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CASHEW TECHNOLOGIES DEVELOPED FOR FARMERS FOR ADOPTION

1) High Yielding Varieties of Cashew

A total of 40 cashew varieties have been developed and released in the country for general cultivation. Among them 27 are selections and 13 are hybrids. Twenty one varieties are having kernels with export grade (W 180 – W 240). Among the 40 varieties, 28 varieties are recommended for cultivation since 12 varieties have been withdrawn from multiplication as they have undesirable characters such as small nut size and kernel size.

2) Softwood Grafting Technique in Cashew

Softwood grafting technique had been standardized in the early eightees both at NRC Cashew and AICRP on Cashew. This technique has been commercialized for large scale production of cashew grafts. In India over 60 lakh cashew grafts are being produced annually by this method both by Government and Private Sectors. Over 80 Regional Nurseries as approved by Directorate of Cashewnut and Cocoa Development (Govt. of India), Kochi are existing and producing quality grafts of improved and high yielding cashew varieties.

3) Nutrient Management in Cashew

Recommended fertilizer doses for cashew have been determined to different agro-climatical zones where cashew is grown. If continuously chemical fertilizers are applied to the soil, the soil health is affected. It is desirable to have more than 1.0 organic carbon content in the soil. Experiments were conducted by applying chemical fertilizer alone, organic manures alone and in different combinations of inorganic fertilizers and organic manures. It has been found that farm yard manure or compost of 30 to 35 kg/adult tree or 20 of poultry manure per adult tree along with chemical fertilizers gave best results.

4) Soil and Water Conversation Technique

Terrace with crescent bund treatment is the best soil and water conservation technique for cashew garden grown in flat to medium slopes. The available water during pre-monsoon, monsoon and post monsoon season can be efficiently utilized for higher yields using proper soil and water conservation techniques like terrace with crescent bund coupled with the application of 20 kg poultry manure. The cost involved per tree for this structure is between Rs. 30 - 50.

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5) High Density Planting

The recommended spacing for cashew is presently 7.5m x 7.5m or 8m x 8m. In order to increase the yield per unit area the best option would be to go for high density planting through efficient utilization of space available in the initial years of orchard life. High density planting is more suitable for soils with low fertility. Further, high density planting reduces weed growth due to early ground coverage by the crop canopy and also reduction in soil temperature thereby increase in soil moisture content especially during peak summer season and also through mulching effect.

Regular pruning is needed to contain the canopy. In later years for instance, 11th year after planting, it is necessary to thin out the tree population to 50 per cent by removing every alternate tree in each row.

Cashew yield can be increased by 2 to 3 folds by high density planting as compared to the normal density planting.

6) Intercropping in Cashew Orchard Pineapple can be grown as intercrop in cashew garden profitably for the first 7 years. Both main and intercrop can be planted simultaneously . Normally pineapple can be grown as intercrop in the interspace available between two rows of cashew plants. Here spacing maintained for cashew is 8m x 8m (156 trees/ha) or 7.5 m x 7.5 m (175 trees/ha) or 10 m x 5 m (200 trees/ha). The net return from cashew orchard in the initial years of plantation can be enhanced through growing pineapple as intercrop. Other advantages of growing pineapple in trenches dugout across the slope between two rows of cashew are better soil and water conservation which will have indirect benefit over main crop (cashew) resulting in 1.5 times increase in yield as compared to plot where cashew alone is grown and low weed growth. Pineapple can be grown as intercrop under irrigated as well as unirrigated conditions in west coast region where rainfall received is from 3000 to 3500 mm distributed over a period of five months. Other crops such as Tapioca, Turmeric, Ginger, Cucurbits, Colocasia, Elephant Foot Yam have been found to be suitable intercrops in West Coast region while Colocasia, Brinjal, Groundnut, Blackgram were found to be good intercrops in East Coast region.

7) Vermicomposting of Cashew Biomass

Organic content in the soil is desirable for increasing the cashew yield through better moisture retention of the soil. Cashew is deciduous tree which provides approximately 5 tonnes of cashew biomass fall out (leaves, twigs, flowers and apples) per hectare in a well established cashew orchard. The biomass decomposes gradually thereby steadily releasing nutrients to the soil. Use of

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earthworm for production of vermicompost from cashew biomass is a low cost technology for adoption in the cashew orchard. Further, utilizing earthworms to enhance the decomposition process has multifold benefits such as, providing aeration in the sub-soil, addition of micro-nutrients and enhanced microbial activity. The vermicompost can be incorporated into soil of cashew orchards for boosting production. Percent recovery of vermicompost will be approximately 65 per cent and thus 3.5 tons of vermicompost can be produced per ha of adult cashew garden per year. The cost of vermicompost produced from cashew biomass comes to about Rs. 1.1 per kg. The vermicompost contains important plant nutrients required by cashew and also useful micro organisms.

8) Irrigation and drip irrigation

Cashew is presently being cultivated in various tracts of the country mostly under rainfed conditions. However, trials conducted at his centre by adopting various irrigation methods indicated that nut retention and yield was better in the irrigated plots. Yield can be doubled through providing protective irrigation of 200 litres of water per tree once in 15 days from January to March during the summer season.

Irrigating 80 litres/tree once in four days through drippers from December to March (Total irrigation of 2400 litres / tree/ season) can also increase yield substantially.

9) Fertigation Water soluble fertilizers like Diammonium phosphate, urea and muriate of potash are used for fertigation through drip lines from December to March and application of 2 kg castor cake to soil during August. Fertigation is done once in a week from December to March. With fertigation quantity of nutrients (through fertilizers and organic manure) to be applied can be reduced to half of the quantity of recommended nutrients. Yield can be increased from 1 ton per ha in case of high density planting without irrigation to 2 tons per ha with fertigation of 1/4th of the recommended fertilizer nutrients and remaining 1/4th applied to soil in the form of castor cake.

10) Pruning in Cashew

Majority of the cashew plantations were established without proper training and pruning or canopy management. Such plantations become unmanageable due to erratic branching and uneven spreading of canopy and finally leading into cashew forests. The lower branches die due to shading effect resulting in less number of flowering and fruiting branches per unit canopy area. In order to rejuvenate trees of with low yield heading back by severe pruning can be adopted in order to improve the yield performance provided they are potential yielders. Heading back is to be done after the annual harvest of the crop and

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the trees get ready with a new canopy for flowering and fruiting in the ensuing flowering season. Depending on the variety the flowering on the severely pruned trees takes place either in the same year or next year. However, precaution needs to be taken to monitor each plant for the attack of cashew stem and root borer on the severely pruned trees.

11) Top Working for Rejuvenation of Senile Cashew Orchards

Mostly old cashew plantations are of seedling origin and have become senile. Further, cashew plantations raised from grafts of varieties not recommended for the region also give low yield. Such trees can be rejuvenated by grafting with scion sticks of improved and high yielding varieties on new shoots arising on beheaded stumps. Top worked trees start flowering and fruiting in the very next year after grafting with new vigor. May-June is the right time for beheading and July-August is for grafting. However, precaution needs to be taken to monitor each plant for the attack of cashew stem and root borer on the top worked trees.

12) Management of Tea Mosquito Bug (TMB)

Integrated Pest Management involving resistance and adopting spraying of insecticides is a good package to manage TMB. Mid season/late season flowering cashew varieties such as Bhaskara, are able to escape from the severity of the pest to a certain extent. This Bhaskara variety developed from NRC Cashew was released to coastal region of Karnataka during March 2006.

Among the various insecticides evaluated against this pest, lambda cyhalothrin (0.003%) and carbaryl (0.1%) had shown longest residual action up to one week against nymphs and adults. Need based sprays are recommended during most vulnerable periods of crops such as flushing, flowering and fruiting stage of the crop.

13) Management of Cashew Stem and Root Borer (CSRB) Integrated Pest Management involving chemical insecticides and adopting phytosanitation measures is found very effective in managing CSRB.

Swabbing the pest infested portion after removal of different stages of pest occurring internally and drenching the root zone with chlorpyriphos (0.2%) as post extraction prophylaxis (PEP) was found effective in reducing reinfestation upto 70.7 per cent.

There exists large population of CSRB grubs in dead cashew trees and also in CSRB infested cashew trees. The trees having more than 50 per cent of bark circumference damaged / having yellow canopy are considered as trees beyond recovery. It is essential to adopt phytosanitation by removing the dead

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trees and trees beyond recovery by uprooting during monsoon season, prior to emergence of adult beetles and dispose off suitably without delay to reduce build-up of pest inoculum in a given locality. It has been seen that through phytosanitation, the spread of cashew stem and root borer to healthy trees can be effectively prevented.

14) On-Farm Level Cashewnut Processing

On-farm level cashew nut processing is advantages for getting better return from the cashewnut produced by the farmers. Cashew farmers normally sell their cashewnuts to traders who in turn sell the nuts to the cashew processors. The profit which otherwise would have gone to middle men can be earned by the farmers themselves through processing the cashewnuts by the adoption of on-farm level cashewnut processing units. The firewood based units available in Maharashtra was improved by using LP Gas at NRCC.