Simulating the effects of different potassium and water supply regimes on soil water content and water table depth over a rotation of a tropical Eucalyptus grandis plantation

FOREST ECOLOGY AND MANAGEMENT

卷:418

Article

Christina, M.^1,2,3  le Maire, G.^1,2,4  Nouvellon, Y.^1,2,5  Vezy, R.^1,6  Bordon, B.⁷  Battie-Laclau, P.^1,2,8  Goncalves, J. L. M.⁷  Delgado-Rojas, J. S.⁷  Bouillet, J. -P.^1,2,7  Laclau, J. -P.^1,2,7,9 

[1] CIRAD, UMR Eco&Sols, F-34398 Montpellier, France

[2] Univ Montpellier, Eco&Sols, CIRAD, INRA,IRD,Montpellier SupAgro, Montpellier, France

[3] CIRAD, UR AIDA 115, F-34398 Montpellier, France

[4] Univ Estadual Campinas, NIPE, BR-13083970 Campinas, SP, Brazil

[5] Univ Sao Paulo, Dept Ciencias Atmosfer, BR-05508900 Sao Paulo, SP, Brazil

[6] INRA, UMR 1391, ISPA, F-33140 Villenave Dornon, France

[7] Univ Sao Paulo, ESALQ, BR-13418900 Piracicaba, SP, Brazil

[8] Univ Sao Paulo, CENA, BR-13400970 Piracicaba, SP, Brazil

[9] Univ Estadual Paulista, Dept Solos & Recursos Ambientais, BR-18610300 Botucatu, SP, Brazil

关键词: Water resources;    Groundwater;    Brazil;    Eucalyptus;    Deep roots;    Nutrients;   

DOI  :  10.1016/j.foreco.2017.12.048

来源: Elsevier

【 摘 要 】

Although large amounts of potassium (K) are applied in tropical crops and planted forests, little is known about the interaction between K nutrition and water supply regimes on water resources in tropical regions. This interaction is a major issue because climate change is expected to increase the length of drought periods in many tropical regions and soil water availability in deep soil layers is likely to have a major influence on tree growth during dry periods in tropical planted forests. A process-based model (MAESPA) was parameterized in a throughfall exclusion experiment in Brazil to gain insight into the combined effects of K deficiency and rainfall reduction (37% throughfall exclusion) on the water used by the trees, soil water storage and water table fluctuations over the first 4.5 years after planting Eucalyptus grandis trees. A comparison of canopy transpiration in each plot with the values predicted for the same soil with the water content maintained at field capacity, made it possible to calculate a soil-driven tree water stress index for each treatment. Compared to K-fertilized trees with undisturbed rainfall (+K+W), canopy transpiration was 40% lower for K deficiency (-K+W), 20% lower for W deficit (+K - W) and 36% lower for combined K deficiency and W deficit (- K - W) on average. Water was withdrawn in deeper soil layers for -W than for + W, particularly over dry seasons. Under contrasted K availability, water withdrawal was more superficial for -K than for +K. Mean soil water content down to 18 m below surface (mbs) was 24% higher for - K+ W than for +K+W from 2 years after planting (after canopy closure), while it was 24% lower for +K-W and 12% lower for -K W than for +K+W. The soil-driven tree water stress index was 166% higher over the first 4.5 years after planting for - W than for +W, 76% lower for -K than for +K, and 14% lower for -K -W than for +K+W. Over the study period, deep seepage was higher by 371 mm yr(-1) (+122%) for -K than for +K and lower by 200 mm yr(-1) (- 66%) for -W than for +W. Deep seepage was lower by 44% for -K- W than for +K+ W. At the end of the study period, the model predicted a higher water table for -K (10 mbs for -K+W and 16 mbs for -K-W) than for +K (16 mbs for +K+W and 18 mbs for +K-W). Our study suggests that flexible fertilization regimes could contribute to adjusting the local trade-off between wood production and demand for soil water resources in planted forests.

【 授权许可】

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