[Application of NIRS to detecting total N of cucumber leaves growing in greenhouse].

Non-destructive testing, as a new, rapid, non-destructive technology, is the direction of agricultural produce testing in the future. In this study, the nitrogen content of cucumber leaves was predetermined using near infrared spectroscopy technology. The main results were as follows: The authors measured the nitrogen content in cucumber leaves with Kjeldahl method and near infrared spectroscopy, then established a model between them, and processed a external verification next. The verification results showed that the determination coefficient of the model was 0.4066, relative standard deviation is 0.1559, and calibration standard deviation is 0.72; Then the authors predicted the cucumber leaves nitrogen content with this model, and the results showed that the mean absolute percent error was 0.59, average relative error was 13.88, and correlation coefficient of the chemical values and predicted values was 0.6377. So it was proved that this model had a certain feasibility in vegetable leaves nitrogen testing.

[Application of synchrotron radiation X-ray fluorescence to investigating the distribution of trace elements in different organs of greenhouse rape].

The trace elements distribution in the root and leaf of greenhouse rape was determined with synchrotron radiation XRF, and many essential elements for human health were found, including Co, Mn, Ni, Fe, Cu, Zn, K and Ca, among which the contents of Ca, Mn, Fe, Cu and Zn are especially higher than the other elements. The results proved that the contents of different elements in different parts of leaves and roots were inequable. Generally, the contents of K, Ca and Mg in the roots are significantly higher than those in leaves, while the contents of Fe, Co, Ni, Cu and Zn in the leaves are apparently higher than those in roots. And the contents of all the elements in lateral roots are much lower. The contents of K, Ca and Co in the central section of leaf were higher than those in the edge, and the contents are gradually increasing from the edge to center; the contents of Cu, Mn, Fe and Ni in the tip of leaf were higher than those in base, and it increases gradually from the base to the tip of leaf; the content of Zn in the leaf is absolutely uniform; all the elements in the middle of root were higher than those in two ends, and the contents in the base of root are commonly higher than those in the tip of root.

[Phytoavailability and chemical speciation of cadmium in different Cd-contaminated soils with crop root return].

Pot experiments were conducted under greenhouse condition to investigate the effects of crop root return on succeeding crops growth, Cd uptake and soil Cd speciation in Cd-contaminated soil and artificial Cd-contaminated soil. The results showed that the amount of root residue returned to soil by corn and kidney bean growth successive for 3 times was 0.4%-1.1%. The Cd returned to soil by root residue was 1.3%-3.5% to the total soil Cd. There was no significant difference in the shoot dry weights of winter wheat and Chinese cabbage grown on the 2 Cd-contaminated soils with and without root return. While Cd concentration of Chinese cabbage increased significantly in the Cd-contaminated soil with corn or kidney bean root return. Light fraction of soil organic matter increased with root return in both of the Cd-contaminated soils. The percentage of Cd in the light fraction of soil organic matter increased with root return in the artificial Cd-contaminated soil. Soil carbonates-bound Cd concentration decreased significantly with corn root return in the Cd-contaminated soil. Soil exchangeable Cd concentration decreased and soil Fe-Mn oxide-bound Cd concentration increased significantly with kidney bean root return in the artificial Cd-contaminated soil.