Bielorai, H., Agric. Res. Organization, The Volcani Center, Bet Dagan, Israel
Vaisman, I., Agric. Res. Organization, The Volcani Center, Bet Dagan, Israel
Feigin, A., Agric. Res. Organization, The Volcani Center, Bet Dagan, Israel

A long-term drip irrigation experiment was conducted on a grumusol (Typic chromoxerent) soil at Zor'a, Israel in 1978, 1979, and 1980 to study the influence of municipal effluent on the growth, yield, and line quality of drip-irrigated cotton (Gossypium hirsutum L.), var. 'Acala SJ-2'. Two sources of irrigation water were used: (i) municipal effluent and (ii) fresh water. The N concentration in the effluent was about 50 mg/L during the 3 years of experimentation. The treatments included three seasonal amounts of effluent and fresh water application: 350, 440, 515 mm; and five levels of N: 0, 90, 150, 180 and 230 kg ha-1 (average of the 3 years), added to the fresh water only, via the drip system. The cotton plants irrigated with effluent grew taller, with more vegetative growth than did the plants irrigated with fresh water. The seed cotton yield obtained in 1978 was relatively low as a result of excessive vegetative growth and lodging of the plants. In the 1978 season, the seed cotton yield averaged 4.35 and 4.04 Mg ha-1 for the effluent and freshwater treatments, respectively. When growth was retarded in the 1979 and 1980 seasons by delaying irrigation and adjusting fertilizer management, average yields increased to 4.95 and 4.57 Mg ha-1 for the two water qualities, respectively. Lint percentage was 39.0 and 40.2 for the effluent and freshwater treatments, respectively. The lint quality, as determined by strength, length, and micronaire was the same for cotton irrigated with effluent as for cotton irrigated with fresh water. Municipal effluent can be used effectively as a source of irrigation water and plant nutrients, and with appropriate management, high production can be obtained. Drip irrigation increases irrigation and fertilization efficiency and minimizes ecological hazards.A long-term drip irrigation experiment was conducted on a grumusol soil at Zor'a, Israel in 1978, 1979, and 1980 to study the influence of municipal effluent on the growth, yield, and line quality of drip-irrigated cotton. Two sources of irrigation water were used: municipal effluent and fresh water. The N concentration in the effluent was about 50 mg/L during 3 years of experimentation. The cotton plants irrigated with effluent grew taller, with more vegetative growth than did the plants irrigated with fresh water. The seed cotton yield obtained in 1978 was relatively low as a result of excessive vegetative growth and lodging of the plants. In the 1978 season, the seed cotton yield averaged 4. 35 and 4. 04 Mg ha** minus **1 for the effluent and freshwater treatments respectively. When growth was retarded in the 1979 and 1980 seasons by delaying irrigation and adjusting fertilizer management, average yields increased to 4. 95 and 4. 57 Mg ha** minus **1 for the two water qualities, respectively. Lint percentage was 39. 0 and 40. 2 for the effluent and freshwater treatments, respectively. Results indicate that drip irrigation increases irrigation and fertilization efficiency and minimizes ecological hazards.