Success Stories

In-situ Green Manuring in Paddy and Coconut

Background

Paddy and coconut constitutes the major crop cultivated in Kanyakumari District. They occupy a total area of 17,500 (during both the Kharif & Rabi seasons) and 24,000 hectares respectively. In recent years, farmers are practicing excess application of inorganic fertilizers without organics due to its non- availability. Although the SRI is introduced, the farmers are not attaining the targeted yield (8.5 9.0 t/ha) due to the deterioration of soil fertility status. The average yield in the farmers holding is only 4.5 -5.5 t/ha in these soil. The soil is also acidic and therefore mitigating the ill effects by adding suitable organic/inorganic amendment is also not practiced by the farmers. In the case of coconut severe button shedding is noticed due to the decline in soil organic carbon status. The average yield was only 64 nuts/palm/year as against the potential yield of 100 120 nuts/palm/year. The cattle population is also less in the district. In the recent years, farmers started composting of organic wastes, but it is also not sufficient to meet the required quantity of organic manures. The availability of green leaf manure is also less because the green leaf manure trees viz. Thespesia, neem, Pungam were cut down for fuel purpose. Labour scarcity is yet another reason for the limitation in the usage of green leaf manures. Therefore green manuring is the only alternate way.Krishi Vigyan Kendra, Kanyakumari realized the importance of green manuring and so training and demonstrations (FLD) were conducted since 2008.

Interventions

Only few farmers (< 15 %) are applying the soil test based balanced application of fertilizers and most of the farmers are applying fertilizers based on their economic status which resulted in the imbalance in fertilizer schedule. The farmers simply ignore about organic manuring except few farmers are doing organic manuring which are lower than the recommended dosage due to non availability, high cost and labour involved. Due to the decline in the soil organic carbon status and soil health, the yield and quality of these crops were affected. Therefore our KVK intervened to disseminate the technology of insitu-green manuring with Daincha (Sesbania aculeate) and Kolinchi (Tephrosia purpurea).

Details of Technology

The in-situ green manure application by sowing the Kolinchi / Daincha seeds @ 20 kg/ha and incorporation in the soil before first season paddy. Immediately after flowering, the crop was incorporated in to the soil (45 -50 days after sowing).

In the case of coconut, Daincha seeds were sown @ 50g/ basin around the coconut palm coinciding the SouthWest and also Northeast monsoon rains. The crop was incorporated in to the soil immediately after of flowering (45 -50 days after sowing).

Nutrient Content of Green Manures

SlNo

Name of Green Manure

Nutrient Content(%) on Dry Weight Basis

N

P2O2

K2O

1

Tephrosia spp.

2.0

0.7

1.0

2

Daincha

3.5

0.5

1.8

Result

The yield of wet biomass ranged from 4.5 to 5.25 ton/ha. The mean N: P: K content on air dry basis was 1.9, 0.6 and 1.0 % respectively for Kolinchi (Tephrosia purpurea) in paddy fields and 2.9, 0.6 and 1.2 for Daincha (Sesbania aculeate) in coconut fields. This envisaged the increase in the soil organic carbon content from 0.41 to 0.45 per cent. The available status of N, P & K was marginally increased. The in-situ incorporation of Kolinchi (Tephrosia purpurea) improved the vigour of the rice crop due to the presence of alkaloid tephrosin which played significant role in inducing pest and disease resistance of the crop and improved the yield in paddy.

Impact

Horizontal Spread

Apart from the FLD, the technology was transferred to the farmers through trainings, field visits, diagnostic visits & seminars, etc. The farmers Interest groups of paddy and coconut in Thovalai, Agastheeswaram and Kalkulam taluks of the distict which has major area were well trained in this technology. The extension functionaries of the district understood the viability of the technology demonstrated. The farmers demanded to supply the seeds on subsidy from the Govt. officials. They started purchasing the seeds and showed enthusiasm in raising green manure in their fields. The technology has spread to 1000 to 1500 hectares in the district.

Economic Gain

The green manuring increased the yield of paddy and coconut. In paddy, increase in yield was obtained from 4.5 -5.5 t/ha to 4.9 to 6.2 t/ha and in coconut the yield was increased from 64 to 68 nuts/palm/year to 76 to 85 nuts/palm/year. The percent yield increase ranged from 8.9 to 12.7 in paddy and 18.8 to 25 in coconut. The green manure application resulted in additional income of Rs. 4000 to 7000 per hectare in paddy and Rs. 46-96 per palm in coconut.

SlNo

Particulars

Yield of Green Manure

Increase in Yield due to Green Manure

Additional Cost Incurred(Rs.)

Additional Income(Rs.)

BCR

1

Paddy

4.5 to 5.2 (t/ha)

0.4 to 0.7 (t/ha)

2200 to 3200 (Per acre)

4000 to 7000

2.02 to 2.19

2

Coconut

6.5 to 8.6 kg/palm/year

12 to 17 (Nuts/ palm /year)

30 to 40 (Per Palm /year)

46 to 96 (Per palm/year) (Rs. 8/ coconut)

2.13 to 2.4

Because of this high return from in-situ green manuring, the farmers started practicing regularly. The technology is spreading very fast, but the only constraint is the increase in price of green manure seeds in the local market due to high demand.

Employment Generation

Six man days are required for green manuring in coconut and three man days are required for paddy in an area of one acre. Hence an additional employment can be generated.