Spectral inversion of maize with different ratios of black clay in the eastern mining area by inoculation with AM fungi

In order to improve the present situation of strong viscosity,poor permeability and low nutrient availability of black clay in open pit mining area of eastern grassland,two levels of inoculation with AM fungi were set up:inoculation with arbuscular mycorrhizal fungi (M) and control group without inoculation (CK). At the same time,the clay was set up with four different proportions:sand (S),clay (N),sandy soil and clay with mass ratio of 1:1 ( S:N = 1:1) and mass ratio of 3 ∶ 1 (S ∶ N = 3 ∶ 1). Hyperspectral remote sensing technique was used to monitor the effects of arbuscu- lar mycorrhizal fungi inoculation on plant growth and development under different substrates. The differences of typical spectral characteristic parameters under different treatments were compared, and the characteristic parameters with high correlation with chlorophyll content were screened. Stepwise regression and BP neural network modeling method were used to invert the chlorophyll content,which laid a theoretical foundation for monitoring the effect of microbial reclamation. The results showed that the chlorophyll content of maize after inoculation with AM fungi was higher than that of the control group. The growth condition of the inoculated group was stronger than that of the control group by comparing the trilateral parameters. That is,the inoculation with arbuscular mycorrhiza could promote plant growth. The black clay after the sand ratio had higher chlorophyll content and better growth condition than pure clay. Under the condition of inoculation,when the ratio of sand to clay was 1 ∶ 1,the chlorophyll content of maize increased most obvi- ously. Selecting 10 spectral characteristic parameters with high correlations,using stepwise regression and BP neural network to establish the model of chlorophyll content for control and inoculation respectively. BP neural network meth- od showed better estimation ability. The model determination coefficient and model test determination coefficient of the control group were 0. 860 and 0. 896,respectively. The model determination system of the inoculation group was the model de-termination system. The coefficient of determination of number and model test is 0. 857 and 0. 890 respec- tively,which could be used to estimate the chlorophyll content of maize leaves.