Grazing every month minimizes size but boosts photosynthesis in Stipa grandis in the steppe of Inner Mongolia, China

In order to explore the effects of grazing frequency on functional traits and to test whether Slipa gandis has compensatory photosynthesis during the frequent grazing period, we investigated morphological traits, biomass allocation, photosynthetic traits, and chlorophyll fluorescence parameters of the species in Inner Mongolia, China. The grazing frequency treatments included fencing （To）, grazing in May and July （T1, i.e., two months per year） and grazing from May to September （T2, i.e., continuous five months per year）. Results indicate that T1 and T2 treatments did not affect individual biomass, but T2 treatment negatively affected individual size, i.e., plant height, stem length, and leaf length. Physiological traits of S. grandis were significantly affected by grazing, year, and their interaction. In July 2014 （i.e., dry environment and low relative humidity）, the photosynthetic rate, transpiration rate and water use efficiency were highest under T2 treatment, which was caused by the increase in stomatal conductance. However, in July 2015 （i.e.,

Morphological and productivity responses of Buffel grass(Cenchrus ciliaris)and Guinea grass(Panicum maximum)ecotypes to simulated grazing in a semi-arid environment

Background Livestock production is an economically significant activity in grassland-based production systems with herbivory,a critical process in modifying plant structure and regulating biomass dynamics in these areas.Methods A grazing simulation experiment was undertaken in a semi-arid environment in Kenya to determine the effects of clipping frequency and intensity on the morphology and productivity of Cenchrus ciliaris and Panicum maximum grass ecotypes.The ecotypes were clipped at different frequencies(every 2,4,and 12 weeks)and different intensities(5,10,and 15 cm clipping heights).The morphological responses of the grass ecotypes and biomass yields were determined.Results The grass ecotypes showed significantly(p<0.05)varied responses to cutting frequency and intensity.Morphological parameters,tillering,and biomass production were all affected by clipping frequency and intensity.The highest dry matter(DM)yields were recorded under low frequency(LF)clipping,followed by moderate frequency(MF)clipping and high frequency(HF)clipping.LF clipping in C.ciliaris ecotype Kilifi was 20%and 31%more compared to MF and HF clipping.No significant difference in yields was found by cutting the C.ciliaris ecotype Magadi at 4-and 12-week intervals,even though clipping at 2-week intervals cumulatively yielded less biomass.There was a biomass yield reduction in P.maximum ecotype Taveta of 23%and 25%for MF and HF clipping,respectively,while for ecotype Isinya,the reduction was 13%and 15%for MF and HF,respectively.Clipping intensity had a significant(p<0.05)effect on cumulative yields in C.ciliaris ecotypes,but not P.maximum.Ecotypic differences were apparent in both C.ciliaris and P.maximum ecotype DM yields.Conclusions The results in this study suggest that clipping range grass ecotypes less frequently(4-and 12-week intervals)and at 10 and 15 cm stubble heights results in higher biomass yields.Generally,LF and MF grazing and cutting strategies are advantageous for semi-arid lands.Combinations of frequent and high-intensity utilization grazing strategies should be discouraged as they are likely to lead to reduced biomass yields and negative effects both on grasses and on the environment.