EFFECT OF CLIMATIC FACTORS ON CROP AGRICULTURE RESEARACH INSTITITUTE (ARI)TANDOJAM
MASHOOQ HUSSAIN ODHANO ASSISTANT RESEARACH OFFICER AGRICULTURE CHEMISTRY (SOILS) SECTIONAGRICUTLURE RESEARCH INSTITUTE TANDOJAM
As elevation increases, the average temperature decreases.Above a certain elevation, low temperatures make itimpossible for trees to grow, as seen here on WashingtonsMount Rainier.
Pakistan’s Resource Base LAND (in million hectare) Geographical area = 79.6 Area under cultivation = 27.6% (21.87) Crop area irrigated = 22.6% (17.99) Rainfed Agriculture area = 4.97% (21.87) Forest = 4.5% (3.61) Culturable waste = 11.7% (9.31) Range Lands = 59% (46.96)
Climate Wind,Temperature Rainfall Sunshine, CO2 level Solar Radiation Photosynthetic Evapo-transpiration (ET) Activity Crop Water Demand Canal/ground water Water Availability Agriculture (Crop Yield)
Climate and Food Production Weather and Climate are the key factors in food productivity Being open to vagaries of nature, food production are highly vulnerable to climate change phenomena
What is Crop? A crop is a volunteered or cultivated plant (any plant) whose produce is harvested by man at some point of its growth stage. Crops refer to plants of same kind that are grown on a large scale for food, clothing, and other human uses. They are non- animal species or varieties grown to be harvested as food, livestock fodder, fuel or for any other economic purpose (for example, for use as dyes, medicinal, and cosmetic use). Major crops include sugarcane, pumpkin, maize (corn), wheat, rice, cassava, soybeans, hay, potatoes and cotton. While the term "crop" most commonly refers to plants, it can also include species from other biological kingdoms. For example, mushrooms like shiitake, which are in the fungi kingdom, can be referred to as "crops". In addition, certain species of algae are also cultivated, although it is also harvested from the wild. In contrast, animal species that are raised by humans are called livestock, except those that are kept as pets. Microbial species, such as bacteria or viruses, are referred to as cultures. Microbes are not typically grown for food, but are rather used to alter food. For example, bacteria
What is Climate? Climate is defined as an areas long-term weather patterns. The simplest way to describe climate is to look at average temperature and precipitation over time. Other useful elements for describing climate include the type and the timing of precipitation, amount of sunshine, average wind speeds and directions, number of days above freezing, weather extremes, and local geography.
Climate Related climatic factors of Agricultural Productivity CO2 Temperature Solar Radiation Precipitation Others (Wind speed and direction, Soil Moisture, Water vapour, etc.) Basic understanding of these factors helps manipulate plants to meet human needs of food, fiber and shelter The parameters also help understand impacts of climate change and devise adaptation/mitigation strategies
Rainfall and Water Rainfall is the most common form of precipitation. It is the falling of water in droplets on the surface of the Earth from clouds. Other forms of precipitation are freezing rain, sleet or ice pellets, snowfall, and hail. The amount and regularity of rainfall vary with location and climate types and affect the dominance of certain types of vegetation as well as crop growth and yield
Light Light is a climatic factor that is essential in the production of chlorophyll and in photosynthesis, the process by which plants manufacture food in the form of sugar (carbohydrate). Other plant processes that are enhanced by this climatic factor include: stomatal movement, phototropism, photomorphogenesis, translocation, mineral absorption, and abscission.
Light (Contin;) Light is that visible portion of the solar radiation or electromagnetic spectrum. It is a form of kinetic energy that comes from the sun in tiny particles called quanta or photons, travelling in waves. Three properties of this climatic factor that affect plant growth and development are light quality, light intensity, and day length or photoperiod. Light quality refers to the specific wavelengths of light; light intensity is the degree of brightness that a plant receives; and daylength is the duration of the day with respect to the night period.
Temperature : The degree of hotness or coldness of a substance is called temperature. It is commonly expressed in degree Celsius or centigrade (C) and degree Fahrenheit (F) This climatic factor influences all plant growth processes such as: Photosynthesis, respiration, transpiration, breaking of seed dormancy, seed germination, protein synthesis, and translocation. At high temperatures the translocation of photosynthate is faster so that plants tend to mature earlier. In general, plants survive within a temperature range of 0 to 50 C .Enzyme activity and the rate of most chemical reactions generally increase with rise in temperature. Up to a certain point, there is doubling of enzymatic reaction with every 10 C temperature increase But at excessively high temperatures, denaturation of enzymes and other proteins occur. Excessively low temperatures can also cause limiting effects on plant growth and development. For example, water absorption is inhibited when the soil temperature is low because water is more viscuous at low temperatures and less mobile, and the protoplasm is less permeable. At temperatures below the freezing point of water, there is change in the form of water from liquid to solid. The expansion of water as it solidifies in living cells causes the rupture of the cell walls. The favorable or optimal day and night temperature range for plant growth and maximum yields varies among crop species.
Air The air is a mixture of gases in the atmosphere. According to Miller (2001), about 75% of this air is found in the troposphere, the innermost layer of the atmosphere which extends about 17 km above sea level at the equator and about 8 km over the poles. In addition, about 99% of the clean, dry air in the troposphere consists of 78% nitrogen and 21% oxygen. The remainder consists of argon (slightly less than 1%), carbon dioxide (0.036%), and traces of other gases. The oxygen and carbon dioxide in the air are of particular importance to the physiology of plants. Oxygen is essential in respiration for the production of energy that is utilized in various growth and development processes. Carbon dioxide is a raw material in photosynthesis. The air also consists of suspended particles of dust and chemical air pollutants such as carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), sulfur trioxide (SO3), nitrogen oxides, methane (CH4), propane, chlorofluorocarbons (CFCs), solid particles of dust, soot, asbestos and lead, ozone and many more. However, the composition of this climatic factor is susceptible of
Relative Humidity The amount of water vapor that the air can hold depends on its temperature; warm air has the capacity to hold more water vapor than cold air. There is almost one-half reduction in the amount of water vapor that the air can hold for every 10 C drop in temperature. Relative humidity (RH) is the amount of water vapor in the air, expressed as the proportion (in percent) of the maximum amount of water vapor it can hold at certain temperature. For example, an air having a relative humidity of 60% at 27 C temperature means that every kilogram of the air contains 60% of the maximum amount of water that it can hold at that temperature . The amount of water vapor in the air ranges from 0.01% by volume at the frigid poles to 5% in the humid tropics. Compared to dry air, moist air has a higher relative humidity with relatively large amounts of water vapor per unit volume of air. The relative humidity affects the opening and closing of the stomata which regulates loss of water from the plant through transpiration as well as photosynthesis. A substantial understanding of this climatic factor is likewise important in plant propagation. Newly collected plant cuttings and bareroot seedlings are protected against dessication by enclosing them in a sealed plastic bag. The propagation chamber and plastic tent are also commonly used in propagating stem and leaf cuttings to ensure a condition with high relative humidity.
Wind Air movement or wind is due to the existence of pressure gradient on a global or local scale caused by differences in heating. On a global scale it consists of the jet stream flow and movement of large air masses. On the local scale only a smaller quantity of air moves. Surface winds are lower and less turbulent at night due to the absence of solar heating. When air that is close to the ground cools, it contracts and the pressure rises; when it warms, it expands and loses pressure. Where both cold and warm air occur in proximity, as over a lake and its adjacent shore, the cold flows to the direction of the warm air or from high to low pressure area to correct the pressure imbalance. This also happens in tropical Asia but in a larger and more complex way, as the monsoon winds. This climatic factor serves as a vector of pollen from one flower to another thus aiding in the process of pollination. It is therefore essential in the development of fruit and seed from wind-pollinated flowers as in many grasses. Moderate winds favor gas exchanges, but strong winds can cause excessive water loss through transpiration as well as lodging or toppling of plants. When transpiration rate exceeds that of water absorption, partial or complete closure of the stomata may ensue which will restrict the diffusion of carbon dioxide into the leaves. As a result, there will be a decrease in the rate of photosynthesis, growth and yield .Each of the above discussed climatic factors has been shown to produce limiting effects on various growth processes. However, the various climatic factors always operate together and interact with each other under natural conditions.
Changing Climatic Trends Increasing concentration of CO2 in the atmosphere Pre-industrial revolution (1789) 280 ppm Present (2004) 380 ppm Expected level (2050) 550 ppm Rising surface temperatures Global Av. Temp. rise (20th century) 0.6 °C Projections for 2100 1.4 to 5.8 °C Changing rainfall patterns
So in what ways is agriculture part of the problem? CO2: pastoral farms emit CO2 – more meat is being consumed in MICs, so more pigs, poultry and cattle are being reared, so more CO2. More machinery powered by fossil fuels are being used as farm production becomes mechanised, e.g. huge combine harvesters Methane: cows in particular give out a lot of methane, but so do rice paddy fields. Other material left to rot will also produce methane Nitrous oxide: results from the breakdown of both organic (manure) and inorganic (oil based) fertilizer.
Projections of IPCC for South Asia Increase in surface temperature will contribute to snowmelt resulting in risk of floods Indus river inflows will decrease by 27% by the year 2050 Land degradation will cause land to shrink from present 0.8 ha per capita to 0.3 by 2010 Areas in mid and high latitudes will experience increase in crop yield whereas in lower latitudes will experience a general decrease, under elevated CO2 conditions
Semi-arid areas Crop models showed that increase in temperature of 0.9 and 1.8°C resulted in reduction in length of wheat growing season by 4 and 8 days respectively At 0.9°C increase in temperature, wheat grain yield increased by 2.5% whereas at 1.8°C increase, the grain yield decreased by 4% The increase in temp. would reduce the productivity of rice crop due to heat stress and reduction in growing season length
Arid areas Crop modeling studies showed a non significant trend in wheat yields under increased temperature scenarios (0.9 °C and 1.8°C) Wheat straw yields were reduced by 7% and 12% with temperature increases of 0.9°C by 2020 and 1.8°C by 2050
Impacts on Food ProductionDue to Increasing Temperatures Shift in spatial crop boundaries will have enormous economic and social impact. e.g. Rice transplantation, Cotton picking etc. Increase/decrease in crop yields Rise in evapotranspiration rates, calling for greater efficiency of water use Shift in timing of developmental stages of pests in Crop-weed-pest relationships
Extreme Weather Events In addition to changing climate, increased variability in weather may occur with consequent frequent extreme events such as heat waves, droughts, wind storms and floods having negative impacts on agriculture
Effect of water supplies Decreased Surface Water Supplies Reduction in yield and quality of crops due to water stress during critical growth stages Shift in cropping patterns Nitrogen volatilization losses from ammonical fertilizers
Due to Change in PrecipitationPattern More dependency on ground water in the face of low precipitation – danger of depletion of aquifer due to injudicious pumping – increased cost of cultivation – soil salinization due to poor quality ground water
b) Increased Water Supplies Potential development of Water logging and Salinity/Sodicity Denitrification losses from ammonical and nitrate based fertilizers Shift in cropping patterns Increased incidence of plant diseases
EFFECT OF CLIMATE CHANGE ON AGRICULTURE Climate change may have beneficial as well as detrimental consequences for agriculture. A warming climate and decreasing soil moisture can also result in increasing need for irrigation. Benefits to agriculture might be offset by an increased likelihood of heat waves, drought, severe thunderstorms and tornadoes. With the virtually certain likelihood of warmer and more frequent hot days and nights, there are projected to be increased insect outbreaks impacting agriculture, forestry and ecosystems. (IPCC )
PAKISTAN AGRICULTURE- STRENGTHS AND CHALLENGES Strong strides made in increasing the production in the past 50 years, mainly due to adoption of HYVs and other technological developments Subsistence agriculture with small land holdings Wide variation in regional productivities Majority still depend on rain-fed agriculture Frequently affected by extreme weather events such as droughts and cyclones Significant proportion of population still reels under poverty, mal-nutrition and chronic hunger
The Agricultural Research Institute (ARI) examined the vulnerability of agricultural production to climate change, with the objective of determining differences in climate factors impacts on agriculture by region and by crop. The study found that increases in temperature (by about 2ºC) reduced potential grain yields in most places. Reductions in yields as a result of climate factors are predicted to be more pronounced for rain fed crops (as opposed to irrigated crops) and under limited water supply situations because there are no coping mechanisms for rainfall variability.
Effect of Climate factor on Soybean According to studies, soybean yields could go up by as much as 50 per cent if the concentration of carbon dioxide in the atmosphere doubles. If this increase in carbon dioxide is accompanied by an increase in temperature, as expected, then soybean yields could actually decrease. If the maximum and minimum temperatures go up by 1°C and 1.5°C respectively, the gain in yield comes down to 35 per cent.
Potential Impact of Climate factor onRice Production in Pakistan Overall, temperature increases are predicted to reduce rice yields. An increase of 2-4ºC is predicted to result in a reduction in yields. Although additional CO2 can benefit crops, this effect was nullified by an increase of temperature.
While temperature rise is what we hear about….It is rainfall change that will have more effect.Those area that become drier will be unable to grow as muchwithout irrigation – and currently, much irrigation practiceis highly wasteful and can bring long-term damage to the soil.Extreme events are another cause of concern – unusuallyheavy storms or unexpectedly long periods withoutprecipitation or unexpected heat-waves.These all give challenges to agriculture that reduced theproduction temporarily – challenges the idea of food security.Then global warming causes icecap and glacier melt thatcreate rising sea levels and loss of good agricultural land tosalt marsh.
What the regional needs are Climate information systems in place (Systems to enhance climate predictability) Water management technologies adopted (Improvements in water collection, drainage, irrigation distribution systems, maximize use of water in livestock production, etc.) Better integrated management of natural resources and production systems (this includes water management, conservation agriculture, crop and pasture rotations, adjustment of planting dates, etc.) Technological innovations to reduce climatic risks (biotechnology innovations to improve drought resistance and pests and disease resistance, invasive species, and improvements in irrigation infrastructure). Institutional innovations with capacity built for early warning systems for climate (improved policy and regulatory frameworks for water management, agricultural and catastrophic risk insurance, etc.). Bottom-up participatory processes for climate change
CONCULSI0N The climate change will have impact on agriculture, and agriculture is the livelihood and most of the Indian population is dependent on it. The country should set up a National Food Security Board, to be headed by the Prime Minister, and establish at least 50 huge modern storages to build stocks of food grains to counter any emergency. He finally stressed the adoption of alternative crops to suit different weather models, a strategy that may help immensely in times of poor monsoon.