CAJ | 학술논문

为了提高缓控释氮肥释放氮量的测定效率，避免样品消煮过程中的强酸与毒害气体物质等问题，该研究基于杜马斯法原理，利用碳氮分析仪，测定2种缓控释氮肥在25℃静水释放试验中，第1、3、7、14和28天肥料浸出液的氮浓度，计算缓控释氮肥释放氮量，并与传统常规的凯氏蒸馏滴定法测定结果间进行比较。结果表明：2种方法肥料浸出液中N浓度测定结果之间呈极显著线性相关关系，相关系数r=0.991（n=30，P<0.01）。依据2种方法测定结果计算的氮素养分释放期彼此相差小于20%，符合国家标准《GB/T 23348-2009缓释肥料》及化工行业标准《HG/T 4215-2011控释肥料》的允许差范围。相比较传统的凯氏蒸馏滴定法，杜马斯-碳氮分析仪法测定缓控释氮肥释放氮量过程简便快捷，样品无需消煮，不涉及强酸不产生有毒有害物质。该结果为缓控释氮肥释放氮量新的测定方法提供了科学依据。
위료제고완공석담비석방담량적측정효솔，피면양품소자과정중적강산여독해기체물질등문제，해연구기우두마사법원리，이용탄담분석의，측정2충완공석담비재25℃정수석방시험중，제1、3、7、14화28천비료침출액적담농도，계산완공석담비석방담량，병여전통상규적개씨증류적정법측정결과간진행비교。결과표명：2충방법비료침출액중N농도측정결과지간정겁현저선성상관관계，상관계수r=0.991（n=30，P<0.01）。의거2충방법측정결과계산적담소양분석방기피차상차소우20%，부합국가표준《GB/T 23348-2009완석비료》급화공행업표준《HG/T 4215-2011공석비료》적윤허차범위。상비교전통적개씨증류적정법，두마사-탄담분석의법측정완공석담비석방담량과정간편쾌첩，양품무수소자，불섭급강산불산생유독유해물질。해결과위완공석담비석방담량신적측정방법제공료과학의거。
The Kjeldahl distillation-titration method (KDTM) is a standard method used by most laboratories to measure total nitrogen (N) in the Kjeldahl digests of fertilizer samples. However, the KDTM procedure generally is labor intensive and time-consuming for sample digestion process, in which concentrated acids and poisonous gas have a negative impact on the environment and health of laboratory operators. The purpose of this article was to investigate whether the methods of Dumas process (total organic carbon/total nitrogen analyzer, TOC/TN analyzer) can be used to determine N contents in the release solutions from slow/controlled release nitrogen fertilizers (S/CRNFs). Two kinds of S/CRFs with 43.2% and 37.3% of total N content were selected. The solutions containing 10% of S/CRNFs were collected after incubating at 25℃ for 1, 3, 7, 14 and 28 days, respectively. In the TOC/TN analyzer, the solution samples diluted 400 times were oxidized in the combustion tube in the presence of oxygen at high temperature (800℃) using Pt as catalyst. We compared the N values measured by Dumas method and KDTM procedure. The result showed that a linear relationship can best describe the measured N concentration generated by both methods: y (Dumas-N)=0.905 x(Kjeldahl-N)+0.040. The Pearson’s correlation coefficient was 0.991 with a significance level (n=30, P<0.01). Paired samples t-test indicated that there was no significant (P>0.05) difference of the N release contents of the S/CRFs measured by TOC/TN analyzer and KDTM method. Cumulative N release rates of two fertilizers after incubating for 14 and 28 days determined by TOC/TN analyzer were higher than that by KDTM method. However, a positive linear correlation with r=0.997 (n=30, P<0.01) was verified between the two methods. The regression equation was y (TOC/TN analyzer)=0.908x (KDTM method)+0.818. Thus the results suggested that measured N release of S/CRNFs by TOC/TN analyzer agreed very well with that measured by KDTM method. The N release period is an important parameter for assessing the quality of the S/CRNFs. The relative percentage difference of the N release periods of the S/CRNFs was less than 20% between the two N determination methods, which was the acceptance criteria for evaluating the N release period with the national standards “GB/T 23348 -2009 slow-release fertilizer”and the chemical industry standard“HG/T 4215-2011 controlled-release fertilizers”. It is suggested that the TOC/TN analyzer according to Dumas principle can be an alternative to the labor-intensive and time-consuming KDTM procedure for measuring N release of S/CRNFs. The TOC/TN analyzer is easy to handle and no preparation of sample digestion for N analysis is necessary.