Low sugarcane productivity in Brazil is due to insufficient rainfall and would benefit from irrigation. Thus, the application of treated wastewater, such as treated domestic sewage (TDS), becomes an ...alternative water and nutrient source for sugarcane cultivation. The objective of this research was to evaluate the productivity, soil fertility, fertilizer savings and nutritional balance during 2 years of sugarcane crops using TDS applied through subsurface drip irrigation. The experiment was conducted in the field under a randomized block design with five treatments, with two dripline depths and two water qualities (domestic sewage and surface reservoir) and finally non-irrigated plots. Productivity, nutritional balance, and soil fertility were measured during two harvest cycles. The irrigated treatments presented greater productivity in both ratoons (28.5% and 42.8%) and, consequently, higher nutrient extraction compared to the input, which provided a reduction of average soil fertility during the cycles evaluated. The dripline depths and the water qualities applied influenced concentrations of sodium in the soil profile, with highest levels in TDS treatments. Treatments with TDS also showed, in both cycles, significant savings of up to 100% on the application of nitrogen and phosphorus. Therefore, TDS applied by subsurface drip can be used as an irrigation alternative in sugarcane cultivation.
•Subsurface drip in sugarcane with application of domestic wastewater is part of a pilot study in largest producing area of the world under a very atypical dry season.•Two depths of dripper line ...installation and two water sources, besides the rainfed cultivation.•Physiological attributes, water quality, vegetative growth, productivity and technological quality were measured.•Water management performed by the TDR technique and the irrigated plots were fertigated based on water quality and depths applied.•Treated domestic wastewater applied through subsurface drip increased the sugarcane productivity by almost 100% in relation to the non-irrigated plots.
The water scarcity is one of the main factors contributing to the reduction of productivity in agricultural crops, and the use of alternative water source in the irrigation is an option to minimize water stress. The objective of this study was to evaluate the water relations, vegetative growth, productivity and technological quality of sugarcane irrigated with treated domestic sewage by subsurface drip during its second ratoon. The research was performed at the School of Agricultural Engineering of the State University of Campinas—SP, through a randomized block design with five treatments, with two depths of dripper lines installation and two water sources, which are: irrigation with wastewater from domestic sewage applied to 0.20m depth, and to 0.40m, irrigation with fresh water from a surface reservoir to 0.20m depth and to 0.40m and finally non-irrigated plots. Irrigation management was performed following the soil water balance through the time-domain reflectometry technique and all irrigated treatments were fertigated according to the water source applied. Leaf water potential, chlorophyll, gas exchange, leaf nutrition, vegetative growth, productivity and quality technological were measured during the second ratoon of sugarcane. Soil moisture changed according to the depth of the dripper lines installation, being higher for irrigated treatments. The leaf water potential, chlorophyll, gas exchange and nitrogen and magnesium concentration in the leaves also were higher for irrigated plots. The irrigated treatments with sewage had the largest stem and sugar yield compared with the rainfed, being the dripper line irrigated with sewage to 0.20m presenting the greatest differences reaching 95% and 86% with a productivity of 233.69Mgha−1 and 37.06Mgha−1 for stem and total recoverable sugar, respectively; however, there were not significant differences between the irrigated plots. The technological quality of sugarcane was considered appropriate to all treatments.
Conflicts over water use and the high demand for food and biofuels have motivated the use of wastewater in irrigated agriculture. The study aimed to evaluate the nitrogen losses through nitrate ...leaching and nitrous oxide emission for sugarcane first ratoon irrigated by subsurface drip (SDI) with fresh water and treated domestic sewage (TDS) and traditional crop management under rainfed conditions. Therefore, the following treatments were implemented: T1—non-irrigated and topdressing fertilization; T2—irrigated with TDS, with fertigation; T3—irrigated with TDS, without fertigation; T4—irrigated with fresh water, with fertigation; T5—irrigated with fresh water, without fertigation. The nitrogen (
N
) fertilizer applied corresponded to 120 kg ha
−1
to all treatments, with broadcast fertilization for nonirrigated cropping and, for the irrigated plots, it was performed by supplementing the concentration of the nutrients in the TDS and freshwater. All the fertigated treatments had lower leaching losses than nonirrigated treatment with topdressing fertilization, the total
N
loss for nonirrigated plots differed significantly from irrigated treatments, with a total loss of 16.36 kg N ha
−1
. The application of TDS by SDI to meet the needs for water and nutrients resulted in a decrease of
N
losses by NO
3
−
leaching and N
2
O emissions, compared with traditional sugarcane cultivation under non-irrigated with topdressing fertilization (total of 16.36 kg ha
−1
for T1), being the nitrate leaching the main factor that contributed to the
N
loss with a loss of 71% for T1 (11.50 kg ha
−1
). Irrigation with TDS, in addition to providing nutrients and water for sugarcane cultivation, can help minimize nitrogen contamination compared to conventional management methods through SDI systems.
•We evaluate two installation depths of the dripper for the drip irrigation system.•We evaluate if there was an influence of water quality on the water storage in the soil.•For the experimental area, ...the installation of the drip tube to 0.2m deep presented the best results.•Different layers in the soil profile should be considered for calculating water depth.•The treated sewage effluent did not affect the distribution of water in the soil.
Knowledge about soil moisture is essential to maximize irrigation efficiency because it allows the application of water in the proper quantity and at the proper time, thus improving water management. The objective of this study was to evaluate water storage in the soil profile when using a subsurface drip irrigation system at two emitter installation depths (0.20 or 0.40m) and two water qualities (treated sewage effluent (TSE) and freshwater) in two crop cycles of sugarcane (Saccharum officinarum L.) in Campinas—SP (Brazil). The experiment was conducted in the experimental area of FEAGRI-UNICAMP, Campinas—SP, Brazil, adopting a randomized block design (RBD) in a factorial 2×2+1 with 3 replications. The factors studied included the installation of dripper tube at two depths (0.2 and 0.4m) and two qualities of water (TSE and freshwater) plus a non-irrigation control. The TDR (time domain reflectometry) technique was used to evaluate the moisture in the soil profile by installing five probes with rods at 0.2m up to 1.0m depth. Replacement of the calibration equation provided by the TDR reduced the water depth between the first ratoon and the sugarcane plant and reduced the excess humidity from 0.029 and 0.045cm3 to 0.002 and 0.007cm3 when the drippers were installed at 0.2m depth (T2 and T4). The installation of a 0.2m drip tube proved to be an ideal solution for both environmental management and water use efficiency when using treated sewage effluent. No effect on the water distribution in the soil was observed when comparing the water qualities. For management of subsurface drip irrigation by the water balance in the soil, different layers in the soil profile should be considered to calculate the water depth, using the depth of the drip tube installation as a reference.
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