施肥对甜菜生长季中黑土氮素时空变异特征效应

Effects of Fertilization on Spatial-temporal Variation of Black Soil Nitrogen at Different Sugar Beet Growth Stages

为揭示施肥对甜菜生长季节黑土氮形态动态变化规律,采用不同施肥处理研究甜菜生长季（5—9月）东北黑土0～90 cm无机氮（铵态氮和硝态氮）和有机氮各组分（酸解总氮、氨态氮、氨基糖态氮、氨基酸态氮、酸解未知态氮及非酸解态氮）时空动态变异特征。结果表明,施肥处理在甜菜生育前期（5—7月）对铵态氮和硝态氮时空变化有显著影响。土壤硝态氮主要分布在0～50 cm且含量高于铵态氮,相比无肥有作物对照（CK2）,施氮肥处理在甜菜幼苗期增加了土壤0～30 cm铵态氮和硝态氮含量,同时增加块根糖分增长期（7月）土壤0～70 cm硝态氮的消耗。与不施氮相比,施氮肥可以增加0～30 cm土壤酸解总氮、氨态氮和氨基酸态氮的含量。土壤酸解总氮、氨态氮和氨基酸态氮含量在0～90 cm呈明显递减的空间梯度变化,但施氮肥处理可以平衡0～50 cm土壤氨基酸含量;土壤氨态氮随着甜菜生育时期进行呈先增加后下降的变化规律;土壤氨基糖态氮含量时空变化不显著;土壤未知态氮含量随时间变化与氨态氮、氨基糖态氮和氨基酸态氮含量变化趋势相反;施氮肥处理（N120）和无作物对照（CK1）土壤非酸解态氮在甜菜生长后期（7—9月）均出现深层残留。有机氮各组分含量（除氨基糖态氮和氨基酸态氮外）随甜菜生育进程遵循三次曲线方程的分布规律;甜菜生长过程中,土壤酸解有机氮组分中的氨态氮和氨基酸态氮为无机氮主要贡献者。

An experiment of four fertilization treatments in sugar beet field was conducted to study the spatial-temporal variability characteristics（0- 90 cm surface soil, from May to September） of black soil inorganicnitrogen（ammonium nitrogen and nitrate nitrogen） and organic nitrogen content（hydrolizable nitrogen,ammoniac nitrogen, amino sugar nitrogen, amino acid nitrogen, unknown nitrogen and unhydrolysable nitrogen）in the whole sugar beet growth season. The results showed that nitrogen fertilization treatment had impact onthe spatial and temporal variation of ammonium nitrogen and nitrate nitrogen in soil. The content of nitratenitrogen in soil was mainly distributed in 0-50 cm layer and higher than that of ammonium nitrogen in soil.Compared with controls, contents of ammonium nitrogen and nitrate nitrogen in 0- 30 cm surface soil wereincreased by nitrogen fertilizer treatment at sugar beet seedling stage, and consumption of nitrate nitrogen in 0-70 cm surface soil was increased at the root sugar accumulation stage（July）. Compared with no nitrogen fertilizer treatments, the contents of hydrolizable nitrogen, ammoniac nitrogen and amino acid nitrogen in soilwere increased in 0- 30 cm layer by applying nitrogen fertilizer. The contents of hydrolizable nitrogen,ammoniac nitrogen and amino acid nitrogen in the soil space of 0- 90 cm were obviously decreasing in agradient, and the content of soil amino acid nitrogen could be balanced in 0-50 cm layer by nitrogen treatment.The content of soil ammoniac nitrogen in soil presented a first increase and then decrease rule along with thesugar beet growing and that of amino sugar nitrogen in soil had no significant spatial and temporal change. Thecontent of unknown nitrogen had opposite change tendency to that of ammoniac nitrogen, amino sugar nitrogenand amino acid nitrogen in soil as the time went on. Soil unhydrolysable nitrogen appeared deep layer residuesin nitrogen fertilizer treatments and leisure treatments soils at later growth stage of sugar beet. Except aminosugar nitrogen and amino acid nitrogen, the contents of organic nitrogen components in soil followed the curveequation of the distribution of three times with time variation law of sugar beet growing stage. Hydrolizablenitrogen, ammoniac nitrogen and amino acid nitrogen of organic nitrogen components in soil were majorcontributors for inorganic nitrogen in growth period of sugar beet.