# Climate Effects on Tallgrass Prairie Responses to Continuous and Rotational Grazing
## 4 Discussion  
This study provided a direct comparison of vegetation productivity in continuous and rotational grazing management systems in tallgrass prairies of the Southern Great Plains. The large climate variation during the study period allowed us to examine the differences in response to climate under continuous and rotational grazing management. Many studies indicated that multi-paddock rotational grazing can improve grassland productivity by allowing post-grazing recovery [25; 32; 49]. Our study found that the rotational grazing had higher vegetation production in rep b but not in rep a. Both average growing season EVI and GPP were higher in rep a than rep b probably caused by their inherent differences such as soil type. Additionally, our results indicated that productivity of tallgrass prairie was greatly controlled by climate, more specifically by the seasonality of air temperature and precipitation. This finding is also supported by other studies that compared the continuous and rotational grazing in the same experiment from perspectives of aboveground biomass ([PERSON] et al., 2019) and landscape pattern ([PERSON] et al., 2019), which were also presented in this issue. The initial experiment design was to put around 25 cow-calf pairs in each of the treatments. However, the stocking rate in the continuous grazing system was adjusted according to the paddock conditions (considering woody encroachment, climate, species composition and desirable species, and grass growth). With reduced stocking rate in continuous grazing systems, the vegetation production was still similar with rotational grazing systems that had higher stocking rates. Thus, the concept of adaptive grazing management [19; 21; 23; 50; 51; 52; 53], adjusting grazing management depending on the vegetation and climate conditions, might be better to help ranchers to understand the necessity of adjusting their grazing routine to achieve sustainable and profitable usage of pastures. Since little differences in vegetation growth were detected between Ca and Ra, it indirectly demonstrated that rotational grazing has higher grazing capacity, as Ca had a reduced stocking rate. Variations in EVI among paddocks in rotational grazing systems were small (Figure 11), indicating their similarity in vegetation growth. The relative small variations among paddocks in different years demonstrated that rotational grazing generated evenly distributed grazing pressure on tallgrass prairies in different climate conditions. Even with a higher stocking rate, the rotational grazing management generated similar vegetation responses with continuous grazing and an evenly grazed vegetation pattern. The results indicate the rotational grazing may support higher livestock production while maintaining sustainable usage of the tallgrass prairie pastures in the region. The interaction of climate variability and grazing management makes the study complicated. There were very dry (2011 and 2012) and wet years (2013 and 2015) during the study period. Even the drought years had different characteristics. For example, 2011 was a growing season-long drought year and 2012 was a summer drought and hot year. The seasonal distribution of Ta and P generated different impacts on vegetation. Their dynamics combined with different grazing management controlled the grassland phenology and productivity. Thus, it is hard to conclude a general comparison between C and R for the entire study period. The average EVI only converged in very dry years (2011 and 2012) among treatments (Figure 5) and large variations exist in other years. Although 2012 was a drier and hotter year than 2016, they had comparable EVI. This difference was caused by the seasonal distribution of Ta and P. There was more precipitation in spring 2012 (March-April) than in 2016, which facilitated the vegetation growth in spring and early summer in 2012. It was hot and dry in summer 2012. Favorable vegetation growth in spring and a hot and dry summer induced a flash drought and quickly suppressed vegetation growth [45; 54; 55].