured in the third or fourth week following anthesis when stems contained 300 to 400 mg TNC. Thereafter TNC content declined up to maturity.Flag leaves of individual shoots or all plants in micro‐plots were labelled with14C 5 days prior to anthesis, at anthesis or 5 days after anthesis to observe long term movements of assimilates during grain filling. After a chase period of two to three days, 60 to 80 % of total14C recovered in the shoot was in the stem. From totall4C recovered two to three days after labelling, Kolibri had translocated 12.5 to 27.0 % into the grains by maturity whereas this portion was significantly higher for the breeding line93117(22.5 to 43.9 %). It was concluded that genotypes differ in the translocation of soluble carbohydrates from the stem to the grains. These differences were not related to parameters describing the ‘source‐sink’ relationship, such as leaf area, grain number or grain size. However, the lower translocation rates of Kolibri coincided with a lower TNC concentration in the stem dry matter. This was due to a higher stem weight at anthesis, a longer period of stem elongation and a higher incorporation of assimilates into structural carbohydrates in non elongating stem parts after anthesis. It was therefore suggested that the accumulation of TNC in the stem and the remobilisation of these reserves for grain filling are determined partly by factors related to the carbohydrate metabolism in t

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00688.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractSieve grading of cereal kernels by means of quantitative image analysisIn former investigations several possibilities to apply computerized quantitative image analysis (CQJA) in the field of crop science have been reported. In the present studies applicability of this technique have been tested to accurately determine sieve grading of barley kernels. Accordingly, CQJA seems to be appropriate for measuring and processing digitalized image information of the respective length and thickness of grain kernels both, at high velocity and precision, and it can be done at any classification of kernel sizes. Contamination of the cereals by broken grain and/or other non‐grain material can be discriminated by integrating threshold levels of minimum and maximum diameters respectively. It is argued that major advantages of the proposed automated CQJA‐equipment could be (1) control of sieve grading and calibration processes of seeds and (2) sieve grading of the kernels of individual ears for breeding purpo

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00689.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Books Reviewed in this Article:Klapp, E., und W. Opitz von Boberfeld: Gräserbestimmungsschlüssel für die häufigsten Grünland‐ und Rasengräser.Klapp, E., und W. Opitz von Boberfeld, Kräuterbestimmungsschlüssel für die häufigsten Grünland‐ und Rasenkräuter.Bopp, M. (Ed.): Plant Growth Substances.Basedow, T.: Der Einfluß gesteigerter Bewirtschaftungsintensität im Getreidebau auf die Laufkäfer (Coleoptera, Carabidae).Schnell, G., Ch. Leuthold, E. Zürcher und K. Büchel (Hrsg.): Waldsterben – Aufforderung zu einem erweiterten Naturverständnis. Denk‐ und Handlungsansätze für den Umgang mit dem Lebendigen.Diez, Th., und H. Weigelt: Böd en unter landwirtschaftlicher Nutzung.Jacob, F., E. J. Jäger und E. Ohmann, Botanik.Meteorologie. Meyers Lexikonredaktion; wissenschaftliche Bearbeitung: Schirmer, H., W. Buschner, A. Cappel, H. G. Matthäus und M.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00690.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY