Water hardness affecting glyphosate efficiency for weed control and tomato (Lycopersicon esculentum L.) yield production

The reduced use of herbicides such as glyphosate (N-(phosphonomethyl)glycine), as an effective method for weed control in the field, is an important goal, which may be achieved by using sustainable strategies for crop production. In the arid and semi-arid areas due to the use of ground water for crop production, water hardness may affect glyphosate efficiency, which is of economic and environmental significance. The objective was to investigate how water hardness (0 (W1), 200 (W2), 300 (W3) and 400 mg l-1 (W4)) affect the efficiency of glyphosate (0 (G1), 100 (G2), 150 (G3), 200 g ha-1 (G4)) (0, 75, 112.5, 150 g ha-1 acid equivalent) on weed growth (Convolvulus arvensis, Malva sylvestris and Cynodon dactylon) and tomato (Lycopersicon esculentum L.) yield in the field using a factorial experiment on the basis of a complete randomized block design with three replicates. The single and the interaction effects of water hardness and glyphosate significantly affected different weeds (158 g weed weight for W2G1, and 25.3 g for W1G4) and tomato plant measured parameters. Increasing water hardness decreased glyphosate efficiency in controlling weeds, but it enhanced plant height. Higher water hardness increased tomato leaf area, however, higher glyphosate rates decreased it. Treatments W1G2 (1617 g plot-1) and W1G4 (220.8 g plot-1) resulted in the highest and the least tomato yield, respectively. At the highest level of glyphosate, W2 resulted in the highest tomato yield, compared with the other treatments. The highest and the least plant dry weight was resulted by W4G2 (232.7 g) and W1G4 (196.8 g), respectively. The proper concentrations of water hardness and glyphosate may efficiently control weeds and results in optimum tomato yield in the arid and semi-arid areas.