华北平原菜田有机氮素净矿化速率的季节性差异

Seasonal Differences in Net Mineralization Rate of Organic Nitrogen in Vegetable Field of North China Plain

大量投入的有机肥所释放的氮素在菜田氮素推荐中不容忽视,但目前缺乏相关的有机氮矿化速率用于指导菜田施肥。本研究汇总最近10年来我国华北平原菜田田间试验资料,分析了根据植物吸收法计算的菜田土壤及有机肥中的有机氮素表观净矿化的结果,比较其季节性差异。结果表明,设施和露地菜田有机肥氮素矿化的季节性差异明显,设施菜田中冬春茬和秋冬茬每周土壤有机氮素矿化平均速率分别为2.9,6.2 kg/hm2,而露地菜田分别为3.6,0.6 kg/hm2;设施菜田中冬春茬和秋冬茬每周有机肥氮素矿化平均速率分别为3.6,3.2 kg/hm2,露地菜田分别为1.8,-0.3 kg/hm2;菜田土壤有机肥氮素当季释放比例介于-14.9%～34.9%。分析表明,氮素淋洗影响了对有机氮素矿化的准确估算,有机肥氮素表观矿化量与其总氮投入量及其与土壤氮素盈余没有显著相关。另外,季节性土壤温度差异又是有机氮素矿化关键的影响因素。

The high input of nitrogen released from organic manure could not be ignored for nitrogen recom-mendation in vegetable field ,however ,the unknown parameters on nitrogen mineralization rate released from soil and organic manure influenced the use of N fertilizer recommendation .In this study ,the required data to calculate appar-ent net N mineralization rates released from soil and organic manure were selected from the published papers related to vegetable trials in Northern China ,in order to understand the differences in growing seasons and land use type . The results showed that significant differences on the average rates of mineralized nitrogen released from organic ma -nure between open field and soil-bound greenhouse field .The average rates of weekly net mineralized nitrogen （WNMN） from soil in greenhouse field were 2.9 kg/ha and 6.2 kg/ha in winter-spring season（WM） and autumn-winter season（AW）,respectively;however,the average rates of WNMN from soil in open field was 3.6 kg/ha and 0 .6 kg/ha in WM season and AW season , respectively .The average rates of WNMN from organic manure in soil-bound greenhouse field were 3.6 kg/ha and 3.2 kg/ha in WM and AW,respectively.The average rates of WNMN from organic manure in open field were 1.8 kg/ha and -0.3 kg/ha in WM and AW,respectively.The proportion of seasonal mineralized nitrogen in manure accounted from -14.9% to 34.9% after applied in vegetable field .The accuracy in the rate of WNMN was influenced by nitrogen leaching ,which was also related to soil temperature .The results in linear regression analysis showed that no significant correlation was investigated between the amount of mineralized nitrogen and total nitrogen input from manure ,and nitrogen surplus in greenhouse and open fields under different seasons .These parameters to describe the rates of WNMN released from soil and manure in vegetable fields are significantly efficient nitrogen management .