On-farm diagnosis and management of iron chlorosis in groundnut

Iron (Fe) chlorosis is a major nutritional constraint to groundnut (Arachis hypogaea L.) productivity in many parts of the world. On-farm research was conducted at a Fe-chlorotic site to evaluate the performance of three geno types (TMV-2, ICGS-11, and ICGV-86031), three fertilizer practices [no fert ilizer control, farmers practice (125:200:0 kg NPK ha(-1)), recommended pra ctice (20:50:30 kg NPK ha(-1))], and two Fe treatments (non-sprayed control and foliar FeSO4 sprays) for their effect on Fe-chlorosis and haulm and po d yields. These treatments were tested in a strip-split plot design with fo ur replicates. Results revealed that TMV-2 and ICGS-11 were susceptible to Fe-chlorosis and produced significantly smaller hauln and pod yield, wherea s, ICGV-86031 was tolerant to Fe-chlorosis. Farmer's fertilizer practice ha d the highest incidence of Fe-chlorosis. Extractable Fe and chlorophyll con tent in the fresh leaves were the best indices of Fe-status and were signif icantly (P<0.01) correlated with visual chlorosis ratings. Foliar applicati on of FeSO4 (0.5 w/ v) was effective in correcting Fe-chlorosis and increas ed pod yield by about 30 to 40% in susceptible genotypes. These results sug gests that use of tolerant genotypes such as ICGV-86031 or foliar applicati on of FeSO4 in susceptible genotypes such as TMV-2 and ICGS-11 in combinati on with recommended fertilizer levels is an effective management package fo r alleviating Fe-chlorosis in groundnut.