TIMETIME AND AND STAGE OF STAGE OF HARVEST AND HARVEST AND HARVESTING HARVESTING TECHNIQUESTECHNIQUES

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AbstractAbstract•Time and stage of harvest of crop play greater role in attaining good crop produce.

•Premature or delayed harvest adversely affects quality and quantity of produce.

•Factors considered for time of harvest are economic part aimed, products utility and post harvest storage.

•All the crops are having certain criteria(physiological maturity and harvest maturity symptoms)for harvesting the produce.

•All over the globe, different method viz., manual and mechanical methods are practiced depending upon the purpose, time and labour availability.

Learning objectives•To learn the criteria for harvesting and maturity symptoms of various crops

•To study the harvesting time, stage, methods and machineries available for harvesting. Nex

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IntroductionIntroduction• Time of crop harvest is one of the most important strategy

influences yield, quality and storage of crop.• Premature or delayed harvest often adversely affects quality of

the produce.• Pre-mature or immature harvest is desirable for certain

products that are preferred juicy and succulent. Produce may become more fibrous and tough or hard if harvested at full maturity, as in the case of pulse crops for vegetable purpose and millets for consumption as fried grain.

• If the crops such as cereals, pulses and oilseeds are left in the field for too long after maturity, the crop will be predisposed to pests and germination is inevitable due to vagaries of weather.

• There are different stages for various crops, which demarked as maturity stages, harvesting in those stages gives high income and good quality produce.

• Farmers are following traditional techniques for harvesting the crops produce, but advancement of science and technology gave way for new innovation and equipments and machineries for harvesting the produces.

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Main BodyMain Body

I. TIME OF HARVESTING II. STAGE OF HARVEST III. METHOD OF HARVESTING

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Time Of HarvestingTime Of Harvesting• Reaping what has been sown is literally known as

harvesting.• Yields are expected to be high in crops .• In order to realize the expected yield, the crop must be

harvested when the economic product is at its optimal quantity and quality.

• Generally, crops are harvested when they are said to be mature.

• Ideal time to harvest depends on a number of factors, including the economic part, utilization of the product and post harvest storage.

Economic part• The economic product could be the grain, root, leaf,

stem or other parts for different crops.• Translocation of the stored food from parts of economic

importance to other parts will reduce the yield of desired products.

• Crops are to be harvested when the desired product is at its maximum quality and quantity. (Cont)..

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Utilization •Economic product may be same, but, it may be desirable to

harvest in fresh or dry.•Maize may be harvested fresh or dry, depending on the

intended use. •Similarly pigeon pea, cowpea, peas etc. •The purpose of growing the crop determines when it is best to

harvest it in order to have the highest quality and quality of the desired product.

Post harvest storage •Harvested produce often requires some form of storage at the

site of production, before disposal.•The produce may deteriorate in such storage if harvested at

improper moisture content.•There must be supplementary drying facilities for drying the

produce to safe moisture content for storage.

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MaturityMaturity

• Crops can be harvested at physiological maturity or at harvest maturity or storage maturity depends on situation or need of produce

Physiological maturity• Crop is considered to be at

physiological maturity when the translocation of photosynthates is stopped to economic part.

• It refers to a developmental stage after which no further increase in drymatter in the economic part.

• In cereals, moisture content of grains is very high during milking stage and it gradually deceases due to accumulation of photosynthates. Next Previous End

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• A steep fall of moisture content from 40% to 20% is an indication of attaining physiological maturity.

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

• At this stage, plant reaches maximum dry weight, increasing production inputs doesn’t produce any gains in yield.

• The grains at this stage are of hard dough consistency.

• If grain is harvested prior to its physiological maturity, it would have low drymatter, poor quality and will shrivel upon drying.

• Various crops have different indicators of maturity .

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Physiological maturity Physiological maturity symptoms of some field symptoms of some field cropscropsRice Golden yellow colour of the grain and senescence of lower

leaves

Wheat Complete loss of green colour from the glumes before

physiological maturity. Centre spikes are used as indicator

grains.

Barley Loss of green colour from the glumes or peduncle

Maize Black layer in the placental region of corn kernels

Sorghum Black layer formation in the placental region of grain

Pearl millet Appearance of bleached peduncle in some varieties

Redgram Green pods turning brown, about 25 days after flowering

Soybean Loss of green colour from leaves

Groundnut Development of black colour in the inner shell of the pod

Pulses Turning of green pods to brown colour

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Harvest MaturityHarvest Maturity• Harvest maturity for a crop is when

the product of interest is at best quality and maximum yield.

• Determining maturity, the highest yield of the produce may be the best indicator followed by the farmers.

• In certain grains, harvesting is done around 25% moisture,

• But, in most cases, harvesting grain crops is at 15 to 18% moisture.

• When the crops are grown for forage, the best time for harvest is when the crop has attained maximum vegetative yield, coupled with high quality.

• It is best to cut cereal crops at ear-heads emerging stage for fodder.

(Cont)

Harvest maturity of sorghum

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•Harvest maturity generally occurs 7-10 days after physiological maturity.

•The important process during this period is loss of moisture from the plants and grains.

•The general symptoms of harvest maturity are yellowing of leaves, drying of grains or pods.

•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.

Storage maturity • When there is no scope or chance for post

harvest drying, the crop is to be harvested at a stage where it can be directly stored.

•For grains, <14% moisture content is advocated.

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Harvest maturity symptoms of Harvest maturity symptoms of some important crops some important crops

Rice Hard and yellow coloured grains, golden yellowing of leaves

Wheat Yellowing of spikelets

Sorghum Yellow coloured ears with hard grains

Pearl millet &

Foxtail millet

Compact ears, upon pressing, hard seeds come out

Finger millet Brown coloured ears with hard grains

Pulses Brown coloured pods with hard seeds inside pods

Groundnut Pods turn dark and dark coloured patches inside the shell. Kernels red

or pink. On pressing the kernels, oil is observed on fingers.

Sugarcane Leaves turn yellow, sucrose content is >10% and brix reading >18%

Tobacco Leaves slightly yellow in color, specks appear on the leaves

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STAGE OF HARVESTSTAGE OF HARVEST

• 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.

• If the harvesting is delayed for the sake of immature pods, mature pods may shatter.

• If harvested earlier, yield is less due to several immature pods.

This problem can be over come by Harvesting pods or ears when 75 %of them are

mature, orPeriodical harvesting or picking of pods, Inducing uniform maturity by spraying paraquat or

sodium salt. (Cont)…

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Criteria for harvesting of cropsCriteria for harvesting of cropsRice 32 days after flowering

Less than 4-9% green grains Milky grains - less than 1% Moisture content of grains - less than

20% 80% of panicles are straw coloured

and grains in lower portion of panicle is in hard dough stage.

Sorghum 40 days after flowering Grain moisture content - less than

28%Pearl millet 28 to 35 days after flowering

Maize Less than 22 to 25% moisture in grain Husk colour turns pale brown 25 to 30 days after tassellilng

Wheat About 15% moisture in grain Grains in hard dough stage

Sugarcane The ratio of brix of top and bottom part of cane must be nearly one

Brix - 18 to 20% Sucrose - >10%

Redgram 35-40 days after flowering 80-85% of pods turn brown

Blackgram and greengram Pods turn brown or black

Cotton Bolls fully opened

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• For deciding harvesting date of fodder crops, some more additional aspects are to be considered.

• They are: toxins present in the crop, nutritive value, purpose of harvest (whether for stall feeding or for storage) and single or multi-cut.

• When toxins are present, they are generally high in early stage. Ex. Durrin, a toxic principle present in sorghum is high up to 30 days after sowing.

• The nutritive value of fodder crop (especially protein content), decreases and fibre content increases with the advancement age of the crop.

• For stall feeding, crops are harvested when protein content is high and also when the fodder is succulent with more leaves at young stage.

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

• Crops with ratooning ability are harvested at periodical intervals, while, others are harvested as a single cut.

• At the time of first cutting, atleast two active leaves have to be left for quick regeneration.

(Cont)…

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GrazingGrazing• Grazing by the animals in pasture is another

method of harvesting of forage crop. Three important methods of grazing are, Continuous Grazing Rotational Grazing Rational Grazing. Continuous Grazing• Continuous grazing is allowing the livestock on the

pasture lands throughout the growing season without any restriction.

• This system of grazing requires less labour and animal performance is good.

• Uneven grazing is the only disadvantage in this system.

• The livestock tend to return to the new growth that is succulent and palatable and don’t feed on more mature material. Next EndPrevious

Rotational Grazing Rotational Grazing • Rotational grazing system is one in which the field

is divided into several sub-units and animals are allowed to graze in sub-units one after another.

• The carrying capacity is 10 to 25%. This also like continuous grazing, but cost on labour and fencing are more.

Rational Grazing• Rational grazing, also known as strip grazing,

represents the most intensive grazing system.• The idea is to provide a day’s ration for the herd

and then to a fresh supply of forage the next day.• This system may provide 15 to 40% yield increase

over the rotational system, but more labour is required in this system.

• Soilage which is cutting grass and stall feeding is not a grazing system, but it is an alternative to grazing. Next Previous End

METHOD OF HARVESTINGMETHOD OF HARVESTING• Different methods of harvesting are followed in different

countries, largely depending on timely labour availability and costs associated with harvesting.

• Manual harvesting is still the major method of harvest in developing countries while mechanized harvesting dominates in developed countries.

Manual Harvesting •Manual harvesting is most common in under-developed and developing countries.•Even in developed countries, certain crops are harvested manually for highest quality and premium price (delicate vegetables and fruits).•Certain crops are handpicked without using any tools.•The sickle, spade and digging rods (crowbars) are the major traditional tools for harvesting and digging.•In manual harvesting, sickle is the most important tool.

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Manual Harvesting • The other tool used for

harvesting is knife especially for harvesting of plants with woody stems.

• In inderminate crop, harvesting is done at intervals as the economic product comes to maturity at different periods.•Pods or fruits are picked at periodical intervals. • Harvestin greengram, blackgram cotton etc., is known as picking and is done at 15 days interval.

• The output is low and the effort required for operation is high.

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Mechanized Mechanized harvesting harvesting • Developing countries

like India, five types of reapers are used.

• They are, tractor side mounted, tractor front mounted, power tiller operated, self propelled walking and self propelled riding types have been developed for harvesting wheat, rice, soybean, finger millet and mustard.

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Combine HarvestingCombine Harvesting

• Combine harvesting of rice, wheat and soybean has been accepted by farmers in regions with labour shortage during harvesting period.

• These are more suitable for custom hire service.

• Animal and tractor drawn potato and groundnut diggers and digger shakers have been developed and commercialized.

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Thrasing EquipmentThrasing Equipment

• Traditionally, this is practiced by bullock trampling, which is arduous and time consuming.

• Later, animal drawn thresher was used.

• These have been gradually replaced by power threshers.

• Multi-crop threshers are ideal for threshing major cereals, oilseeds and pulses. (Cont)…

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• Threshers have been fabricated for separating groundnut pods from the plants.

• Maize shellers and groundnut decorticators of different sizes have been developed and commercialized.

• Good designs of cleaners, graders, driers, decorticators, storage structures, rice mills, dhal mills, oil mills and other processing equipment are commercially available for primary processing, value addition and recycling wastes.

• These equipments help in minimizing losses and maintaining the quality of the produce.

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SummarySummary•Time of crop harvest is most important to get quality produce.•Ideal time to harvest depends on economic part, utilization of the product and post harvest storage of produce.•Crops can be harvested at physiological maturity or at harvest maturity or storage maturity depends on need of produce.•Harvest maturity for a crop is when the product is at best quality and maximum yield.•When there is no scope or chance for post harvest drying, the crop is to be harvested at a stage where it can be directly stored is called storage maturity.

(Cont)…

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Problem in harvesting Problem in harvesting • When harvesting coincides with heavy rain or

cyclones, there will be a problem in harvesting the matured crops.

• The crop may be submerged and the seeds may start germinating on the plant itself.

• These problems are common in monsoon season crops especially rice in south India and can be overcome by growing dormant varieties.

• Most of the rice varieties have few days of dormancy. The other way of saving the crop is by spraying 500 litres / ha of 25% salt solution which hastens maturity by 8 days.

• When the economic product is underground, harvesting is difficult if the soil dries due to lack of rain.

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•Different methods of harvesting are followed in different countries, largely depending on timely labour availability and costs associated with harvesting.•Manual harvesting is most common in under-developed and developing countries.•Developing countries like India, tractor side mounted, tractor front mounted, power tiller operated, self propelled walking and self propelled riding types are used.•Combine harvesting of rice, wheat and soybean has been accepted by farmers in regions with labour shortage during harvesting period.•Multi-crop threshers are ideal for threshing major cereals, oilseeds and pulses.

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AssessmentAssessment• At physiological maturity, transport

ofphotosynthates are stopped to reproductive parts (True/False).

• Black layer formation in the placental region is the physiological maturity symptom of sorghum (True/False).

• Harvest maturity generally occurs one month after physiological maturity (True/False).

• Durrin, a toxic principle present in sorghum is high in early stage of crop (30 days after sowing) (True/False).

• Manual harvesting is still the major method of harvest in developing countries while mechanized harvesting dominates in developed countries (True/False).

• Combine harvesting of rice, wheat and soybean has been accepted by farmers (True/False).

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ReferencesReferences

• Dayanand, T.B. and A. Hosein, 1987. Black layer and grain maturity in grain sorghum. Crop Science, 9: 473-476.

• Hanuff, J.W. and R.D. Wych. 1982. Visual indication of physiological maturity of hard red spring wheat. Crop Science, 22:584-588.

• Reddy, S.R. 2008. Principles of crop production. Kalyani Publisher, Ludhiana.

• Yellamanda Reddy, T. and Sankara Reddi, G.H. 1995. Principles of Agronomy. Kalyani Publisher, Ludhiana.

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