Modification of crop ecology in maize (Zea mays) through fertility levels and weed control measures under temperate conditions of Kashmir

Abstract

A field experiment was conducted during kharif seasons of 2008 and 2009 at Sher-e-Kashmir University of Ag- ricultural Sciences and Technology Kashmir to study the effect of fertility levels, mulching and weed management practices on the microclimate of crop, soil temperature, phenological changes and yield of maize (Zea mays L.). The experiment was conducted in a split-plot design with three replications and consisted of four treatments viz; N , N + Azotobacter, N , and N + Azotobacter in main plots and five treatments viz; polyethylene mulch, 90 90 120 120 straw mulch @ 1.0 tonne/ha, hand weeding at 30 and 60 DAS, atrazine @1.0 kg a.i./ha and weedy check in sub- plots. Results revealed that N + Azotobacter produced grain yields at par with N , resulting in saving of 30 kg N/ 90 120 ha. Highest grain yield 5.14 t/ha, stover and biological yield with concomitant increase in yield attributes viz; num- ber of cobs/plant, number of rows/cob, number of grains/row, cob length, cob diameter, 1,000-grains weight was obtained with polyethylene mulch. Polyethylene mulch also helped plants to reach phenological stages two to four days earlier as compared to unweeded check. Percentage of light interception by crop at the middle of the canopy was maximum with N + Azotobacter, more than other fertility levels. However, N treatment recorded the high- 120 90 est percentage of light interception among all the fertility levels, when recorded at the bottom of the canopy. Light interception was most with polyethylene mulch among all the weed control treatments when recorded at the middle of the canopy, whereas it was most with weedy check treatment when recorded at the bottom of the canopy. The peak values for the interception of radiation were observed at 90 DAS. The soil temperature in the polyethylene mulched plots was 680C higher as compared to un-mulched plots. Modification of crop ecology through polyethylene mulch and straw mulch resulted in 73.4% and 72.6% more grain yield, respectively, as com- pared to uncontrolled weedy check. Benefit cost ratio was the highest with N + Azotobacter and atrazine @ 1.0 120 kg/ha, respectively.