Copper is one of the most essential micronutrients. Plants require very small amounts of microelements (less than 1 ppm). Slight deficiencies in them or toxic levels of them can lead to severe yield losses or damage to standing crops. Poultry manures, sewage sludge, swine, composted refuse, fly ash, burnt tires, and copper wires often contain potentially toxic levels of metals and pose a considerable environmental risk from metals if their use is unregulated in agricultural fields (Baker 1974). The repeated use of Bordeaux sprays can cause Cu toxicity in plants (Reuther and Smith 1954). Hewitt (1953) observed that Cu consistently induces Fe chlorosis in crops. Generally, Cu toxicity has been associated with soil Cu levels of 150 and 400 ppm (Baker 1974). Copper toxicity in sugarcane was reported when the root copper content was in the range 54-375 ppm (Bakker 1999). Experiments were conducted on the influence of excess copper on the growth of and uptake of nutrients by sugarcane at IISR, Lucknow, during 2002-2003. Single bud setts of sugarcane (Saccharum officinarum hybrid, CoLk 8102) were planted in polyethylene pots filled with refined sand at three levels of copper (as copper sulfate): 0.065 (control), 65.0, and 130 ppm Cu (excess). The high Cu supply reduced (Table 16.21) root number and length, leaf area, leaf length, width and perimeter, plant height, and the fresh and dry weights of different plant parts (Table 16.22). The Cu concentration increases with increased Cu supply. Excess Cu caused reductions in chlorophyll a and b and carotenoid content (Table 16.23), as well as the specific activity of catalase (Table 16.24), while peroxidase activity increased with high levels of Cu in the growing medium. An excess of Cu caused significant reductions in calcium content (Table 16.25) in different plant parts. High levels of Cu depressed the uptake of Fe and Zn in leaves and shoots, and increased Mn content (Jain et al. 2008).

Growing Soilless

Growing Soilless

This is an easy-to-follow, step-by-step guide to growing organic, healthy vegetable, herbs and house plants without soil. Clearly illustrated with black and white line drawings, the book covers every aspect of home hydroponic gardening.

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