基于制种玉米茎流与根系分形特征的土壤水分动态模拟

发布时间：2018-03-29 02:15

  本文选题：隔沟交替灌溉　切入点：时滞效应　出处：《中国农业大学》2016年博士论文

【摘要】：甘肃河西地区光热资源丰富、天然隔离条件良好,凭借独有的地理资源优势,已发展成全国最大的杂交玉米制种基地。近年来,灌区地下水位下降,河流供水量减少,水资源短缺已然成为玉米制种产业发展的瓶颈。隔沟交替灌溉条件下制种玉米水分传输机制与模拟研究,对实现制种玉米节水高效栽培,发展该区农业节水事业具有重要的理论价值和现实意义。本文以制种玉米为研究对象,采用土壤水分廓线仪、土壤含水量监测系统、包裹式植物茎流计和自动气象站等仪器,于2012-2014年在中国农业大学石羊河试验站,对不同灌水技术下制种玉米蒸腾耗水规律及控制因子、茎流时滞效应及影响因素、茎流估算模型、根系分形特征及根系吸水模型等方面进行了系统的试验研究和定量模拟,取得了以下成果：(1)各灌水方式的日茎流量关系为：常规沟灌隔沟交替灌畦灌。茎流观测期内,常规沟灌日茎流量变化范围80.8-884.0mLd-1,茎流日均值为498.1 mLd-1；隔沟交替灌日茎流量变化范围47.1-786.5 mL d-1,均值为455.7 mL d-1；畦灌日茎流量变化范围38.5-629.1 mL d-1,均值为337.7 mL d-1。(2)小时尺度：抽穗期南侧母本(SFP)茎流主要影响因素为太阳辐射(咫)、相对湿度(尼H)、和饱和水汽压差(VPD),灌浆期和成熟期主要影响因素为Rs；抽穗期北侧母本(NFP)主要影响因素为Rs和VPD,灌浆期为Rs,成熟期为Rs、RH和VPD；抽穗期父本(MP)茎流的主要影响因素为Rs、RH和VPD,灌浆期为Rs,成熟期为大气温度(Ta)、Rs、RH和VPD对父本茎流均显著影响。日尺度下：Rs、Ta为SFP茎流的主要影响因子；NFP和MP茎流主要影响因子为Rs。(3)父本、母本茎流均滞后于Rs,超前于VPD、乃和RHo各生育期茎流相对Rs的滞后程度为：成熟期灌浆期抽穗期。父本滞后Rs的时间明显长于母本,父本各生育期滞后时间为30 min、60 mmin和75 mmin,母本为15 mmin、30 min和45 min,而父本超前VPD、Ta和RH的时间则短于母本。采用ARIMAX模型对制种玉米茎流量进行估算,母本和父本的模拟值与实测值斜率分别为1.021和1.059,决定系数分别为0.928和0.871,与多元回归模型相比,ARIMAX模型估算值更接近于实测值,模拟误差较小,父本、母本均方根误差分别为3.65 gh-1和4.71 g 11-1,平均绝对误差分别为2.44 g h-1和3.65 gh1。(4)隔沟交替灌条件下制种玉米根系主要集中在0-80 cm土层内,所占比例在90%以上,垄两侧植株根系呈非对称分布,根长密度(RD)在垂向和水平向分别呈三次多项式函数和高斯函数变化。分形维数(FD)与根长密度呈对数关系,相关系数达到极显著水平,分形维数与根长密度具有相同的季节性变化特征,根长密度大于0.2 cm cm-3的区域具有明显的分形特征,低于0.2 cmcm-3的区域分形特征不明显。分形维数在垂向和水平向均呈二次函数变化。(5)RD和FD模型模拟的土壤含水量与实测值之间的垂直方向变化趋势吻合较好。RD模型在80-120 cm模拟值偏大,低估该层根系吸水能力。比较而言,FD吸水模型模拟效果更好。综合考虑各生育期模型应用效果,FD模型能准确模拟抽穗期、灌浆期和成熟期内湿润侧和干燥侧20cm、40 cm、60 cm和80 cm深度的土壤含水量,均方根误差在0.001 cm3 cm-3和0.013 cm3 cm-3以内,相对均方根误差小于6%。
[Abstract]:Gansu Hexi area rich solar energy resources, natural isolation in good condition, with unique geographical advantages in resources, has become the country's largest hybrid maize production base. In recent years, the groundwater level decline, river water decreased, water shortage has become the bottleneck of the development of a maize industry. Alternate furrow irrigation conditions and simulation study on the mechanism of maize seed moisture transmission, to achieve efficient water-saving cultivation of maize seed production has important theoretical value and practical significance of the development of water-saving agriculture in this area. Based on the cause of corn as the research object, the soil moisture profile, soil moisture monitoring system, package type plant stem flow gauge and automatic weather station instrument. In 2012-2014 years at the China Agricultural University experimental station of Shiyang River, water regulation and control factor of consumption under different irrigation systems of maize transpiration, sap flow time lag effect and influence Factors, stem flow estimation model, Root Fractal Characteristics and root water uptake model was investigated and the quantitative system, achieved the following results: (1) the relationship between daily sap flow irrigation method: conventional furrow irrigation, alternate furrow irrigation irrigation. Sap flow during the observation period, conventional furrow irrigation daily stem flow changes the range of 80.8-884.0mLd-1, stemflow daily average is 498.1 mLd-1; alternate furrow irrigation on the stem flow range of 47.1-786.5 mL D-1, the average is 455.7 mL D-1; irrigation daily sap flow rate range of 38.5-629.1 mL D-1, the mean value of 337.7 mL d-1. (2): heading south female hour scale (SFP) as the main influencing factors of solar radiation the stem flow, relative humidity (is) (H), and the saturated vapor pressure difference (VPD), the main factors affecting grain filling stage and mature stage of Rs; heading north parent (NFP) as the main influencing factors of Rs and VPD, filling period is Rs, the mature period is Rs, RH 鍜孷PD锛涙娊绌楁湡鐖舵湰(MP)鑼庢祦鐨勪富瑕佸奖鍝嶅洜绱犱负Rs,RH鍜孷PD,鐏屾祮鏈熶负Rs,鎴愮啛鏈熶负澶ф皵娓╁害(Ta),Rs,RH鍜孷PD瀵圭埗鏈�鑼庢祦鍧囨樉钁楀奖鍝�.鏃ュ昂搴︿笅锛歊s,Ta涓篠FP鑼庢祦鐨勪富瑕佸奖鍝嶅洜瀛愶紱NFP鍜孧P鑼庢祦涓昏�佸奖鍝嶅洜瀛愪负Rs.(3)鐖舵湰,姣嶆湰鑼庢祦鍧囨粸鍚庝簬Rs,瓒呭墠浜嶸PD,涔冨拰RHo鍚勭敓鑲叉湡鑼庢祦鐩稿�筊s鐨勬粸鍚庣▼搴︿负锛氭垚鐔熸湡鐏屾祮鏈熸娊绌楁湡.鐖舵湰婊炲悗Rs鐨勬椂闂存槑鏄鹃暱浜庢瘝鏈，

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