共查询到14条相似文献,搜索用时 62 毫秒
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对油用牡丹茎秆的穿刺力学特性进行研究,旨在为油用牡丹果荚的高效采收提供依据。以洛阳地区采摘的丹凤白品种的油用牡丹为研究对象,利用质构仪测定油用牡丹茎秆强度,分析茎秆穿刺力、直径、相对含水率等物理特性参数,以及茎秆纤维素、半纤维素、木质素等化学组分的含量。以穿刺力为试验指标,探究穿刺位置、相对含水率、穿刺速度对茎秆穿刺力的影响。结果表明:随茎秆直径的增加,茎秆的穿刺力明显增大;随相对含水率的提高,穿刺力逐渐下降;穿刺力与穿刺速度呈正相关。在茎秆的化学组分中,木质素含量的平均值最高(24.980%),其次为纤维素含量(17.269%),最后为半纤维素含量(16.935%);相对含水率对穿刺力有显著影响,而穿刺位置和穿刺速度对穿刺力影响不显著。研究结果可为油用牡丹茎秆穿刺力学特性研究提供参考。 相似文献
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为了探索利用茎秆直径微变化诊断玉米水分亏缺状况的最优指标,采用桶栽的方法,开展了不同水分处理条件下拔节期夏玉米茎秆直径微变化中的日最大收缩量(MDS)、日增长量(DI)和当日恢复时间(RT)3个指标的变化规律及其与土壤相对含水率之间相关关系方面的试验研究。结果表明,(1)不同处理间的MDS和DI受水分亏缺影响差异较为明显,RT对土壤相对含水率的响应较为一致;(2)玉米日最大收缩量MDS和日增长量DI受到环境因素的影响较大,与土壤相对含水率θ的相关系数较小;(3)恢复时间RT与土壤相对含水率θ的相关系数最高,且受水分亏缺处理的影响较小,可以作为诊断玉米水分亏缺状况的较好指标。综上可知,与MDS和DI相比,RT更适合诊断夏玉米水分亏缺状况。 相似文献
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作物茎秆抗倒性综合评价指标的力学分析 总被引:1,自引:0,他引:1
应用力学理论分析了茎秆"临界力"和各类"倒伏指数",评价作物抗倒性的缺陷和优点;建立了作物茎秆的"非完善压杆"力学模型;用小挠度理论推导出了作物茎秆最大挠度和转角的表达式。通过对该表达式的分析,提出了用茎秆"挠度指数"、茎秆"倾斜指数"以及茎秆"载荷敏感度"作为作物抗倒性的综合评价指标,该指标具有理论分析合理、物理意义明晰、测量方便以及操作简单等优点。同时还给出了切实可行的田间测量方法,为抗倒伏研究和相关农业机械的设计提供参考。 相似文献
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小麦茎秆机械强度的力学评价研究 总被引:1,自引:0,他引:1
农作物茎秆强度的研究对于农机研发、抗倒伏研究均具有重要意义,目前大多截取秸秆的一部分进行室内力学研究,这种方法破坏性强且难以表征作物在田间的实际生物力学特性。为此,以自然生长状态的小麦为研究对象,运用弹性梁弯曲理论,分析小麦茎秆在横向受迫条件下产生的回弹力T,并给出回弹力的具体表达式,发现回弹力T与反映小麦茎秆强度特性的弹性模量E、截面惯性矩I有关。同时,设计了单株小麦回弹力实验测量系统,在小麦收获期使用该测量系统进行实验验证,比较测量值与理论计算值之间的差异,结果表明测量曲线与理论曲线基本吻合,通过分析同一小麦茎秆不同作用点处回弹力的差异,可反映出不同茎节处的机械强度。研究表明:将回弹力作为小麦茎秆机械强度的综合评价指标是可行的,可为农作物茎秆力学特性检测仪器设计以及收获机械的设计提供理论依据。 相似文献
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为了探讨喷灌和液膜覆盖对玉米生产的调控作用,在大田喷灌条件下,分析了3个土壤水分灌溉下限对液膜覆盖玉米生长发育过程的影响。通过对比试验,研究了液体地膜盖对玉米产量结构和水分利用效率(WUE)的影响。结果表明,高、中、低水分处理(灌水量分别为51.8、35.0、31.4 mm)生物累积量分别达到16 699.99、14 216.38和 13 239.14 kg/hm2,液膜覆盖高水分处理有利于干物质的累积,玉米的干物质累积曲线呈“慢-快-慢”趋势。液膜覆盖显著提高了玉米的百粒质量, 相似文献
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Effects of partial root-zone irrigation on the nitrogen absorption and utilization of maize 总被引:1,自引:0,他引:1
To investigate the dynamic change of plant nitrogen (N) absorption and accumulation from different root zones under the partial root-zone irrigation (PRI), maize plants were raised in split-root containers and irrigated on both halves of the container (conventional irrigation, CI), on one side only (fixed partial root-zone irrigation, FPRI), or alternatively on one of two sides (alternate partial root-zone irrigation, APRI). And the isotope-labeled 15N-(NH4)2SO4 was applied to one half of the container with (14NH4)2SO4 to the other half so that N inflow rates can be tracked. Results showed that APRI treatment increased root N absorption in the irrigated zone significantly when compared to that of CI treatment. The re-irrigated half resumed high N inflow rate within 5 days after irrigation in APRI, suggesting that APRI had significant compensatory effect on N uptake. The amount of N absorption from two root zones of APRI was equal after two rounds of alternative irrigation (20 days). The recovery rate, residual and loss percentages of fertilizer-N applied to two zones were similar. As for FPRI treatment, the N accumulation in plant was mainly from the irrigated root zone. The recovery rate and loss percentage of fertilizer-N applied to the irrigated zone was higher and the residual percentage of fertilizer-N in soil was lower if compared to those of the non-irrigated zone. The recovery rate of fertilizer-N in APRI treatment was higher than that of the non-irrigated zone but lower than that of the irrigated zone in FPRI treatment. In total, both FPRI and APRI treatments increased N and water use efficiencies but only consumed about 70% of the irrigated water when compared to CI treatment. 相似文献
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Fusheng Li Jiangmin Yu Shaozhong Kang Jianhua Zhang 《Agricultural Water Management》2010,97(2):231-239
Partial root-zone irrigation (PRI) is an effective water-saving irrigation method but the heterogeneous soil moisture distribution that may affect soil enzymatic activities and crop water use. With pot-grown maize, we investigated the dry mass accumulation, crop water-use efficiency and the activities of four major soil enzymes from jointing to grain filling stages of maize plants subjected to PRI and also different ratios of inorganic to organic N fertilizers. Three irrigation methods, i.e. conventional irrigation (CI), alternate PRI (APRI) and fixed PRI (FPRI) and three ratios of inorganic to organic N, i.e. 100% inorganic (F1), 70% inorganic + 30% organic (F2) and 40% inorganic + 60% organic (F3), were applied. Compared to CI, PRI reduced total dry mass and water consumption of maize by 9.5 and 15.7%, respectively, which led to an increase of canopy water-use efficiency by 7.4%. Within the same irrigation method (CI, APRI or FPRI), added organic N increased total dry mass and canopy WUE. During the whole period, maximal soil catalase, urease and acid-phosphatase activities occurred in the wet root-zone of PRI, but maximal invertase activity occurred in the dry root-zone of PRI. When organic N was the most (F3), APRI increased soil catalase, urease and invertase activities at jointing stage if compared to CI, but PRI reduced the acid-phosphatase activity from jointing to filling stages. Soil catalase, urease and invertase activities generally increased with more organic manure, but the maximal acid-phosphatase activities occurred under moderate amount of organic N (F2). Our results indicate that APRI increases canopy WUE and the catalase, urease and invertase activities in its wet zone and organic N plays a major role in enhancing canopy WUE and soil enzymatic activities. 相似文献
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Iran is one the most important centers of diversity for chickpea in south western Asia. Landraces are well adapted to local environmental conditions, and have evolved a range of morphological, phenological and physiological mechanisms to efficiently utilize the available water in a dry environment. In order to study some of these mechanisms, 150 genotypes of chickpea (Kabuli type) were evaluated using Augmented Designs for Preliminary Yield Trials under stress (Rainfed) and nonstress (Irrigated) conditions in Research Field of Mashhad College of Agriculture, Ferdowsi University of Mashhad, during 2005-2006 growing season. Then, based on the obtained results, four candidate genotypes for drought tolerance and two susceptible ones were evaluated in a pot experiment at open door situation in stressed (25% Field Capacity) and non-stressed (Field Capacity) conditions based on a factorial trial in Randomized Complete Block Design. There were positive and highly significant correlations between quantitative drought resistance indices such as MP, GMP, STI and HM with yield in stress and nonstress conditions. Also, there were positive and high significant correlations for SSI and DRI with yield in nonstress and stress conditions, respectively. Based on drought resistance indices and DRI, MCC544, MCC696 and MCC693 genotypes were superior to others, so they can be viewed as promising genotypes for drought resistance. These results were approved using three dimensional scatter graph and multivariate biplot graph. In stress condition, there were negative and high significant correlations between yield and days to flowering. Drought stress decreased leaf area per plant in all genotypes, significantly. In stressed and non-stressed conditions, leaf area in susceptible genotypes was more than that in tolerant genotypes, thus drought tolerance may be attributed to less transpiration and water loss because of smaller leaf size and reduced leaf area expansion in tolerant genotypes when drought stress develops. 相似文献