Optimizing water and nitrogen use for maize production under semiarid conditions

Authors : Hafiz Mohkum HAMMAD, Ashfaq AHMAD, Farhat ABBAS, Wajid FARHAD

Pages : 519-532

Doi:10.3906/sag-1204-45

View : 16 | Download : 12

Publication Date : 2012-10-01

Article Type : Research Paper

Abstract :Water and nitrogen are among the most important crop inputs for optimum production of maize insert ignore into journalissuearticles values(Zea mays L.);. A comprehensive experiment was conducted during 2009 and 2010 under the semiarid conditions of Pakistan to evaluate the effects of water and N applications on the growth and yield of irrigated maize. The objective was to formulate water and N best management practices insert ignore into journalissuearticles values(BMPs); for the above conditions. Three irrigation regimes insert ignore into journalissuearticles values(525, 450, and 375 mm ha-1); with 5 N rates insert ignore into journalissuearticles values(0, 75, 150, 225, and 300 kg ha-1); were tested using a split plot with a randomized complete block design. The results revealed that the irrigation and N treatments significantly affected growth and development of the crop plants. Photosynthesis and transpiration rates were influenced by the applied nutrients. The N application at 225 kg ha-1 resulted in maximum values for photosynthesis insert ignore into journalissuearticles values(26.90 and 27.63 µmol m-2 s-1 during 2009 and 2010, respectively); and transpiration insert ignore into journalissuearticles values(5.23 and 5.43 m mol m-2 s-1 during 2009 and 2010, respectively);. The highest values for leaf area index insert ignore into journalissuearticles values(4.93); and grain yield insert ignore into journalissuearticles values(8.40 t ha-1); were also recorded at this N treatment during both growing seasons. On the other hand, the mean crop growth rate insert ignore into journalissuearticles values(19.23 g m-2 day-1); and biological yield insert ignore into journalissuearticles values(16.22 t ha-1); were achieved with the 300 kg N ha-1 treatments in 2009 and 2010. Nitrogen use efficiency insert ignore into journalissuearticles values(NUE); was optimum at 75 kg N ha-1 during both seasons. The highest water use efficiency insert ignore into journalissuearticles values(WUE); insert ignore into journalissuearticles values(16.48 and 18.64 kg ha-1 mm-1 during 2009 and 2010, respectively); was achieved by application of 225 kg N ha-1 with an irrigation water depth of 525 mm during both growing seasons. Water stress at the vegetative stage reduced the grain yield by 12.2%, whereas the same treatment at the grain filling stage reduced the grain yield by 22.6%. In the semiarid environment of Pakistan, the application of water at 525 mm ha-1 with 225 kg N ha-1 gave the optimum production of the irrigated maize tested in this experiment. These crop inputs may be considered as water and N BMPs for this region or for those with similar agricultural and environmental conditions. Agricultural inputs based on these BMPs may result in similar NUE and WUE values.
Keywords : Key words Crop growth, maize yield, nitrogen use efficiency, photosynthesis, transpiration, water use efficiency