Effect of sleeve length on characteristics of wetted front during bubble-root irrigation
Chen Junying1,2, Wu Pute1,2, Zhu Delan1, Zhang Zhitao1,3, Fan Xiaokang1
1.College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China; 2.Insititute of Soil and Water Conservation, CAS & MWR, Yangling, Shaanxi 712100, China; 3. Department of Biological and Agricultural Engineering, Texas A&M University, College Station, TX 77843, USA
摘要 为了研究不同配套产品对涌泉根灌土壤入渗湿润体特性的影响,以黏壤土为例,采用PVC和PP棉2种材料,分别制作长度为10,15,20,25和30 cm 的5个涌泉根灌配套套筒进行试验,分析涌泉根灌不同配套产品土壤入渗湿润锋随时间的运移关系.结果表明:2种材料的土壤表面水平湿润半径与时间的自然对数呈线性关系,表层土壤开始出现湿润的时间与套筒长度无关;2种材料的土壤最大水平湿润半径和湿润深度随套筒长度的增大而增大,并与时间呈幂函数关系,其中,PVC材料的水平和垂直向的幂指数分别为0.38和0.17;PP棉材料的水平向幂指数为0.40,垂直向幂指数随管长的增大而减小,并与管长呈线性关系.研究还建立了由表面水平湿润半径反演最大水平湿润半径和湿润深度的预测模型.经验证,模型预测精度较高.研究结果可为涌泉根灌不同配套产品的系统设计、田间布设间距和宽度等参数的确定提供参考.
Abstract：In order to study the effect of sleeve length on the characteristics of wetted front in bubble-root irrigation, a series of experiments were done to measure the wetted front of a clay loam soil formed during bubble-root irrigation in which five sleeve lengths(10, 15, 20, 25 and 30 cm)and two kind of sleeve materials, namely PVC and Polypropylene(PP)were used, respectively. The result showed that there is a linear relationship between the radius of wetted front on soil surface and logarithm of time for the two kinds of sleeves. The time when soil surface starts to be wetted is unrelated to the sleeve length. The radius and depth of wetted front in soils are increased with increasing sleeve length for both kinds of sleeves and a power function with time is exhibited. For the radius and depth of wetted front, their power indexes are 0.38 and 0.17 in the case of PVC sleeves. For PP sleeves, the power index of wetted front radius is 0.40, the index of wetted front depth, however, is decreased with increasing depth and a linear relationship remains between the index and sleeve length. Further, prediction mo-dels were built for determining the maximum radius of wetted front on soil surface and the deepest depth of wetted front in soil from a known radius of wetted front on soil surface at a time instance. It was confirmed the accuracy of the models is satisfactory. The results can be useful for designing sleeves and determining space and width of ridge in a farm field.
[1]Mubarak I, Mailhol J C, Angulo-J R,et al. Temporal variability in soil hydraulic properties under drip irrigation[J]. Geoderma, 2009, 150(1/2):158-165.[2]Bhatnagar P R, Chauhan H S. Soil water movement under a single surface trickle source[J]. Agricultural Water Management, 2008, 95(7):799-808.[3]Cote C M,Bristow K L,Charlesworth P B,et al.Analysis of soil wetting and solute transport in subsurface trickle irrigation[J].Irrigation Science,2003,22(3/4):143-156.[4]Patel N, Rajput T B S. Dynamics and modeling of soil water under subsurface drip irrigated onion[J]. Agricultural Water Management, 2008, 95(12):1335-1349.[5]梁海军,刘作新,王振营,等.地下渗灌土壤水分运动数值模拟[J].农业工程学报,2008,24(10):11-14. Liang Haijun, Liu Zuoxin, Wang Zhenying, et al. Numerical simulation of soil water movement under infiltration irrigation[J]. Transactions of the CSAE, 2008,24(10):11-14.(in Chinese)[6]曾辰,王全九,樊军. 初始含水率对土壤垂直线源入渗特征的影响[J].农业工程学报,2010,26(1):24-30. Zeng Chen, Wang Quanjiu, Fan Jun. Effect of initial water content on vertical line-source infiltration characteristics of soil [J].Transactions of the CSAE, 2010, 26(1): 24-30.(in Chinese)[7]王振华,郑旭荣,任杰,等.灌水频率对地下滴灌线源入渗土壤水分运动规律影响的试验研究[J].水利学报,2007,38(S1):299-302. Wang Zhenhua, Zheng Xurong, Ren Jie, et al. Study on effects of irrigation frequency on soil water-transport of line source permeation under subsurface drip irrigation[J]. Journal of Hydraulic Engineering, 2007, 38(S1): 299-302.(in Chinese)[8]程慧娟,王全九,白云岗,等. 垂直线源灌线源长度对湿润体特性的影响[J].农业工程学报,2010,26(6):32-37. Cheng Huijuan, Wang Quanjiu, Bai Yungang, et al. Influence of line source length of vertical line source irrigation on wetted soil change characteristics[J].Transactions of the CSAE, 2010,26(6): 32-37.(in Chinese)[9]黎朋红, 汪有科, 马理辉,等. 涌泉根灌湿润体特征值变化规律研究[J]. 水土保持学报, 2009, 23(6): 190-194. Li Penghong, Wang Youke, Ma Lihui, et al. Study on eigenvalues of wetted soil under surge root irrigation [J]. Journal of Soil and Water Conservation, 2009, 23(6): 190-194.(in Chinese)[10]牛文全,樊晓康,Zhou Xiaobo,等. 初始含水率对涌泉根灌土壤渗透特征的影响[J].排灌机械工程学报, 2012,30(4):491-496. Niu Wenquan, Fan Xiaokang, Zhou Xiaobo, et al. Effect to initial water content on soil infiltration characteristics during bubble irrigation[J]. Journal of Drai-nage and Irrigation Machinery Engineering, 2012, 30(4):491-496.(in Chinese)
