Crop establishment methods and moisture mitigation practices in rice fallow blackgram for productivity enhancement in cauvery delta zone of Tamil Nadu

With extensive adoption of mechanised harvest in paddy, the population of blackgram in the rice - blackgram relay cropping system is drastically affected due to the chain traverse by combine harvester. This has emerged as another major abiotic stress in addition to moisture stress at flowering stage of the crop, which resulted in poor yield.

The studies were conducted during post rainy seasons of 2015–16 to 2017–18. with six treatments viz., T₁ - Sowing blackgram by broadcasting 7–10 days prior to manual harvest of paddy, T₂ - Sowing blackgram by no till seed drill on the day of harvest of paddy, T₃ - Sowing blackgram by broadcasting 4–6 days prior to harvest of paddy by combine harvester, T₄-T₁ + Life saving irrigation with mobile sprinkler once at 30–35 DAS, T₅-T₂ + Life saving irrigation with mobile sprinkler once at 30–35 DAS, T₆-T₃ + Life saving irrigation with mobile sprinkler once at 30–35 DAS.

The results indicated that higher grain yield of 875 kg ha⁻¹ was obtained with blackgram sown 7–10 days prior to manual harvest of paddy plus life saving irrigation on 30–35 DAS with mobile sprinkler using farm pond water, which was 31.6% higher than that of blackgram sowing with no till seed drill. The study also indicated that farm pond dug at an area of 100 m³ would be sufficient to irrigate 1 ha of blackgram through mobile sprinkler once at flowering stage (30–35 DAS by which the net return could be increased by ' 61416 ha⁻¹.