摘要:

AbstractComparative stress physiology of tepary beans (Phaseolus acutifolius) as “minor crop” and mwezi moja beans (Phaseolus vulgaris) as high‐yielding variety in tropical agricultureThe study deals with the ecophysiological demands of the “minor pulse” tepary beans (Phaseolus acutifolius) – possessing a high nutritional value – as well as of the high‐yielding kenyan bean variety mwezi moja (Phaseolus vulgaris, GLP 1004).Special reference is dedicated on the drought resistance of the crops in order to make recommendations for potential cultivation in the semi‐arid and arid drylands of South and Southeast Kenya.Newly constructed growth containers gave possibilities to simulate different durations and intensities of water stress under controlled environmental conditions in climatic chamber experiments.It was observed and recorded that teparies possess different mechanisms of morphological and physiological adaptation to high temperature and water stress, apparently including the ability of osmotic adjustment. The patterns of adaptation to water stress are combined with defined hydrature periods closely connected with the reduction of soil moisture.There was no evidence of morphological adaptation of mwezi moja leaves to water stress. It was observed and recorded that there is a partial drought resistance within the upper leaf unit, apparently caused by osmotic adjustment.The crop seems to be less adapted than tepary beans to marginal cropping areas (e.g. in agroecological zone, AE2, L 6 or LM 6; ace. to: Jätzoldand Schmidt1982/83) of the drylands due to high crop water requirements (about 30 % more than the “minor pulse”), low drought resistance and a high relative yield decrease under water stress – in spite of a short vegetation

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00779.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractCardamom seeds are considered recalcitrant, with relatively low retention of germinability during storage. Thus, a study tested the effects of drying temperatures on moisture loss and reduction in germinability of cardamom seeds. In addition, the effect of storage material and temperatures on retention of germinability was evaluated. The mature seeds of cardamom contained a high percentage of water at harvest, and germinability at harvest was around 62 %, confirming the recalcitrant nature of the seeds. Seed germinability was completely lost at moisture levels below 50 % (dry wt. basis) and higher temperatures reduced moisture levels and germinability faster. Drying at 20°C retained some degree of germinability for 7 days. In terms of storage, sealed polythene containers and low temperature (5°C) was optimal for maintaining some degree of germinability of cardamom seeds during storage for approximately 15 day

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00780.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA field trial was conducted on clay loam soil (Typic Haplustalf) with rice (Var.IR.60) as the test crop to find out its rooting behaviour under submerged conditions as influenced by zinc sources. Three different zinc sources viz., zinc sulphate, zinc blended urea and zinc blended suphala were applied in different combinations. Root length density was measured at 40, 55, 70 and 85 days after transplanting at 5 cm intervals of depth upto 25 cm. The results revealed that root length density decreased with depth in all the treatments at all the stages. There was progressive increase in root length density with advancing age of the crop. Zinc sulphate applied alone and in combination with NPK had increased the root length density compared to absolute control and NPK alone in the initial stages. Zincated urea provided higher root density compared to 2incated suphala.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00781.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe relationship of the stage‐to‐stage changes in alfalfa herbage leaf percentage and the corresponding changes in fiber components represented by neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) was tested in alfalfa crop diverse in stand and canopy ages, stages of maturity harvested across seasons in two separate years. Regression analyses showed that for all fiber components, leaf percentage consistently provided highly significant linear relationships for predicting herbage fiber content; NDF (r2= 0.915), ADF (r2= 0.937) and, ADL (r2= 0.851). These were highly comparable with the application of the mean stage by weight (MSW) system for predicting NDF (r2= 0.946), ADF (r2= 0.891) and ADL (r2= 0.841) thus indicating the practical use of leaf percentage as a good alternative approach for predicting fiber content of the alfalfa c

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00782.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe need to increase forage production for the growing livestock population in the Mediterranean region necessitates the evaluation of various promising forage species with respect to maximum herbage yield, optimum time for harvest and seed yield. Seven forage legumes, woolly pod vetch (Vicia villosasubsp.dasycarpaaccession 683), narbon vetch (V.narbonensisaccession 67), common vetch (V. sativaselections 2541, 2037, 2020), common chickling (Lathyrus sativusselection 439) and ochrus chickling (L. ochrusselection 104) were compared over two years with contrasting rainfall. In both years the entries were sown in November and their primary growths sampled periodically during growth. For each sample, phenology, total dry matter, leaf area index (LAI) and, at maturity, total dry matter, seed yield and harvest index, were recorded.In both seasons, narbon vetch attained the highest dry matter and seed yields, and there was very limited variability in the maximum dry matter yield of the other entries. In general, the maximum dry matter occurred at 20–50 % podding in woolly pod vetch, 100 % podding in common vetch selection 2541 (local), narbon vetch and common chickling and at maturity in common vetch selection 2037, selection 2020 and ochrus chickling.Throughout the vegetative to early flowering stages, woolly pod vetch had the highest dry matter yield and LAI. Possible uses of each species as animal feed are discusse

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00783.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractEffects of environment on time and rate of nutrient accumulation by crops affects fertilizer nutrient use efficiency. The effect of planting date on rate, time and amount of nitrogen (N) accumulated by maize from a Hamerly cl soil (Aeric Calciaquoll) was examined with and without supplemental irrigation. Maize was planted on three dates spaced at 2‐to 3‐week, intervals; the earliest planting date was 1 May in 1984 and 1985. N accumulation was examined as uni‐ and diphasic tanh[k(time)] functions and solved for total N accumulation at harvest, time of maximum N accumulation rate and the time coefficient of N accumulation. A diphasic function, which indicates two periods of intense N accumulation, provided the closest agreement with observed N accumulation. As planting was delayed, time required to reach maximum N accumulation rates, τ (uniphasic) or τ1and τ2(diphasic), decreased from an average of nearly 75 to 42 days (uniphasic) and from nearly 65 to 35 days and 100 to 75 days after planting for τ1and τ2, respectively. Maximum N accumulation rates increase from about 59 to 75 mg N plant−1day−1(uniphasic) or 35 to 65 mg N plant−1day−1and 20 to 70 mg N plant−1day−1for the first and second maxima in the diphasic model, respectively. Average maximum total N accumulation ranged from 2.85 g N plant−1for early plantings to 1.5 g N plant−1for plantings made on 25 June. The time coefficient, k (uniphasic) or k1(diphasic), tended to increase from average values of about 0.04 to>0.09 day−1for k and from about 0.04 to>0.105 day−1for k1. The second time coefficient, k2, of the diphasic function varied widely between about 0.075 to>0.12 day−1and showed complex relationships with planting date. Periods of N accumulation shortened and intensity of N accumulation increased a

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00784.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractThe assimilation and translocation pattern of radioactive 14‐C‐assimilates and how it may affect nitrogen fixation was studied in conventional and semi‐leafless pot grown field peas (Pisum sativumL.). Leaf areas, plant development patterns and yield components and their influence on protein content, protein yield and seed yield were studied by using simple regression, multiple regression and factor analyses over a period of two years of field grown material.It was shown that roots and nodules received most of the carbon assimilate from the lower leaves at the beginning of flowering. Four weeks later most of the assimilates came from the upper leaves. Furthermore, it was discovered that stipules were more important than leaflets in supplying the roots and nodules. Field studies supported the results obtained in pot grown material. They also showed that in order to achieve high seed and protein yield it is more important to have many generative nodes instead of a few with several pods on each. In semi‐leafless types, vegetative upper nodes and late flowering are also important factors. An ideotype suited for both high seed yield, high seed protein yield and high protein content is di

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00785.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractSuitability of not seeded test squares in crop fields for reliable ascertainment of weed threshold levels by quantitative image analysisThe possibility to measure weed ground cover using a computerized image analysis system has been reported in former investigations. In the present studies suitability of not seeded test squares in crop fields for reliable detection of weed ground cover for precise determination of weed threshold levels (beyond that crop yield losses are economically greater than costs for weed control) has been tested.Test squares in which weed grew without competing crop as well as corresponding squares including both, growing crop and weeds, were examined for weed ground cover by computer assisted quantitative image analysis of color slides taken from the respective squares. In the squares, that includes crop and weeds, the former was removed immediately before taking the slides.In both seasons from the beginning of weed growth in October to the latest feasible application time of herbicides in April weed growth as measured by ground cover in the not seeded test squares did not differ significantly from that grown under competition of winter barley.Results indicate, that up to the growth stage of weed where herbicides if ever should be applied at the latest, crop‐free test areas in the same field could serve for correct determination of weed growth by image analysi

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00786.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Books Reviewed in this Article:Basedow, Th., Bauers, Chr. und Lauenstein, G.: Ergebnisse vierjähriger Untersuchungen zur gezielten Bekämpfung der Getreideblattläuse.Schwertmann, U., R. J. Rickson and K. Auerswald (Eds.): Soil erosion protection measures in Europe.Spaar, D., H. Kleinhempel und R. Fritzsche. Kernob

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1990.tb00787.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY