珍稀乡土树种福建柏苗期DRIS营养诊断

Nutrient diagnosis of Fokienia hodginsii seedlings using DRIS

以我国珍稀乡土树种福建柏的1年生播种苗为研究对象,对苗期的DRIS营养诊断技术进行了系统研究。运用D-最优饱和设计法进行了福建柏苗期N、P、K3因素10处理盆栽施肥试验。与以往的研究仅以某月份或特定时间的取样制定的营养诊断标准不同,以整个生长季节(6～12月份)内选取的共计10 0份苗木叶片养分含量测定值为依据,成功制定了DRIS图解法及指数法的营养诊断标准,经检验其诊断正确率较高,验证了DRIS营养诊断方法可以排除1年生苗木不同月份叶龄的影响。福建柏苗期叶片3元素浓度最佳比值范围为N/ P=11.4 12 1±1.4 137;K/ N=0 .5 0 32±0 .10 39;K/ P=5 .6 16 8±1.0 6 0 4。DRIS诊断标准分别经各月份苗木叶片养分元素含量回代检验,所诊断的苗木N、P、K需肥次序与实际施肥量基本一致。以生长中期的8月份各处理苗木为例,列出各元素的DRIS诊断指数及相对需肥次序,诊断正确率达90 %以上。

Fokienia hoginsii is a native and endangered tree species in Southern China, with great potentials in afforestation for the region. The conventional cultivation technique for Fokienia hoginsii seedlings, however, has been challenged as demands for its seedlings in afforestation escalate. The nutrient diagnosis of seedlings is a critical information that can be used for guiding field fertilization. Using one-year-old seedlings, we systematically analyzed the method of Diagnosis and Recommendation Integrated System (DRIS) for successful seedling cultivations. DRIS was based on nutrient ratios instead of isolated concentration value of each nutrient in tissue analysis and has been applied in several fields in China, United States, and Canada (e.g., forestry and horticulture) as an additional measure for diagnosing nutritional status. In this study, we provided a comprehensive literature review on DRIS and the detailed methods for management applications. Our experiments were conducted in the greenhouse of Fujian Agriculture and Forestry University, located in Nanping city, Fujian province of China. Our study objective was to establish adequate DRIS norms for Fokienia hoginsii seedlings by developing an index of nutrient concentration of leaves. The D-optimum saturation Design was use in the pot experiment for three nutrients (N, P, and K). Seeds were sowed in March and samplings were taken from June through December at monthly base-a major difference from previous studies that ignored changes over time. We successfully developed DRIS diagrams and exponent norms for the species. Based on data from 100 leave samples, we found that the adequate ratio among the nutrient elements were: N/P=11.4121±1.4137, K/N=0.5032±0.1039, and K/P=5.6168±1.0604, with a very high diagnostic accuracy of DRIS. The experimental results further indicated that short supplies of N, P, and K matched well with the actual quantity of fertilizers. Using seedlings in August, for example, we found that two norms were well matched with a diagnostic correct probability of 90%. We also found that that DRIS results were not influenced by leaf age, suggesting that the sampling time for DRIS can beat any stages from spring to winter. Clearly, the norms can be widely applied in seedlings culture for detecting and managing nutrients needs.