Maturity and Harvesting-2 Point Wise Notes For Competitive exam


Harvest-maturity symptoms of important crops-

Crop                                  Symptoms
Wheat Yellowing of spikelets
Finger millet Brown coloured ears with hard grains
Groundnut 1) Pods turn dark from light colour

2) Dark coloured patches inside the shell

3) Kernels red to pink

4) On pressing the kernels, oil is observed on fingers

Tobacco 1) Leaves slightly yellow in colour

2) Specks appear on the leaves

Sugarcane 1) Leaves turn yellow

2) Sucrose content more than 10 per cent

3) Brix reading more than 18 per cent

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

• Moisture content of grains for safe storage

Crop Moisture content (%)
Paddy, raw rice 14
Parboiled rice 15
Wheat, barley, maize, sorghum, pearl millet, finger millet and pulses 12
Coriander, chillies, fenugreek 10
Groundnut pods, rapeseed and mustard 6

Respiration of grains increases with increase in temperature.

• In case of bag storage, stacking is done up to 13 bags high.

• The stack should be brought to pyramidal shape.

• During storage of grains, insecticides for spraying should have low mammalian toxicity (malathion and dichlorvos (DDVP)).

• When pest population cannot be controlled by spraying and major pests are more than 2/kg of sample, fumigation is resorted to.

• Generally fumigation is done with aluminium phosphide (2 tablets/tonne of produce) or methyl bromide (3-5 ml/100 kg produce).

Aluminum phosphide tablets absorb moisture from the atmosphere and release phosphine gas.

Panicles of rice, when drenched in rain water, are dipped in five percent sodium chloride (common salt) solution before threshing.

• The grains thus obtained can be stored in ordinary gunny bags for 10 days without drying.

• Wet paddy can be stored for about two months by mixing powdered salt @ 5% to the heap.

• Most of the seeds should not be dried at a temperature above 38 °C.

Storage life of seeds decreases as storage temperature increases.

• Harrington’s thumb-rule states that for every 5 °C increase in storage temperature, the lifespan of seeds decreases by half within a temperature range of 0 to 50 °C

High moisture seeds are more susceptible to damage from high temperature.

• As moisture content increases, rate of seed deterioration increases.

• Harrington’s thumb rule states that for seeds of 5 to 14% moisture content, each 1% reduction in moisture content approximately doubles seed storage life.

• Shortage of fodder occurs during summer in south India and during winter in north India due to very high and low temperatures respectively.

Shortage of irrigation water makes fodder production difficult in summer in south India.

• To overcome this problem, green fodder is stored mainly as hay and silage.

Hay is any forage crop cut before dead ripe stage and dried for storage.

Straw is less nutritious and palatable than hay.

• Good quality hay should be leafy, pliable, green in colour with characteristic pleasant smell and aroma.

• Hay made from mixed herbage of grass and legume is highly nutritious and palatable.

• Hay can be made from any grass or leguminous fodder crop.

Bermuda grass (Cynodon dactylon) is one of the best grasses that are suitable for hay and it is equivalent to timothy grass (Setaria sphacelata) of western countries.

• Grasses suitable for hay making are Anjan grass (Cenchrus ciliaris), Dichanthium annulatum, Echinochloa colonum and Eleusine flagellifera.

Oats, maize and sorghum can also be made into good hay but maize and sorghum are most suitable for silage making.

Legumes are less suitable for hay making though these hays are more more nutritious due to leaf shedding during drying and curing.

Cowpea is less susceptible to leaf shedding, lablab and Pillipesara are moderately susceptible and berseem and shaftal are highly susceptible.

• For most of the grasses, 50% flowering is the most suitable time for harvesting for hay making.

• Leguminous fodder has to be cut at full bloom stage for hay making.

Optimum time of harvesting for hay making in different crops-

Crop Time of harvesting
Grasses, clover, lucerne Early bloom to full bloom
Cereals Soft dough to medium dough stage
Soybean Pod half grown
Cowpea First pod maturity

• Loss of fodder and feeding value is unavoidable in hay making.

• When hay is dried in the open field, a minimum loss of 10% in feeding value occurs.

• Under normal conditions, dry matter loss in the field drying of hay may be 10-25%.

• In wet weather conditions, leaching, bleaching and leaf shedding may account for losses up to 40 to 60%.

Silage is the product formed by the fermentation of green fodder stored under anaerobic conditions.

• Silage can be preserved for 12-18 months.

• The process of making silage is known as ensiling.

• In humid regions, subjected to frequent rains, ensiling is easier than hay making. • Nutrient losses are less in silage making than in hay making.

Maize is the most suitable crop for hay making.

Fodder yield from maize is higher than most of the other crops.

Sorghum and Sudangrass are also well suited for silage.

• A mixture of grass and legume makes good silage.

Forage legumes such as Lucerne, cowpea, sunhemp and pillipesara can also be used for making silage.

• Two types of fermentation processes known as lactic acid and butyric acid fermentation occurs depending on the conditions during silage making

Preservatives are added to the silage to inhibit butyric acid type of fermentation by reducing pH or by the addition of carbohydrates or both.

• Substances such as molasses, cereal grains, citrus pulp etc. act as preservatives by adding carbohydrates to the fodder.

• Sodium metabisulphite @ 400g/100 kg of fodder modifies fermentation process and reduces objectionable odour.

• Characteristics of good silage are

1) Green, fruity with pleasing taste and without moulds, sliminess and objectionable odour

2) Uniform in colour and moisture content

3) pH< 4.5

4) low ammonia content

5) little or no butyric acid

6) 3-13% lactic acid

Dark brown colour of silage indicates excessive heating.

• To obtain good quality silage, the crop has to be harvested at proper stage, moisture content to be 55-75% at the time of ensiling, carbohydrate content high and entry of air avoided.

Silage can be a substitute for green fodder but not equal to it.

Carbohydrates are lost as carbon dioxide and organic acids due to respiration and fermentation.

• Loss of carotene and vitamin C occurs when the temperature during fermentation is high.

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