等氮滴灌对宿根蔗产量及土壤氧化亚氮排放的影响

Effects of fertigation under equal nitrogen on ratoon yield and nitrous oxide emissions in soil

关键词:  氧化亚氮, 甘蔗生产, 无机氮, 灌溉施肥, N₂O排放

Key words:  nitrous oxide, sugarcane yield, inorganic nitrogen, fertigation and fertilizer, N₂O emission

摘要:

为得到合理的水肥管理措施,研究等氮量下不同滴灌施肥比例对宿根蔗产量以及不同生育期蔗田土壤氧化亚氮(N₂O)通量和无机氮含量的影响,并分析蔗田土壤N₂O通量与无机氮含量之间的关系。该文以自然降雨W₀为对照,设置2种滴灌灌水量水平W₁(田间持水量的75%)和W₂(田间持水量的85%),等量氮肥(N 300 kg·hm^-2)下设4种滴灌施肥比例F₁₀(100%基肥)、F₅₅(50%基肥,50%滴灌追肥)、F₃₇(30%基肥,70%滴灌追肥)、F₁₉(10%基肥,90%滴灌追肥),测定不同处理宿根蔗产量、农艺性状(单茎重、株高、蔗茎直径、公顷有效茎数)、3个生育期蔗田土壤N₂O通量以及土壤硝态氮、亚硝态氮和铵态氮的含量。结果表明:(1)W₁F₅₅和W₂F₅₅处理甘蔗产量较高,分别为102.4 t·hm^-2和97.8 t·hm^-2; 相同灌水量下F₅₅处理土壤N₂O排放通量较低。(2)蔗田土壤N₂O通量与土壤铵态氮含量之间呈显著负相关,相关系数为-0.497(P<0.05,n=24); 合理的滴灌施肥比例能有效提高甘蔗产量并减少土壤N₂O的排放。因此认为,等氮条件下滴灌施肥比例为5:5的处理,不仅宿根蔗相对高产,而且能减少蔗田土壤N₂O的排放。

Abstract:

In order to get reasonable water and fertilizer management measures, the effects of different fertigation proportions under the same nitrogen(N)rate on the yield of ratoon and nitrous oxide(N₂O)flux and inorganic N content in soil at the different growth stages were studied, the relationships between soil N₂O flux and inorganic N content were analyzed. Taking natural rainfall(W₀)as the control, two drip irrigation levels, W₁(75% of field water capacity)and W₂(85% of field water capacity)and four fertigation proportions at the same N rate(N 300 kg·hm^-2), F₁₀(100% basal fertilizer), F₅₅(50% basal fertilizer, 50% fertigation topdressing), F₃₇(30% basal fertilizer, 70% fertigation topdressing)and F₁₉(10% basal fertilizer, 90% fertigation topdressing)were designed. Agronomic traits(stalk weight, plant height, stalk diameter and effective stalks per hectare)and yield of sugarcane, the N₂O flux and the contents of nitrate, nitrite and ammonium nitrogen in soils at the three growth stages were determined. The results were as follows:(1)The ratoon yields in W₁F₅₅ and W₂F₅₅ were higher, i.e. 102.4 t·hm^-2 and 97.8 t·hm^-2, respectively; Soil N₂O emission flux in F₅₅ was lower under the same irrigation amount.(2)There was a significant negative correlation between soil N₂O flux and ammonium nitrogen content, with a correlation coefficient of -0.497(P<0.05, n=24); A reasonable fertilization proportion with drip irrigation can effectively increase sugarcane yield and reduce soil N₂O emission. Therefore, the treatment with a fertigation proportion of 5:5 under the same N rate can not only have a relatively high yield of ratoon, but also reduce the N₂O emission from the sugarcane soil.