摘要
把NO_3^-—N 包括到碱解氮的测定结果中,可以更好地反映土壤供氮能力。为此,研完了在碱解扩散条件下,各种还原剂对标准NO_3^-—N 的回收率。结果表明:FeSO_4、饱和Ag_2SO_4—FeSO_4、Zn 粉、Zn—FeSO_4均不理想,而Devarda 合金(D.A.)可使NO_3^-—N 还原率稳定在95%左右,用它作还原剂所测得的碱解氮可以解释冬小麦吸氮量变异的92%,是衡量土壤供氮水平的可靠指标。其测定条件为2.00g 1 mm 土样,0.05gD.A.,5m11.0mol/L NaOH,40℃扩散24h.
A modified soil nitrogen availability index was presented on thebasis of the authors'previous work which revealed that nine commonly usedindexes were not good enough for Hebei plain soils.When the amounts ofNO_3^-—N were included the soil test values with alkali-hydrolysismicrodiffusion method would excellently correlate with plant N uptakes.The comparison of NO_3^-—reducing power of some reductants,which wererecommended by other researchers indicated that FeSO_4,Zn,Ag^-—FeSO_4and Zn-FeSO_4 were not satisfactory to be used in the alkali-hydro lysismicrodiffusion method but the NO_3^-—N recovery using Devarda aIloy wasmore than 95%.The modified microdiffusion method using D.A.as areduetant explained a signifcantly greater percentage of the variability inN uptake by wheat than any of the nine indexes mentioned above andProvided a simple and reliable index of N availability of soils from 33locations in Hebei plain.
出处
《河北农业大学学报》
CAS
CSCD
北大核心
1993年第3期52-55,共4页
Journal of Hebei Agricultural University
关键词
土壤
氮
预测
河北平原
Soil
nitrogen supply
prediction
