227 / 2023-09-28 09:07:08

Dynamic monitoring of winter wheat growth and health status in coal mining subsidence area combined with active and passive remote sensing

Coal-grain composite area,Mining subsidence,Red-edged vegetation index,Regularity of growth,Winter wheat (Triticum aestivum L.),Crop health index in subsidence area (SACHI)

The contradiction between efficient mining of coal and productivity improvement of cultivated land is more prominent in coal-grain composite area, which restricts grain production and threatens food security. Therefore, to ascertain the impact of mining subsidence on crop growth and health status? What's the pattern? It can provide some scientific basis for solving the contradiction between coal mining and arable land productivity improvement. In this study, a variety of red-edged vegetation indices, which are sensitive to vegetation growth and health, were introduced to explore the differences in growth time, growth rate and growth rate variation of subsidence area (SA) and check area (CK) winter wheat. Then, the vegetation index NDRE2, which was the most sensitive for monitoring growth differences, was combined with the red-edged chlorophyll index Clre, the normalized difference moisture index NDMI and the soil salinization index SI-T to construct the crop health index in subsidence area SACHI to comprehensively evaluate the health status of winter wheat. The results showed that: (1) The selected subsidence area lagged behind the start time of the over wintering season, the start of growing season and the start time of the end of growing season compared with the check area. (2) Differences in growth stages of each growth stage: The effects of mining subsidence on the growth of winter wheat in subsidence area 1 (SA1) area were as follows: growth and development were slower than check area 1 (CK1), and the decline and maturity rate was accelerated compared with that in the comparison zone. The effects of mining subsidence on the growth of winter wheat in subsidence area 2 (SA2) area were summarized as follows: the over wintering season was not obvious, the growth was delayed after rejuvenation, and the maturity and aging rate accelerated to a certain extent. (3) The mean contribution rate of the first principal component of SACHI for SA and CK was between 90.99% and 92.01%, indicating that SACHI could synthesize most of the information of the four components. (4) NDRE2, Clre, NDMI and SACHI were highly positively correlated, with the mean correlation coefficients between 0.979 and 0.981, 0.974 to 0.980 and 0.884 to 0.912, respectively, and SI-T and SACHI showing a high negative correlation, and the mean correlation coefficient was between -0.925 and -0.894. (5) The health status of SA1 winter wheat in the whole life cycle was poor compared with that in the CK1 region; Based on the subsidence time, it could be seen that the effects of mining subsidence on the health status of winter wheat in the SA2 was mainly manifested in the length of growing season 2 (LOS 2) and end of growing season (EOS). Based on the multi-vegetation index and comprehensive model, the impact of mining subsidence on the growth and health of winter wheat can be effectively explored, which can provide a theoretical basis for the efficient mining of coal and the increase of cultivated land capacity in coal-grain composite areas.