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Scientia Silvae Sinicae ›› 2023, Vol. 59 ›› Issue (10): 76-88.doi: 10.11707/j.1001-7488.LYKX20230190

• Research papers • Previous Articles     Next Articles

Water Consumption Pattern and Crop Coefficient Curve Construction of Short-rotation Populus tomentosa Plantations

Lingya Li1,2,3,Nan Di4,Jinqiang Liu1,2,3,Xiaoning Zhao1,2,3,Songyan Zou5,Haiman Fu6,Benye Xi1,2,3,*   

  1. 1. State Key Laboratory of Efficient Production of Forest Resources Beijing 100083
    2. Key Laboratory for Silviculture and Forest Ecosystem Research in Arid- and Semi-Arid Region of National Forestry and Grassland Administration Beijing 100083
    3. Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University Beijing 100083
    4. School of Ecology and Environment, Inner Mongolia University Hohhot 010021
    5. Chongqing Forestry Investment and Development Company Chongqing 401147
    6. Industrial Development Planning Institute of National Forestry and Grassland Administration Beijing 100010
  • Received:2023-05-06 Online:2023-10-25 Published:2023-11-01
  • Contact: Benye Xi

Abstract:

Objective: This study aims to clarify the long-term water consumption pattern of short-rotation Populus tomentosa plantation during the rotation period and construct a (basic) crop coefficient curve, so as to provide a basis for water-saving irrigation and management of P. tomentosa plantation. Method: We continuously monitored the transpiration (Tr), soil evaporation (Es), and stand evapotranspiration (ET) of 2–6-year-old P. tomentosa plantations under sufficient water supply. At the same time, we also collected data of meteorological factors, daily trunk growth (DGR), leaf area index (LAI), and groundwater level, and further calculated reference crop potential evapotranspiration (ET0), basic crop coefficient (Kcb), and crop coefficient (Kc). Result: 1)The main growth stages of the stand were different each year, but the growth rate was the fastest from May to July, during which the diameter growth of trees in this period accounted for 69%~88% of the total growth in the whole growth season, and the cumulative ET accounted for 47%~61% of the total ET in the whole growth season. According to the average DGR and LAI seasonal dynamics of stand during the rotation period, the growth stages of P. tomentosa plantation were divided into the early growth stage, development stage, middle growth stage, and late growth stage, and the corresponding periods were from early April to mid-April, from mid-April to mid-June, from mid-June to mid-August, and from mid-August to the end of October, respectively. 2)The results showed that there were significant seasonal changes in Tr, Es, and ET in the stand, but the change patterns were quite different in different stand ages. In addition, the seasonal variation of stand Tr was significantly positively correlated with ET0 only in 3–6-year-old stands (P<0.05), and there was positive correlation betweenEs and ET0 (P<0.05) only in 2-year-old and 6-year-old stands, but there was a positive correlation between ET and ET0 in all stand ages (P<0.05). The annual total ET and Tr increased exponentially (P<0.001) and linearly (P=0.004) with the increase of stand age, respectively, while the stand Es gradually decreased with the plant age, but suddenly increased significantly in the 6-year-old stand. The proportions of Tr and Es in ET increased and decreased yearly, respectively and tended to be stable in 5–6-year-old stands. 3)There were significant differences in seasonal variation characteristics of Kcb and Kc in different stand ages. The seasonal variation of Kcb and Kc was not affected by groundwater level, however, it was controlled by LAI in 3–6-year-old stands (P<0.05). Moreover, bothKcb (R2 = 0.44–0.87) and Kc (R2 = 0.42–0.77) could establish an excellent quantitative relationship model with LAI. In addition, we constructed the (basic) crop coefficient curve and list of P. tomentosa plantations according to the change patterns of Kcb and Kc and the divided tree growth stages. Conclusion: The seasonal dynamic characteristics of evapotranspiration, transpiration, and evaporation of P. tomentosa stands have interannual changes. The fluctuation of ET0 is an essential factor in controlling the seasonal dynamics of water consumption, but the control mode varies with water consumption components and stand ages. The growth stage of P. tomentosa can be divided into four periods, and the key period of water management in stands is from May to July every year. The established (basic) crop coefficient curve, list, and prediction model of P. tomentosa plantation can be used to estimate the stand water consumption and thereby formulate and optimize the irrigation schedule. In addition, the results can not only provide a reference for the efficient water management of other tree species, but also help deepen the understanding of the water relationship of the plantation.

Key words: transpiration, evapotranspiration, soil evaporation, Populus tomentosa; plantation, water management

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