CAJ | 학술논문

以不同肥效期的15个自制包膜尿素为检测样品，以肥水质量比为1/5的恒温静水溶出法为控释尿素的培养方法，同时采用常规方法和工作曲线折光率法测定培养液中的尿素含量，并对养分释放曲线进行Richards 方程的非线性回归分析用以计算样品的肥效期，对比研究现配工作曲线折光率法与同期培养工作曲线法同常规方法测定结果之间的异同，以期为控释尿素养分释放测定提供更准确的快速测定方法。研究结果表明：系列标准尿素溶液分别培养0、1、6、7、14、21、28和56 d后，其折光率与浓度之间的关系均可用直线方程表示(决定系数≥0.998)，其中同期培养曲线的预测误差为0.34～1.13 g/L，而现配曲线的预测误差为0.71～4.85 g/L，采用尿素标准溶液工作曲线检测同等培养期的尿素溶液有利于提高测定结果的准确性。与H2SO4消煮法（常规方法）相比，采用新鲜工作曲线折光率法测定控释尿素养分释放的计算结果提高10%以上，采用标准尿素溶液与包膜尿素同期培养的方法，折光率法测定结果与常规方法之间的系数为0.990。为进一步分析折光率法检测包膜尿素肥效期准确性，采用Richards方程模拟2种方法所测的释放曲线并计算养分达到75%的时间点即肥效期，结果表明，常规方法和折光率法测得15个包膜尿素的肥效期为21.9～245.9和22.0～210.1 d，两者相差最小值和最大值分别为0.2和41.4 d，相对偏差则分别为0.8%和25.1%。其中肥效期较短的包膜尿素的测定偏差较小，肥效期较长尤其是达到180 d以上的包膜尿素可能由于后期释放过于缓慢导致预算误差扩大，其误差区间为27.6～40.4 d，这属于可接受范围。说明了同期培养工作曲线折光率法可以作为常温条件下的控释尿素养分释放的速测方法，并可利用模型较准确地预测包膜尿素的肥效期。研究结果可为包膜尿素养分释放率及肥效期的快速、准确测定提供参考。以不同肥效期的15箇自製包膜尿素為檢測樣品，以肥水質量比為1/5的恆溫靜水溶齣法為控釋尿素的培養方法，同時採用常規方法和工作麯線摺光率法測定培養液中的尿素含量，併對養分釋放麯線進行Richards 方程的非線性迴歸分析用以計算樣品的肥效期，對比研究現配工作麯線摺光率法與同期培養工作麯線法同常規方法測定結果之間的異同，以期為控釋尿素養分釋放測定提供更準確的快速測定方法。研究結果錶明：繫列標準尿素溶液分彆培養0、1、6、7、14、21、28和56 d後，其摺光率與濃度之間的關繫均可用直線方程錶示(決定繫數≥0.998)，其中同期培養麯線的預測誤差為0.34～1.13 g/L，而現配麯線的預測誤差為0.71～4.85 g/L，採用尿素標準溶液工作麯線檢測同等培養期的尿素溶液有利于提高測定結果的準確性。與H2SO4消煮法（常規方法）相比，採用新鮮工作麯線摺光率法測定控釋尿素養分釋放的計算結果提高10%以上，採用標準尿素溶液與包膜尿素同期培養的方法，摺光率法測定結果與常規方法之間的繫數為0.990。為進一步分析摺光率法檢測包膜尿素肥效期準確性，採用Richards方程模擬2種方法所測的釋放麯線併計算養分達到75%的時間點即肥效期，結果錶明，常規方法和摺光率法測得15箇包膜尿素的肥效期為21.9～245.9和22.0～210.1 d，兩者相差最小值和最大值分彆為0.2和41.4 d，相對偏差則分彆為0.8%和25.1%。其中肥效期較短的包膜尿素的測定偏差較小，肥效期較長尤其是達到180 d以上的包膜尿素可能由于後期釋放過于緩慢導緻預算誤差擴大，其誤差區間為27.6～40.4 d，這屬于可接受範圍。說明瞭同期培養工作麯線摺光率法可以作為常溫條件下的控釋尿素養分釋放的速測方法，併可利用模型較準確地預測包膜尿素的肥效期。研究結果可為包膜尿素養分釋放率及肥效期的快速、準確測定提供參攷。
이불동비효기적15개자제포막뇨소위검측양품，이비수질량비위1/5적항온정수용출법위공석뇨소적배양방법，동시채용상규방법화공작곡선절광솔법측정배양액중적뇨소함량，병대양분석방곡선진행Richards 방정적비선성회귀분석용이계산양품적비효기，대비연구현배공작곡선절광솔법여동기배양공작곡선법동상규방법측정결과지간적이동，이기위공석뇨소양분석방측정제공경준학적쾌속측정방법。연구결과표명：계렬표준뇨소용액분별배양0、1、6、7、14、21、28화56 d후，기절광솔여농도지간적관계균가용직선방정표시(결정계수≥0.998)，기중동기배양곡선적예측오차위0.34～1.13 g/L，이현배곡선적예측오차위0.71～4.85 g/L，채용뇨소표준용액공작곡선검측동등배양기적뇨소용액유리우제고측정결과적준학성。여H2SO4소자법（상규방법）상비，채용신선공작곡선절광솔법측정공석뇨소양분석방적계산결과제고10%이상，채용표준뇨소용액여포막뇨소동기배양적방법，절광솔법측정결과여상규방법지간적계수위0.990。위진일보분석절광솔법검측포막뇨소비효기준학성，채용Richards방정모의2충방법소측적석방곡선병계산양분체도75%적시간점즉비효기，결과표명，상규방법화절광솔법측득15개포막뇨소적비효기위21.9～245.9화22.0～210.1 d，량자상차최소치화최대치분별위0.2화41.4 d，상대편차칙분별위0.8%화25.1%。기중비효기교단적포막뇨소적측정편차교소，비효기교장우기시체도180 d이상적포막뇨소가능유우후기석방과우완만도치예산오차확대，기오차구간위27.6～40.4 d，저속우가접수범위。설명료동기배양공작곡선절광솔법가이작위상온조건하적공석뇨소양분석방적속측방법，병가이용모형교준학지예측포막뇨소적비효기。연구결과가위포막뇨소양분석방솔급비효기적쾌속、준학측정제공삼고。
The rapid method to evaluation of controlled release fertilizer had been established in China, which included the eletrical conductivety (EC) method and the refractive index(RI) method.The RI method was only applied for polymer coated urea. The substrates of the coated ureas were organic chemicals, however, during the the incubation, the urea release could be transformed into inorganic form such as NH4+, which would influence the test accurateness of the RI method. It was possible to incubate a working curve companied with tested samples would cancellthe effect of urea form change. So 15 self-made coated ureas with different longevities were taken as samples, which were divided into three groups according to their nutrient release rates, and the samples were incubated in still pure water under the constant temperture of (25±0.5)℃with the fertilizer/water ratio of 1/5, at the same time standard concentration urea solution was incubated under the same condition to get a working curve. And the urea incubation solutions were collected after 1, 7, 14, 21, 28, 42, 56, 70, 98, 126, 154, 210, 266 days during the incubation with renewal of pure water. After that the routine determination of H2SO4 degestion method and the RI method with a working curve at the same incubation interval companied with the tested samples were applied to test nutrient release rate of the coated urea, further more the Richards equation was applied to make a nonliner analysis for each nutrient release curve and calculate the longevities of coated ureas. Finally, the results tested by different methods were used to analyse their similarities and differences and offer a more accurate and rapid determination for polymer coated urea. The results were as follows. Firstly, the EC values of a series of standard concentration urea solution increased with the incubaiton period prolonged, but urea mass concentration and their RI values always had a significant linear correlation relationship (r2≥0.998) after 0, 1, 6, 7, 14, 21, 28 and 56 days during the incubation. However, the errors tested of the fresh working curves were from 0.71 to 4.85 g/L, which would be decreased to the range of 0.34 to 1.13 g/L by using working curves at a same incubation interval companied with samples. Secondly, compared to the routine determination of H2SO4 degestion, the data of nutrient release rate of coated ureas were lifted more than 10%by using the RI method with the fresh working curve, but the new RI method based on the working curve at a same incubation inerval would cancellthe difference of results, which had a conversion coefficient of 0.990 with the traditional one’s. Thirdly, in order to further analysis the accurateness of the new RI method, the Richards equation was applied to model nutrient release curve and calculate the longevity of each sample whose time point to nutrient release amount getting 75%. Results showed that the longevities tested of 15 coated ureas were 21.9-245.9 days and 22.0-210.1days respectively by using the rountine and new method, the minimum and maximum deviation of the new method was 0.8% and 25.1% respectively. The probable reason was that, when the coated ureas with a longer longevity getting more than 180 days were taken as samples, because of nutrient being released too slowly during the later stage, it was easy to bring the greater deviation tested, and their errors were from 27.6 to 40.4 days, but it was acceptable according to routine to label the longevity of controlled release fertilizer and permitted to move up or down about two months. In summary, it was proved that the RI method based on a working curve at the same incubation companied with tested samples was a rapid determination for coated urea, and the longevity would be forecasted accurately by using the Richards equation. Furthermore, the result of this study could offer a reference of a rapid and accurate method to test the nutrient release rate and longevity of polymer coated urea.