摘要:

AbstractThe effect of flat seedbed, traditional ridge and furrow and improved drainage of broad bed and furrow (BBF) on grain and straw yield of durum wheat, chickpea and lentil at several Vertisol sites between 1988—1991 was such that on three crops the BBF system gave the highest grain and straw yields at all locations and seasons. This was followed by traditional ridge and furrow system and the least yield was obtained from flat seed beds. The extent of drainage influence on yield was dependent on rainfall quantity, location (clay content) and crop species. The advantages of the BBF technology in improving drainage and increasing crop yield are discussed in their contexts of better cropping system

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00170.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractData gathered from 45 farms in the Kagera Region of Tanzania were used to estimate critical nutrient levels (CNL) of foliar tissue and norms of the Diagnosis and Recommendation Integrated System (DRIS) for bananas (Musaspp.) grown in the highlands of East Africa.CNL values are proposed as 3.1 % N, 1.13 % Ca, 0.48 % Mg, 18.4 ppm Zn and 10.0 ppm B. Optimum ranges for cation ratios were estimated as 0.54—0.67 for K/(K + Ca + Mg), 0.22—0.32 for Ca/(K + Ca + Mg) and 0.09—0.15 for Mg/(K + Ca + Mg). Productivity of bananas and foliar levels of P, K, S, Fe, Mn and Cu were too weakly related to estimate CNLs for these nutrients. A set of DRIS norms for East African Highland bananas is pres

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00171.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe growth ofM. truncatulaandM. aculeatagenotypes collected from sites of contrasting altitudes and winter temperatures was compared under different temperature regimes. Genotypes collected from mild winter environments produced more shoot dry matter, had higher leaf area and lower specific leaf weight than those from cold environments; however these effects were largely related to seed size forM. aculeata.Only genotypes from mild environments were responsive to temperature.Frost tolerance of the genotypes was tested using a laboratory freezing test based on seedling survival. There was a relationship between frost tolerance and winter temperature at site of collection forM. aculeata, with the most frost tolerant genotypes coming from high altitudes. All genotypes ofM. truncatulademonstrated low survival rates following frost damage. Genotypes from high altitudes represent a promising source for breeding for first tolerance with greater variation mM. aculeatathanM. truncatula.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00172.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractField experiments were conducted at the Sugarcane Breeding Institute, Coimbatore, India during 1989–93 to study the productivity and water use efficiency of sugarcane under different methods of irrigation. The results showed that there could be a 44 % saving in water with higher water use efficiency in drip irrigation compared to conventional furrow irrigation. Among drip irrigation systems in the plant crop, sub surface drip (Biwall) at 40/140 cm spacing recorded a significantly higher number of millable canes, cane length and single cane weight compared to either conventional furrow irrigation or furrow irrigation based onIW/CPE(Irrigation Water Cumulative Pan Evaporation) ratio. In ratoon crop, Biwall irrigation at 60/120 cm gave significantly higher cane length and single cane weight compared to any other methods of irrigation. However, cane and sugar yields in Biwall irrigations were on par with conventional furrow irrigation but superior to either surface drip or furrow irrigation based inIW/CPErati

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00173.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractGram sorghum [Sorghum bicolor(L.) Moench] is grown on marginal land and johnsongrass [Sorghum haiepense (L.) Pers]is the most common and hard to control weed in this crop. The agronomic performance of gram sorghum at different nitrogen (N) and johnsongrass infestation levels in the field has not been adequately investigated. Therefore, research was conducted on a Decatur silty clay loam soil(Rhodic Paleudult)to determine the influence of N rates (0, 40, 80 and 120 kg ha‐1) and johnsongrass infestation levels (0, 2, 4, 6 and 8 plants per 5 m crop row) on the growth and yield of grain sorghum (cv. GK522G) and johnsongrass. Increase in N rates increased seed weight, seed yield and percent protein in grain sorghum as well as dry matter and percent protein of johnsongrass. The increase in johnsongrass infestation (from 0 to 8 plants per 5 m crop row) significantly decreased the performance of grain sorghum and johnsongrass at all the N rates. The results suggest that 40 kg N ha‐1with up to 2 johnsongrass plants per 5 m crop row or 80 kg N ha‐1with up to 4 johnsongrass plants per 5 m crop row produced grain sorghum yields equivalent to absence of johnsongrass in the

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00174.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIdentification of Miscanthus Varieties by their IsozymesWith the aim of testing the possibility of identifying Miscanthus varieties, zymograms of 13 isozymes from 65 plants ofM. smensis, M.×giganteusandM. saccharifloruswere analysed using starch‐gel electrophoresis. The zymograms of root, rhizome, and leaf tissues were compared. After similarity between the zymograms of the different types of tissues had been established, the tissue of young leaves was used for analysis. The zymograms of the different isozymes are variable in most cases and show as many as nine patterns. The large variation between the varieties allows an identification of each of the varieties analysed. About half of the plants could be attributed toM.×giganteus.In this group of plants, different variants were found in the isozymes of diaphorases and glutamate‐oxalacetate‐transammases. These variants might indicate thatM.×giganteusincludes more than one genotype. Some of the plants which were assumed to belong toM.×giganteuscould clearly be excluded from this variety. Although some of the varieties can only be unequivocally identified by their flowers, it is possible to analyse the isozymes even in the dormant state of the rhizomes, thus, this method offers a simple way of identifymg Miscanthus varieties by the principle of exclusion, independent of the physiological state of

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00175.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractNitrogen Uptake and Nitrogen Residuals of Winter Oil‐Seed Rape and Fallout RapeThe objective of the investigation was a study of the relationship between seed dry‐matter production and vegetative dry‐matter production in oil‐seed rape crops and their dependence on the production conditions. In addition to the relationship between the N‐uptake during the vegetation period and the N‐residue after harvest was of major interest. Furthermore the potential for N‐uptake in fallout rape was measured. Over two vegetation periods factorial field experiments with winter oil‐seed rape, cv. Lirabon, different drilling techniques and different nitrogen fertilization levels were tested. Measured traits were: the dry‐matter accumulation including root mass and fall‐off leaf‐material mass, the N‐uptake of both the oil‐seed crops and the fallout rape stands, and, simultaneously, the soil NO3‐N content. Finally the harvest indices and the N‐harvest indices were calculated.Combined with a N‐uptake of up to 330 kg N/ha, oil‐seed rape crops produced up to 200 dt dry matter/ ha. At seed yield levels of 33dt/ha (d.m.), harvest indices varied from 0.14—0.23 and N‐harvest indices varied from 0.30–0.50. As a result of the residue of vegetative plant material at harvest, leaf losses before harvest and the soil NO3‐N‐contents at harvest up to 275 kg N/ha remained in the field. After the harvest of oil‐seed rape, the soil NO3‐N‐contents were quickly reduced by emerging and growing fallout rape stands. However, following soil‐preparation measures in the autumn, a con

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00176.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe seeds of groundnut cultivar GG‐2 were categorized according to their test weight (100 seed weight) as bold (58.2 g), medium (37.9 g), small (24.9 g), small wrinkled (13.4 g) and control (30.3 g) seed lot. The variation in their size and dimension was also taken into account. The overall germination percentage was high for medium size seeds and was closely followed by bold seeds. The performance of the small and small wrinkled seeds was comparable to that of control. The seed vigour was found to be higher with heavier seeds. Small seeds exhibited equally good performance in response to seed germination and growth of the seedling components. There were no significant differences for the development of hypocotyl, epicotyl and plumul

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00177.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe relation between stand density and structure of spring rape (Brassica napusL.) was described with the aid of comprehensive measurements of structure. The structural components measured were plant height, stem diameter at root collar, site of the lowest pod on the main raceme, number of pods on the main raceme, site of the lowest branch on the main stem, number of primary branches and number of pods on the branches. The experiment was conducted at two nitrogen levels, 110 and 180 kg ha', and was replicated in 3 years, 1988, 1989 and 1990. Stand density was varied by using five different seeding rates and the number of plants m‐2evaluated immediately prior to harvest was used to express the stand density. In the years considered, the densities varied between 16 and 520 plants m‐2. The relationship between plant density and rape plant structure was adequately described each year by a mukivariate second degree polynomial model. Varying the nitrogen application rate seemed to have no influence on this relationship. Denser plant stands produced thinner and shorter plants, the shortening occurring in the pod‐producing section of the main raceme. Further, with increasing stand density, the number of branches decreased as did the number of pods on the branches and on the main raceme. These changes in plant structure retarded at densities over 150—200 plants m‐2. This seems to be the minimum density that should be achieved in ra

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00178.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe aim of this study was to investigate whether symbiotic nitrogen fixation in white clover nodules limits nitrogen supply and hence clover growth by repeated defoliation at two cutting heights. Other possible factors governing symbiotic nitrogen fixation in the field were also elucidated. Using15N, a 2‐year field experiment including white clover (Trifolium repensL. cv. Ladino) and perennial ryegrass (LoliumperenneL. cv. Bastion) in monocultures and in mixtures was conducted in Eschikon, Switzerland. The effect of two cutting heights (4 cm and 10 cm above ground level) on the performance of symbiotic nitrogen fixation of white clover in the different sward‐types was investigated. After each harvest, the plots were fertilized with 3 g N m‐2(equivalent to 30 kg N ha‐1cut‐1or 210 kg N ha‐1year‐1). In both years, white clover grown in a mixture with grass received a significantly higher percentage of nitrogen from symbiotic fixation compared with clover grown in monoculture. This phenomenon is attributed to the strong competitiveness of ryegrass in soil nitrogen uptake. Consequently, white clover in the clover‐ryegrass mixture was more dependent on symbiotic nitrogen fixation than that grown in monoculture. The cutting height did not preferentially influence symbiotic nitrogen fixation, as opposed to the uptake of mineral nitrogen from the soil. From this finding it is suggested that symbiotic nitrogen fixation did not limit the supply of nitrogen to clover and hence its growth. It is proposed that symbiotic nitrogen fixation in white clover is regulated by the demand for nitrogen rather than by the availability of carbohydrate reserves in the stolons. Symbiotic nitrogen fixation should thus be looked upon as an integrated plant growth factor and not as an isol

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00179.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY