Growth, yield and nutrient uptake of maize (Zea mays) as influenced by tillage and potassium management under conservation agriculture

A field experiment was carried out during the rainy (kharif) season (July-October) of 2016 at the research farm, New Delhi, to study the effect of time of K application on the performance of maize (Zea mays L.) under conservation agriculture. The maximum values of yield-attributing characters, viz. cob length (16.3 cm), cob girth (13.6 cm), cob weight (5.6 t/ha), grain rows/cob (13.7), grains/cob (3, 567) and test weight (215 g) in maize were recorded with ZT-bed + residue followed by zero tillage (ZT) + residue and conservation tillage (CT)-No residue. The treatment, K₂ [half recommended dose (RD) at basal and half at tasseling) showed significantly higher values of yield attributes than all other treatments. The highest grain (4.66 t/ha) and stover (9.51 t/ha) yields were recorded in ZT-bed + residue over ZT + residue and CT-No residue. Half dose of K at sowing + half at tasseling recorded significantly higher grain (4.46 t/ha) and stover (8.65 t/ha) yield than other treatments in subplots which are at par with one-third at sowing + one-third at knee high (30 days after sowing) + one-third at tasseling_. The yield improvement with ZT-bed + residue was 11.21% over CT-No residue and 7.37% over ZT + residue. ZT-bed + residue registered significantly higher N, P and K content in seed and stover and uptake during the period of study followed by ZT + residue and CT-No residue. The total N (119 kg/ha), P (27 kg/ha) and K uptake (181 kg/ha) were maximum with ZT-bed + residue which was significantly higher than ZT + residue and CT-No residue. Among the timing of K application practices, higher N, P and K content in grain, stover and total uptake in maize was observed in half at sowing + half at tasseling, which was statistically at par with one-third at sowing + onethird at knee high (30 days after sowing) + one-third at tasseling but significantly higher than recommended dose as basal (60 kg K₂O/ha).