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1.
This paper reviews current knowledge regarding the influence of plant density on the growth and yield of the faba bean crop (Vicia faba L.). An analysis is also made of sowing rate and other factors that may modify optimum plant density, including environmental conditions; in this sense, should be made a differentiation between faba crops grown in temperate conditions and those grown in Mediterranean and semi-arid conditions. The genotype also prompts variations in optimum plant density, depending on the botanical type (mayor, equina or minor) and the growth habit (determinate versus indeterminate) of the cultivar selected. Sowing date also influences optimum seeding rate, which is lower for autumn–winter sowing under temperate and Mediterranean conditions and increases as the sowing date is delayed. For the spring-sown crops typical of temperate conditions, optimum plant density will be higher due to the shorter growing season. With a longer growing season and under optimum environmental conditions, there is normally no additional response to densities over 20 plants m−2, while in suboptimal conditions, optimum plant density may increase to over 60 plants m−2. Although the faba bean crop displays considerable plasticity in response to variations in plant density, mainly with regard to number of pods per square meter, it is not wholly clear to which component of yield this should really be ascribed. Number of stems per plant appears to be the most influential factor, although further research is required to confirm this.  相似文献   

2.
This study was conducted to investigate whether density, above-ground biomass and nitrogen (N) concentration of Cirsium arvense (L.) Scop. cause serious reductions in faba bean ( Vicia faba L.) yield. A 2-year field experiment (1991–93) with four Cirsium densities (0, 4, 16, 64 plants m–2) was carried out. Statistical analysis showed a significant effect of Cirsium density on faba bean yield. Multiple regression analysis showed that the main factors causing faba bean yield losses were the density and above-ground biomass of Cirsium . The results of this study demonstrate that Cirsium competition reduces faba bean yield. The mean faba bean yield losses over the 2 years were 10, 12 and 8% for above-ground biomass, seed and stem, respectively, for a Cirsium density of 16 plants m–2.  相似文献   

3.
Efficient management of legumes in order to maximize benefits depends on a correct field assessment of N2 fixation. A field experiment was conducted during a 6-year period (2001–2002 to 2006–2007) in Córdoba (Southern Spain) on a rainfed Vertisol within the wheat-chickpea and wheat-faba bean rotation framework of a long-term experiment started in 1986. The aim was to determine the effect of tillage systems [no tillage (NT) and conventional tillage (CT)] on chickpea and faba bean N2 fixation. Fixation was calculated using the 15N isotopic dilution (ID) and 15N natural abundance (NA) methods with the reference being the wheat crop. The strong inter-annual rain variation caused great differences in the behaviour of both leguminous plants with regard to grain yield, nodule biomass and N2 fixation. The NT system showed more nodule biomass than the CT system in both legumes. The ID method was more accurate than the NA method in determining N2 fixation. The average amount of fixed N in faba bean (80 kg ha?1 year?1) was much greater than that in chickpea (31 kg ha?1 year?1). The Vertisol under the NT system offered more favourable conditions for the stimulation of the N2 fixation, with fixed N values that were significantly higher than under CT. The N added to the system through N2 fixation was low in faba bean and virtually nonexistent in chickpea, only in terms of above-ground biomass.  相似文献   

4.
In order to investigate the significance of seed source on yield and related characters 47 seed lots of seven faba bean varieties and 24 seed lots of five dry pea varieties were tested in three series of field trials. The grain yield of the faba bean varieties tested was considerably modified by seed source, whereas only small and nonsignificant effects of seed source were found in dry peas. In general, seed sources with a high thousand grain weight, a high protein content, high portions of undamaged and healthy seeds, and in faba beans a high degree of cross-fertilization exhibited superior grain yields. Production of high-performance seed proved to be the most difficult for the large-seeded and white-flowered faba bean varieties. Based on a tabular summary on factors affecting effects of seed source problems of seed production in both grain legumes and their impact on yield are discussed.  相似文献   

5.
Two semi-leafless pea cultivars and two highly lodging-resistant faba bean cultivars were grown in a series of replacement trials conducted on a highly fertile loam soil near Gottingen from 1992 to 1995. Cultivation as well as harvesting of mixed crops of both species proved possible. In spite of the delayed harvest of the mixed crop stands determined by the later pod ripening of the faba beans (varying between seasons from -f 5 to +21 days), noticeable seed losses due to pod shattering were not observed for the overripe peas. Standing ability of the peas was considerably improved by mixed cropping. Lodging began later and was less severe at harvest. Within mixtures with 50 % or more faba bean proportions at sowing (relative to the seeding rate of the pure stands) the peas, n i most cases, remained nearly upright until harvest and instead of the usual 'Plattlager', i.e., prostrate but upright top, frequently a more highly inserted 'Hohllager', i.e., upright but collapsed at higher nodes, was observed. In contrast to these remarkably synergistic effects for standing ability, such effects proved to be only small and nonsignificant for grain yield (−1.5–2.9%). Yield stability of the mixed crops was higher than that of the pure stands of both species. Estimates of the stability parameters, ecovalence, deviation from regression and environmental variance were at least halved. Yield proportions of peas and faba beans in the harvested seed of the mixtures did not correspond with the seed proportions at sowing. They differed considerably between seasons and cultivar combination. Higher yield proportions of faba beans were observed under wet and cold weather conditions and for the cultivar combination Victor/Disco, whereas higher yield proportions of peas were found under dry and warm weather conditions and for the cultivar combination Mythos/Baroness .  相似文献   

6.
Competition for soil resources plays a key role in the crop yield of intercropping systems. There is a lack of knowledge on the main factors involved in competitive interactions between crops and weeds for nutrients uptake. Hence, the purpose of this work was to compare the effects of arbuscular mycorrhial fungi (Funneliformis mosseae) colonization in interspecific competitive relations and its effect on nutrients uptake and weed control in dill and common bean intercropping. Two field experiments were carried out with factorial arrangements based on randomized complete block design with three replications during 2013–2014. The factors were cropping systems including a) common bean (Phaseolus vulgaris L.) sole cropping (40 plants m−2), b) dill (Anethum graveolens L.) sole cropping at different densities (25, 50 and 75 plants m−2) and c) the additive intercropping of dill + common bean (25 + 40, 50 + 40 and 75 + 40 plants m−2). All these treatments were applied with (+AM) or without (-AM) arbuscular mycorrhiza colonization. In both cropping systems, inoculation with F. mosseae increased the P, K, Fe and Zn concentrations of dill plants by 40, 524, 57 and 1.0 μg kg−1 DW, respectively. Intercropping increased Mn concentration in common bean (4.0 μg kg−1 DW) and dill (3.0 μg kg−1 DW), and also seed yields of both crops (198 g m−2 and161 g m−2, respectively). AM colonization improved seed yields of dill and common bean by 169 and 177 g m−2 in 2013 and 2014, respectively. Moreover, AM application enhanced competitive ability of dill + common bean intercrops against weeds at different intercropping systems. Intercropping significantly changed weed density compared to sole cropping, as weed density was decreased in the dill + common bean intercropping. Diversity (H), Evenness (E) and richness of weed species of weeds for intercrops were higher than those for sole crops.  相似文献   

7.
Tubers of water yam (Dioscorea alata L.) are an important source of carbohydrates for millions of people throughout the tropics. Planting of the crop in the Caribbean and Central America is usually carried out between March and July. As water yam is very sensitive to small variations in photoperiod, changes in the planting date may greatly affect crop development and growth. The aim of this study was to assess the change in the radiation use efficiency (RUE) as a function of the planting date, and its effect on yam growth and yields. For this, we adapted the CropSyst model to simulate yam development and growth. The model was modified, calibrated and tested using two independent data sets from field experiments carried out in Guadeloupe (French Antilles) under non-limiting conditions for water and nutrients and over a wide range of planting dates and photoperiods (e.g. from 12.9 h in March to 11.3 h in October). The planting-harvest period varied from 4.4 months for the late planting dates to 9.1 months for the early planting dates. The RUE was relatively stable in the vegetative phase, increased after tuber initiation (TI) to reach a maximum value during the exponential phase of tuber growth, and then decreased towards the end of growth. The mean value of RUE increased from the early (March, 1.4 g MJ?1) to the intermediate planting dates (July, 2.7 g MJ?1), and then decreased for the late planting dates (October, 1.3 g MJ?1). Maximum RUE was negatively correlated with photoperiod. This particular behaviour of RUE was induced by a source–sink interaction which was controlled by crop development and photoperiod. The model described yam development and growth satisfactorily for all the planting dates: e.g. R2 > 0.92 for the correlation between modelled and measured tuber biomass. Yields varied little from the early to the intermediate planting dates because of an offset between the length of the vegetative phase, which determined leaf area, and the level of RUE after TI, which determined the capacity of the crop to fill tubers. Growth and yield drastically decreased for the late planting dates because photoperiod induced fast TI which strongly affected the leaf area. The model was a powerful tool to identify the underlying mechanisms affecting yam yields for some early planting dates, and to assess the factors involved in the high year-to-year variability currently observed in water yam yields.  相似文献   

8.
The intercropping of rapeseed with frost-sensitive companion plants (CP) has recently been proposed as a way to mitigate the negative environmental impact of rapeseed crops. Using mixed-effect linear models, we compared the yield and weed amounts of rapeseed intercropped with different CP species with that of rapeseed as a sole crop in an unique dataset of 79 field experiments covering a wide range of climate, soil and practices conditions in the northwestern part of France, from 2009 to 2015. Bayesian model averaging procedure was used to determine the relative contributions of sites characteristics to the effects of intercropping.Before winter, field pea and faba bean had accumulated the largest amounts of dry mass, with more than 100 g m−2. Rapeseed biomass was reduced by 56% by non-legume CPs and by only 18% by legume CPs, the largest decrease being caused by pea. Non-legumes decreased the nitrogen nutrition index of rapeseed by 7%, whereas pea and faba bean increased this index by 6% and 3%, respectively. Intercropping with non-legume and legume CPs reduced weed amounts by 52% and 38% respectively, with no difference between CP species. Non-legume CPs decreased rapeseed yield at harvest by 0.58 t ha−1, whereas faba bean and faba bean + lentil increased yield by 0.16 and 0.12 t ha−1 respectively, when fertilized at the recommended rate. Intercropping with faba bean, lentil or a mixture of both made it possible to reduce nitrogen applications by 30–40 kg ha−1 with no significant decrease in rapeseed yield. Faba bean and faba bean + lentil mixtures had the best overall performance. This work suggests that intercropping rapeseed is promising, particularly in soils with low nitrogen content with an early sowing date in the late summer.  相似文献   

9.
In a field experiment, peas (Pisum sativum L.) and oats (Avena sativa L.) were grown as sole crops and intercrops, fertilized with horse manure and yard-waste compost derived from shrub and garden cuttings at 10 t C ha−1 each. The objectives were to compare the effects of these organic fertilizer and cropping system in organic farming on (a) yield of peas and oats, grown as the sole crop or intercropped, as well as N2 fixation and photosynthetic rates, (b) the yield of wheat as a succeeding crop, (c) microbial biomass indices in soil and roots, and (d) microbial activity estimated by the CO2 evolution rate in the field and the amount of organic fertilizers, recovered as particulate organic matter (POM). In general, organic fertilizer application improved nodule dry weight (DW), photosynthetic rates, N2 fixation, and N accumulation of peas as well as N concentration in oat grain. Averaged across fertilizer treatments, pea/oat intercropping significantly decreased nodule DW, N2 fixation and photosynthetic rate of peas by 14, 17, and 12%, respectively, and significantly increased the photosynthetic rate of oats by 20%. However, the land equivalent ratio (LER) of intercropped peas and oats exceeded 1.0, indicating a yield advantage over sole cropping. Soil microbial biomass was positively correlated with pea dry matter yields both in sole and intercropped systems. Organic fertilizers increased the contents of microbial biomass C, N, P, and fungal ergosterol in soil and CO2 production, whereas the cropping system had no effects on these microbial indices. According to the organic fertilizer recovered as POM, 70% (manure) and 64% (compost) of added C were decomposed, but only 39% (manure) and 13% (compost) could be attributed to CO2–C during a 101-day period. This indicated that horse manure was more readily available to soil microorganisms than compost, leading to increased grain yields of the succeeding winter wheat.  相似文献   

10.
Wheat (Triticum aestivum L.)/maize (Zea mays L.) strip intercropping is widely practiced in arid regions of northwestern China because of its high land use efficiency. However, its sustainability has been questioned because it consumes much more water than sole cropped wheat or maize. The present study was conducted to investigate the effects of water limitation on the yield advantage and water use of this system. Three field experiments were conducted in the Hetao Irrigation District in Inner Mongolia during the growing seasons of 2012–2014. Each experiment comprised two water applications, in which one was full irrigation and the other was a period of water limitation during the co-growth period of intercropping.The interspecific competition in wheat/maize intercropping was intensified by water stress. For water limitation applied during the wheat booting/maize V5 stage (Exp. I, second irrigation was not applied), the yield advantage of intercropped wheat (IW) over sole wheat was enhanced, whereas that of intercropped maize (IM) over sole maize was reduced compared with full irrigated treatments; for water limitation applied during the wheat jointing/maize V2 stage (Exp. II, first irrigation was not applied), the yield advantages of both IW and IM were greatly reduced; for water limitation applied during the wheat grain filling/maize V9 stage (Exp. III, third irrigation was not applied), the yield advantage of IW was slightly improved, whereas that of IM was reduced. The yield advantage of intercropping under limited irrigation was 25%, 3%, and 18% in Exps. I–III, respectively, whereas that under full irrigation ranged between 22 and 24%.Under well-watered conditions, wheat/maize intercropping used 24–29% more water than the weighted means of sole crops with the water use efficiency equivalent to sole crops. After the application of water limitation, 60 mm irrigation water was saved by intercropping every year, whereas the reduction of water use ranged from 25.1 to 70.8 mm; the changes in water use of intercropping relative to sole crops was reduced to 18–24%; the changes in water use efficiency stayed at nearly zero in Exps. I and III but decreased to a value of −13% in Exp. II. These results indicated that water limitation could be applied during wheat booting or filling stage in wheat/maize intercropping to save irrigation water in our study area.  相似文献   

11.
Field experiments were carried out under unstressed conditions of soil water during two summer crop growing seasons (1998–99 and 1999–2000 seasons) in a South African semi‐arid region (Bloemfontein, Free State, South Africa). The aim of this study was to investigate shade effects on beans intercropped with maize in terms of plant mass and radiation use. The experimental treatments were two cropping systems (no shading/sole cropping and shading/intercropping) and two row orientations (north–south and east–west). At the top of bean canopies shaded by maize, incident radiation was reduced by up to 90 %. Shading reduced total dry matter of beans by 67 % at the end of the growing season, resulting in yield losses. The dry matter partitioning into leaf and stem (the ratios of leaf and stem to total biomass) was about 50 % higher in intercropping than sole cropping. In contrast, intercropped beans had 40 % lower dry matter partitioning into pod (the ratio of pod to total biomass). Fraction of radiation intercepted by sole‐cropped beans steeply increased until canopy closure (0.9) and then slowly decreased, while fraction of radiation intercepted by intercropped beans remained constant between 0.0 and 0.2 throughout the growing seasons. However, intercropped beans had 77 % higher radiation use efficiency (RUE) than sole‐cropped beans. In contrast, for maize, no effect of intercropping (shading) was found on growth, partitioning, yield, radiation interception or RUE. Consequently, lower bean yield losses can be attained in association with late shading rather than early shading. This can be controlled by growing crops with different temporal and spatial treatments. As regards row treatment, no effect of row direction was found on growth, partitioning, yield, radiation interception or RUE.  相似文献   

12.
Field experiments were conducted in 2006 and 2007 to evaluate the competitive ability of bush type red kidneybean (RKB) (Phaseolus vulgaris L.) cultivars against redroot pigweed (Amaranthus retroflexus L.). Three cultivars of RKB (Akhtar, Sayyad and D81083) and five A. retroflexus densities (0, 4, 8, 16 and 32 plants m−2) were established in a factorial arrangement. A. retroflexus had a greater plant height and growth rate (GR) but a lower leaf area index (LAI) than RKB cultivars in almost all treatments. Higher densities of A. retroflexus increased LAI and GR but decreased yield of RKB cultivars. The cv. Sayyad and D81083 had the greatest and lowest LAI and GR, respectively, in competition with A. retroflexus. The maximum intercepted photosynthetically active radiation (PAR) at noon by A. retroflexus was 90.4 and 66.0% in competition with cv. D81083 and Sayyad, respectively. The seed yield and pod number per plant of RKB cultivars decreased severely with increasing A. retroflexus density. A. retroflexus seed number m−2 was the highest and lowest in competition with cv. D81083 and Sayyad, respectively. The competitive ability of RKB cultivars was compared using parameters estimated through two-parameter yield loss-relative leaf area model. The relative ranking of the RKB cultivars examined for their competitiveness, supported by modeling results, was Sayyad > Akhtar > D81083.  相似文献   

13.
For biomethane production, the cup plant (Silphium perfoliatum L.) is considered a promising alternative substrate to silage maize (Zea mays L.) due to its high biomass potential and associated ecological and environmental benefits. It has also been suggested to grow cup plant on less productive soils because of its presumed drought tolerance, but robust information on the impact of water shortage on biomass growth and substrate quality of cup plant is rare. Therefore, this study assesses the effects of soil water availability on the chemical composition and specific methane yield (SMY) of cup plant. Furthermore above-ground dry matter yield (DMY) was analysed as a function of intercepted photosynthetic active radiation (PAR) and radiation use efficiency (RUE). Data were collected in a two-year field experiment under rainfed and irrigated conditions with cup plant, maize, and lucerne-grass (Medicago sativa L., Festuca pratensis Huds., Phleum pratense L.). The cup plant revealed a slight decrease of −6% in the SMY in response to water shortage (less than 50% of plant available water capacity). The average SMY of cup plant [306 l (kg volatile solids (VS))−1] was lower than that of maize [362 l (kg VS)−1] and lucerne-grass [334 l (kg VS)−1]. The mean drought-related reduction of the methane hectare yield (MHY) was significantly greater for cup plant (−40%) than for maize (−17%) and lucerne-grass (−13%). The DMY reduction in rainfed cup plant was mainly attributed to a more severe decrease in RUE (−29%) than for maize (−16%) and lucerne-grass (−12%). Under water stress, the mean cup plant RUE (1.3 g MJ−1) was significantly lower than that of maize (2.9 g MJ−1) and lucerne-grass (1.4 g MJ−1). Compared to RUE, the reduced PAR interception was less meaningful for DMY in rainfed crops. Hence, the cup plant is not suitable for growing on drought prone lands due to its high water demand required to produce reasonably high MHYs.  相似文献   

14.
B. Bjerg    E. Kbmeyer    B. O. Eggum    T. Larsen    G. Röbbelen  H. Sørensen 《Plant Breeding》1988,101(4):277-291
Ten inbred lines of fabe beans (Vicia faba L.) selected according to their quality characters have been investigated for carbohydrates, proteins, and antinutritional compounds. Digestible energy, N-balance trials with growing rats comprising determination of the protein digestibility and biological value were used as criteria in connection with comprehensive chemical-biochemical analysis. The chemical composition of the ten lines showed a considerable diversity as cad the results from the rat crisis. However, the content of vicine and convicine in all or the investigated lines were below the level previously found to have effects on the nutritive value, Starch, protein and fibre were the quantitatively dominating seed constituents, and all showed great variation among the lines. The starch content was not correlated to the quality or nutritive value of the seed, whereas the protein content was negatively correlated to the biological value and net protein utilization. These correlations followed the content of essential amino acids, lysine, threonine and methionine in the faba bean proteins. The content of the sulfur-containing ammo acids cysteine and methionine are especially dominant factors for protein quality. A simple method for total sulphur determination was found nut 10 be a sufficiently reliable technique for evaluating the content of methionine and cysteine in the faba beans. Tannin, insoluble- and total dietary fibre are phenolic aromatic compounds which were negatively correlated with the faba bean quality as expressed by digestible energy, the protein digestibility and the biological value of the faba beans. The results obtained have also revealed, that it is not sufficient to consider tannin as a group in relation to the faba bean quality. We need to separate and evaluate the different types, of phenolics in relation to the variations in quality of faba beans. Some of the low molecular weight (LMW) phenolics in the faba beans seem 10 be involved in inhibitory effects on hydrolase enzymes, chymotrypsin and trypsin. Trypsin and chymotrypsin from different animals were different in their sensitivity to faba bean inhibitors and additional experiments are required to reveal details about these effects. It has also been revealed that fructosans Lind LMW carbohydrates (oligosaccharides) are important in relation to the quality of faba beans.  相似文献   

15.
Agroforesry is a common traditional practice in China, especially in the saline-alkaline regions, like the lower North China Plain (LNCP) characterized by lower yields of food crops. Adding trees to the agricultural land creates additional fruitsets or woody biomass besides food crops, enabling farmers to diversify the provision of farm commodities. However, the productivity of many agroforestry systems has been lower than expected in recent years, highlighting the need for a mechanistic understanding of below- or above-ground interactions. The study combined investigation and experimental data together to evaluate the effects of long-term intercropping agroforestry system [jujube tree (Zizyphus jujuba Mill. var. inermis (Bunge) Rehd.)/winter wheat–summer maize] on soil fertility balance, crop production and system economic efficiency over the past 22 years in LNCP, with a view to developing an effective fertilization management for the moderately alkaline soils. Except remain higher pH, the soils are basically free of sodic and soil salinity is not the major restriction factor for intercrops, even through there are some fluctuation with season and distance from jujube tree. The intercropping system significantly reduced soil nutrient contents, like soil organic C (SOC), total N (TN), available P (avail. P) and K (avail. K) in most parts of the ecotone of the system, but increased those nutrients in the belt of underneath the edge of tree canopy, The growth of intercrops at the belt of 3.5 m from tree was severely negative stressed by jujube tree in term of lower soil moisture, nitrate, avail. P and K although receiving more photosynthetically active radiation (PAR), whereas the winter wheat growing at the 2.5 m row had more water and nutrients supplied and thus produced more grain yield. Uneven fertilization to the ecotone (about 1–2.5 m of the intercrop field boundary) could partly offset the consumption and competition for nutrients between the tree and the intercrops, and improved the grain yields by 12.1% and 14.5% in the ecotone regions (distance from jujube trees) of 1.5 m for winter wheat and 2.5 m for summer maize by increasing respective yield components. Although the mean grain yield of intercropped winter wheat and summer maize was reduced by 35.6 and 35.2%, respectively, compared to sole cropping system, the intercropping system proved to be a profitable land use type based on net income and economic returns, in addition to the wood and ecological benefits of the jujube tree in the moderate desalinate- alkaline regions.  相似文献   

16.
Annual wormwood interference on soybean crop growth and yield may result from competition and allelopathy, which are modulated by crop management. Allelochemicals released by annual wormwood (e.g. artemisinin) may affect the crop directly or indirectly through the effect on the nitrogen fixing symbiont, Bradyrhizobium japonicum. The objectives were (i) to quantify the crop response (i.e. biomass production, nodulation and yield) to weed interference and (ii) to determinate the relative change of competition and allelopathy interferences, when a sublethal dose of herbicide is applied. Two split plot field experiments with three replications were used. The experiment involved a factorial combination of five weed–crop density (soybean/annual wormwood, plants m?2) levels: D1, pure soybean, 40/0 plants m?2; D2, 40/2 plants m?2; D3, 40/4 plants m?2 and D4, 40/8 plants m?2, and D5, pure annual wormwood, 0/8 plants m?2, two activated carbon (allelopathy) levels: C?, with activated carbon (reduced allelopathy) and C+, non activated carbon applied (with allelopathy) and two herbicide levels: H?, untreated and H+, treated with a sub-lethal dose of glyphosate. Activated carbon to adsorb allelochemicals (with and without activated carbon) and glyphosate application (with and no herbicide) were assigned to sub-plots. Increasing weed density did not affect crop biomass at flowering, but changed nodule number and soybean yield with a different pattern depending on carbon and herbicide treatment. Relative crop yield decreased with increasing relative weed biomass. This decrease was particularly drastic when allelopathy was reduced by activated carbon and without herbicide application. The maximum yield losses of 33% in 2006 and 17% in 2007 were observed with the highest weed density (8 plants m?2). In contrast, without carbon (high allelopathy level), soybean yield remained stable within the explored range of annual wormwood biomass, despite the fact that weed biomass at high densities (D4) was high enough to generate competition. The lack of response to increasing weed density could be related to the indirect effect of allelochemicals interacting with soil microorganisms (i.e. B. japonicum) that positively affected the nodulation (e.g. larger nodules in 2006 and increased nodules biomass due to higher number of roots in 2007 at high densities). With herbicide application, soybean yield of both carbon treatments remained stable when biomass of annual wormwood increased. This research provided strong evidence in support of the existence of positive effect of allelopathic and competitive interactions between annual wormwood and soybean crop under field conditions that may be overridden under herbicide application.  相似文献   

17.
Parental lines, F1 and F2 hybrids from a 7×7-diallel of topless faba beans and eight standard cultivars were grown in single-rows for two years at four sowing dates on a highly fertile loam soil near Göttingen. In grain yield, F1 hybrids showed 21 to 54% advantage over the higher yielding parent. Compared with the midparental value an average heterosis of 50% was observed for grain yield. Corresponding heterosis mean values ranged from 3 to 37% for yield components and up to 11% for phenological traits. The grain yield of the highest yielding topless F1 hybrid was equal to that of Alfred, the highest yielding indeterminate standard cultivar. High grain yield in the topless hybrids was closely correlated with high biomass yield, late ripening and tall plants generally having a high number of podded nodes and pods on the main stem. Due to their agronomic advantages, i.e., lower plant length, reduced lodging sensitivity and earlier ripening, efforts at breeding topless hybrids seemed to be worth-while in faba beans. However, their yielding ability must be improved further before they can compete with normal, semi-dwarf and stiff-strawed cultivars.  相似文献   

18.
The parasitic weed Orobanche crenata inflicts major damage on faba bean, lentil, pea and other crops in Mediterranean environments. The development of methods to control O. crenata is to a large extent hampered by the complexity of host–parasite systems. Using a model of host–parasite interactions can help to explain and understand this intricacy. This paper reports on the evaluation and application of a model simulating host–parasite competition as affected by environment and management that was implemented in the framework of the Agricultural Production Systems Simulator (APSIM). Model-predicted faba bean and O. crenata growth and development were evaluated against independent data. The APSIM-Fababean and -Parasite modules displayed a good capability to reproduce effects of pedoclimatic conditions, faba bean sowing date and O. crenata infestation on host–parasite competition. The r2 values throughout exceeded 0.84 (RMSD: 5.36 days) for phenological, 0.85 (RMSD: 223.00 g m−2) for host growth and 0.78 (RMSD: 99.82 g m−2) for parasite growth parameters. Inaccuracies of simulated faba bean root growth that caused some bias of predicted parasite number and host yield loss may be dealt with by more flexibly simulating vertical root distribution. The model was applied in simulation experiments to determine optimum sowing windows for infected and non-infected faba bean in Mediterranean environments. Simulation results proved realistic and testified to the capability of APSIM to contribute to the development of tactical approaches in parasitic weed control.  相似文献   

19.
The carbon dioxide (CO2) concentration of the global atmosphere has increased during the last decades. This increase is expected to impact the diurnal variation in temperature as well as the occurrence of extreme temperatures. This potentially could affect crop production through changes in growth and development that will ultimately impact yield. The objective of this study was to evaluate the effect of CO2 and its interaction with temperature on growth and development of soybean (Glycine max (L.) Merr., cv. Stonewall). The experiment was conducted in controlled environment chambers at the Georgia Envirotron under three different temperatures and two CO2 regimes. The day/night air temperatures were maintained at 20/15, 25/20 and 30/25 °C, while the CO2 levels were maintained at 400 and 700 ppm, resulting in six different treatments. Plants were grown under a constant irradiance of 850 μmoles m−2 s−1 and a day length of 12 h; a non-limiting supply of water and mineral nutrients were provided. Five growth analyses were conducted at the critical development stages V4, R3, R5, R6 and R8. No differences in start of flowering were observed as a function of the CO2 level, except for the temperature regime 25/20 °C, where flowering for the elevated CO2 level occurred 2 days earlier than for the ambient CO2 level. For aboveground biomass, an increase in the CO2 level caused a more vigorous growth at lower temperatures. An increase in temperature also decreased seed weight, mainly due to a reduction in seed size. For all temperature combinations, final seed weight was higher for the elevated CO2 level. This study showed that controlled environment chambers can be excellent facilities for conducting a detailed growth analysis to study the impact on the interactive effect of changes in temperature and CO2 on soybean growth and final yield.  相似文献   

20.
In order to better understand how mixed crop cultures mitigate stressful conditions, this study aims to highlight the beneficial effect of the intercropping legume-cereal in enhancing soil phosphorus (P) availability for plant growth and productivity in a P-deficient soil of a northern Algerian agroecosystem. To address this question, common bean (Phaseolus vulgaris L. cv. El Djadida) and maize (Zea mays L. cv. Filou), were grown as sole- and inter-crops in two experimental sites; S1 (P-deficient) and S2 (P-sufficient) during two growing seasons (2011 and 2012). Growth, nodulation and grain yield were assessed and correlated with the rhizosphere soil P availability. Results showed that P availability significantly increased in the rhizosphere of both species, especially in intercropping under the P-deficient soil conditions. This increase was associated with high efficiency in use of the rhizobial symbiosis (high correlation between plant biomass and nodulation), plant growth and resource (nitrogen (N) and P) use efficiency as indicated by higher land equivalent ratio (LER > 1) and N nutrition index (for maize) in intercropping over sole cropping treatments. Moreover, the rhizosphere P availability and nodule biomass were positively correlated (r2 = 0.71, p < 0.01 and r2 = 0.62, p < 0.01) in the intercropped common bean grown in the P-deficient soil during 2011 and 2012. The increased P availability presumably improved biomass and grain yield in intercropping, though it mainly enhanced grain yield in intercropped maize. Our findings suggest that modification in the intercropped common bean rhizosphere-induced parameters facilitated P uptake, plant biomass and grain yield for the intercropped maize under P-deficiency conditions.  相似文献   

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