A study of the changes in plant and soil nutrients associated with moorburning and grazing

摘要

From the Summary: "The work has consisted of the measurement of processesudconnected with the normal management of grouse moors in theudGlen Clova area of Angus.udThe problems associated with burning have been summarisedudtogether with the remits of previous work.udThe geology and topography of Glen Clova have beenuddescribed briefly, and the vegetation of the Rottal area ofudthe glen has been described in detail with respect to theudparticular parts under consideration.udA method of ring counts has been used to define the ageudof Calluna stands.udThe methods used for analysis of mineral nutrients haveudbeen described. One method, Atomic Absorption Spectroscopy,udhas required extensive calibration and has been described inudmore detail.udIt has been shown that the temperature and duration ofudheath fires depends upon the age of the vegetation.udThe temperature and duration of a fire determined theudloss of nitrogen in the form of smoke.ududThe temperature of a fire has been shown to affect theudsolubility of nutrients in ash. Increase in temperatureudcaused a greater release of soluble potassium and calcium,udbut a decrease in soluble phosphate, The release of mineraludnutrients from Calluna leaf litter has been compared withudthat from ash.ududExperiments were instigated to measure the effect ofudgrazing upon the yield and mineral content of Calluna, theudgreatest effect being found 5 - 10 years after burning.udThe addition of mixed fertiliser to some of the standsudwas found to increase the yield and nutrient content of theudleaven of Calluna.ududSoil samples from 22 stands of Calluna were analysed inudNovember each year, for three years, and the total contentudof nitrogen, phosphate, potassium, magnesium, calcium andudiron estimated. In the first instance other analysesudincluding pH, conductivity, organic carbon and mechanicaludanalysis were performed in order to distinguish between theudtwo soil types present. Significant changes in the nutrient content of the soils have been discussed.udA balance sheet of the losses and gains to the ecosystemudwas prepared to indicate the changes in mineral nutrients.udit has been calculated that the potential losses of individual nutrients by leaching, ignition and grazing could beudreplaced over a period of 15 years from rainwater, withudthe exception of phosphate which is only present in smalludquantities in rainwater.udThe implications of the results have been discussed."