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| DOI：doi：10.13522/j.cnki.ggps.20180502 |
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| Using Soil Matric Potential in Sandy Soil as an Proxy for Irrigation Time in Sprinkle Irrigation of Potato Irrigation Time in Sprinkle Irrigation of Potato |
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FENG Zhiwen, WAN Shuqin, KANG Yaohu, SUN Qinghua, WANG Qiang
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1.Inner Mongolia Potato Engineering and Technology Research Center, Inner Mongolia University, Hohhot 010021, China;
2.Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resource Research, Chinese Academy of Sciences, Beijing 100101, China; 3. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; 4. Agricultural Office of Tuanbo Town, Jinghai County, Tianjin 301636, China
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| Abstract: |
| 【Objective】 Irrigating time is a key parameter in irrigation schedule and in this paper, we evaluated the feasibility of using soil matric potential measured at a specific location in soil as an indicator to determine the timing of sprinkle irrigation of potato in a sandy soil. 【Method】Two drought-resistant cultivars, Shepody (weak drought-resistant) and Favorita (strong drought-resistant), were used as the model plants in a two-year field experiment. The soil matric potential measured at 20 cm underneath the ridge after seedling stage was used as proxy for irrigation time. For each treatment we measured soil moisture distribution, yield and water use efficiency of the potatoes. In 2012, we compared three soil matric potentials: -20 kPa, -30 kPa and -40 kPa, and in 2013 we added another matric potential of -10 kPa. 【Result】The indicative matric potential can be used to improve soil moisture distribution under sprinkle irrigation. With the indicative soil matric potential increasing, the average matric potential in 0~30 soil increased and became more stable, yet the soil matric potential in soil below 40 cm was not very sensitive to the indicative matric potential. The yield of the two cultivars decreased linearly with the decrease in the indicative soil matric potential, and dropping the matric potential below -15.8 kPa led to a yield reduction at 1.8% per 1 kPa, caused mainly by decrease in larger potato weighting >250 g and medium potato weighting in 150 g ≤W<250 g although the number of tubers per plant remained unaffected. Irrigation water use efficiency increased linearly with the decrease in soil matric potential at a rate of 1.3% per kPa.【Conclusion】Under large-scale sprinkler irrigation, the soil matric potential measured at 20 cm below the ridge can be used as a proxy for irrigation time. For potatoes grown in sandy soil studied in this paper, -15.8 kPa can be used as the indicative matric potential initially and it can be reduced as plant grow. This was proven able to sustain yield and in the meantime improve irrigation water use efficiency. |
| Key words: soil moisture; sprinkler irrigation; sprinkler; irrigation water use efficiency; soil |
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