Ibi Qemlas
Mind Map by , created more than 1 year ago

University Plants from cell to crop (Week 7) Mind Map on Resource use efficiency in agriculture, created by Ibi Qemlas on 02/11/2015.

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Ibi Qemlas
Created by Ibi Qemlas over 9 years ago
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Resource use efficiency in agricultureLightUpper Limits of FoodproductionRadiation use efficiency is thelimiting factorPrinciples of canopystructureCanopy structure andphotosynthesisCanopy structure determines (1) how much radiation is absorbed and(2) photosynthetic efficiency of the canopy as a wholeCanopy light interception dependsonCanopy size (surfacearea)CanopygeometryThe higher the leaf area index the lower the the extinction coefficient (k) of thespecies / varietyHave more leaf area at a higher rate of photosynthesisUprightcanopieshigher productivity efficiency because there is a large sunlight area exposurehigher exposed ground resulting in water loss, ground evaporationand weed risk compared to flatter leaves that cover more ground.Natural systems are irregular and heterogeneousbecause of:Several interacting layers of different speciesoccupying different niches down the canopy intime and spaceLarge proportion of interceptingelements are non-photosyntheticBy comparing light response curves at each point in the canopy we candetermine the proportion of the canopy that is light limited or lightsaturated.Leaves with a low extinction coefficient for radiation can have a very high leaf areain a light-limited state and therefore a higher canopy photosynthesis rate - it doesntsaturate.The Extinction Coefficient (k) and Beer’s Law can be used to define canopy architecture and link fand LLeaf Area Index (L) and Fractional Interception (f) can be used to describe vegetationcapture system and there is a functional relationship between f and L for differentcanopy architecturesComplex and irregular canopies require more sophisticated techniques to bemeasuredDisadvantageachieve canopy closurelaterAdvantageRadiation useefficiencycanopy photosynthesis is closely linked to radiation use efficiency(RUE)EnvironmenteffectorsPhotosynthesis determines how productive a crop can be thus It is the amount of lightthat a canopy intercepts that is most strongly related to biomass and yield potential.MeasuringConversion is required in order to adjust the biomass (g m-2) of aspecies for the chemical energy values (kJ g-1) of its differentconstituents (carbs, lipids and protein)1. Measuring light response curves for individual leaves = controlled environmentcabinet that is the first step to assess photosynthesis within a canopy2. Measuring whole canopies in controlled-environments = allow us to controlphysical factors (temperature, CO2, humidity, soil moisture) whilst allowingleaves within a canopy of vegetation to interact as if in a natural environment3. Measuring canopy responses in the real world = although it is not in a controlledenvironment it is in a more realistic situationNitrogenTemperatureWaterIndividual leaves display a curved response of photosynthesis to PAR – leafresponse curveCanopies of vegetation display a generally linear response (`Conversion coefficient’) -integration of individual leaf curvesPresentDouble click this nodeto edit the textClick and drag this buttonto create a new node