Dryland Agriculture an Introduction:-
At present there is a talk about second green revolution. The International Food Policy Research Institute, Washington, opined”with the rising demand for food in coming decades, India will have to depend on the rainfed areas to help increase supply”. India contains about 47 mha as drylands out of 108 mha of total rainfed are which amounts nearly 43 %. The semi arid tracts are not only large but also agriculturally important. In India, such tracts cover 84 districts, spreading over 47 mha which is more than one-third net sown area. But their contribution to total food grain production is about a fifth in the country.
WEATHER: MOST VARIABLE FACTOR IN DRYLAND AREAS
Unfavourable deviated weather from the normally expected one is called aberrant weather. Aberrant weather is a common feature of rainfed agriculture. Crop production in dry areas is mainly dependent upon rainfall, which is received during the south west monsoon. The rainfall is seasonal, erratic and highly variable with space & time. Vagaries of monsoon rains and breaks of varying duration are most common in India. Three important aberrations in the rainfall behavior have been commonly observed. These are:
• The commencement of rains may be quite early or considerably delayed.
• There may be prolonged breaks during the southwest monsoon season during which most of the dryland crops are grown
• Rains may terminate earlier than normal cessation date or may continue beyond the normal rainy season.
Anomalies in the distribution of south west monsoon rainfall are well known. Based on the analysis of historical rainfall records, have brought out the following main features of rainfall distribution in India.
• There is large variation in the dates of commencement of the southwest monsoon rainfall from year to year in different parts of the country.
• The monsoon rainfall is of sequential nature with dry spells interspersed with wet spells, dry spells extending from few days to several weeks.
• There is a large year to year variation in the dates of cessation of south west monsoon rainfall in different parts of country.
• There is variation in the quantum of rainfall received from year to year and t he coefficient of variation of rainfall increases with decrease in monsoon rainfall.
• High intensity rainfall occurs in association with the movement of cyclones/depressions resulting in sizeable loss of rain water through run-off and deep drainage.
Weather is the most variable factor in rainfed crop production. It is the one which can be least controlled. However, various approaches, often referred as contingent plans, have been evolved over the years, for efficient weather management. The infrastructure requirements have to be developed and established by the government and other agencies as people themselves will not be in a position to adopt contingency measures more effectively because of their poor resource base. Some of the management options that can be adopted to mellow down the adverse effects of aberrant weather are discussed here.
CONTINGENCY CROP PLANNING
Contingency planning refers to mitigate any unexpected, unusual, unfavourable and hence unwanted accidental weather situations occurring at any time without prior knowledge at any time before the crops are sown or even after the crops are sown. The contingency crop planning therefore is proposed to mitigate such situation through the choice of appropriate crop and varieties, cropping systems or other necessary relevant farm practices. To develop a contingency plan for an area, a detailed study of the rainfall data should be done first. Based on this rainfall data, the planning should be done. In any areas generally following rainfall situation may occur:
1. Early onset of monsoon.
2. Normal onset of monsoon followed by immediate prolonged dry spell.
3. Delayed onset of monsoon.
4. Early cessation of rains.
5. Extended monsoon.
LATE ONSET OF MONSOON
During some of the years the onset of south west monsoon gets delayed so that the crops/varieties which are regularly grown in the region cannot be sown in time. Delayed sowing of the crops can lead to reduced and even uneconomical crop yields. Under these circumstances, two management options are available.
1. Transplantation-This is the surer way of compensating the delay in the commencement of sowing rains, through transplantation is labour intensive operation. Extensive studies carried out indicated that both long and medium duration varieties of finger millet should be transplanted for maintaining yield levels whenever sowing is delayed.
2. Alternate Crops/Varieties-certain crops/varieties can perform better even if sown late in the season. Depending on the receipt of rains, such crops and varieties can be selected. Castor (Aruna) is more remunerative in red soils of telengana (AP) then pigeonpea under late sown conditions. Sunflower, because of its shorter duration, performs better than groundnut when sowings are delayed beyond September first fortnight in relatively deeper red soils. In western Rajasthan, short duration green gram and cowpea are more remunerative than pearl millet when sown late.
DRY SPELL IMMEDIATELY AFTER SOWING
Dry spells are common in dryland agriculture. Due to dry spell after sowing of crop it might result in poor germination due to soil crusting, withering of seedlings and poor establishment of crop stand. The adverse effect of moisture stress should be mitigated to avoid total crop failure. It is necessary to maintain proper plant stand to ensure better yield. Therefore it is better to resow the crop than to continue with inadequate plant stand.
MID SEASON CORRECTION OR DRY SPELLS DURING CROP PERIOD
After sowing of crops and early growth any unexpected or unfavourable weather abnormality like long dry spell of 3 to 6 weeks, drought or early cessation of monsoon may occur. Unexpected or accidental occurrence of unfavourable weather after sowing is contingency and crop planning to overcome this contingency is called contingency crop planning. To mitigate the damaging effects of droughts after sowing of crop following mid season corrections are recommended:
1. Ratooning-The rate of soil moisture depletion increases with increasing leaf area. If drought occurs at 40- 50 DAS, reduction in leaf area either by rationing or thinning plant population can mitigate the adverse effects of drought. Sorghum and pearl millet responds to rationing. 2 % urea sprays after drought period is useful for indeterminate crops like castor, pigeon pea and groundnut.
2. Mulching-If the break in monsoon is very brief, soil mulching was found to be tool in extending the period of storage of water in the soil profile due to reduced heat load on the soil and hence the evaporation losses which in turn leads to extended periods of water availability. Repeated intercultivations in black soils results in formation of soil mulch on the surface. It acts as barrier to evaporation loss from soil profile. Deep cracks formed due to drought increases the loss of stored water by evaporation. Soil mulch minimizes deep cracking leading to reduced evaporation losses.
3. Thinning-If drought occurs during pre-flowering stage thinning is useful. Every third plant or alternate row may be removed to reduce the soil moisture loss and preserve it. Moisture stress of 35-50 days can be lessened by such thinning.
4. Weed Control-Weed control is very essential to save the crop from onslaught of drought as weeds rob soil moisture and nutrients as well.
5. Rain water harvesting and recycling-In situ water harvesting and / or runoff recycling are the potent measures for crop life saving during the periods of moisture stress. There is no control over the receipt of rainwater but it can be managed in a way better what is being done at present after it is received. Supplementary irrigation provided to the crop through rainwater harvesting and recycling particularly during the grain formation stage will be very much rewarding. Run-off recycling holds immense prospects in deep black soil where the seepage losses are very less. High intensity rains are quite common during the rainy season contributing 75% of seasonal rainfall. The inevitable runoff (10-40% of the total rainfall) could be stored in dugout ponds of appropriate sizes and recycled to the donor area, in the event of severe moisture stress.
6. Stripping of crop leaves- Generally, photosynthesis occurs in the upper 3-4 leaves. Hence excluding these leaves, lower leaves from the plant may be removed to reduce transpirational losses.
7. Intercropping and risk distribution-Application of meteorological information in terms of the frequency and probability of breaks in monsoon rains can be made to select a combination of crops of different durations in such a way that there is time lag in the occurrence of their grow for appropriate intercropping systems. The choice of intercrop depends upon the pattern of rainfall. There are 3 possibilities as:
1. Rainfall more uncertain in the early part of season.
2. Rainfall more uncertain in the later part of season.
3. Rainfall more or less uniformly distributed (in other words, the risk is uniformly distributed).
Region System
Hisar Pearlmillet + Cowpea
Agra Pearlmillet+ greengram
Banglore Pigeonpea + Cowpea
Hyderabad Sorghum + pigeonpea
Akola Sorghum + greengram
EARLY WITHDRAWAL OF MONSOON
Early withdrawal of monsoon before rabi seeding leads to problem of crop stand establishment and terminal drought. Therefore, rabi seeding should be as far as possible in early September to avoid the above two problems. All the suggested measures to mitigate the adverse effect of prolonged dry spells during crop period are necessary to overcome the soil moisture stress during the early withdrawal of monsoon.
EXTENDED MONSOON
Extended monsoon is seldom a problem in dryland agriculture. It benefits long duration kharif crops taken as a component crops in intercropping system and is also advantageous for rabi crops.
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References:
1-Principles & Practices of Dryland Agriculture- K. Govindan & V. Thirumurugan
2-Dryland Agriculture- S.C. Panda
3-Sustainable Development of Dryland Agriculture in India- Editor R.P. Singh
4-Principles of Agronomy-S.R. Reddy
5-Handbook of Agriculture- ICAR publications
Tuesday, April 14, 2009
Determinate And Indeterminate tomato
What is the difference between "determinate" and "indeterminate" tomatoes?
Determinate varieties of tomatoes, also called "bush" tomatoes, are varieties that are bred to grow to a compact height (approx. 4 feet).
They stop growing when fruit sets on the terminal or top bud, ripen their entire crop at or near the same time (usually over a 2 week period), and then die. Once this first flush of fruit has ripened, the plant will begin to diminish in vigor and will set little to no new fruit.
Determinate tomato varieties are often referred to as “bush” tomatoes, because they do not continue growing in size throughout the growing season. They are generally smaller than indeterminate tomatoes, with most growing to a compact 4-5 feet.
They may require a limited amount of caging and/or staking for support, should NOT be pruned or "suckered" as it severely reduces the crop, and will perform relatively well in a container (minimum size of 5-6 gallon).
Indeterminate varieties of tomatoes are also called "vining" tomatoes. They will grow and produce fruit until killed by frost and can reach heights of up to 10 feet although 6 feet is considered the norm. They will bloom, set new fruit and ripen fruit all at the same time throughout the growing season.
They require substantial caging and/or staking for support and pruning and the removal of suckers is practiced by many but is not mandatory. The need for it and advisability of doing it varies from region to region.. Because of the need for substantial support and the size of the plants, indeterminate varieties are not usually recommended as container plants.
Determinate varieties of tomatoes, also called "bush" tomatoes, are varieties that are bred to grow to a compact height (approx. 4 feet).
They stop growing when fruit sets on the terminal or top bud, ripen their entire crop at or near the same time (usually over a 2 week period), and then die. Once this first flush of fruit has ripened, the plant will begin to diminish in vigor and will set little to no new fruit.
Determinate tomato varieties are often referred to as “bush” tomatoes, because they do not continue growing in size throughout the growing season. They are generally smaller than indeterminate tomatoes, with most growing to a compact 4-5 feet.
They may require a limited amount of caging and/or staking for support, should NOT be pruned or "suckered" as it severely reduces the crop, and will perform relatively well in a container (minimum size of 5-6 gallon).
Indeterminate varieties of tomatoes are also called "vining" tomatoes. They will grow and produce fruit until killed by frost and can reach heights of up to 10 feet although 6 feet is considered the norm. They will bloom, set new fruit and ripen fruit all at the same time throughout the growing season.
They require substantial caging and/or staking for support and pruning and the removal of suckers is practiced by many but is not mandatory. The need for it and advisability of doing it varies from region to region.. Because of the need for substantial support and the size of the plants, indeterminate varieties are not usually recommended as container plants.
Importance of Vegetable production
Importance of Vegetable Production
1. Importance in human nutrition
2. Vegetables are important source of farm income
3. Vegetables have aesthetic value
4. Vegetables production for medicinal purpose
5. Roll of vegetables in national economy
6. Flexibility in production programme-unlike the fruits with vegetables the production programme can be adjusted and changed for better profits according to needs. With fruits it is difficult time taking and also expensive to change the production programme if it turns out to be unprofitable.
7. More yield per unit area-vegetables give higher total yield per unit area per unit time than cereals and other crops. The following table compares the yield per hectare of various crops:
Crops Average total yield per hectare in quintals
Wheat 20-25
Rice 25-30
Cauliflower 125-175
Watermelon 200-225
8. More net return per unit area
Crops Net return per hectare
Wheat 1000-1200
Rice 1000-1500
Cauliflower 1600-2200
Chillies 2500-3000
1. Importance in human nutrition
2. Vegetables are important source of farm income
3. Vegetables have aesthetic value
4. Vegetables production for medicinal purpose
5. Roll of vegetables in national economy
6. Flexibility in production programme-unlike the fruits with vegetables the production programme can be adjusted and changed for better profits according to needs. With fruits it is difficult time taking and also expensive to change the production programme if it turns out to be unprofitable.
7. More yield per unit area-vegetables give higher total yield per unit area per unit time than cereals and other crops. The following table compares the yield per hectare of various crops:
Crops Average total yield per hectare in quintals
Wheat 20-25
Rice 25-30
Cauliflower 125-175
Watermelon 200-225
8. More net return per unit area
Crops Net return per hectare
Wheat 1000-1200
Rice 1000-1500
Cauliflower 1600-2200
Chillies 2500-3000
Turmeric Processing Technology
Turmeric processing technology-Botanical name of turmeric is curcutha longa L. It is an important spice which is used for yellow colour and special flavour. Rhizomes of turmeric are often found in violet yellow colour. Central rhizomes are like tubers and small rhizomes like fingers coming out from the central one. It contains 1.8 to 5.4% curcumin due to this it has yellow colour. Some amount of starch and 2.5 to 7.2% oil is also obtained. It is used in the form of spices for colouration and flavour. In this very form it is used in medicine and cosmetic goods manufacturing. There are two types of turmeric produced in central India. One has solid and dark colour and the other long, soft and light colour.
Washing-At first rhizomes are separated after digging out from the soil and these are washed, so that particles of soil, spray residues and unuseful particles attached with the rhizomes are removed. For this rhizomes are kept soaked in water throughout the night. Later on rhizomes are taken out and water is sprayed. This process can be achieved by soaking and spraying equipment. Spraying is done at low pressure and wide angle jet. At the time of washing rhizomes are divided in two parts. First part from middle is called mother rhizomes. The second part of it which is long and thin is called Doctor Rhizome. Mother rhizome is kept for seed while Daughter rhizomes are further processed and sold.
Boiling/Blanching/Cooking:-The next step of processing is boiling or blanching. Traditionally boiling is done in metal or mud pots alongwith ¾ water. Top of the pots are covered with a lid or dry leaves. Boiling process is continued till foams and white foams start coming out. These come out with a special quality of flavour. Rhizomes are tested by pressing with fingers. If rhizomes are soft and inner colour has become yellow instead of red then this process is said to be complete.
By using developed method of boiling or blanching both colour and quality are improved. Time taken is less. In the developed method bulbs are treated with 0.1% Soda (Sodium Carbonate, Sodium bicarbonate or Ammonium Carbonate) and water solution. The time required for this process is 30 minutes to 6 hours. Boiler is used in the developed method which is metal kettle open from the top. Soda solution is filled in it and it is heated from the bottom by electric heater or fuel oil. Perforated frame loaded with turmeric tubers or bulbs are sunk here. Water from all sides of perforations enters inside making turmeric tubers soft. After 30 or 40 minutes bulbs/tubers are taken up and tested alongwith the frame. Cooking at the optimal level is important as overcooking spoils the colour and undercooking renders the product brittle resulting in breakage of rhizomes during drying and polishing. Once the water in the vessel starts boiling it may take 45-60 minutes to complete the cooking. Cooking at optimal level is indicated by the frothing of the liquid and the release of the characteristic turmeric aroma.
Drying -Cooked rhizomes are cooled first and spread slowly in the yard for drying. It takes at least 10 to 15 days for drying in the sun. Tubers are brought up and down in the middle of drying so that all are dried well. Mother rhizome takes comparatively more time while Doctor rhizome dries up quickly. Therefore these are dried separately also. After drying these become hard and solid. Completely dried turmeric holds 6% moisture content.
Polishing-Dried rhizomes are rubbed against ground or below the foot to take out the hard layer over them and small roots are removed. By this process colour of turmeric becomes bright or shining. Later on removed roots, light garbage and thin layerings are cleaned.
Machine is also used for polishing. For this a drum having 0.9m diameter and 0.6m length is used. It is kept horizontally on a shaft and operated by a handle. Average capacity of this machine comes to 32kg per batch. Dry turmeric 32kg approx.is filled and polishing is done at least for 7 minutes. During this period water is also sprinkled which causes improvement in the colour of turmeric.
Manual polishing consists of rubbing the dried turmeric fingers on a hard surface or trampling them under feet wrapped in gunny bags. The improved method is by using hand operated barrel or drum mounted on a central axis, the sides of which are made by expanded metal mesh. When the drum filled with turmeric is rotated, polishing is effected by abrasion of the 3 surface against the mesh as well as by mutual rubbing against each other as they roll inside the drum. The turmeric is also polished in power operated drums.
Colouring-Exporting turmeric is given special colour by mixing yellow so that powder and processed materials can give better look and quality. Cleaning is done by two methods. One is dry colouring and the other wet colouring. In the first process dry powder of yellow colour is sprayed on boiled turmeric and rightly mixed. Powder is known as middle crome. In the wet colouring process its solution is prepared in water which is sprayed on rhizomes and mechanically mixed. After colouring is complete for one week these are dried. Later on these rhizomes are kept in sacks and closed for exporting (Adulteration-Lead chromate is sometimes used to produce a better finish. This should be actively discouraged.)
Grinding or Powder making-Traditionally dried and polished turmeric are cut into pieces and beaten in mortar and pestle. After this is milled or ground with hand operated chakki. Hammer mill is also used for grinding. Powder should be so fine that it passes through 300 micron sieve and nothing is left over the sieve.
Processing of turmeric by traditional method-In India, at various places different methods and equipments are used, but basic method is mentioned below in a process flow sheet.
Turmeric rhizomes
Washing
Boiling/Blanching/Cooking
Drying
Colouring
Grinding/Powdering
Sieving
Packaging
Marketing
Washing-At first rhizomes are separated after digging out from the soil and these are washed, so that particles of soil, spray residues and unuseful particles attached with the rhizomes are removed. For this rhizomes are kept soaked in water throughout the night. Later on rhizomes are taken out and water is sprayed. This process can be achieved by soaking and spraying equipment. Spraying is done at low pressure and wide angle jet. At the time of washing rhizomes are divided in two parts. First part from middle is called mother rhizomes. The second part of it which is long and thin is called Doctor Rhizome. Mother rhizome is kept for seed while Daughter rhizomes are further processed and sold.
Boiling/Blanching/Cooking:-The next step of processing is boiling or blanching. Traditionally boiling is done in metal or mud pots alongwith ¾ water. Top of the pots are covered with a lid or dry leaves. Boiling process is continued till foams and white foams start coming out. These come out with a special quality of flavour. Rhizomes are tested by pressing with fingers. If rhizomes are soft and inner colour has become yellow instead of red then this process is said to be complete.
By using developed method of boiling or blanching both colour and quality are improved. Time taken is less. In the developed method bulbs are treated with 0.1% Soda (Sodium Carbonate, Sodium bicarbonate or Ammonium Carbonate) and water solution. The time required for this process is 30 minutes to 6 hours. Boiler is used in the developed method which is metal kettle open from the top. Soda solution is filled in it and it is heated from the bottom by electric heater or fuel oil. Perforated frame loaded with turmeric tubers or bulbs are sunk here. Water from all sides of perforations enters inside making turmeric tubers soft. After 30 or 40 minutes bulbs/tubers are taken up and tested alongwith the frame. Cooking at the optimal level is important as overcooking spoils the colour and undercooking renders the product brittle resulting in breakage of rhizomes during drying and polishing. Once the water in the vessel starts boiling it may take 45-60 minutes to complete the cooking. Cooking at optimal level is indicated by the frothing of the liquid and the release of the characteristic turmeric aroma.
Drying -Cooked rhizomes are cooled first and spread slowly in the yard for drying. It takes at least 10 to 15 days for drying in the sun. Tubers are brought up and down in the middle of drying so that all are dried well. Mother rhizome takes comparatively more time while Doctor rhizome dries up quickly. Therefore these are dried separately also. After drying these become hard and solid. Completely dried turmeric holds 6% moisture content.
Polishing-Dried rhizomes are rubbed against ground or below the foot to take out the hard layer over them and small roots are removed. By this process colour of turmeric becomes bright or shining. Later on removed roots, light garbage and thin layerings are cleaned.
Machine is also used for polishing. For this a drum having 0.9m diameter and 0.6m length is used. It is kept horizontally on a shaft and operated by a handle. Average capacity of this machine comes to 32kg per batch. Dry turmeric 32kg approx.is filled and polishing is done at least for 7 minutes. During this period water is also sprinkled which causes improvement in the colour of turmeric.
Manual polishing consists of rubbing the dried turmeric fingers on a hard surface or trampling them under feet wrapped in gunny bags. The improved method is by using hand operated barrel or drum mounted on a central axis, the sides of which are made by expanded metal mesh. When the drum filled with turmeric is rotated, polishing is effected by abrasion of the 3 surface against the mesh as well as by mutual rubbing against each other as they roll inside the drum. The turmeric is also polished in power operated drums.
Colouring-Exporting turmeric is given special colour by mixing yellow so that powder and processed materials can give better look and quality. Cleaning is done by two methods. One is dry colouring and the other wet colouring. In the first process dry powder of yellow colour is sprayed on boiled turmeric and rightly mixed. Powder is known as middle crome. In the wet colouring process its solution is prepared in water which is sprayed on rhizomes and mechanically mixed. After colouring is complete for one week these are dried. Later on these rhizomes are kept in sacks and closed for exporting (Adulteration-Lead chromate is sometimes used to produce a better finish. This should be actively discouraged.)
Grinding or Powder making-Traditionally dried and polished turmeric are cut into pieces and beaten in mortar and pestle. After this is milled or ground with hand operated chakki. Hammer mill is also used for grinding. Powder should be so fine that it passes through 300 micron sieve and nothing is left over the sieve.
Processing of turmeric by traditional method-In India, at various places different methods and equipments are used, but basic method is mentioned below in a process flow sheet.
Turmeric rhizomes
Washing
Boiling/Blanching/Cooking
Drying
Colouring
Grinding/Powdering
Sieving
Packaging
Marketing
Ginger Processing
Forms of ginger- Ginger is usually available in three different forms:
• Fresh (green) root ginger
• Preserved ginger in brine or syrup
• Dried ginger spice.
Fresh ginger is usually consumed in the area where it is produced, although it is possible to transport fresh roots internationally. Both mature and immature rhizomes are consumed as a fresh vegetable.
Preserved ginger is only made from immature rhizomes. Most preserved ginger is exported. Hong Kong, China and Australia are the major producers of preserved ginger and dominate the world market.
Making preserved ginger is not simple as it requires a great deal of care and attention to quality. Only the youngest tenderest stems of ginger should be used. It is difficult to compete with the well established Chinese and Australian producers; therefore processors are advised against making this product.
Dried ginger spice is produced from the mature rhizome. As the rhizome matures the flavour and aroma become much stronger. Dried ginger is exported, usually in large pieces which are ground into a spice in the country of destination. Dried ginger can be ground and used directly as a spice and also for the extraction of ginger oil and ginger oleoresin.
This brief outlines the important steps that should be taken pre-harvest and post-harvest to produce dried ginger.
Processing dried ginger-There are two important factors to consider when selecting ginger rhizomes for processing:
a. Stage of maturity at harvest. Ginger rhizomes can be harvested from about 5 months after planting. At this stage they are immature. The roots are tender with a mild flavour and are suitable for fresh consumption or for processing into preserved ginger. After 7 months the rhizomes will become less tender and the flavour will be too strong to use them fresh. They are then only useful for drying. Mature rhizomes for drying are harvested between 8 and 9 months of age when they have a high aroma and flavour. If they are harvested later than this the fibre content will be too high.
b. Native properties of the type grown. Gingers grown in different parts of the world can differ in their native properties such as flavour, aroma and colour and this affects their suitability for processing. This is most important when preparing dried ginger, which needs rhizomes with a strong flavour and aroma. Himachel, Maran, Mananthody and Kuruppampady are good varieties for the preparation of dried ginger. Size of rhizome is an important factor to consider when drying ginger – medium sized rhizomes are the most suitable for drying. Large rhizomes often have a high moisture content which causes problems with drying.
Making dried ginger-Dried ginger is available in a number of different forms – the rhizomes can be left whole or they may be split or sliced into smaller pieces to accelerate drying. Sometimes the rhizomes are killed by peeling or boiling them for 10 to 15 minutes, which causes the rhizomes to become blackened. They have to be whitened (bleached) by treating with lime or sulphurous acid. The only product which is acceptable for the UK market is cleanly peeled dried ginger.
The process for dried ginger:
• The fresh rhizome is harvested at between 8 to 9 months of age.
• The roots and leaves are removed and the rhizomes are washed.
• The rhizomes have to be ‘killed’ or inactivated. This is done by peeling, rough scraping or chopping the rhizome into slices (either lengthwise or across the rhizome). The skin should be peeled off using a wooden scraper made from bamboo to prevent staining the rhizome. Whole unpeeled rhizomes can be killed by boiling in water for 10 minutes.
• After peeling and washing, the rhizomes are soaked for 2-3 hours in clean water then soaked in a solution of 1.5-2.0% lime (calcium oxide) for 6 hours. This produces a lighter coloured (bleached) rhizome. After soaking, the rhizomes are drained.
• The rhizomes are dried. The traditional method is to lay the pieces on clean bamboo mats or on a concrete floor and sun-dry until a final moisture content of 10%. Drying may take anything from 7 to 14 days depending upon the weather conditions. During drying, the rhizomes lose between 60 and 70% in weight.
• In rainy conditions, a mechanical drier such as a tray drier should be used to accelerate the drying process. Sliced ginger pieces take only 5-6 hours to dry when a hot air drier is used. Whole peeled ginger rhizomes take about 16-18 hours to dry in a mechanical drier. It is important to monitor the air flow and temperature during drying. The drying temperature should not exceed 60°C as this causes the rhizome flesh to darken. See the Practical Action Technical Brief on drying for further information on the different types of drier available.
• After drying, the rhizomes are cleaned to remove any dirt, pieces of dried peel and insects. An air separator can be used for large quantities, but at the small scale it is probably not cost effective.
• The dried rhizomes should be packaged into air-tight, moisture proof packaging for storage or export.
• Fresh (green) root ginger
• Preserved ginger in brine or syrup
• Dried ginger spice.
Fresh ginger is usually consumed in the area where it is produced, although it is possible to transport fresh roots internationally. Both mature and immature rhizomes are consumed as a fresh vegetable.
Preserved ginger is only made from immature rhizomes. Most preserved ginger is exported. Hong Kong, China and Australia are the major producers of preserved ginger and dominate the world market.
Making preserved ginger is not simple as it requires a great deal of care and attention to quality. Only the youngest tenderest stems of ginger should be used. It is difficult to compete with the well established Chinese and Australian producers; therefore processors are advised against making this product.
Dried ginger spice is produced from the mature rhizome. As the rhizome matures the flavour and aroma become much stronger. Dried ginger is exported, usually in large pieces which are ground into a spice in the country of destination. Dried ginger can be ground and used directly as a spice and also for the extraction of ginger oil and ginger oleoresin.
This brief outlines the important steps that should be taken pre-harvest and post-harvest to produce dried ginger.
Processing dried ginger-There are two important factors to consider when selecting ginger rhizomes for processing:
a. Stage of maturity at harvest. Ginger rhizomes can be harvested from about 5 months after planting. At this stage they are immature. The roots are tender with a mild flavour and are suitable for fresh consumption or for processing into preserved ginger. After 7 months the rhizomes will become less tender and the flavour will be too strong to use them fresh. They are then only useful for drying. Mature rhizomes for drying are harvested between 8 and 9 months of age when they have a high aroma and flavour. If they are harvested later than this the fibre content will be too high.
b. Native properties of the type grown. Gingers grown in different parts of the world can differ in their native properties such as flavour, aroma and colour and this affects their suitability for processing. This is most important when preparing dried ginger, which needs rhizomes with a strong flavour and aroma. Himachel, Maran, Mananthody and Kuruppampady are good varieties for the preparation of dried ginger. Size of rhizome is an important factor to consider when drying ginger – medium sized rhizomes are the most suitable for drying. Large rhizomes often have a high moisture content which causes problems with drying.
Making dried ginger-Dried ginger is available in a number of different forms – the rhizomes can be left whole or they may be split or sliced into smaller pieces to accelerate drying. Sometimes the rhizomes are killed by peeling or boiling them for 10 to 15 minutes, which causes the rhizomes to become blackened. They have to be whitened (bleached) by treating with lime or sulphurous acid. The only product which is acceptable for the UK market is cleanly peeled dried ginger.
The process for dried ginger:
• The fresh rhizome is harvested at between 8 to 9 months of age.
• The roots and leaves are removed and the rhizomes are washed.
• The rhizomes have to be ‘killed’ or inactivated. This is done by peeling, rough scraping or chopping the rhizome into slices (either lengthwise or across the rhizome). The skin should be peeled off using a wooden scraper made from bamboo to prevent staining the rhizome. Whole unpeeled rhizomes can be killed by boiling in water for 10 minutes.
• After peeling and washing, the rhizomes are soaked for 2-3 hours in clean water then soaked in a solution of 1.5-2.0% lime (calcium oxide) for 6 hours. This produces a lighter coloured (bleached) rhizome. After soaking, the rhizomes are drained.
• The rhizomes are dried. The traditional method is to lay the pieces on clean bamboo mats or on a concrete floor and sun-dry until a final moisture content of 10%. Drying may take anything from 7 to 14 days depending upon the weather conditions. During drying, the rhizomes lose between 60 and 70% in weight.
• In rainy conditions, a mechanical drier such as a tray drier should be used to accelerate the drying process. Sliced ginger pieces take only 5-6 hours to dry when a hot air drier is used. Whole peeled ginger rhizomes take about 16-18 hours to dry in a mechanical drier. It is important to monitor the air flow and temperature during drying. The drying temperature should not exceed 60°C as this causes the rhizome flesh to darken. See the Practical Action Technical Brief on drying for further information on the different types of drier available.
• After drying, the rhizomes are cleaned to remove any dirt, pieces of dried peel and insects. An air separator can be used for large quantities, but at the small scale it is probably not cost effective.
• The dried rhizomes should be packaged into air-tight, moisture proof packaging for storage or export.
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