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| DOI：10.13522/j.cnki.ggps.2019429 |
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| Effects of Subsurface Drip Irrigation with Micro-nano Bubble Water on Rhizosphere Soil Nutrients and Yield of Alfalfa |
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CAO Xuesong, ZHENG Hexiang, WANG Jun, LI Heping, FENG Yayang, YUE Xianghong
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1. Institute of Water Resources for Pastoral Area of China Institute of Water Resources and Hydropower Research,Huhhot 010020, China; 2. Inner Mongolia Agricultural University, Huhhot 010018, China;
3. Dalate Qi Soil and Water Conservation Work Station, Ordos 014300, China
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| Abstract: |
| 【Background】The normal survival of animals cannot be separated from oxygen, and the normal growth and development of plants cannot be separated from oxygen. With oxygen, the plant's root system can maintain normal breathing and exert its function of absorbing nutrients and water. The respiration of crop roots not only supplies energy for plant life activities, but also the intermediate metabolites of respiration provide the necessary raw materials for plant material synthesis. However, flood disasters, high groundwater levels, excessive one-time irrigation, compacted soil, and soilless cultivation can easily make the soil rhizosphere soil or nutrient solution poorly ventilated, and the crop roots and microbial respiration are weakened, leading to crops Hypoxic stress with abnormal respiration and growth. Aerated irrigation skillfully solves the short board shortfall of oxygen in the crop root zone caused by insufficient soil permeability in the crop root zone, making agricultural production more efficient.【Objective】 This study is to explore the effects of different dissolved oxygen levels on the rhizosphere soil nutrients and yield of alfalfa under the condition of subsurface drip irrigation with micro-nano bubble water and to analyze the quality of dissolved oxygen in micro-nano bubble water suitable for subsurface drip irrigation of alfalfa based on high yield.【Method】The field test method was used, with the irrigation quota of 75% FC (where FC is the field water capacity in the soil),and three micro-nano bubbles water dissolved oxygen mass concentration levels(low (1.8 mg/L), medium (5.0 mg/L) and high (8.2 mg/L)) were set. The effects of mass concentration of dissolved oxygen in different micro-nano bubbles on the rhizosphere soil nutrients and yield of alfalfa under subsurface drip irrigation were analyzed.【Result】Compared with the non-aerated treatment, subsurface drip irrigation with micro-nano bubble water can increase the available nitrogen in the rhizosphere of alfalfa by 13.18%~65.49%, increase the available phosphorus by 7.02%~31.14%, and reduce the available potassium by 3.34%~15.77%. With the growth period, the content of available nitrogen in the soil showed a downward trend, and the content of available phosphorus and available potassium increased first and then decreased. With the increase of the dissolved oxygen mass concentration in micro-nano bubble water, the content of available nitrogen, available phosphorus and available potassium in the soil decreased. Excessive dissolved oxygen mass concentration in micro-nano bubble water does not utilize the absorption of nutrients by alfalfa root system, thereby inhibiting the plant growth and reducing the yield. When the irrigation quota was 22.5 mm and the dissolved oxygen content of micro-nano bubbles was 5.0 mg/L, the maximum yield of alfalfa hay was 17 758.95 kg/hm2.【Conclusion】Subsurface drip irrigation with micro-nano bubble water can enhance the permeability of moist bodies in rhizosphere soil, promote the respiration of alfalfa roots and absorption of nutrients, and increase hay production. It is recommended that the concentration of dissolved oxygen in micro-nano bubble water of alfalfa under subsurface drip irrigation is 5.0 mg/L. |
| Key words: aerated irrigation; micro-nano bubble water; subsurface drip irrigation; alfalfa; rhizosphere soil nutrients; yield |
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