(a) Terrain, Topography, and Altitude
- dependent on the geo-ecological conditions; terrain, topography, slope and altitude.
- paddy cultivation requires leveled fields, tea plantations perform well in the undulating topography in which water does not remain standing.
- Orchards of coconut are found at low altitudes, preferably closer to the sea level, while the apple orchards in the tropical and sub-tropical conditions perform well above 1500 metres above sea level.
- Cultivation of crops is rarely done 3500 m above sea-level in the tropical and sub-tropical latitudes.
- highly rarified air, low-pressure, low temperature, and shortage of oxygen at high altitudes are the serious impediments not only in the cultivation of crops, but also in keeping dairy cattle.
- soils of high mountainous tracts are generally immature which are also less conducive for agriculture.
- topographical features also affect the distribution of rainfall.
- the windward side gets more rainfall than the leeward side.
- Apart from altitude and aspects of slope, the nature of the surface also affects the agricultural activities.
- gullied land is least conducive for cropping.
- The Chambal ravines in Madhya Pradesh, Rajasthan, and Uttar Pradesh have put over thousands of hectares of good arable land out of agriculture.
- The crops to be grown, their patterns and combinations controlled by the temperature and precipitation conditions.
- each crop has a specific zero temperature below which it can not be grown.
- also an optimal temperature in which the crop is at its greatest vigour.
- For each stage of crop life, i.e. germination, foliation, blossoming or fructification a specific zero and optimum can be observed in temperature.
- The upper limit of temperature for plants growth is 60°C under high temperature conditions, i.e. at over 40°C, crops dry up, if the moisture supply is inadequate.
- In contrast to this, the chilling and freezing temperatures have a great adverse effect on the germination, growth and ripening of crops.
- Crops like rice, sugarcane, jute, cotton, chilli and tomatoes are killed or damaged at the occurrence of frost.
- minimum temperature for wheat and barley is 5°C, maize 10°C, and rice 20°C.
- impact of temperature on cropping patterns may be seen from the fact that the northern limit of the regions in which date-palm bear ripe fruit coincides almost exactly with the mean annual temperature of 19°C.
- essential factor in the limit of grape orchards seem to be temperature. Grapes ripen only in those countries in which the mean temperature from April to October exceeds 15° C.
- Crops like winter-wheat and barley perform well when the mean daily temperature ranges between 15°C and 25°C.
- tropical crops like cocoa, coffee, spices, squash, rubber and tobacco require over 18° C temperature even in the coldest months, while crops like wheat, gram, peas, lentil, potato, mustard, and rapeseed require a temperature of about 20°C during the growth and development, stage and relatively higher (over 25°C) during the sowing and harvesting periods.
- All crops need moisture.
- Take water and moisture from the soil.
- Available from the rains or from irrigation systems.
- Within wide temperature limits, moisture is more important than any other climatic factor in crop production.
- There are optimal moisture conditions for crop development just as there are optimal temperature conditions.
- Excessive amount of water in the soil alters various chemical and biological processes, limiting the amount of oxygen and increasing the formation of compounds that are toxic to plant roots.
- Excess of water in the soil, therefore, leads to stunted growth of plants.
- The problem of inadequate oxygen in the soil can be solved by drainage practices in an ill-drained tract. Heavy rainfall may directly damage plants or interfere with flowering and pollination.
- Cereal crops are often lodged by rain and this makes harvest difficult and promotes spoilage and diseases.
- Heavy rainfall at the maturity of wheat, gram, millets, oilseeds, and mustards cause loss of grains and fodder.
- Indian farmers all over the country have often suffered on account of failure of rains or fury of floods.
- Devastating consequences on the crops, their yields and production.
- Soil drought has been described as a condition in which the amount of water needed for transpiration and direct evaporation exceeds the amount of water available in the soil.
- Damages the crops when plants are inadequately supplied with moisture from the soil.
- drought prone areas of India lie in the states of Rajasthan, Gujarat, Madhya Pradesh, Chhattisgarh, Jharkhand, Maharashtra, Andhra Pradesh, Karnataka, Tamil Nadu, Orissa, Bundelkhand (U.P.), Uttarakhand, H.P.J&K, south-west Punjab and Haryana.
- Where the average annual rainfall is less than 75 cm, agriculture is considered a gamble on monsoon.
- The incidence of drought and its intensity can be determined from the annual, seasonal and diurnal distribution of rainfall.
- drought prone areas of India, dry farming is practiced, while in the more rainfall recording regions, intensive agriculture of paddy crop is a common practice.
- Occurrence of snow reduces the ground temperature which hinders the germination and growth of crops.
- Land under snow cannot be prepared for sowing because of permafrost.
- Melting of snow may cause hazardous floods in the summer season, affecting the crops, livestock, and land property adversely.
- Have both, direct and indirect effects on crops.
- Direct winds result in the breaking of plant structure, dislodging of cereals, fodder and cash crops and shattering of seed-heads.
- Fruit and nut crops may be stripped from the trees in high winds.
- Small plants are sometimes completely covered by wind-blown dust or sand.
- The indirect effect of winds are in the form of transport of moisture and heat in the air.
- Important determining physical factor.
- Determines the cropping patterns, their associations and production.
- Fertility of soil, its texture, structure and humus contents have a direct bearing on crops and their productivity.
- The alluvial soils are considered to be good for wheat, barley, gram, oilseeds, pulses, and sugarcane; while the clayey loam gives good crop of rice.
- Regur soil is known for cotton, and sandy soil for bajra, guar, pulses (green-gram, black-gram, red-gram, etc.).
- The saline and alkaline soils are useless from the agricultural point of view unless they are reclaimed by chemical fertilisers and biological manures and fertilisers.
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