A field experiment was conducted to investigate the relative performance and effects of legume intercropping system on productivity of little millet with two different row ratios under rainfed condition during the kharif seasons
(2016-17), with a sequential cropping during rabi
season at Centre of Excellence in Millets, Athiyandal, Tiruvannamalai District of Tamil Nadu using randomized block design with ten treatments of sole crops. The intercropping system treatments are., T1 -
Little millet sole crop - Horsegram, T2
- Little millet sole crop - Mothbean, T3
- Little millet + Pigeonpea (4:1) -Horsegram, T4
- Little millet + Pigeonpea (4:1) - Mothbean, T5
- Little millet + Pigeonpea (6:1) - Horsegram, T6
- Little millet + Pigeonpea (6:1) - Mothbean, T7
- Little millet + Lablab (4:1) - Horsegram, T8
- Little millet + Lablab (4:1) - Mothbean, T9
- Little millet + Lablab (6:1) - Horsegram and T10
- Little millet + Lablab (6:1) - Mothbean. The treatments were replicated thrice and sown in replacement series. The little millet variety Co (Samai) 4, was sown with Pigeonpea (Co (Rg) 7), lablab (Co 13) followed by sequential crops of horsegram (Paiyur 2) and moth bean (TMV (Mb) 1). Economic benefits like net returns and B:C ratio was calculated according to market price of each crop.
Indices for evaluation of cropping system
The cropping system approach is a holistic management of variant and invariant resources to optimize the food production. Various indices are used to assess and evaluate the efficiency and sustainability of the systems. These indices are generally computed from the data collected by traditional survey methods.
For comparison between treatments, the yields of all intercrops were converted into little millet equivalent yield on price basis. Grain equivalent yield (GEY) is used to convert the yield of different crops is to one unit.
Land equivalent ratio (LER) is the relative size of land under a sole crop system which will be necessary for obtaining the same yield as in intercropping system.
Yaa and Ybb - Yield of ‘a’ and ‘b’ in sole crop situation.
Yab and Yba - Yield of ‘a’ and ‘b’ in intercropping situation.
Relative crowding coefficient (RCC) indicates whether a crop, when grown in mixed population, has produced more or less yield than expected in pure stand (RCC>1 = Intercropping system is advantageous).
Zab- Sown proportion of ‘a’ in combination with ‘b’.
Zba- Sown proportion of ‘b’ in combination with ‘a’.
Aggressivity gives a simple measure of how much relative yield increase in component ‘a’ is greater than that for component ‘b’.
The competitive ratio was calculated using the following formula.
LERa - Land equivalent ratio of ‘a’.
LERb - Land equivalent ratio of ‘b’.
Relative net return index (RNRI) is an important function to find the profitability in intercropping system and it is calculated by the formula given by Jain and Rao, (1980) (RNRI>1 = Intercropping system is advantageous)
Pi - Unit price of the product of the main crop (Rs/kg).
Pj - Unit price of the product of the inter crop (Rs/kg).
Yi - Yield of the main crop (kg/ha).
Yj - Yield of the inter crop (kg/ha).
Yii - Pure crop yield of ‘i’.
Dij- Differential cost of cultivation of ijth crop combination in comparison to ith sole crop.