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Effect Of Precision Guided Cultivation On Weed Control In Wide Row Cropping Systems
1M. Gupta, 2
1. University of Queensland, School of Land, Crop and Food Sciences
2.

Wide row cropping has been traditionally followed in summer crops but it is also becoming popular in winter crops such as chickpeas and lupins.  High precision guidance systems with 2 cm accuracy offer unique opportunities to cultivate closer to the row and increase weed control efficiency in wide row cropping systems. Two field experiments were conducted in chickpeas with a Real Time Kinematic Differential Global Positioning System (RTK-DGPS) controlled mechanical cultivation. Cultivation treatments were 2 cm, 5 cm and 15 cm from the row at six weeks after emergence (6WAE) in first experiment, and 7.5 cm and 15 cm from the row at 5WAE in second experiment. Percentage of weeds removed, crop damage, crop and weed biomass at flowering, and crop yield were measured. For experiment 1, weed removal rates were 59%, 55% and 49% for 2 cm, 5 cm and 15 cm treatments, respectively.  Random errors in the accuracy of GPS caused about 20% crop damage for 2 cm treatment. Thus, crop yield of 5 cm treatment tended to be highest and similar to the weed-free treatment.  Significant yield differences were most likely precluded by large spatial variability of weed density among treatments. Much higher weed removal rates were observed in experiment 2 (77% and 54% for 7.5 cm and 15 cm treatments, respectively), primarily due to lower weed density and earlier cultivation.  This resulted in a trend to higher crop biomass at flowering for 7.5 cm treatment (4.6 t/ha compared to 4.0 t/ha for 15 cm).  The same trend was found for crop yield. Precision mechanical weed control 5 to 7.5 cm from the row was effective and would help farmers control herbicide escapes, and slow development of herbicide-tolerant species.  
 

M. Gupta            Precision Weed Management    Poster    2010