兰州大学机构库
黄土高原苹果树/鸭茅复合系统产量、光能利用及蒸散发特征研究
Alternative TitleProduction, light utilization and evapotranspiration in apple tree and cocksfoot agroforestry systems on the Loess Plateau of 中文na
曹铨
Subtype博士
Thesis Advisor沈禹颖
2020-09-16
Degree Grantor兰州大学
Place of Conferral兰州
Degree Discipline草学
Keyword黄土高原 果园生草 光能利用 蒸散分配 土壤水分平衡
Abstract果园生草模式不仅可以增强果园的生态服务功能,还能生产饲草、提高土地的利用效率。庆阳南部是我国重要的苹果产区之一,苹果种植多以旱作为主,生草对果园产量和土壤水分平衡过程的影响机理仍不清晰,果园生草管理模式还不成熟。本研究在甘肃庆阳西峰(多年平均降雨为527 mm)11龄苹果(Malus pumila M. cv Qingguan)园中开展,设置鸭茅常规刈割(苹果树生育期刈割2-4次)和鸭茅加强刈割(苹果树生育期刈割4-6次)两种处理,以苹果园清耕处理为对照,于2016-2018年(降雨量分别为478、746和574 mm)在果树生育期监测苹果树/鸭茅复合系统产量、冠层结构、光能利用、水分动态、苹果树细根长密度及蒸发蒸腾等指标,旨在厘清苹果树/鸭茅复合系统产量、光能利用、水分消耗特征与其关键影响因素之间的关系,阐明生草影响果园水分平衡和苹果产量的机制,为黄土高原苹果园生草模式的推广和应用提供理论依据。主要结果如下: 1. 2016-2018年果园行间种植鸭茅对苹果产量、苹果的单果重、果径、可溶性糖含量及可滴定酸含量均无显著影响(P>0.05);三年间苹果树/鸭茅复合系统中干草产量达到2.07-6.32 t hm-2。2016和2017年加强刈割较常规刈割分别使鸭茅的干物质产量提高了11.5%和45.9%,2018年刈割频率对鸭茅的产量无显著影响(P>0.05)。行间种植鸭茅改变了苹果园光合有效辐射(PAR)分配格局、提高光能利用效率。2016-2018年苹果树生育期果树冠层累计PAR截获量分别占总PAR的37.8%-44.3%。鸭茅的PAR截获量占总PAR的18.2-24.3%。苹果树生育期内加强刈割处理下鸭茅的叶面积指数较常规刈割处理分别降低14.1%-34.0%,PAR截获量分别减少8.7%-16.5%,光能利用效率分别提高6.3%-33.5%。 2. 种植鸭茅对苹果园土壤水分动态及土壤水分平衡的影响效应受苹果树生育期降雨分布的影响。鸭茅对果园0-80 cm土层水分变化的影响较大,对80-160 cm土层水分变化影响较小。行间种植鸭茅在干旱时期降低了0-80 cm土层水分含量,而在多雨时期可增加0-80 cm土层水分含量。分析苹果树生育期土壤水分平衡特征发现,行间种植鸭茅在2016年不仅显著增加了苹果树行间0-100 cm土层水分的消耗(P<0.05),也显著增加了苹果树行上0-200 cm土层水分的消耗(P<0.05),对深层水分含量无影响;2017年对行间各土层以及苹果树行上0-100 cm土层含水量无影响,但是显著减少了苹果树行上100-300 cm土层水分补给(P<0.05);2018年仅增加了行间0-100 cm土层水分消耗,对苹果树行间深层土壤水分和苹果树行上各土层土壤水分含量均无影响。增加鸭茅刈割频率有助于在2016年减少对苹果树行间和苹果树行上0-100 cm土层水分的消耗,在2017年增加对苹果树行上100-200 cm土层水分的补给。 3. 种植鸭茅改变了果园蒸发和蒸腾的分配关系,但在加强刈割处理下没有显著影响果园总蒸散量。与清耕模式相比,2016-2018年常规刈割处理下苹果树冠层下蒸散量分别增加了19.1%、6.4%和11.4%;加强刈割处理苹果树冠层下蒸散量分别增加了11.8%、2.3%和9.0%。常规刈割处理下果园总蒸散量仅在2016显著高于加强刈割和清耕处理,其余年份总蒸散量在处理间无显著差异(P>0.05)。两种刈割处理下苹果树蒸腾量仅在2018年显著低于清耕处理(P<0.05),其余两个年份苹果树蒸腾量在处理间均无显著差异。 4. 2018年连续测定的苹果树蒸腾量的结果表明常规刈割处理下每月苹果树的日平均蒸腾速率仅在干旱时期显著低于清耕处理(P<0.05)。苹果树的蒸腾速率与苹果树叶面积指数、太阳净辐射、大气温度、大气水汽压差以及0-160 cm土层含水量均显著相关。根据苹果树和鸭茅的叶面积指数变化改进的双作物系数法能够用于估算苹果树/鸭茅复合系统和清耕果园蒸散量及其分配。 5. 与清耕相比,苹果树行间种植鸭茅后,2016年显著促进了土壤深层(100-300 cm)苹果树细根长生长,对行上深层细根长密度影响显著(P 0.05);2018年显著抑制了行间深层苹果树细根长密度(P 0.05)。农林复合系统中苹果树细根生长对降雨的响应有助于在不同降雨年份改变苹果树水分利用策略。 综上,本研究表明黄土高原地区苹果园行间种植鸭茅可提高果园光能截获利用效率、减少土壤水分蒸发、提高降雨利用效率,通过分析苹果园生草复合系统冠层结构、根系分布及资源利用过程,阐明了旱作条件下行间生草影响果园蒸散发格局和果园生产力的机理。因此,我们建议在黄土高原地区实施苹果园行间生草管理模式以同步提高当地苹果产业的经济和生态效益。 关键词:黄土高原;果园生草;光能利用;蒸散分配;土壤水分平衡
Other AbstractPlanting cover crops in orchard does not only enhance the ecological service, but also produce forage and improve land use efficiency. The southern area of Qingyang is one of the major apple production areas in 中文na, apple orchards in this area are mainly under rain-fed conditions, and the effects of cover crop on the system production and soil water dynamics are still uncertain. This study was conducted in a 11-year-old apple orchard (Malus pumila M. cv Qingguan) which is located in Xif英语, Qingyang (local annual precipitation is 527 mm), Gansu Province of 中文na. The experiment included two treatments of intercropping cocksfoot in orchard and one treatment of clean tillage. The two intercropped patterns were: cocksfoot harvested with a normal frequency (NF: 2-4 times during the apple tree growing season), and cocksfoot harvested with a high frequency (HF: 4-6 times during the apple tree growing season). The system yields, canopy structure, light utilization, soil water dynamics, fine root l英语th density (FRLD), and evapotranspiration (ET) of apple tree/cocksfoot agroforestry system were monitored in the apple tree growth period of 2016-2018 (the rainfall were 478, 746 and 574 mm, respectively), with the purpose of clarifying the mechanisms of light and water utilization in apple tree and cocksfoot agroforestry, and providing a theoretical basis for the promotion and application of cover crops in orchard in the Loess Plateau. The main results are as follows: 1. Planting cocksfoot in orchard showed no significant effect on the fruit yield, single fruit weight, fruit diameter, soluble sugar content and titratable acid content of apples in 2016-2018 (P>0.05). The dry matter yield of cocksfoot in apple tree/cocksfoot agroforestry systems ranged from 2.07 to 6.32 t ha-1 in three years. The dry matter yield of cocksfoot under HF was 11.5% and 45.9% higher than that under NF in 2016 and 2017, respectively. There was no significant effect of mowing frequency on the yield of cocksfoot in 2018 (P>0.05). Planting cocksfoot in apple orchard changed the distribution and interception pattern of photosynthetically active radiation (PAR) and improved the radiation utilization efficiency in apple orchard. During 2016-2018, the cumulative PAR intercepted by apple trees accounted for 37.8%-44.3% of the total PAR, respectively, and the cumulative PAR intercepted by cocksfoot accounted for 18.2-24.3%. The leaf area index (LAI) of cocksfoot under HF was decreased by 14.1%-34.0%, compared to that under NF. PAR interception by cocksfoot under HF was also reduced by 8.7%-16.5% compared to that under NF, and the light utilization efficiency under HF was 6.3%-74.0% and higher than that under NF, respectively. 2. The effect of sowing cocksfoot on soil water dynamics and soil water balance in apple orchard was affected by rainfall distribution during the apple tree growing period. The effect of sowing cocksfoot on soil water content in 0-80 cm soil layer was greater than that in 80-160 cm soil layer. The existing of cocksfoot reduced the soil water content in 0-80 cm soil layer in interrows in the drought period, while increased the soil water content in 0-80 cm soil layer in interrows after heavy rainfall. In 2016, cocksfoot cover crop not only significantly increased the soil water depletion in 0-100 cm soil layer in interrows in 2016 (P<0.05), but also significantly increased soil water depletion in 0-200 cm soil layer in tree row (P<0.05), no significant differences were found in deep soil layers. In 2017, cocksfoot significantly reduced the water replenishment in 100-300 cm soil layers in tree rows (P<0.05). In 2018, soil water consumption increased only in 0-100 cm soil layer in inter-rows, while soil water content in deep soil layers in inter-rows and the entire soil layers in the tree rows were not affected. Increasing the mowing frequency of cocksfoot reduced the water consumption in 0-100 cm soil layer in inter-rows and tree row in 2016, while increased the soil water replenishment in 100-200 cm soil layer of the tree row in 2017. 3. Planting cocksfoot in apple orchard changed the partitioning of ET between evaporation and transpiration, but it did not significantly affect the total system ET of the orchard under HF treatment. ET under the tree canopy under NF increased by 19.1%, 6.4% and 11.4% compared to that under CT in 2016, 2017 and 2018 respectively, and that under HF was 11.8%, 2.3% and 9.0% higher. The total system ET under NF was significantly higher than that under HF and CT only in the dry year of 2016, and there was no significant difference among the three treatments in other years (P>0.05). The transpiration of apple trees under NF and HF was significantly lower than that under CT only in 2018 (P<0.05), and there was no significant difference under three treatments in the other two years. 4. Continuously measured apple tree transpiration in 2018 showed that the monthly average transpiration under NF was significantly lower than that of CT only during the drought period (P<0.05). The transpiration rate of apple trees was significantly correlated with LAI of apple tree, solar net radiation, atmospheric temperature, water vapor pressure difference and soil water content in 0-160 cm soil layer. The dual crop coefficient method, calibrated according to the LAI of cocksfoot, was capable to estimate the ET and its components in apple/cocksfoot systems. 5. Compared with CT, the increase of FRLD of apple trees in deep soil layers (100-300 cm) was significantly promoted in 2016 after sowing cocksfoot in the apple orchard, and the effects were significant in tree row (P<0.05). In 2018, the FRLD of apple trees in deep soil layers in interrows was significantly inhibited (P<0.05), but there was no significant difference in deep soil layers in tree rows (P>0.05). The response of FRLD of apple tree in the agroforestry system to rainfall variation was helpful to improve the water use strategy of apple trees in different rainfall years. In conclusion, this study showed that planting cocksfoot in orchard on the Loess Plateau can improve the light interception and utilization efficiency, reduce soil evaporation, and improve rainwater utilization efficiency. We clarified the mechanisms of light and water utilization in the apple tree based agroforestry by analyzing both aboveground and belowground plant structure and resources utilization. Therefore, we suggest applying cover crops in orchard to simultaneously improve the economic and ecological benefits of the fruit tree planting systems in the Loess Plateau of 中文na. Keywords: Loess Plateau; Planting cover crops in orchard; Light utilization; Evapotranspiration partitioning; Soil water balance
Pages109
URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/448634
Collection兰州大学
Affiliation草地农业科技学院
First Author AffilicationCollege of Pastoral Agriculture Science and Technology
Recommended Citation
GB/T 7714
曹铨. 黄土高原苹果树/鸭茅复合系统产量、光能利用及蒸散发特征研究[D]. 兰州. 兰州大学,2020.
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