MSc

An Investigation was carried out at Cropping Systems Research Centre, Karamana, Thiruvananthapuram to study the fodder production potential of four legumes (cowpea variety CO -5, cowpea variety C-152, cowpea variety Karnataka local and Sesbania rostrata) under three levels of lime (0,125 and 250 kg per hectare) and three levels of phosphorus (0, 30 and 60 kg P2 O5 per hectare) in summer rice fallow. To study the residual effect, a bulk crop of paddy was raised in the first crop season retaining the same layout. The trial was laid out as a split – plot experiment in RBD with three replications.
Application for lime increased the growth attributes like plant height, number of leaves, LAI and number of branches, in all fodder legumes. Various growth parameters were increased due to the application of phosphorus. Combined application of lime and phosphorus improved the growth parameters through the indirect effect of increased availability of nutrients. Combined application of higher levels of lime and phosphorus decreased the nodulation in Sesbania rostrata.
Combined application of 125 kg lime and 60 kg P2 O5 improved the crude protein content. Application of 250 kg lime increased the plant phosphorus content which however decreased with increasing levels of application of phosphorus. Combined application of 125 kg lime and 60 kg P2 O5 resulted in more plant potassium content. Increase in lime levels from O to 125 kg increased calcium content of legumes. Combined application of 125 kg lime and 30 kg P2 O5 produced more magnesium cont3ent in plant than 250 kg lime and 60 kg P2O5 treatment combination.
Available nitrogen content in soil after the experiment increased with the combined application of 250 kg lime and 30 kg P2O5. Combined application of moderate levels of lime and phosphorus resulted in more available phosphorus and potassium contents. Available calcium content of soil increased with increasing level of lime, but magnesium content of soil was found to decrease with the application of 250 kg lime.
Sesbania rostrata and cowpea variety CO – 5 produced taller plants, while Sesbania rostrata followed by cowpea variety C – 152 recorded more number of leaves and LAI. Sesbania rostrata also recorded maximum number of branches, but was poor in nodulation where the combined application of 250 kg lime and 60 kg P2O5 declined the stem nodulation.
Green fodder yield was maximum in cowpea variety C-152, while dry fodder production was maximum in Sesbania rostrata.
Sesbania rostrata recorded highest crude protein, phosphorus, calcium and magnesium contents where as CO-5 had maximum plant potassium content.
Available soil potassium content was lowest under cowpea variety CO-5.
Uptake of nutrients were maximum in Sesbania rostrata and minimum in Karnataka local.
The trial also indicated the suitability of Sesbania rostrata as a fodder crop on account of its higher dry matter production and nutrient content.
Cowpea variety C-152 was found to be more economic as a fodder crop under summer rice fallow conditions.