Dynamic analysis of grassland leaf area index changes under different grazing strategies based on multispectral UAV
Disorderly grazing in grassland on abandoned cultivated land hindered the sustainable development of the grassland in Hainan Island.Grassland grazing experiments were conducted according to different grazing methods(rotational grazing and continuous grazing)and different grazing intensities(severe,moderate,and slight).Multispectral UAVs and vegetation canopy analyzers were used to obtain daily-scale grassland leaf area index(LAI)during the grazing period,and the impact of different grazing strategies on changes in grassland leaf area index and cattle behavior were also quantitatively analyzed.Results showed that rotational grazing under moderate grazing intensity was beneficial to improving grassland LAI.Under severe grazing intensity the proportion of areas where LAI increased in rotational grazing and continuous grazing grassland accounted for 3.21%and 12.65%of the total grassland area,respectively.Under moderate grazing intensity the proportion of areas where LAI increased in rotational grazing and continuous grazing grassland accounted for 52.01%and 25.83%of the total grassland area,respectively.Under slight grazing intensity the proportion of areas where LAI increased in rotational grazing and continuous grazing grassland accounted for 61.02%and 60.37%of the total grassland area,respectively.Under severe grazing intensity the proportion of cattle's feeding time to the total behavior was always the highest.As the proportion of feeding time increased,the reduction of grassland LAI was also increased,but when the proportion of feeding time increasing to 70.88%-73.42%,the reduction of grassland LAI was gradually decreased.At this time,the leaf area index of the grassland dropped to 79.60%-79.90%of the initial leaf area index(before grazing on the first day),which meant that the number of leaves fed by the cattle was upto the limit that the LAI of the grassland could supply on the day.When this limit was exceeded,individual livestock competition would be intensified.At the same time,the proportion of time spent by cattle on gnawing behavior greatly increased.All these results will help to select the best grass and livestock management methods at the pasture scale,to provide theoretical methods and decision-making support for the sustainable development of tropical grassland livestock systems from a new perspective,and to assist the construction of the National Pilot Zone for Ecological Conservation(Hainan).
grazing strategygrasslandleaf area indexmultispectralHainan Island
NETL
NSTL
万方数据
维普
