Effect of Drip Fertigation on Growth, Yield Attributes and Yield of Cotton

, during rabi 2010 - 2011 to study the effect of drip fertigation on growth, yield attributes and yield of cotton. In this study, growth parameters such as plant height, leaf area index (LAI), sympodial branches, dry mater production, root length, root dry weight were found to be enhanced by drip irrigation at 100 per cent Pan Evaporation (PE) along with 100 per cent drip fertigation (Recommended Dose of Fertilizer(RDF) as Water Soluble Fertilizer (WSF)). This combination of drip irrigation 100 per cent PE with drip fertigation 100 per cent RDF as WSF also increased yield attributes such as number of bolls plant -1 , boll weight and seed cotton yield.

hybrid RCH -2 (BG II) was used.The main plot treatments consisted of two drip irrigation regimes viz., 75 per cent Pan Evaporation (PE) (I 1 ) and 100 per cent PE (I 2 ).The subplot treatments consisted of six fertigation levels viz., 75 per cent Recommended Dose of Fertilizer (RDF) as commercial fertilizers (F 1 ), 100 per cent RDF as commercial fertilizers (F 2 ), 125 per cent RDF as commercial fertilizers (F 3 ), 50 per cent RDF as WSF (F 4 ), 75 per cent RDF as WSF (F 5 ) and 100 per cent RDF as WSF (F 6 ).The RDF level was 150:75:75 kg NPK/ha.The growth parameters, yield attributes and yield were recorded and statistically analyzed.

Growth parameters
Growth parameters such as plant height, leaf area index, leaf water content, and dry matter production were influenced by irrigation regimes and fertigation levels (Table 1).
The plant height recorded under drip irrigation at 100 per cent PE with drip fertigation of 100 per cent RDF as WSF (I 2 F 6 ) was 92.6 cm at 120 DAS.The increased plant height under this treatment was mainly due to the continuous availability of the required quantity of water along with the required nutrients.This was in conformity with the findings of Sankar et al. (2007).The treatment combination of drip irrigation at 100 per cent PE with drip fertigation of 100 per cent RDF as WSF (I 2 F 6 ) was more effective in increasing the LAI (3.51 at 60 DAS).Increased proliferation of roots resulting in quick canopy growth might have enhanced higher production and translocation of photosynthates from source to sink (Veeraputhiran, 2000).The same treatment combination has also registered higher RLWC of 88.0 per cent at 90 DAS.Drip irrigation, because of favourable moisture supply, recorded the higher value of stomata conductance and transpiration rates, which led to increase in LAI (Sammis and Wilkam, 1986).
The higher dry matter production was recorded under drip fertigation of 100 per cent PE with drip fertigation of 100 per cent RDF as WSF (I 2 F 6 ) (5089 kg at harvest).Fertilizers applied through drip irrigation as water soluble fertilizers in desired split doses throughout the crop growing period, according to its requirements, might have enhanced availability of nutrients by the continuous supply of nutrients up to 120 DAS.This might have reflected on the plant growth rate and higher DMP.These results are also in agreement with the findings of Shanmugam et al. (2007).

Yield attributes
Yield attributes such as number of sympodial branches, number of bolls and boll weight were influenced by irrigation regimes and fertigation levels (Table 2).Higher number of sympodial branches were recorded under drip irrigation of 100 per cent PE with 100 per cent RDF as WSF through drip fertigation (I 2 F 6 ) (36.0 at harvest).The higher number of bolls were recorded under drip irrigation at 100 per cent PE with drip fertigation of 100 per cent RDF as WSF (I 2 F 6 ) which recorded 40.0 bolls plant -1 .The higher boll weight of 6.0 g was recorded under drip irrigation at 100 per cent PE with drip fertigation of 100 per cent RDF as WSF.This might be due to the fact that the adequate nutrients supplied from these treatments had created more conducive environment for the roots to absorb the nutrients more effectively, when compared to drip fertigation of 100 per cent RDF as commercial fertilizers.The growth parameters were also higher under this treatment, which might have contributed to higher yield.This might also be due to more photosynthesis, ultimately increase in dry matter with an increase in the amount of fertilizer level.This sort of favourable effect of higher NPK dose on yield attributes was also noted by Halemani et al. (2004).Thind et al. (2011) reported that application of drip irrigation resulted in an average increase of 5 per cent in seed cotton yield as compared to checkbasin.

Seed cotton yield
Combined effect of drip irrigation at 100 per cent PE with 100 per cent RDF as WSF (I 2 F 6 ) registered higher seed cotton yield of 2381 kg ha -1 .This was followed by drip irrigation at 75 per cent PE with 100 per cent RDF as WSF (I 1 F 6 ), which recorded 2172 kg ha -1 of seed cotton yield.(Table 2).
The increase in cotton yield with drip irrigation at 100 per cent PE were mainly attributed to greater and consistent availability of soil moisture and nutrients, resulting in better crop growth, yield components which ultimately, reflected on the seed cotton yield.Increased yield might be due to application of water soluble fertilizer, which favoured uptake of nutrients associated with increased growth and yield attributes.Similar results were expressed by Janat and Somi (2001).

Conclusion
Among the irrigation regimes, drip irrigation at 100 per cent PE recorded higher growth rate and yield attributes. Drip fertigation of 100 per cent RDF as WSF (I 2 F 6 ) recorded higher yield and yield attributes.Hence, based on this study, it could be concluded that drip irrigation of 100 per cent PE with fertigation of 100 per cent RDF as WSF (I 2 F 6 ) would be an ideal practice to achieve higher productivity in hybrid cotton.