This centre was sanctioned during VIIIth Five year plan and started functioning at A.D. Agriculture College & Research Institute, Tamil Nadu Agricultural University, Tiruchirapalli (Tamil Nadu) w.e.f. January 01, 1997. The centre is situated in Agro ecological region 8 ( Eastern Ghats and Tamil Nadu uplands and Deccan plateau, hot semi-arid region) and located at 10045’N Latitude and 78036’E Longitude.
- Groundwater Quality Map of Tamil Nadu was prepared and distributed to stakeholders
- Delineation and Characterization of Salt affected soils using IRS 1B LISS II Data: In Tiruchirappalli district, out of the total geographical area of 4,40,412 ha, 7,362 ha are slightly salt affected (pH 8.2 to 9.0), 10,729 ha are moderately salt affected (pH 9.0 to 9.6) and 64 ha are strongly salt affected (pH >10).
- Reclamation of sodic vertisols in conjunction with soil and water conservation practices under rainfed condition: Raised bed with 405cm/30cm size with FYM / pressmud @12.5 t/ha was found suitable for sunflower under rainfed conditions.
- Sodic soil Reclamation Technology using gypsum: Application of gypsum @ 50 % GR along with green manure @ 6.25 t ha-1 increased the grain yield of rice to a tune of 1674 to 2300 kg / ha at various locations when compared to control. The pH of soil reduced to the level of 8.3 – 8.7 and ESP to the level of 13-20 due application of gypsum from the initial level of 8.7-10.0 and 23-42, respectively.
- Sodic soil Reclamation Technology using Distillery Spent Wash (DSW): The grain yield of rice increased to the tune of 1560 to 2428 kg / ha in various locations due to application of DSW 5 lakh litres ha-1 when compared to control. The pH of the soil reduced to the level of 8.3 – 8.8 and ESP to the level of 14 – 19 % due to application of DSW from the initial level of 8.6 -10.0 and 24 -32, respectively.
- DSW to Reclaim Alkali Water: Feasibility of managing alkali water with distillery spent wash (DSW) has also been demonstrated and found effective to reclaim alkali waters. One litre of DSW in 250 litres of alkali water is sufficient to neutralize RSC of 10 meq/l and could be used to irrigate the sugarcane crop without any adverse effects.
Evaluation of plants for sodicity tolerance:
Crops and varieties
The coarse grained rice variety TRY 1 and fine grained variety ADT 45 tolerates up to an ESP of 26
Green gram variety Pusa Bold tolerates an ESP of 16.
- At higher ESP level of 36, pearlmillet cultivar UCC 17 performed better.
- Up to an ESP of 16, the crops viz., Maize (COH M4), Sunflower (CO 4), Sesame (CO 1), Bhendi (Parbhani Kranti), Cluster bean (Pusa Naubuhar) performed better.
- The threshold ESP for the sunflower variety CO4 and hybrid TCSH1 were 16.5 and 13.0, respectively.
- The ESP at 50% yield reduction for sunflower variety CO4 and hybrid TCSH1 were 37 and 34, respectively
- The threshold ESP for okra varieties were 13.5, 15.5 and 16 for hybrid No10, Arkha anamika and Parbhani kranti, respectively.
- The ESP at 50% yield reduction for okra varieties were 31, 34 and 30 for hybrid No10, Arkha anamika and Parbhani kranti, respectively.
- Threshhold ESP for cotton was fixed at 33 for varieties and 28 for hybrids
- Tamarindus indica, Bambusa bamboo, Lueceana leucocephala, Acacia leaucophloea, and Azardiracta indica are suitable for agroforestry in rainfed sodic soils.
- Evolving planting techniques with amendments for raising tree crops in sodic soils under rainfed condition: i) Pit with auger hole (120 cm) was the best method of planting for establishment and growth of tree species (Neem and Tamarind) under rainfed sodic soil condition; ii) Application of amendments viz., DSW @ 75 ml / kg soil with gypsum @ 25 % GR for neem and DSW @ 150 ml/ kg of soil for tamarind were found to be better for establishment and growth.
- Nutrient management for rice under sodic soil conditions: Addition of urea @ 112.5 kg N/ha with organics like daincha or subabul or FYM or rice husk ash @ 5 t/ha, 15 t /ha and 5 t /ha respectively resulted in higher grain yield in case of rice.
Site Specific Nutrient Management (SSNM) for rice in salt affected soils of Tamil Nadu:
- As per SSNM, the N requirement for a yield target of 6 t / ha was 162 kg/ ha without amendment and 137 kg/ ha with Gypsum and was 30 and 134 kg N ha during I and II year of DSW reclamation, respectively.
- The P requirement as per SSNM approach varied between 25 to 35 kg P2O5 ha for a yield target of 6 t/ ha.
- The K requirement varied between 66 to 76 kg K2O ha for a yield target of 6 t/ ha irrespective of the amendments.
Integrated Farming System suitable for problem soil areas of Tamil Nadu: In comparison with a pure crop programme for 0.40 ha, the IFS programme (0.30 ha for crop and 0.10 ha for poultry and fisheries) has yielded high net returns and BC ratio of 2.36 which is 1.33 higher than the crop alone programme.
Water quality map of Tamil Nadu from existing data base: The water quality map of Tamil Nadu was prepared in 1:250,000 scale. The results indicate that 73.2% of water samples were found to be of good quality, 21.1% moderately saline and 5.7% were saline.
Intensive Investigations on ground water quality of Tamil Nadu:
- Tiruchirapalli district: Of the 597 water samples collected from Tiruchirapalli district, 365 (61%) are good. 90 (15%) marginally saline, 53 (8.8 %) saline, 15 (2.5 %) high SAR saline, 27 (4.5 %) marginally alkali, 41 (6.8 %) alkali and 6 (1%) highly alkali .
- Perambalur District: Among the total samples (680) collected from Perambalur district, the distribution of good, Marginally saline, saline, high SAR saline, marginally alkaline, alkaline and alkaline were 52.4,26.8, 3.2, 0.88, 10.4 and 5.88 per cent respectively.
- Ariyalur district: Among the total samples (835) collected from Ariyalur district, 67.8 % is coming under good quality, 6.35 is marginally saline, 19.9 % is marginally alkaline, 3.54 % is alkaline, and 2.04 % is saline.
- Namakkal district: Among the total samples collected from Namakkal district, 62.3 % is coming under good quality, 27.1 is marginally saline, 6.5 % is marginally alkaline, 1.9 % is alkaline, and 8.5 % is saline.
- Tanjore district: Out of the total samples collected in Tanjore district, 84.2 % is coming under good quality, 2.19 % is marginally saline, 9.3 % is marginally alkaline, 3.6 % is alkaline, 0.46 % is saline and 0.25 % high SAR saline.
- Thiruvarur district: In Thiruvarur district, 83.2 % is coming under good quality, 9.93 % is marginally saline, 3.72 % is marginally alkaline, 1.24 % is alkaline, 0.62 % high SAR saline and 1.24 % highly alkaline.
- Nagapattinam district: In Nagapattinam district, 72.6 % is characterized under good quality, 12.7 % is marginally saline, 7.8 % is saline, 2.9 % is marginally alkaline, 2.9 % is alkaline, and 4 % is high SAR saline.
Scheduling irrigation with alkali water for sugarcane under sodic soil condition using drip irrigation: Drip irrigation with 80% pan evaporation (PE) registered significantly the highest cane yield of 102.96 and 98.84 t/ha respectively for plant and ratoon crops.
Fertigation to sugarcane under drip irrigation using ameliorated alkali water:
- Drip irrigation to sugarcane at 80% PE with gypsum at 50% GR recorded the highest average cane yield of 104.9 t ha-1.
- Drip irrigation to sugarcane saved irrigation water up to 29.5% as compared to furrow irrigation.
- Drip irrigation with gypsum bed treated water in combination with soil application of gypsum @ 50% GR recorded the highest average cane yield of 113.4 t ha-1
- Drip irrigation with gypsum bed treated water in combination with soil application of gypsum @ 50% GR reduced the soil pH and ESP.
Drip irrigation to vegetables in alkali soil using amended alkali water: The soil application of gypsum @ 50 % GR significantly increased the yield of both Okra (12.6 % in 2009 – 10 and 12.8 % in 2010-11) and cluster bean (22.1 % in 2009 – 10 and 20.9 % in 2010-11). Among the irrigation treatments, drip irrigation of spent wash treated water recorded the highest yield in Okra and drip irrigation of gypsum bed treated water recorded highest yield in cluster bean crop.
Conjunctive use of canal and sodic water for rice based cropping systems:
- During shortage or limited supply of canal water, conjunctive use of canal and alkali water in 1:1 cyclic mode for rice and alkali water alone for greengram or vegetables can be recommended for alkaline environment of Cauvery irrigation command area.
- For amending alkali water gypsum bed method proved to be superior.
- Continuous use of alkali water for rice and greengram or vegetables resulted in yield decline of 25% in rice and 37% in greengram and 20% in brinjal with increased ESP of 25-34.
- Greengram (Pusa bold or VBN(GG) 2) or brinjal (Co2) can be recommended as follow-up after rice with alkali water irrigation for higher profitability.
- The change in chemical properties of soil viz., pH and ESP due to use of canal + alkali water was observed to be better than use of alkali water alone for both crops.
Integrated use of distillery effluent and fertilizer for sustaining soil health and yield of sugarcane: Application of inorganic fertilizers omitting K and 25 per cent N and P, in combination with 1.25 lakh litres ha-1 of treated distillery effluent gave higher cane yield as that of NPK combination leading to a saving of K.