Maturity and Harvesting Point Wise Notes For Competitive exam

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Maturity

• Post-harvest losses are estimated to be about 25 per cent.

• Harvesting cost constitute 20 to 50% of total production cost in different crops.

• Closer row spacing of less than 40 cm helps in increasing the cotton yield, but increases the levels of non-lint material in the harvested produce.

• Removal of entire plants or economic parts after maturity from field is called harvesting.

• Portion of the stem that is left on the field is known as stubble.

• If the crop is harvested early, the produce contains high moisture and more immature grains.

Late harvesting results in shattering of grains, germination even before harvesting during rainy season and breakage during processing.

• Crops can be harvested at physiological maturity or harvest maturity.

• Crop is considered to be at physiological maturity when the translocation of photosynthates is stopped to economic part.

Physiological maturity refers to a developmental stage after which no further increase in dry matter occurs in the economic part

In cereals, moisture content of grains is very high during milking stage and it gradually decreases due to accumulation of photosynthates.

• The moisture content falls steeply from 40 percent to 20 percent which is an indication of attaining physiological maturity.

• At physiological maturity, translocation of carbohydrates is stopped due to formation of abscission layer between rachis and grain.

• The attainment of physiological maturity can be seen from external symptoms like

1) black-layer formation in sorghum and maize

2) loss of green colour from glumes in wheat

3) bleaching of peduncle beneath the ear in some varieties of pearl millet

4) turning of green pods to brown colour in pulses

5) loss of green colour from leaves in soybean

• Black layer formation near sorghum grain attachment coincides with cut-off of assimilate translocation.

• Desiccation is an important harvest management practice to hasten harvest especially for hybrids which stay green even at harvest maturity.

• Increased levels of the stay-green trait in sunflower may result in desiccation becoming a more common harvest management practice.

• Paraquat is applied as a desiccant.

• Harvest maturity generally occurs 7 days after physiological maturity.

• Crop is harvested at physiological maturity when there is need to vacate the field for sowing another crop.

• Under all other situations, it is advisable to follow harvest-maturity.

• As maturity depends on climate, maturity symptoms are good indicators for deciding the time for harvesting

• Harvesting date can also predicted by calculating degree-days.

• Determination of harvesting date is easier for determinate crops and difficult for indeterminate crops.

• At a given time, the indeterminate plants contain flowers, immature and mature pods or fruits.

• In indeterminate crops uniform maturity is induced by spraying paraquat or sodium salt.

• In fodder crops when toxins are present, they are generally high in early stage.

• In sorghum dhurrin is high up to 30 days after sowing.

• In fodder crops, protein content decreases and fibre content increases with the advancement age of the crop.

75% of the nitrogen requirement is used by grasses during vegetative stage.

• Nitrogen content of fodder grasses varies from 2-3% in the initial stages and 0.5-0.75% at flowering.

Protein content is high in fodder grasses during early stages.

• For stall feeding, fodder crop is harvested when protein content is high and also when the fodder is succulent and leafy.

• Harvesting is delayed by a few more days to get more dry matter if the purpose is hay making.

• Good quality silage with long preservative characters is obtained when fodder contains more carbohydrates and less protein at the time of harvest.

• Fodder grasses regenerate well when the stubble is left with at-least two nodes above ground level.

In fodder trees, the stubble height has to be around one metre for convenience in harvesting at subsequent cuts.

Soilage which is cutting grass and stall feeding is not a grazing system, but is an alternative to grazing.

Combine harvester reaps two to nine rows at a time depending on its size and is equipped with 8 to 10 HP engine.

• Losses due to shattering in paddy crop were 2.93% higher during manual harvesting in comparison to combine harvesting.

• Harvesting green gram, blackgram, cotton etc. is known as picking and is done at 15 days interval.

• Problems in harvesting occur especially when it coincides with heavy rain or cyclones.

• Sometimes due to heavy rains or cyclones seeds may start germinate on the plant itself. It can be overcome by growing dormant varieties.

• Most of the rice varieties have few days of dormancy.

• Crops can be saved from heavy rains or cyclones by spraying 500 litres/ha of 25% salt solution which hastens maturity by 8 days.

• Groundnut is harvested by running blade harrows (pedda guntaka) with two pairs of animals.

• Tractor drawn sweep cultivators (with inverted ‘V’ shaped blades) are also used to harvest groundnut.

• Separating fruits or seeds from the plants or ears is called threshing.

• Separating grain or seed from chaff is known as winnowing.

Moisture content of grains at the time of harvesting of crops is 18-20%.

• Moisture content for safe storage of most of the crops is 14%.

• In general 4-5 days of sun-drying is required for different produce to bring the moisture to a safe level.

• In tropical regions, one-day drying under full sunshine throughout the day brings down grain moisture content of rice from 24% to 14%.

Sprouting and moulding of wet grains of rice is overcome by mixing powdered common salt at 5 kg/100 kg grain.

Wet paddy can be stored by mixing with paddy husk for a period of 7 days.

Artificial drying uses steam to dry the produce, but it is expensive.

• Losses due to different pests during storage are estimated to be around 6.5%. Insects – 2.55% Rodents – 2.50% Birds – 0.85% Fungi and microorganisms – 0.68%

• Under storage conditions protein and free amino nitrogen contents decrease in rice and sorghum.

Aflatoxin levels are higher in sorghum than rice.

Quality losses are more in the produce stored in coastal areas compared to inland areas due to higher humidity in coastal areas.

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