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Comparison of soil hydrological characteristics for main cropland and orchard in dry highland of the Loess Tableland |
Wang Shiyan1, Wang Li1, Zhang Jing2, Zhang Linsen3 |
1.State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water conservation,Chinese Academy of Sciences, 712100, Yangling, Shaanxi, China;
2.College of Resources and Environment,Northwest A&F University, 712100, Yangling, Shaanxi, China;
3. College of Horticulture, Northwest A&F University, 712100, Yangling, Shaanxi, China |
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Abstract [Background] Soil water is the main factor limiting the recovery of vegetation and thesustainable development of agriculture and forestry in the region of the Loess Tableland. Soil watercontent in 9-year apple orchard, 19-year apple orchard, corn field, and wheat field was investigated in the Changwu Tableland to define the soil hydrological characteristics and soil drying state of main cropland and orchard on the Loess Plateau. [Methods] The water storage capacity of soil in a profile of 600 cm was measured using a neutron probe (CNC503B) from April to October in 2014. [Results] 1)The 9-year orchard had the largest soil water storage in 0 -600 cm soil profile, followed by the corn field, wheat field and 19-year orchard in which soil water storage averaged 186.5, 183.6, 158.6 and 132.8 cm, respectively. There was no significant difference between the corn field and 9-year orchard, but significant differences existed among other fields. 2) Soil water content in shallow soil layer (0 - 200 cm) for the 4 fields showed medium variation (10% < CV < 100%), while soil water content in deep soil layer was relatively stable (CV <10%). 3) The depth of soil water depletion for the 19-year orchard was 500 cm, while the depths for the 9-year orchard, corn field and wheat field were all 300 cm. The rain replenishment depth of the 19-year orchard was 250 cm, while the depths for the 9-year orchard, corn field and wheat field were all deeper than 600 cm. 4) Compared with other fields, soil desiccation in the 19-year orchard occurred most severely. Specifically, the 0 -200 cm soil layer dried seasonally, the 200 - 250 cm and 250 - 320 cm soil layers dried severely, and the 320 - 600 cm soil layer dried extremely. Thus, a persistent soil dry layer formed. Soil desiccation in the corn field and 9-year orchard occurred easonally, and a temporary soil dry layer formed in the shallow soil layer in the case of water shortage. [Conclusions] It is scientific to transfer the agricultural structure of Changwu Tableland from field crops to apple economic forest, but the soil-moisture storage will be absent and the soil drying will be severe after the apple forest reaching the later stage of full fruit period, as a result, the economic value and ecological effect of apple forest will be restricted, thus scientific methods shall be taken such as reasonable water management measures and adjusting stand density to realize the sustainable development of economy and ecology in the region of Loess Tableland.
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Received: 23 August 2015
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