水肥优化耦合下设施菜地水、氮响应的定量关系

The Quantitative Response Regularity on Soil Water and Nitrogen by Water-fertilizer Coupling Optimization

采用正交试验设计,研究了微喷灌条件下,设施菜地土壤水分含量和硝态氮含量对水肥耦合的响应规律。结果显示:(1)灌溉施肥后,0~60 cm土层土壤含水量下降。青菜成熟期时,土壤含水量高于幼苗期和旺长期。(2)在青菜的不同生育时期,各水肥因子对土壤含水量的影响主次程度不同,施肥量、灌水量和肥料配比对土壤含水量的影响较大,灌水周期对土壤含水量的影响相对较小。(3)土壤硝态氮含量受灌溉施肥的影响波动幅度随土壤深度的增加而减缓。灌水后,0~10 cm土层硝态氮含量最高,达到380.53 mg/kg。(4)高肥低水和低肥高水的水肥耦合方式均会造成表层土壤硝态氮积累,引起氮肥流失。各水肥因子中,施肥量对土壤硝态氮含量影响最大,灌水量和肥料配比的影响次之,灌水周期对土壤硝态氮含量的影响最小。研究结果证实在微喷灌条件下,通过水肥优化耦合可以有效避免氮肥淋失。

In this paper, the response regularity of soil moisture and nitrate content was studied under microspray irrigation condition by orthogonal experimental design. The results showed:(1) after fertigation, soil water content of 0~60cm soil depth decreased. However, soil moisture was higher than the period of seedling and vigorous growing stage, when Brassica chinensis L. stepped into a mature stage.(2) during different growth period, specific to disparate water and fertilizer factors, influ-ence degree each on soil moisture were not identical. Influence from the factors of fertilizer application rate, irrigation rate and fertilizer mixing ratio were much greater than the factor of irrigation cycle.(3) the influence degree of irrigation schedule on soil nitrate content decreased as soil layer increase. Soil nitrate content of 0 ~10cm depth was the highest among all the soil layers, which was up to 380.53 mg/kg after irrigation.(4) water-fertilizer coupling mode of both high fertilizer application rate-low water quota and low fertilizer application rate-high water quota, lead to nitrate accumulation on soil surface and thus caused nitrogen lose. Among all the water and fertilizer factors on soil nitrate content effect, fertilizer application rate was the maximum, irrigation cycle the minimum, while effects of irrigation rate and fertilizer mixing ratio were between them. The results confirmed that water-fertilizer coupling optimization under microspray irrigation condition, can effectively avoid nitrogen leaching.