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1.
Lack of water during vegetative and/or reproductive growth stages is one of the most limiting factors for bean growth. The purpose of this study was to evaluate the effects of water stress applied during two phenological stages (flowering and pod filling) on growth, yield and yield components. Two genotypes of bean ( Phaseolus vulgaris L.) were used in this study, cv. Carioca, an indeterminate Brazilian landrace, and cv. Prince, a determinate cultivar grown in Europe. Carioca appears to be generally stress-tolerant while Prince is intolerant. Plants were grown in large plastic pots covered with a black plastic sheet to protect the soil from rain and evaporation. The water stress treatments were: control (well-watered plants), WSFS (water stress during flowering stage) and WSPFS (water stress during pod-filling stage). Water stress reduced yield and yield components at both flowering and pod-filling stages. The parameters affected were seed weight, number of seeds per plant and number of pods per plant. Number of seeds per pod and seed weight were not affected. No effects of water stress were detected on harvest index. Time to maturity was slightly prolonged, especially for WSFS. Water stress at both stages resulted in lower accumulated water loss compared to the control plants. Water stress during both phenological stages reduced other growth parameters, the number of trifoliate leaves, stem height, number of main branches and number of nodes on the main stem. 相似文献
2.
M. L. Praba J. E. Cairns R. C. Babu & H. R. Lafitte 《Journal of Agronomy and Crop Science》2009,195(1):30-46
Rice is used as a model cereal to study drought response at the molecular level, with the goal of applying results to other cereals. To assess the relevance of results from rice to other species, the kinetics of drought development and plant response of tolerant and susceptible tropical rice ( Oryza sativa L.) and subtropical wheat ( Triticum aestivum L.) cultivars were compared under vegetative and reproductive stage drought in pot experiments. Water was withheld during reproductive stage until plant available soil moisture content was 30 % of field capacity (FC) or leaf wilting was observed, and then reapplied. Rice reached 30 % FC 9 days after withholding water and wheat after 13 days. Before rewatering, both species reached leaf water potentials of −12 bars and similarly low transpiration rates. Stress reduced leaf relative water content, leaf elongation and membrane stability. When water stress was imposed during reproductive stage, pollen fertility was most affected in wheat, while panicle exsertion and anther dehiscence were severely affected in rice. When water stress was imposed during vegetative stage, wheat was less affected to vegetative stage drought than rice. The nature of differences between tolerant and susceptible cultivars was similar for the two species. However, the differential growth habitats and growth rate of plants needs to be considered in these kinds of experiments. 相似文献
3.
A series of trials to increase understanding of the summer dormancy trait in Phalaris aquatica was conducted. Autumn‐sown and younger, spring‐sown plants of two cultivars (cvv), known to contrast in expression of summer dormancy, were established and then tested over the following summer under three moisture regimes: long drought; drought + mid‐summer storm; or full irrigation. The autumn‐sown plants of cv. Atlas PG expressed substantial but incomplete summer dormancy under all moisture regimes and exhibited the characteristic responses including significant growth reduction and herbage senescence. The summer‐dormant cv. Atlas PG used 31 mm less soil water over the summer and also began to rehydrate its leaf bases from conserved soil water before the drought broke. The non‐dormant cv. Australian grew whenever moisture was applied and also responded to the mid‐summer storm with a decline in dehydrin expression in leaf bases, whereas no decline occurred in Atlas PG, presumably because it remained dormant. The irrigated, younger, spring‐sown swards of cv. Atlas PG had restrained growth and produced only about 37 % of the herbage of cv. Australian. Drought reduced activity and growth of young plants of both cultivars but while Australian regrew in response to the storm, cv. Atlas PG, grew much less (59 % of Australian) indicating that dormancy, although only partially expressed after spring sowing, was reinforced by summer drought. Australian used more soil water over summer than Atlas PG, and it is suggested that this is why cv Australian is limited to the higher rainfall zones of south‐eastern Australia, particularly where soil water holding capacity is limited. 相似文献
4.
Old and New Cultivars of Soya Bean (Glycine max L.) Subjected to Soil Drying Differ in Abscisic Acid Accumulation,Water Relations Characteristics and Yield 
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下载免费PDF全文 J. He Y.‐L. Du T. Wang N. C. Turner Y. Xi F.‐M. Li 《Journal of Agronomy and Crop Science》2016,202(5):372-383
Two old (Huangsedadou and Longxixiaohuangpi (LX)) and two new (Jindou 19 (JD) and Zhonghuang 30 (ZH)) soya bean (Glycine max (L.) Merr.) cultivars were used to investigate the influence of soil drying on the abscisic acid (ABA) accumulation in leaves, stomatal conductance (gs), leaf water relations, osmotic adjustment (OA), leaf desiccation tolerance, yield and yield components. The greater ABA accumulation was induced by soil drying, which also inducing gs decreased at higher soil water contents (SWC) and leaf relative water content (RWC) significantly decreased at lower SWC in the new soya bean cultivars than in the old soya bean cultivars. The soil water threshold between the value at which stomata began to close and the RWC began to decrease was significantly broader in the new cultivars than in the old cultivars. The new cultivars had significantly higher OA and lower lethal leaf water potential than old cultivars when the soil dried. The old cultivars had greater biomass, but lower grain yield than the new cultivars in well‐watered, moderate stress and severe stress conditions. Thus with soil drying, the new soya bean cultivars demonstrated greater adaptation to drought by inducing greater ABA accumulation, stomatal closure at higher SWC, enhanced OA and better water relations, associated with increased leaf desiccation tolerance, greater water use efficiency and higher yield. 相似文献
5.
A.M Manschadi J Sauerborn H Stützel W Göbel M.C Saxena 《European Journal of Agronomy》1998,9(4):259-272
Root growth of faba bean genotype ILB 1814 grown under both limited and sufficient moisture supply was studied in 1993–1994 and 1994–1995 at ICARDA's Tel Hadya research station. Crops were sown on two dates in both growing seasons. Root-length density (RLD) and root dry weight were measured at four depths in three locations relative to the crop row. In general, RLD decreased considerably with depth, and by the start of pod-filling, around 60% of the roots were found in the top 15 cm of soil. In the upper 30 cm soil profile, the RLDs of drought-stressed faba beans were significantly lower than those measured beneath well-watered crops. In the deeper soil layers, the RLDs were similar in both moisture supply treatments. An existing root model was employed for the simulation of faba bean root growth. The model estimates the depth of rooting and RLD in each soil layer based on dry matter allocation to the root system, soil layer water contents, genotype-specific rooting characteristics, and soil physical properties. A faba bean growth model provided daily allocation of dry matter to roots as well as soil layer water contents. Overall, with a few modifications, the root model was capable of predicting the RLD of faba bean grown both under limited and sufficient water supply realistically. Limitations of the model and some aspects that need further improvement are discussed. 相似文献
6.
Field beans of indeterminate (cv. Nadwiślański) and determinate (cv. Tibo) growth habits were grown on field plots with a density of 20, 40 and 80 plants m−2 at two levels of nitrogen fertilization: low (20 kg N ha−1 ) and very high (150 kg N ha−1 ). At the phase of intense pod growth the number and the dry matter weight of root nodules as well as their nitrogenase activity and some features of the plants growth were determined, and in the period of ripeness the components of seed yield were established.
It was found that increased density of sowing as well as the high level of nitrogen fertilization inhibited the growth and development of root nodules and limited their nitrogenase activity in both cultivars. Plants of both varieties were characterized by a similar potential of forming the root nodules, however, in plants of the cv. Tibo the nitrogenase activity of nodules was much lower than in the cv. Nadwiślański.
Increased population density of the plants has in both varieties given increased seed yield when calculated per m2 of the soil, compensating in excess the depression of the seed yield from one plant. Such compensation did not occur in the case of the depression of nitrogen fixation under intense nitrogen fertilization. 相似文献
It was found that increased density of sowing as well as the high level of nitrogen fertilization inhibited the growth and development of root nodules and limited their nitrogenase activity in both cultivars. Plants of both varieties were characterized by a similar potential of forming the root nodules, however, in plants of the cv. Tibo the nitrogenase activity of nodules was much lower than in the cv. Nadwiślański.
Increased population density of the plants has in both varieties given increased seed yield when calculated per m
7.
Yield and Yield Components from Intercropping Improved Bush Bean Cultivars with Maize 总被引：2，自引：0，他引：2
Bush bean ( Phaseolus vulgaris L.) is widely intercropped with maize ( Zea mays L.) in North-west Spain. Little information is available on the relative performance of elite bush bean cultivars when intercropped or on the effect of bush bean on performance of the maize crop. This two-environment study presents the interactions between improved bush bean cultivars and maize on yield and yield components. Eight treatments (four bean/maize intercrops and four sole crops, two of bean and two of maize) were tested using a randomized complete block design with four replications in two environments. Bean and maize were planted simultaneously in alternate rows when intercropped. Significant treatment differences were observed for bean and maize moisture, pod and cob percentage, bean and maize yield, ears per plant and ear length. Location effects were significant for bean and maize moisture and pod percentage. Significant treatment by location interactions occurred for pod percentage and ear length. Intercropping reduced yield by between 40 and 60 % for bush bean cultivars, and by 45 % for both maize cultivars. Mean yields were used to calculate the land equivalent ratio (LER), which averaged 1.01 in Pontevedra but 0.93 in La Coruña. Intercropping of bush bean with maize did not make better use of land than conventional sole cropping under these environmental conditions. It is suggested that this was probably due to the amount and distribution of rain in relation to crop growth. Approaches that might be expected to result in improved land usage are presented. 相似文献
8.
U. R. Sangakkara U. A. Hartwig J. Nösberger 《Journal of Agronomy and Crop Science》1996,177(3):145-151
The development of an extensive root system enables plants to overcome water stress. However, there is little information on the response of food legumes to soil moisture, especially during early growth, which determines crop establishment. Thus, an experiment was conducted under controlled conditions to identify the effect of soil moisture and fertilizer potassium on root and shoot growth of french beans ( Phaseolus vulgaris L.) seedlings. The seedlings were grown in a sand medium under a high and low soil moisture regime and with 0.1, 0.8 or 3.0 mM potassium.
Root lengths, dry weights and numbers of root hairs were greater under low soil moisture conditions. Potassium increased root growth irrespective of soil moisture regimes. The impact of potassium on root length was more pronounced under a high soil moisture regime. In contrast, potassium increased root dry weights and root hairs to a greater extent when plants were grown under dry conditions. The lack of adequate soil moisture increased specific leaf weights, and this phenomenon was reduced by the application of potassium. Shoot:root ratios also showed a similar phenomenon. The development of an extensive root system by french bean seedlings under dry conditions to extract a greater quantity of available soil moisture fur establishment and plant growth and the ability of potassium to promote this phenomenon is presented in this study. 相似文献
Root lengths, dry weights and numbers of root hairs were greater under low soil moisture conditions. Potassium increased root growth irrespective of soil moisture regimes. The impact of potassium on root length was more pronounced under a high soil moisture regime. In contrast, potassium increased root dry weights and root hairs to a greater extent when plants were grown under dry conditions. The lack of adequate soil moisture increased specific leaf weights, and this phenomenon was reduced by the application of potassium. Shoot:root ratios also showed a similar phenomenon. The development of an extensive root system by french bean seedlings under dry conditions to extract a greater quantity of available soil moisture fur establishment and plant growth and the ability of potassium to promote this phenomenon is presented in this study. 相似文献
9.
不同土壤及氮肥条件下水稻氮利用效率和增产效应研究 总被引：60，自引：4，他引：60
在土培池条件下,研究了2种土壤(砂土和黏土)和4种施氮水平下4个水稻品种(组合)施用氮利用效率、增产效应及吸氮特性。结果表明,(1)在砂土和黏土上施用氮肥均能显著提高水稻产量,但黏土上的产量显著高于砂土上的,而砂土施用氮肥的增产效应显著高于黏土。(2)不同土壤条件下,水稻对氮肥的利用情况不同。氮素收获指数和氮肥生理利用率呈砂土>黏土的趋势,氮肥表观利用率、氮肥偏生产力和土壤氮素依存率呈黏土>砂土的趋势,而氮肥农艺利用率则因水稻基因型不同在不同土壤上表现有所差异。(3)随施氮水平的提高,氮素收获指数、氮肥农艺利用率、氮肥生理利用率、氮肥偏生产力和土壤氮素依存率,在2种土壤条件下,均呈显著下降趋势;而氮肥表观利用率在砂土条件下呈一直上升趋势,以高肥处理最高,在黏土条件下则呈现先上升,至中肥最大,高肥显著下降的趋势。(4)秸秆吸氮量、籽粒吸氮量和总吸氮量均呈黏土>砂土的趋势,但差异相对较小。(5)在不同土壤条件下,水稻施用氮肥的增产效应、氮肥利用效率和对氮素的积累与分配均存在显著的基因型差异。 相似文献
10.
A.M. Manschadi J. Sauerborn H. Stützel W. Göbel M.C. Saxena 《European Journal of Agronomy》1998,9(4):273-293
This study reports the adaptation of a simple and mechanistic crop growth model for faba bean (FAGS) to growing conditions in the Mediterranean region. The FAGS model was originally developed for small-seeded cultivars grown in the temperate zone under non-limiting water and nutrient conditions. In order to account for the effect of drought stress on faba bean growth, a submodel for the simulation of soil water balance has been included in the FAGS model. The enhanced FAGS model was calibrated using data from field experiments with a large-seeded faba bean genotype (ILB 1814) conducted in 1993–1994 and 1994–1995 at ICARDA's Tel Hadya research station in northern Syria. In both seasons, crops were sown on two dates under different water supply levels. The model was capable of predicting the faba bean phenology, leaf area development, biomass production, and grain yield as well as the soil water extraction using daily climatic data, genotype-specific parameters, and soil physical properties. The calibrated faba bean model was tested against independent experimental data from the 1991–1992 and 1992–1993 growing seasons at Tel Hadya and was able to satisfactorily predict grain yield of crops grown under different drought intensities. Limitations of the model and aspects requiring better understanding to improve model predictions are discussed. 相似文献
11.
二熟制粮食超高产田土肥水技术指标研究 总被引：1，自引：1，他引：0
摘要：通过创造性地引用节水高产栽培、因土平衡施肥等技术,基本做到了经济利用水、肥、土资源;在三年的高产实践中,实现了粮食单产保持1.4t/667m2以上水平的同时,水分生产效率达到2 kg/m3以上高水平,按土壤、肥料实际供应有效养分总量计算的养分生产效率也基本达到7 kg/kg以上,且粮食单产达到1524.75 kg/667m2时,总有效养分生产效率提升至8.07 kg/kg,较好地体现了高产高效同步。 相似文献
12.
[目的]为了探明在高寒冷凉区芸豆生长的水肥耦合效应,[方法]采用田间试验法,研究了施肥和覆膜垄沟种植对旱地芸豆耗水特征、水分利用效率及产量的影响。[结果]结果表明,在底墒较好,降水丰富的年份,施肥和覆膜垄沟种植的产量与农户模式相比,均有显著提高,单株荚数是其产量提高的关键因素;高肥具有明显的增产和提高水分利用效率的作用,在此基础上的覆膜垄沟种植可有效的减少土壤水分损耗,而显著的提高水分利用效率。[结论]在高寒冷凉区,水分和养分都是作物生长的限制因子,在施肥和覆膜垄沟种植方式下,水肥互作效应显著,能够大大的提高产量和水分利用效率。 相似文献
13.
Cassava is predominantly an upland crop that is also cultivated in inland valley swamps (IVS). Identifying physiological traits that can withstand excess moisture stress can aid in the selection and use of stable cassava cultivars in IVS. Three cassava cultivars were evaluated for growth and yield in the upland and IVS ecologies in the 1993–94 crop seasons using a randomized complete block design. In the upland, 80/40 outyielded 87/29 and 'coco', while in the IVS, 87/29 had the highest yield. Highest yielding cultivars in each ecology also had the highest tuberous root bulking rate (TBR), dry matter (DM) production, crop growth rate (CGR), relative growth rate, net assimilation rate (NAR), leaf area index, leaf production rate and leaf life. Positive correlations between these parameters and tuberous root yield were noted. High yield of 87/29 in IVS was partly due to its low tuberous root rotting. High root rotting in 80/40 was partly as a result of the greater depth of tuberous roots in the soil (0.3–0.6 m) as compared to the other cultivars (0.15–0.3 m) where roots were in contact with stressful water levels earlier than others. The yield and yield components, growth and leaf characters were all drastically reduced when the cultivars were grown in IVS as compared to upland. For example, root yields of 'coco', 87/29 and 80/40 were reduced by 53 %, 60 % and 92 %, respectively, in IVS. Selection of cassava cultivars with longer leaf life and leaf area maintenance leading to high CGR, TBR, NAR and harvest index (in IVS and upland), coupled with a shallow tuberous root formation zone (in IVS) can give higher root and leaf yields in the two ecologies. 相似文献
14.
Susceptibility of Faba Bean (Vicia faba L.) to Heat Stress During Floral Development and Anthesis 下载免费PDF全文
下载免费PDF全文 Experiments were conducted over 2 years to quantify the response of faba bean (Vicia faba L.) to heat stress. Potted winter faba bean plants (cv. Wizard) were exposed to temperature treatments (18/10; 22/14; 26/18; 30/22; 34/26 °C day/night) for 5 days during floral development and anthesis. Developmental stages of all flowers were scored prior to stress, plants were grown in exclusion from insect pollinators to prevent pollen movement between flowers, and yield was harvested at an individual pod scale, enabling effects of heat stress to be investigated at a high resolution. Susceptibility to stress differed between floral stages; flowers were most affected during initial green‐bud stages. Yield and pollen germination of flowers present before stress showed threshold relationships to stress, with lethal temperatures (t50) ?28 °C and ~32 °C, while whole plant yield showed a linear negative relationship to stress with high plasticity in yield allocation, such that yield lost at lower nodes was partially compensated at higher nodal positions. Faba bean has many beneficial attributes for sustainable modern cropping systems but these results suggest that yield will be limited by projected climate change, necessitating the development of heat tolerant cultivars, or improved resilience by other mechanisms such as earlier flowering times. 相似文献
15.
不同养分供应下玉米品种产量潜力变异研究 总被引：8，自引：0，他引：8
探讨土壤养分平衡因素是否影响玉米产量潜力的发挥,进而阐明不同养分供应下玉米品种生物学性状和产量潜力变异及其育种意义,为品种选育与区试中应用科学的施肥技术和手段提供依据。采用田间品种对比试验,在山西汾阳碳酸盐褐土上研究不同养分供应对15个全国区试玉米品种产量潜力变异的影响。结果表明,和常规施肥相比,调控施肥改变了玉米的生物学性状,显著增加了单穗粒重和产量;不同养分供应及平衡状况下玉米品种的产量潜力有较大差异,平衡施肥使高养分潜力型品种的产量潜力得到明显提高。土壤养分与作物施肥的养分供应状况显著影响玉米产量潜力的发挥。因此,在玉米高产育种中,应该根据土壤-养分平衡原理来筛选生态适应性品种。 相似文献
16.
A. Datta B. M. Sindel P. Kristiansen R. S. Jessop & W. L. Felton 《Journal of Agronomy and Crop Science》2009,195(3):178-185
Isoxaflutole at 75 g ai ha?1 is registered in Australia for the control of several broadleaf weeds in chickpea (Cicer arietinum L.). Although isoxaflutole provides satisfactory control of problematic weeds, under certain conditions crop injury can occur. Higher air temperature and moisture content of soil are reported to affect the metabolism of soil applied herbicide. Controlled environment experiments were used to determine the tolerance of chickpea to isoxaflutole under a range of temperature and soil moisture levels. For the soil moisture study, the variables examined were two desi chickpea genotypes (Kyabra as a tolerant cultivar and Yorker as a sensitive cultivar), three soil moisture levels [50 % field capacity (FC), 75 % FC and FC] with three herbicide rates [0, 75 (recommended rate) and 300 g ai ha?1]. For the temperature by soil moisture study, the variables examined were two other desi chickpea genotypes (97039‐1275 as a tolerant line and 91025‐3021 as a sensitive line), three temperature regimes (20/5, 30/15 and 35/25 °C), two soil moisture conditions (50 % FC and FC) with the same three herbicide rates. The results demonstrated that the chickpea genotypes exhibited differential tolerance to isoxaflutole, but that differences in response were affected by rate, temperature and soil moisture. Increasing temperature and soil moisture content made the susceptible chickpea genotype more vulnerable to isoxaflutole damage. Injury to the susceptible genotype in terms of increased leaf chlorosis and reduction in shoot height and dry matter production increased as soil moisture increased from 50 % FC to FC and temperature increased from 20/5 to 35/25 °C. Overall damage of the sensitive genotype from increasing rates of isoxaflutole also increased when soil moisture content increased from 50 % FC to FC within the fixed temperature regime of 30/15 °C. The sensitivity of chickpea to isoxaflutole depends on existing temperature and moisture content and the chances of crop damage were enhanced with increasing temperature and moisture levels. 相似文献
17.
Seed yield, oil and phytate concentration in the seeds of two oilseed rape cultivars as affected by different phosphorus supply 总被引：7，自引：0，他引：7
A greenhouse pot experiment was conducted for studying seed and oil yield, P uptake and phytate concentration in the seed of two oilseed rape cultivars (Brassica napus L. var. Oleifera, cv. Bristol and cv. Lirajet), grown on a soil substrate at different levels of plant available phosphorus (6, 19, 31 and 106 mg P-CAL kg−1 soil, resp.). All other nutrients were maintained at a high level. At maturity, seed yield and seed quality were investigated. An increase in the phosphorus soil supply resulted in a significant (P<0.05) increase in seed and oil yield, oil and P concentration of the seeds, and P transported to the seeds. The phytate-phosphorus concentration ranged from 0.5 to 6.9 g kg−1 in the seeds and from 0.9 to 12.8 g kg−1 in rapeseed meal. Insufficient P supply resulted in a reduced concentration of phosphorus and phytate in the seeds. Significant interactions between the factors cultivar and P supply were found for the traits seed yield, oil yield, and P-harvest index. 相似文献
18.
Long-term effect of tillage, crop rotation and N fertilization to wheat on gaseous emissions under rainfed Mediterranean conditions 总被引：1，自引：0，他引：1
S. Menndez R.J. Lpez-Bellido J. Benítez-Vega C. Gonzlez-Murua L. Lpez-Bellido J.M. Estavillo 《European Journal of Agronomy》2008,28(4):559-569
A field study was conducted to assess the effect of N fertilizer application to wheat (Triticum aestivum L.), tillage system and crop rotation on total denitrification N losses, N2O and CO2 emissions under Mediterranean conditions in a long-term trial started 18 years ago on a Vertisol soil. The tillage system consisted of conventional tillage vs. no-tillage and the crop rotation system consisted of two different 2-years rotations: wheat–sunflower (Helianthus annuus L.) (WS) and wheat–faba bean (Vicia faba L.) (WF). Fertilizer rates were 0 and 100 kg N ha−1 applied to wheat splitted in two amendments of 50 kg N ha−1 each. Two different fertilization systems were studied. In the old fertilized plots system fertilizer had been applied for 18 years since the beginning of the trial, and in the new fertilized plots system fertilizer was applied for the first time when this experiment was started. Measurements were carried out after fertilizer applications.
In the long term, continued fertilizer application produced a higher soil total N content. Nevertheless, no increase in denitrification potential, N2O + N2 production by denitrification, N2O or CO2 emissions was observed either by the recent application of N or by the continued application during 18 years. The soil presented a higher potential to denitrify up to N2 than up to N2O. So, denitrification was probably occurring mainly in the form of N2, while N2O emissions were occurring in a great manner by nitrification, both denitrification and nitrification occurring simultaneously at soil field capacity (60–70%) expressed as water filled pore space (WFPS). Conventional tillage induced an increase in soil total N content and in the potential to denitrify up to N2 with respect to no-tillage. This higher potential was translated into higher N2O + N2 production by denitrification presumably stimulated in the short time by the higher available carbon provided by decomposing roots and by the subsequent creation of soil anaerobic microsites. Contrarily, no effect of tillage was observed on N2O emissions because of being produced in an important manner by nitrification, which does not depend on carbon availability. The wheat–faba bean rotation induced higher soil nitrate contents than the wheat–sunflower, although the effect in the long time was not observed regarding soil total N content. The same as for the fertilizer effect, this increase in nitrate content was not followed by a higher denitrification potential or higher N2O + N2 production by denitrification because of the lack of organic matter, while an increase was observed in N2O emissions. 相似文献
19.
The effects of soil water deficit and interspecific plant interaction were studied on the dry matter (DM) yield of white clover and ryegrass and on the morphogenesis of white clover. Plants were grown either: (1) individually (no interaction); or in a mixture of equal plant numbers with either (2) just shoot interaction, or (3) both shoot+root interaction. Plants were subjected to soil water deficits corresponding to no (0 MPa), moderate (−0.5 MPa) or severe (−1.0 MPa) water deficit. Ryegrass had higher above- and below-ground DM yields than white clover. The above- and below-ground DM yield for ryegrass, and the above-ground DM yield, stolon growth and relative growth rate (RGR), and leaf appearance rate (LAR) for white clover decreased as soil water deficit increased. In shoot+root interaction at no and moderate soil water deficit levels, white clover had the highest proportion of above-ground growth in the leaf form (69%) and had, respectively, 11% and 32% more above-ground DM yield than when grown in just shoot interaction; ryegrass had, respectively, 20% and 25% more above-ground DM yield than ryegrass grown in just shoot interaction. In shoot+root interaction at severe soil water deficit, ryegrass had twice as much above-ground DM yield as white clover (3.50 g per plant versus 1.59 g per plant, respectively) and white clover had 60% less above-ground DM yield than when grown in just shoot interaction. In a soil column of restricted depth (30 cm) at no and moderate soil water deficit levels, remarkable increases in shoot biomass yield were observed for both white clover and ryegrass grown in shoot+root interaction. The increased shoot biomass yield of ryegrass can be attributed to benefits from white clover's N fixing ability, whereas the causes for increased white clover biomass yield need to be studied further. However, at severe soil water deficit, ryegrass had a competitive advantage over white clover when grown in shoot+root interaction. This was due to the larger root system of ryegrass and its ability to control transpirational losses more efficiently, thus prolonging its growth period compared with white clover. 相似文献
20.
耕作与保墒措施对小麦不同生育阶段水分利用及产量的影响 总被引：1，自引：0，他引：1
为探明不同耕作与保墒措施下冬小麦不同生育阶段的水分利用特征,采用田间试验,研究了普通耕作、深松、秸秆覆盖、保水剂、有机肥等措施对小麦不同生育阶段的耗水量、干物质积累量、水分利用及产量等的影响。结果表明,在小麦不同生育阶段均以秸秆覆盖和深松处理的保墒、储水效果较佳。在小麦整个生育期中,有机肥处理的耗水量最大,而深松和秸秆覆盖处理较少。在小麦拔节期前,有机肥处理更利于干物质的积累;在小麦拔节-孕穗期,以保水剂和深松处理积累的干物质量较高。孕穗期以后,秸秆覆盖处理的干物质积累量均高于其他处理,且秸秆覆盖处理在小麦全生育期的干物质积累量也较高。除返青-拔节期和孕穗-扬花期外,小麦不同生育阶段的水分利用效率均以秸秆覆盖处理最高,且其产量和水分生产效率均高于其他处理,其产量较普通耕作提高了50.9%,水分生产效率提高了11.7 kg/(mm·hm~2)。综上所述,秸秆覆盖处理较其他措施更能有效地改善小麦不同生育阶段的水分环境,从而促进小麦产量和水分利用率的提高。 相似文献