Suitable area for cashew cultivation
Whether cashew can be grown in maidan regions like Hassan and Tiptur?
Cashew can be grown in maidan tracts like Hassan and Tiptur where the soil type is red sandy loam or red loam or black mixed red clay. Soil fertility and texture and water holding capacity of these soils is better than the soils of west coast region which is the traditional cashew growing area. Irrigation once in 15 days (@200 litres/tree) during peak summer season is highly beneficial in these areas. During winter season, heavy dew fall in the morning and extreme dry condition in the afternoon causes nut dropping. This could be avoided by irrigating the crop and growing tall windbreak tree species all along the border of the cashew orchard.
Whether cashew can be grown on hill slopes?
Cashew can be grown on hill slopes if soil and water conservation measures are taken up right from the beginning. Planting of cashew grafts should be taken up across the slope. Terracing (2m radius) should be done around each plant preferably from the first year onwards by cutting soil from the upper portion of the slope and filling the lower portion so that soil around the plant is flattened. A catch pit of 2 m length, 30 cm width and 45 cm depth should be opened on the upper side of the terrace. Catch pit will trap the water from the slope of hillock, store it and allow it slowly to infiltrate into the soil. Top soil eroded from the exposed portion of hillock also gets trapped in the catch pit.
Why some trees grow robust while others are not?
This may be due to differences in depth of soil (in some place hard laterite patch may be present) or difference in soil fertility or the plantation must have been established with seedlings. If plantations are established with grafted plants, this type of variation is minimum.
Soil and Water Conservation in Cashew Orchards
Whether the yield of cashew increases if light soil working is done around the base of tree? does it improve infiltration?
Yes. It improves. Digging basal area of the plant up to 2 m radius increases infiltration capacity of the soil during initial 3 years of planting. It is advisable to apply thick mulch
immediately after digging to prevent soil erosion due to rains. Besides preventing soil erosion, it helps in retaining soil moisture. These mulches after decomposing serve as organic manure.
How to conserve water in plain lands?
A circular trench (30 cm width and 50 cm depth) should be dug around the plant at a distance of 2 m from the base of cashew plant. This will help in harvesting rain water and enable it to infiltrate gradually. This also prevents surface run off of rain water besides trapping eroded top soil. The circular trench should be filled with dried leaves which will gradually decompose and recycle the nutrients.
Please explain method of coconut husk burial in cashew garden?
Around the plant:- Coconut husk can be buried in circular trench around the plants in layers with a layer of soil between every two layers of husk. The first layer is laid with the convex surface of the husk touching the ground. After spreading a layer of soil on the husks, the second layer of husks is laid in the same position. Thus, three to four layers of husks can be laid in a circular trench of 50 cm depth and 30 cm width. The last layer of husk should be laid with the convex surface facing upwards and covered with soil of 10 cm thickness. About
110-120 husks are needed for this method of husk burial around each plant.
In between two rows:- A rectangular trench of 1 m width (across the slope) and of any convenient length with a depth of 0.5 m should be dug between two rows. Coconut husks should be laid layer by layer with a layer of soil in between in the same fashion as explained above. The last layer should be covered with soil up to 10 cm thickness. About 100 coconut husks are needed to bury in a trench of 3.5 m length. The coconut husk buried will enhance moisture retention of soil and make the same available to the plants during flowering and fruiting, thereby reducing fruit drop. The studies conducted at the Directorate of Cashew Research, Puttur showed that moisture retention was more when soil and water conservation measures were adopted.
Irrigation of Cashew Orchards
Whether cashew grafts need to be watered during first year of planting and later?
In the west coast region, if planting is done with the onset of monsoon in June or in August watering is not required. In east coast planting is done when it rains and if a long dry spell is expected between two rains it is necessary to give protective irrigations. Once the tree starts producing nuts, irrigating @200 litres/tree once in 15 days during the period from January to March is beneficial for cashew which results in doubling of the yield.
Whether drip irrigation is feasible in cashew?
Yes. It is feasible. Drip irrigation improves nut retention which leads to increased production. Normally, drip irrigation of 60-80 litres of water/tree can be given once in four days from second fort night of December to end of March in west coast region. In east coast region, it can be given during dry periods at the time of flowering, nut setting and nut development.
Why some of the grafts planted during monsoon wilt after few months?
Cashew is generally planted under rainfed conditions during monsoon season (June- September). The following may be reasons for wilting of plants in the first year of planting:
The grafts must have been planted during the fag end of the rainy season (after September) or the mulching of the plants must not have been done at the time of planting, resulting in less soil moisture. Futher, Lack of moisture in the soil, during summer months (March-April), particularly in the slopy lands may cause this wilting. Hence, the plants should be watered if wilting is observed in the field.
Manures and Fertilizers for Cashew
Chemical fertilizers if used, will have adverse effect on earthworm. Is it true?
Fertilizer is applied to the cashew tree in circular trenches of 25 cm width at 1.5 m away from the base. Earthworm activity may be affected only in this area. This is very limited compared to the total ground area below the tree where earthworm activity will not be affected. In general, earthworm activity in cashew is observed during monsoon from June to August where sufficient moisture in soil is available. With depletion in soil moisture content, earthworm activity will also get reduced. Fertilizer application is normally done during last week of August or first fortnight of September during which period soil moisture content just starts depleting and sufficient only for the effective absorption of the fertilizers applied. Here the reduction in earthworm activity is not due to fertilizer application, but due to depletion of soil moisture.
What are the precautions to be taken while applying fertilizers?
The following points to be considered while applying fertilizers:
- Sufficient soil moisture should be available at the time of fertilizer application
- Direct contact of fertilizers with roots should be avoided.
- Damage to roots should be minimum while opening trenches for fertilizer application
- Weeds should be uprooted before application of fertilizers at the base of the cashew plant.
- Thin layer of soil has to be applied and mulching with green leaves should be done after fertilizer application
What is Japanese method of composting of cashew leaves?
From a cashew tree 15-20 kg of matured leaves fall into the ground every year. These leaves, cashew apple and other weeds available in cashew orchard can be utilized for the preparation of compost by Japanese method. Select site of about 1.5 width and of any
convenient length for this purpose. By using coconut fronds, construct shed with open top to a height of 1.5 m. Spread cashew leaves, apples and other leaves, layer wise and cover it by cowdung slurry. About 2 kg of cowdung should be added to cashew leaf layer of 1 m length stacked to a height of 0.3 m. Stacking should be done in 4-5 layers and the top layer should be covered with soil. The micro organisms present in cowdung help in faster decomposition. It is necessary to add mixture of rock phosphate and ash to increase phosphorus and potash content. Turn the entire content upside down once in a month. During summer, sprinkle water once in fifteen days. During heavy rainy months cover with thick layer of leaves. By the end of rainy season (Sep-Oct) one can expect good compost which can be used for incorporation into the soil for improving the fertility.
Can organic manure be used for cashew?
It was observed that application of poultry manure along with 500 g N, 125 g P2O5 and 125g K2O/tree/year gave 235 per cent yield increase over control where no organic manure and inorganic fertilizers were applied and 150 per cent yield increase over that plot receiving 500 g N, 125 g P2O5 and 125g K2O/tree as inorganic fertilizers alone. Application of poultry manure alone was not sufficient to get better yield.
Whether vermicompost can be prepared from leaves/apple available in cashew orchards?
The recyclable biomass (leaves, apple etc) available in cashew orchards can be utilized for the preparation of vermicompost. The biomass after treating with cowdung slurry (15% of biomass by weight) is to be decomposed for 20 days and fed to earthworms (Eudrilus sp.). Within five months, from one ton of partially decomposed cashew leaves and apples 0.35 ton of vermicompst can be prepared. This vermicompost is rich in all the major and minor nutrients required for cashew.
Is there any adverse effect if cashew apple is applied around the plant at the base
There is no adverse effect, if cashew apples are applied around the base of the tree. This will enrich the soil nutrients, which are absorbed by the roots of cashew.
Training and Pruning of Cashew
How to give a good shape to the cashew tree when many branches extend at the base of the trunk?
Proper shaping of cashew tree can be done if shape pruning (skirting) and general pruning is done right from the time of planting. If proper shape pruning is not done initially, selective pruning of lower branches, which are unproductive due to over shading, are to be pruned. Immediately after pruning, Bordeaux paste(10%) has to be applied on the cut surfaces.
Whether the cashew trees should be detopped to check the growth? Will this affect yield?
Generally cashew does not grow very tall. Cashew may grow taller due to either close planting or shade effect from the neighbouring tall growing forest tree species on the border or within the cashew garden itself. If cashew grows tall beyond 4 m height without much spread, branch extending 4 m height can be pruned once or twice only. Due to one or two prunings (beheading) of only straight growing main stem, the yield will not reduce significantly.
Intercropping in Cashew Orchards
Whether pineapple can be grown as intercrop in cashew orchards?
Pineapple can be grown in trenches across the slope for the first five years after planting cashew. It is grown in three trenches (spaced 1.0 m apart) between every two rows of cashew planted at a spacing of 8 m x 8 m. The trenches should be 120 cm wide,45 cm deep and of any convenient length. In each trench, two rows of pineapple suckers should be planted 30 cm apart from one another within each row. Generally, 15,000 suckers can be accommodated in one ha. A net profit of 70-80 thousands can be realized from one ha during first five years. Besides this an increase of 30% yield was observed in the plot intercropped with pineapple over the five years in a study conducted at the Directorate. Mean soil moisture content at 0-75 cm depth was also significantly higher as compared to that in check plot( without pineapple).
High Density Planting of Cashew
What is high density planting of cashew?
For high density plating, land with low fertility status where growth of cashew tree is very slow is ideal. For complete ground coverage in the case of plantation raised at a spacing of 8 m x 8 m(156 trees/ha), it requires twelve years. When high density planting is taken up at a spacing of 4 m x 4 m(625 trees/ha) 7-8 years are enough for complete ground coverage. Yield starts declining afterwards as the branches of one tree touch those of others. The branches are to be cut at tip to a length of about 0.5 m to avoid this which facilitate in receiving of about 80 per cent sun light onto the canopy and remaining 20 per cent on to the ground. After 11 years every alternate tree in a row should be uprooted which results in uniform economic yield afterwards. After removing the alternate trees in a row, 312 trees will be left in one hectare. The other spacings normally recommended for high density planting are 5 m x 5 m (400 trees/ha) and 6 m x 6 m (416 trees/ha) in medium fertile soils.
More number of trees per unit area can be planted if the canopy is small. whether such varieties with small canopy can be evolved?
Cashew types with small and compact canopy (semi-tall) are available but the nut size in them is very small. Research is in progress to evolve high yielding cashew varieties having small and compact canopy with medium-bold sized nuts suitable for high density planting.
Cashew with other Plantation Crops
Whether cashew can be grown as an intercrop in coconut garden?
Cashew can be grown as an intercrop with coconut in hill tops but not in valleys. If coconut is grown in hillocks where sunlight is available throughout the day, cashew can be grown as intercrop outside the border rows of coconut as well as inside the few border rows of coconut. Here spacing for coconut palms should be above 7.5 m between rows and between two plants within the row. One cashew plant in the middle of four coconut palms can be planted.
If coconut is grown in valley regions cashew cannot be grown as intercrop. Here sunlight during morning as well as evening is restricted to hardly few hours due to morning and evening shades. In such situations cashew suffers due to lack of sufficient sunlight and produces less flowers and sets minimum nuts.
Cashew orchard is covered by rubber plantation all around. Whether this has got any deleterious effect on cashew?
Presence of rubber plantation nearby cashew orchard may have deleterious effect on cashew crop as rubber plants grow much taller than cashew. Performance of cashew however, depends on how much light in a day cashew tree gets. If both morning and afternoon sunlight is available, performance of cashew will not be affected. It also depends on area of cashew plantation and if area of cashew is more than area of surrounding rubber plantations, performance of cashew will not be affected adversely.
Life of Cashew Orchard
The life of a grafted tree is short, why?
This is not true. A grafted plant can survive for more than 20 years. the cashew orchards are established with grafts by providing a spacing of 7.5 m X 7.5 m or 8 m X 8 m which is sufficient for about 20-25 years.