Drip Irrigation of Cotton with Treated Municipal Effluents: II. Nutrient Availability in Soil

Abstract

The suitability of sewage effluent for drip irrigation of cotton (Gossypium hirsutum) growing on a deep calcareous clay soil (Typic Chromoxererts) was studied during three seasons. Secondary effluent was compared with freshwater at three application rates, the average of which for the three seasons were: low (350 mm yr−1), standard (440 mm yr−1), and high (515 mm yr−1). Fertilizer was applied with the fresh water in order to deliver amounts of nutrients (average for the 3 years) equivalent to those in the effluent that contained 150, 180, and 230 kg N; 32, 37, and 46 kg P; and 80, 100, and 120 kg K ha−1 yr−1 for the three rates, respectively. In addition, the standard amount of fresh water was given with half the quantity of fertilizer, and without fertilizer.The concentration of available N and P in soil was increased greatly in all effluent and fertilizer‐amended freshwater treatments, while available K in the soil was increased to a lesser extent. In general, at equivalent application levels, no significant differences in the level of available N, P, and K in the soil or in their uptake by plants, were detected between effluent and fertilizer‐amended fresh water, although dry matter yield as well as N, P, and K accumulation were greater in the high‐application‐rate effluent treatment. The distribution of NO3‐N in the soil profile was controlled by drip irrigation and practically no build‐up of NO3− was detected below the 0‐ to 0.6‐m depth layer during the irrigation period (in summer). However, during the rainy, winter season, heavy losses of residual NO3‐N occurred, probably mainly through leaching.

Effects of Reclaimed Water on Citrus Growth and Productivity

“…The response of plants and soils to municipal treated effluent is dependent on the quality of the applied effluent and nature and efficiency of the wastewater treatment, with generally higher treated water resulting in the best growth and yields (Basiouny, 1984). Recently, wastewater has been used to increase yield and improve quality of grain crops (Al-Jaloud et al, 1993;Day & Tucker, 1977;Day et al, 1975;Karlen et al, 1976;Morvedt & Giovdane, 1975;Nguy, 1974), cotton Feigin et al, 1984), forage (Bole & Bell, 1978) and vegetable crops (Basiouny, 1984;Kirkham, 1986;Neilsen et al, 1989Neilsen et al, a, b, c, 1991Ramos et al, 1989). Reclaimed water has been successfully used to irrigate many fruit crops; apples (Nielsen et al, 1989a), cherries (Neilsen et al, 1991), grapes (Neilsen et al, 1989a), peaches (Basiouny, 1984) and citrus (Esteller et al, 1994;Kale & Bal, 1987;Koo & Zekri, 1989;Morgan et al, 2008;Omran et al, 1988;Wheaton & Parsons, 1993;Zekri & Koo, 1990).…”

“…In the same study, leaf N contents were slightly lower in plants irrigated with groundwater than wastewater (Parsons et al, 2001b). It was concluded that this was due to elevated levels of organic matter found in wastewater which provided additional N. Higher leaf N was also found in treated wastewater irrigated sweet-cherry (Neilsen et al,1991), apples (Neilsen et al, 1989c), cotton (Feigin et al, 1984) and peach trees (Basiouny, 1984). No significant differences in leaf P contents were found between plants irrigated with either groundwater or wastewater, in spite of wastewater supplying a higher soil P load.…”

“…The quality of the reclaimed water used for irrigation was monitored monthly, and a report of average water constituent concentrations was provided to the growers (Table 1). The level of constituent concentrations in the reclaimed water are not considered to be toxic (Burton & Hook, 1979;Feigin et al, 1984). However, if soil or tissue accumulation were to occur, concentrations of heavy metals (i.e.…”

“…However, if soil or tissue accumulation were to occur, concentrations of heavy metals (i.e. cadmium, lead, and zinc) may approach toxic levels (Campbell et al, 1983;Feigin et al, 1984;Neilsen et al, 1991). Prior to 1994, Zekri & Koo (1993) reported that soil to a depth of 0.5 m beneath trees irrigated with reclaimed water was usually 14.7 mm higher in water content and the trees had 6% higher canopy, leaf color, and fruit crop ratings than trees irrigated with groundwater.…”

“…Because fruit yield was greater from orchards irrigated with reclaimed water, total soluble solids produced per ha were higher in the reclaimed water orchards than the groundwater irrigated orchards. Irrigation with reclaimed water has increased soil concentrations of P, K, Mg, B, Na, and Cl when reclaimed water was used as an irrigation water source (Burton & Hook, 1979;Campbell et al, 1983;Feigin et al, 1984;Neilson et al, 1991). Elemental concentrations in soil samples taken in Aug. or Sept. of each year from orchards irrigated with either reclaimed or ground water varied from year to year but were not significant by years.…”