Class 9 Science
Plants also need various nutrients for growth and development. Deficiency of any nutrient would result in stunted growth of plants. Nutrients are divided into two types, viz. macronutrients and micronutrients.
|Soil||Macronutrients: nitrogen, phosphorus, potassium, calcium, magnesium, sulphur|
|Micronutrients: iron, manganese, boron, zinc, copper, molybdenum, chlorine|
Manure contains large quantities of organic matter and small quantities of nutrients. Manure is made by decomposition of organic waste; like animal excreta and plant waste. Manure can be divided into two types, viz. compost and green manure.
The soil-like material obtained after decomposition of organic waste is called compost. The process by which organic waste is turned into compost is called composting. For this, farmers generally make a pit. Farm waste and animal excreta is dumped into the pit and covered with soil. This is left to decompose. When earthworms are added to hasten the process of composting, the compost is called vermicompost.
Sometimes, a farmer may mulch plants; like hemp or guar; while ploughing the field. The plant gets decomposed in due course of time to produce manure. Such manure is called green manure.
Plant nutrients which are commercially produced in factories are called fertilizers. Fertilizers supply important nutrients; especially nitrogen, phosphorus and potassium.
Artificially supplying water to crops is called irrigation. Agriculture in India is highly dependent on monsoon rains. Hence, farmers often need to supply water to crops through irrigation. Timely irrigation helps in improving farm yield. Wells, canals, rivers and tanks are the main sources of irrigation.
Wells: There are two types of well, viz. dug wells and tube-wells. A dug well allows access to water from water bearing strata. But a tube well allows access to water from deeper strata. Pumps are utilized to lift water from wells. These pumps can be powered by electricity or by diesel engine.
Canals: At many places, a good network of canals has been made to ensure proper water supply to plants. Canals are fed from suitable reservoirs; like rivers or lakes.
River Lift Systems: When it is not possible to supply enough water through normal canal system, then a river lift system is utilized to ensure steady supply. This can happen in areas with uneven topography, or in areas which are far from a water reservoir.
Tanks: Tanks are small storage reservoirs. They intercept and store the run-off of smaller catchment areas.
Rainwater Harvesting: Collection of rainwater for future use is called rainwater harvesting. For this, storage tanks are built either underground or over the ground. Rainwater from rooftops or from drains is channelized to the storage tanks. This helps in ensuring availability of water even during lean season.
Watershed Management: Suitable management of all resources of water to ensure quality of life for plants, animals and human beings in the area is called watershed management. It involves integrated approach of managing all the sources of water; like rivers, rainwater, groundwater, lakes, etc.
Various ways of growing crops can be utilized to maximize farm output. They are as follows:
When two or more crops are simultaneously grown on the same piece of land, it is called mixed cropping. For example; wheat + gram, or wheat + mustard, or groundnut + sunflower are often grown together; under this practice. Mixed cropping ensures better utilization of resources. It also reduces risk and gives some sort of insurance in case of failure of one of the crops.
When two or more crops are grown simultaneously on the same field; in a definite pattern, it is called inter-cropping. Unlike intercropping, no set pattern is followed in mixed cropping. A few rows of one crop alternate with a few rows of another crop. For example; soyabean + maize, or finger millet (bajra) + cowpea (lobia) are grown in this way. Crops with different nutrient requirements are selected for inter-cropping. This helps in better utilization of nutrients. It also helps in preventing spread of pests and diseases to all plants.
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