Crop-weed competition, herbicide efficacy, moisture, crop productivity

To evaluate the effect of irrigation levels and chlorsulfuron doses on productivity and water use of wheat, a field experiment was conducted at Research Farm of CCS Haryana Agricultural University, Hisar, India during rabi seasons of 1998-99 and 1999-2000. Five irrigations (21, 45, 65, 85 and 105 DAS) applied in wheat resulted in highest grain yield and consumptive water use compared to two (21 and 85 DAS) and three (21, 65 and 105 DAS) irrigations. However, the water use efficiency (WUE) was maximum with two irrigations. Increase in the WUE of wheat due to two irrigations over three and five irrigations was 13.7 and 31.8% during 1998-99 and 9.5 and 27.0% during 1999-2000, respectively. More frequent irrigations (five) resulted in more soil moisture extraction from upper and medium soil layers, while two irrigations extracted more water from deeper layers. Different herbicidal treatments had no marked effect on water use by wheat. Maximum grain yield of wheat (4553 and 4849 kg/ha) was attained in the plots treated with chlorsulfuron at 30 g/ha which was statistically at par with its lower dose (20 g/ha)