Simulation of water and nitrogen dynamics as affected by drip fertigation strategies
ZHANG Jian-jun, LI Jiu-sheng, ZHAO Bing-qiang, LI Yan-ting
1、Institute of Agricultural Resource and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 10081, P.R.China
2、State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, P.R.China
摘要 The aim of drip fertigation is synchronising the application of water and nutrients with crop requirements, and maintaining the proper concentration and distribution of nutrient and water in the soil. The wetting patterns and nutrient distributions under drip fertigation have been proved to be closely related to the fertigation strategies. In order to find out the critical factors that affect the nutrient distribution under different drip fertigaiton strategies, a computer simulation model HYDRUS2D/3D was used to simulate the water and nitrate distribution for various fertigation strategies from a surface point source. Simulation results were compared with the observed ones from our previous studies. A 15° wedge-shaped plexiglass container was used in our experiment to represent one-twenty-fourth of the complete cylinder. The height of container is 40 cm, and the radius is 41 cm. The ammonium nitrate solution was added through a no. 7 needle connected to a Mariotte tube with a flexible hose. The soil water content, nitrate and ammonium concentrations were measured. The comparison of simulated and observed data demonstrated that the model performed reliably. The numerical analysis for various fertigation strategies from a surface point source showed that: (1) The total amount of irrigation water, the concentration of the fertilizer solution and the amount of pure water used to flush the pipeline after fertilizer solution application are the three critical factors influencing the distribution of water and fertilizer nitrogen in the soil. (2) The fresh water irrigation duration prior to fertigation has no obvious effect on nitrate distribution. The longer flushing time period after fertigation resulted in nitrate accumulation closer to the wetting front. From the point of avoiding the possibility of nitrate loss from the root zone, we recommended that the flushing time period should be as shorter as possible. (3) For a given amount of fertilizer, higher concentration of the fertilizer applied solution reduces the potential of nitrate leaching in drip irrigation system. While, lower concentration of the fertilizer solution resulted in an uniform distribution of nitrate band closer to the wetted front.
Abstract The aim of drip fertigation is synchronising the application of water and nutrients with crop requirements, and maintaining the proper concentration and distribution of nutrient and water in the soil. The wetting patterns and nutrient distributions under drip fertigation have been proved to be closely related to the fertigation strategies. In order to find out the critical factors that affect the nutrient distribution under different drip fertigaiton strategies, a computer simulation model HYDRUS2D/3D was used to simulate the water and nitrate distribution for various fertigation strategies from a surface point source. Simulation results were compared with the observed ones from our previous studies. A 15° wedge-shaped plexiglass container was used in our experiment to represent one-twenty-fourth of the complete cylinder. The height of container is 40 cm, and the radius is 41 cm. The ammonium nitrate solution was added through a no. 7 needle connected to a Mariotte tube with a flexible hose. The soil water content, nitrate and ammonium concentrations were measured. The comparison of simulated and observed data demonstrated that the model performed reliably. The numerical analysis for various fertigation strategies from a surface point source showed that: (1) The total amount of irrigation water, the concentration of the fertilizer solution and the amount of pure water used to flush the pipeline after fertilizer solution application are the three critical factors influencing the distribution of water and fertilizer nitrogen in the soil. (2) The fresh water irrigation duration prior to fertigation has no obvious effect on nitrate distribution. The longer flushing time period after fertigation resulted in nitrate accumulation closer to the wetting front. From the point of avoiding the possibility of nitrate loss from the root zone, we recommended that the flushing time period should be as shorter as possible. (3) For a given amount of fertilizer, higher concentration of the fertilizer applied solution reduces the potential of nitrate leaching in drip irrigation system. While, lower concentration of the fertilizer solution resulted in an uniform distribution of nitrate band closer to the wetted front.
This work was financially supported by the Non-Profit National Research Institute, Ministry of Finance of China (IARRP-2012-202-3) and the Special Fund for Agro-scientific Research in the Public Interest, China (201203077-04-05).
ZHANG Jian-jun, LI Jiu-sheng, ZHAO Bing-qiang, LI Yan-ting.
2015.
Simulation of water and nitrogen dynamics as affected by drip fertigation strategies. Journal of Integrative Agriculture, 14(12): 2434-2445.
Alva A K, Paramasivam S, Fares A, Delgado J D, Mattos JrD, Sajwan K S. 2005. Nitrogen and irrigation managementpractices to improve nitrogen uptake efficiency and minimizeleaching losses. Journal of Crop Improvement, 15, 369-420
Alva A K, Paramasivam S, Mattos J D, Quaggio J A. 2008.Advances in nitrogen fertigation of citrus. Journal of CropImprovement, 22, 121-146
Assouline S. 2002. The effects of microdrip and conventionaldrip irrigation on water distribution and uptake. Soil ScienceSociety of America Journal, 66, 1630-1636
Bristow K L, Cote C M, Thorburn P J, Cook F J. 2000. Soilwetting and solute transport in trickle irrigation systems.In: Proceedings of the 6th International Micro-irrigationTechnology for Developing Agriculture Conference. CapeTown, South Africa. pp. 22-27
Cote C M, Bristow K L, Charlesworth P B, Cook F J, ThorburnP J. 2003. Analysis of soil wetting and solute transport insubsurface trickle irrigation. Irrigation Science, 22, 143-156
Gärdensäs A I, Hopmans J W, Hanson B R, Šim?nek J. 2005.Two-dimensional modeling of nitrate leaching for variousfertigation scenarios under micro-irrigation. AgriculturalWater Management, 74, 219-242
Huang Y F, Li Y Z, Lu J W. 1996. Simulation of soil nitrogentransport under field conditions II. Verification andapplication. Journal of Hydraulic Engineering, 6, 15-23(in Chinese)
Khalil Ajdary D K, Singh A K, Singh M K. 2007. Modelling ofnitrogen leaching from experimental onion field under dripfertigation. Agricultural Water Management, 89, 15-28
Li J, Zhang J J, Rao M J. 2004. Wetting patterns and nitrogendistributions as affected by fertigation strategies from asurface point source. Agricultural Water Management, 67,89-104
Li J, Zhang J J, Ren L. 2003. Water and nitrogen distributionas affected by fertigation of ammonium nitrate from a pointsource. Irrigation Science, 2, 19-30
Li J, Ji H Y, Li B, Liu Y C. 2007. Wetting patterns and nitratedistributions in layered-textural soils under drip irrigation.Agricultural Sciences in China, 6, 970-980
Li J, Yoder R E, Odhiambo L O, Zhang J J. 2004. Simulation ofnitrate distribution under drip irrigation using artificial neuralnetworks. Irrigation Science, 23, 29-37
Li Y F, Li J, Li B. 2007. Nitrogen dynamics in soil as affectedby fertigation strategies and frequencies for drip-irrigatedtomato. Journal of Hydraulic Engineering, 7, 857-865 (inChinese)
Lv D. 2000. Experimental study and simulation of water andsalt movement in the soil. MSc thesis, Xi’an University ofScience and Technology, China. (in Chinese)
Ma J H. 2004. Development of transfer function model andnumerical prcdiction on nitrate nitrogen leaching risk atfield scale. Ph D thesis, China Agricultural University. (inChinese)
Mualem Y. 1976. A new model for predicting the hydraulicconductivity of unsaturated porous media. Water ResourcesResearch, 12, 513-522
Myrold D D, Tiedje J. 1986. Simultaneous estimation of severalnitrogen cycle rates using 15N: theory and application. SoilBiology & Biochemistry, 6, 559-568
Phogat V, Skewes M A, Cox J W, Alam J, Grigson G, Šim?nekJ. 2013. Evaluation of water movement and nitrate dynamicsin a lysimeter planted with an orange tree. Agricultural WaterManagement, 127, 74-84
Šim?nek J, van Genuchten M T, Šejna M. 2011. The HYDRUSSoftware Package for Simulating Two- and Three-Dimensional Movement of Water, Heat, and Multiple Solutesin Variably-Saturated Media. Technical Manual, ver. 2.0 PCProgress, Prague, Czech Republic.Van
der Laan M, Stirzaker R J, Annandale J G, Bristow K L,du Preez C C. 2010. Monitoring and modelling drainingand resident soil water nitrate concentrations to estimateleaching losses. Agricultural Water Management, 97,1779-1786
van Genuchten M Th. 1980. A closed form equation forpredicting the hydraulic conductivity of unsaturated soils.Soil Science Society of America Journal, 44, 892-1037
Willmott C J. 1982. Some comments on the evaluation of modelperformance. Bulletin of the American MeteorologicalSociety, 63, 1309-1313
Zhang J J. 2002. Experimental investigation and simulation onwater and nitrogen distributions as affected by fertigationfrom a point source. MSc thesis, Chinese Academy ofAgricultural Sciences. (in Chinese)
