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| DOI：10.13522/j.cnki.ggps.20180305 |
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| Soil Nitrate Residue as Affected by the Amount of Water and Nitrogen Applications under Drip Fertigation |
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ZHANG Shaowu, HU Tiantian, LIU Jie, FENG Puyu, ZHANG Meiling
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1. College of Water Resources and Architectural Engineering, Northwest A＆F University, Yangling 712100, China; 2. Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A＆F University, Yangling 712100, China; 3. Inner Mongolia Water Conservancy and Hydropower Survey and Design Institute, Hohhot 010020, China
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| Abstract: |
| 【Objective】This study aims to study the impact of the amount of water and nitrogen applications under drip fertigation on nitrate residue in soil in an attempt to find the optimal fertigation that maintains soil fertility and in the meantime increase nitrogen use efficiency.【Method】The experiment was conducted in a greenhouse with tomato as model plant. We considered the combined effect of irrigation, K, P, N and organic fertilizers under a deign using the quadratic regression orthogonal rotational method. In each treatment, the nitrate content in the plough layer was determined after harvest, which was linked to each of the five factors. 【Result】Nitrate residue in soil was affected mostly by nitrogen application, followed by phosphorus, irrigation and potassium; it was least impacted by organic fertilizer application. When the other factors were at kept 0 level, nitrate residue in soil increased with nitrogen application, parabolically (upward) with phosphorus application, parabolically (downward) with irrigation, potassium and organic fertilizer application. The influence of each of the five factors on soil nitrate residue depended on interaction of the levels of the other factors. In our experiment, the optimum fertilization for keeping nitrate residue in soil at 100~150 mg/kg in the plough layer was as follows: irrigation 455.1~471.5 mm, N application 532.3~586.5 kg/hm2, P application 420.8~466.4 kg/hm2, K application 646.1~723.5 kg/hm2, and organic fertilizer application 25.6~27.9 t/hm2. 【Conclusion】The nitrate residue in the greenhouse soil is generally high, but can be reduced by optimizing the amount of irrigation and fertilizer applications as revealed by our experimental results. |
| Key words: irrigation amount; Nitrogen, phosphorus, potassium and organic fertilizer application rates; soil nitrate N residue; solar greenhouse; quadratic general composite rotatable design |
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