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What is harvest index, economic yield, crop improvement, plant architecture and multipurpose yield?
economic yield = what you get from agriculture
Harvest index = economic yield relative to the total above ground biomass --> how much biomass above ground that is useful yield, through domestication, plants get more useful 'for us' parts than wild varieties
crop impr. = improving the plant such as stronger straw, tolerance for closer planting (stronger straw etc = plant architecture(?)
multip. yield = the plant can be used for several yields --> building material, fuel ...
--> only focus on harvesting index might not be the best (varieties with several good traits can be useful)
What is potential, attainable, actual and gap regarding yield? What is factor productivity, nitrogen recovery, green water?
Potential y. = mscimum possible yield under ideal conditions
attainable y. = can realistically be achieved with limitations
actual y. = what you can actually harvest
yield gap = the difference between attainable and actual yield
f. prod. = the increrased yield per added amount of fertililiser or water (water absorbed into the plant = green water)
nitrogen recovery = how much nitrogen taken up by the crop, cereals: often 30% - most N lost and may pollute ground water
Displacement of minor crops and monoculture, restricted economic yield, crop residues and weed suppression
The GR focused strongly on wheat and rice, other crops got less research, tech, institute support = decline of some minor crops. GR favoured monoculture, reduced diversity, weakend resource cycling, making farmers dependent on external inputs. Restricted ec. yield = GR thought grain was the only yield of the cereals, crop residues and straw can also be important (in tropics): rice straw can feed water buffaloes, wheat/barley = livestock, serve as fuel and building material. Semi-dwarf = less leaves, less weed suppression
What is the example of wheat and rice reaching its yield limit? and rice?
in UK and yaqui vally in mexico: UK = wheat yield close to attainable yield, further progress is slow but possible. Yaqui valley = not yet met yield limit yet (1.5 t/h 1950, 5t/h 1980, 6t/h later)
Rice are more affected by quality = farmers might chose varieties with medium yield but with high quality
What is the IRRI long-term rice experiment? and what is the US corn belt maize?
IRRI = bred the GR varieties. International Rice Research Institute. In 1963-1993, the 90th consecutive crop was harvested (3 rice crops/year = very intense) = the nutrient yield steadily declining (no fallow, no restauration of soil etc) Long-term sustainability of GR was uncertain
US corn belt maize = most productive (maize) area in the world - 10 tons/hectare. ex. of yield in maize kept rising while wheat/rice slowed down. M develop differently than W/R. M can increase both yield and biomass = M useful for several things (residues and grain, different to W/R)
What is agroecosystems, nutrient subsidies + n. cycling, species interactions + s. diversity, ecological niche, biotic community and intercropping?
agr.ecosys: agricultural ecosystems. STRENGTH > can get increased nutrient input through manure and fertiliser > can increase productivity > more external input = nutrient subsidies | n. cycling: how/where/when nutrients are recycled | species interactions=how species interact
S. diversity = the amount of different species | Ecological niche = the role the species perform (predator etc.(?)) | biotic community = made up by several species together | intercropping = growing several crops together
What is agricultural intensification, fallow reduction and soil fertility decline? What is the response to intensificaiton to the green revolution?
agri. intensification = intensify due to more people | fallow red = less fallowing - less restoration of soil fertility, and restoration of nature | soil fertilty decline = more intense agriculture and less fallowing = loosing soil fertility
Green rev. = came as a response to needs related to loss of soil fertility and more productivity. efforts focused on selected crops (wheat and rice) and high-potential areas (good soil, water, irrigation pot., infrastructure, research, seed system etc). Based on single commodities in areas where the chance of success was high
System approach to agricultural development? Diagnostic farming system survet and interdisciplinary research?
system approach = to focus on all what the system can give and not just yield from one crop (care about livestock, crop residue, labour, soil etc)
Diagnostic farm ... = purpose of identify constraints (used in system approach). Identify conditions and constraints, then specialised resarchers develop tailored solutions. Farming system teams include agri. economists, social scientists, agronomists - want tech that are useful, adaptable and acceptable to farmers
What is the different between Marsh vegetation vs. wet rice cultivation?
what is Land equivilant ratio (LER), over-yielding, benefits of intercropping AND monoculture, polyculture, pest control, nutrient complementarity?
LER = measurement on wheter intercropping is more productive than growing crops separately, if LER above 1, intercrop produce more than monoculture. on same amount of land = over-yielding | benefits of intercrop = pests spread less in mixed systems, use light, nutrients differently, often better soil nutient can create symbiosis.
Monoculture = only one species, easier to mechanise and use of herbicides + vulnerable to pests | polyculture = systems of several species (ex intercrop), better pest control, better n. complementarity = use nutrients differently
what is the gree revolution (GR) research strategy and semi-dwarf varieties, and the achievements and uneven outcomes of the green revolution?
GR research strategy = using interdiscipinary research teams on each commodity. semi-dwarf varieties = shorter, stronger-stemmed varieties resistant to lodging, responded well to fertiliser, had broad adaptation, matured early, allowed closer planting, higher harvest index
achievements and uneven outcomes = these varieties had large increase in crop production, benefit for declined in food prices, benefits uneven = some regions benefit more than others (which regions?) if the cost reductions were larger than the prices, farmers earned, but not certain. yield growth started in favourable areas and spread slowly to less favourable areas
New priorities after the system approach? Post-Green-Revolution slowdown and continued need for yield growth?
Post-GR = after GR, cereal prod. growth slowed down. Wheat/rice/maice (1987-2007) did not grow fast enough to meet increasing demand without real price rises - challenge: how continue increase food prod. with sustainagility, social justice, environ. limits?
Is Maize and beans intercropping and grasses and legumes in fooder production good?
maize and beans = good example of land equivalent ratio (LER) = gives higher total yield than growing separately
Legumes add nitrogen, grasses provide fodder biomass
LAI = measurement total leaf area compared to soil surface area, high LAI = take up light efficiently. canopy structure = the leaves highest up recieve more sunlight than those lower down. mixed cropping = two or more crops grown toegether. Relay cropping = planting 1. crop before 2. crop is harvested = growing period overlap. Light-demanding crops = need more light. shade tolerant = do best under shade. shade plantations = some plants like shade --> shade plantations
Genetic erosion, uniform varieties, disease vulnerability, seed replacement, pesticides, seconday pests loss of beneficial organisms?
Wheat and rice yield progress and limits? Maize productivity, plant density, biomass, and biofuel potential?
wheat/rice = yield 8 tons/hectary, growing slowly and steady (even slower for rice)
Maize = no sign of approaching yield limit - increase grain and biomass simultan. ok with increased plant density as well. before: 30k plants/hectare, now: 80k /hectare. maize stover can be used as fodder and biofuel, due to biomass and grain increase. more biomass = more side-use
examples of Shade coffee plantations?
examples of C3, C4, CAM plants?
shade plantations = coffee
C3 = most agricultural systems in forest zones are dominated by the more shade tolerant C3 species
C4 = pearl millet, sorghum and maize
CAM = Pinapple (most imporant agri. plant with CAM)
what are photosynthesis C3, C4, CAM and growth and productivity of tree crops?
C3 = most common photosynthesis,
C4 = adapted to high temperatures, close stomata when ???
CAM = adapted to hot-desert conditions (pinapple most important)
Growth. pro = in branching species --> flowering more difficult to understand and uncertain - Single-stemmed crops grow directly toward flowering and fruiting, stress can delay or reduce fruiting (pinapple, banana) Branching tree crops - less predictable, flowering irregular, good management can improve growth but not neccessary yield
soil fertility p = high yields removed micronutrients (Calium, calsium etc) even with fertiliser for N P and K = the soil had problems get enough overall nutrients from the soil. hard to maintain high yield. long term yield-decline = not fully understood, but even with fertilisers, decline in high yields (soil exhausted and not recovered to produce high yield?). Geo. limitations = GR bypasseed parst of Asia and most of Africa - technologies were not adapted, infrastructure weak, lacking institutions, failed markets.
why is it high yield gap for maize in Sub-saharan africa?
Sub-S A = due to low soil fertilit/use of fertiliser/planting density, bad pest control - breeding and intro of high yielding varieties make no sense unless basic growing conditions are improved first - need this first and not just intro of high yielding varieties (little effect). Recent increase in food $ makes life harder for poor consumers, but create opportunities for food producers. Food $ = farmer incentives. If african farmers had profitagle conditions/good markets/improved growing conditions = increae production
What happend in the 1968 wheat harvest in India and Pakistan?
What was the difference between Punjab and Bihar?
Difference between Punjab & Bihar = uneven benefits for the regions: GR had stronger effect in Punjab due to better conditions (good agri. potential, water supply, infrastructure, input supply, markets, insti. support) Bihar: less good: same seeds, but not right environ. fertil, water, market, support insti. all/all = uneven outcomes