Education of Agroclimatology at ELTE: a Review with Special Focus on Wheat and Grape (Vitis Vinifera)*
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Education of agroclimatology at ELTE: a review with special focus on wheat and grape (vitis vinifera)* Ferenc Ács, ELTE Institute of Geography and Earth Sciences, Department of Meteorology *Invited presentation at Department of Geophysics, Faculty of Science, University of Zagreb, 14th November 2018 Content -- shortly • General remarks • Basic theory (vegetation, environment) Vegetation related basics Environment [natural (climate: biophyisical climate classifications, (agroclimatological zones), social (political decisions, economical aspects] (51 transparencies) • Methods for characterizing cultural vegetation (crop) – environment interaction (long term field experiments, agroclimatological models) (13 transparencies) • Crops which determined human civilizations (e.g. wheat, grape) (31 transparencies) • Closing remarks General remarks • Agroclimatology is a graduate-level course [1st year MSc (MSc = master of science) subject]. • It is educated only on specialization „climatology”. • It is taught from the „earth science” point of you. Agronomical point of view is much less represented in the treatment! Goals • To get basic knowledge referring to vegetation. • To understande better the human-cultural vegetation coevolution. • To answer the question: Why is bread so cheap and what is the cost of this? Vegetation Conquest of the land- surface: stomata, stem, roots, soil Soil is joint product of the parrent material, vegetation and micro- organisms. Stomata – the most relevant organ of vegetation? • For meteorologists YES! „ … the physiology of stomata are just as relevant to understanding climate as are clouds and convection” (Bonan, 2002). • Jarvis (1976) formula represents its simplest model! rst min Fad rc . LAI GLF Fma Vegetation – stomata - rstmin • rstmin is a parameter of special importance! • It represents water vapor transport resistance that exerts when its opening is maximum. Environment as sensed by vegetation • Radiation, base temperature, growing-degree days, photosynthesis, respiration, net photosynthesis and its environmental dependence, photosysntetic efficency (leaf, canopy, ecosystem scale), productivity, water use efficency (WUE), drought, frost (its biophysics), phenology, phenology-physiology relationship, phenometry (vegetation canopy height, leaf area index (LAI)), allocation, soil texture, plant available soil water content, nutrient-soil texture relationship are discussed. Impact of radiation on vegetation Base temperature of some crops (e.g. winter wheat, potato, muskmelon, seasoning pepper) Growing degree days • Vegetation period, • temperature sum [Σi(Ti – Tb)], • temperature sum is strongly correlated with global radiation sum. Photosynthesis • transport of CO2 from air to chloroplast • Light reaction (ATP, NADPH) • Dark reaction. Light reaction – absorption of light • Absorption spectra of chlorofyll Photosynthesis types C3–C4--CAM Respiration • The reverse process of photosynthesis for getting energy • Types: photorespiration, respiration (they differ physiologically) Net photosynthesis Net photosynthesis curve Photosynthetic efficency (PhEf) In average free energy of the dry mass is 17,5 kJg-1 Photosynthetic efficency • Maximum value for leafs: 3-4%. QUANTITY/PHOTOSYNTHESIS C3 C4 Quantum need 15-22 19 Molecular level 10,8–16% 12,6% Molecular level with respect 4,5-6,8% 5,4% to global radiation PhEf efficency Respiration losses in canopy PhEf: canopy scale, year PhEf: ecosystem scale, year PhEf: calculation procedure • Temperate cereals: 2000 g 2000 17,5 kJ 100% p 2 GJ 2 GJ 2000 17,5 104% 1,75% 2 PhEf: rice • PhEf of rice is 2,62%. Let we see that is 0.87% greater than of other temperate cereals. This is almost 50% (0,87/1,75). Productivity • Let we see that productivity is CO2 flux density -2 -1 (mg CO2 m s ) • Productivity, environmental stress functions, LAI • In temperate zones, limiting factor is temperature, in the tropics water availability. WUE, drought, drought tolerance Frost, frost tolerance Phenology phainesthai – appearing, phainomenon – phenomenon, logos – disciple • Phenology is an old science, it relates vegetation morphology (developmental stage) and the environmental variables. Phenophases and their duration for some chosen crops Phenometry • Phenometry treats state variables (morphological characteristics) of vegetation and vegetation canopy. • The two most important state variables: vegetation canopy height(H) and leaf area index (LAI). Remote sensing • Remote sensing is the basic tool in phenometry and phenology. Allocation – organic matter obtained in leafes has to be distributed to all non- photosynthetic parts Plant available soil water content θf = field capacity, θw = wilting point Soil hydraulic properties – soil texture dependence Nutrient availability – soil texture dependence • Sand = particle diameters between 50 – 2000 μm, high water conductivity, low cation exchange capacity (CEC) • Loam = particle diameters between 2 – 50 μm, moderate water conductivity, moderate cation exchange capacity, • Clay = particle diameters below 2 μm, low water conductivity, high ion exchange capacity. Environment Environment = human + climate + soil Human → agricultural politics, agricultural economy, agricultural technics, plant breeding In the modern agriculture, plant production and plant breeding are separated (Lelley, 1980). Climate → radiation, heat and water availability Soil → water and nutrient availability Human – agricultural politics Plant protection zones in the EU Human – Agricultural economy Bee: gratis pollinization Costly • Pesticides • Herbicides • Fungicides Human – agricultural technics • Already American indians knew that maize has to be scarcely planted, otherwise it doesn’t yield. Human – plant breeding • Maize is amazing plant: it grows rapidly. • Record-yields: 1 seed is able to produce up to 800 seeds. And this is only an ear of corn! • Plant breeding is the key of this enormous result. Human – landuse -- past Rivers in the Carpathian Basin before flood control Human – landuse -- present Landcover types Hungary is agricultural land, it has no wild territory. Human – wheat – weed (ragweed) coexistence N surplus because of fertilizing Climate – sunshine duration Area distribution of the annual sunshine duration in Hungary Climate – global radiation Area distribution of annual sum of global radiation (MJm-2) in Hungary Climate -- evapotranspiration, soil water content Annual course of evapotranspiration and soil water content for different soil textures Evapotranspiration, soil water content Area distribution of annual evapotranspiration and soil water content in Hungary Evapotranspiration, soil water content Area distribution of monthly evapotranspiration and soil water content in Hungary (month: July) Climate – according to Thornthwaite Climate – according to Feddema Climate -- frost last frost in spring, first frost in autumn Methods for characterizing crop- environment interaction Most important: to possess independent datasets for crop and environment Fluctuating prices of weat and oat at Dupré de Saint-Maur, Paris Methods for characterizing crop- environment interaction • Longterm experiments [collecting crop and environmental data in the field during long time interval (if possible more than 100 years) to study the effect of human intervention (e.g. fertilizing)] • Agroclimatological models (application of mathematical and physical methods using observed data, goals: to understand the system and to predict the future) Longterm experiments A location of longterm experiments (datasets obtained are treated as national treasury) The impact of fertilization on yield of rape (2004-2007 years average [tha-1]) Agroclimatological models Types: • Phenology models • Statistical yield models • Nutrient transport models • Vegetation disease and pest models • Crop models • Agricultural system analysis mdels Phenology models • Phenology models treat phenophase duration – climate element relationships mostly by using statistical methods. • Climate elements: Factors characterizing heat and/or water availability (global radiation, temperature, different indices etc.) Yield models • Yield models treat crop yield – climate element relationships mostly by using statistical methods (e.g. multiple linear regression model). • Important: yield and environmental data have to be independent. • They are not universal, each of them refer to a concrete location and time interval. Nutrient transport models • These models treat e.g. N, P, K, S, Mn transport in the soil and their uptake by vegetation. • They are closely related to soil water transport modelling. • They serve frequently as submodels in the crop models. Vegetation disease and pest models These models estimate the appearing time, duration and intensity of diseases and pests. INPUT MODEL OUTPUT Vegetation Characterising factors Time appearing, disease or pest duration, related intensity processes Meteorological factors Crop models • They estimate crop’s biomass and yield at the end of the vegetation period. • They can use phenology and nutrient transport submodels. • Their most important part is the net- photosynthesis submodel. • They can be pretty process-based. Crop models their principle structure Crop models • OUTPUT: accumulated PET, ET, soil water, daily net-photosynthesis, accumulated biomass, LAI, seed number, seed mass, dry mass of different vegetation parts. Agricultural system analysis models • They are used in the agricultural economy analysis! Crops which determine human civilizations Civilizations