Real time nitrogen management through leaf colour chart in maize (Zea mays L.) under irrigated ecosystem

Abstract

A field experiment was carried out in medium black soil during kharif 2017 at Agriculture Research Station, Siruguppa, UAS, Raichur, Karnataka to study the “Real time nitrogen management through leaf colour chart in maize (Zea mays L.) under irrigated ecosystem”. The experimental site was low in available N (231 kg ha-1) and P2O5 (24 kg ha-1) where as high in K2O (364.1 kg ha-1). The experiment consisted of nine treatments viz., T1: N application at LCC threshold ≤ 4, T2: N application at LCC threshold ≤ 5, T3: N application at LCC threshold ≤ 6, T4: N application at LCC threshold ≤ 4 upto V6 there after ≤ 5, T5: N application at LCC threshold ≤ 5 upto V6 there after ≤ 4, T6: N application at LCC threshold ≤ 4 upto V6 there after ≤ 6, T7: N application at LCC threshold ≤ 6 upto V6 there after ≤ 4, T8: RDN (150 kg ha-1) and T9: Absolute control. Experiment was laid out in Randomized Complete Block Design with three replications. The experimental results revealed that significantly higher maize grain yield (11,427 kg ha-1) and stover yield (12,914 kg ha-1) was recorded with N application at LCC threshold ≤ 5 upto V6 there after ≤ 4 (T5) as compared to rest of the treatments and it was on par with T2 and T6. This higher grain yield was attributed to higher cob length and cob girth, grain rows, number of seeds and grain weight per cob. Significantly higher gross returns (Rs. 1, 49,293 ha-1), net returns (Rs.1, 06, 312 ha-1) and B: C ratio (3.47) was recorded in N application at LCC threshold ≤ 5 upto V6 there after ≤ 4 (T5) compared to other treatments and it was statistically onpar with N application at LCC threshold ≤ 5 (T2) and N application at LCC threshold ≤ 4 upto V6 there after ≤ 6 (T6). Whereas significantly lower gross return (Rs. 48, 138 ha-1), net return (Rs.14, 565 ha-1) and B: C ratio (1.43) was registered with absolute control compared to rest of the treatments.