Role of Summer Legumes in Sustaining the Rainfed Groundnut Productivity

In the face of quickly shifting weather patterns, sustainable agricultural production is essential. The Green Revolution in India led to intensive farming which led to loss of soil biota and degradation of organic matter content resulted in lower soil quality.

A four-year study (2016 to 2019) was taken up at Regional Agricultural Research Station, Tirupati, Andhra Pradesh, India by growing 6 leguminous crops such as Pillipesara, rice bean, sunhemp, green gram, horse gram and cowpea during summer under rainfed condition as a preceding crop and incorporated before sowing of Kharif groundnut. FYM was also tested as one of the treatments for comparison.

Results revealed that the choice of green manure crop significantly influenced groundnut yields. Growing and incorporating cowpea before Kharif groundnut resulted higher yields (1744 kg/ha) followed by green gram (1699 kg/ha) compared to fallow (1478 kg/ha). Microbial analysis at the end of the experiment revealed that highest fungal population (28.3 ×10⁴ cfu/g) and actinomycet population (24 × 10⁴ cfu/g) was observed in sunhemp followed by cowpea (27×10⁴ cfu/g of soil) and (19.7 × 10⁴ cfu/g) compared to fallow (7 × 10⁴ cfu/g) and (4.7 × 10⁴ cfu/g). The highest bacterial population (33.3 × 10⁶ cfu/g) was observed with green gram followed by horse gram (26.7 × 10⁶ cfu/g) and cowpea (26.3 × 10⁶ cfu/g). The highest organic carbon content (0.5 per cent) was observed with sunhemp followed by horse gram and cowpea (0.49 per cent) compared to fallow (0.45 per cent). Leguminous crops act as cover crops during summer in maintaining the soil temperature and protecting the soil biota and as green manure crops in enriching the soil during Kharif.