Intermittent water application through surface and subsurface drip irrigation

Intermittent water application allows reducing mean irrigation rate to a level which coincides with soil's hydraulic conductivity and minimizes percolation below the main root zone. Field experiment was conducted to confirm the efficiency of this approach, in a clay loam soil. The treatments consisted of two irrigation systems (surface and subsurface drip), and two methods of water application (continuous and intermittent). Drip piping with 0.8-m emitter spacing was placed on the soil surface in the middle of alternative plant rows. Laterals with the same characteristics were buried at 0.45 m in the subsurface plots. The moisture distribution in the soil one day after irrigation, measured by time domain reflectometry instrumentation, indicated that intermittent application in both surface and subsurface plots produced wider wetted patterns. Intermittent or pulsed drip irrigation application has proven its potential to improve sugar beet yield. The results demonstrate that plots irrigated by intermittent application exceeded the continuous irrigated ones in terms of root yield and sugar content

Aerogation: Crop root-zone aeration through subsurface drip irrigation system

Subsurface drip irrigation as a source that provides the water directly to the root zone develops a saturated wetted front in the rhizosphere, particularly when the irrigation is close to 100% of evapotranspiration. Long duration irrigations collect root development around the drip emitters and relatively low hydraulic conductivity, mainly in heavy soils, lead to preservation of saturation in the root layer, resulting in lack of air, which is detrimental to the function of roots and directly influences crop development. The objective of this study is to examine whether the root zone aeration can improve the distribution of moisture in the soil thereby improving plant performance. For the investigation of this approach, a three-year experimental research was conducted, in a sugar beet crop, irrigated by a subsurface drip irrigation system. A technique for ventilating the root zone was developed, which comprises passing air in the irrigation water throughout the duration of irrigation using a venturi device and air supply under pressure after irrigation through a compressor. The air application (aerogation) affected the soil moisture in the root zone reducing the water content or repelled the water from the proximal environment of the emitter. Regarding the crop yield characteristics, the continuous air application gave a higher yield, although not statistically significant, than the conventional (without air) irrigation and aeration at the end of irrigation

ScienceDirect Agricultural use of microfiltered olive mill wastewater: effects on maize production and soil properties

Abstract The disposal of olive mill wastewater (OMWW) is considered as one of the most serious environmental problems in the Mediterranean region. This study constitutes part of a holistic OMWW management approach aiming at the production of high added value products from OMWW with zero discharge. OMWW constitutes an organic material that could be recycled back to the soil after its treatment with microfiltration, and used as liquid fertilizer for plant production, thus leading to an environmentally friendly cultivation method with minor carbon footprint, since wastewater would (partially or fully) substitute mineral fertilizers, fresh water savings, and also economic benefits to the farmer. Microfiltered OMWW (MF-OMWW) was applied to maize cultivation in a clay loam soil using two rates of 25 and 50 Mg ha -1 , with the addition of mineral fertilization of 200 kg N ha -1 . Furthermore, a treatment of only MF-OMWW applied at the rates of 50 Mg ha -1 and an only mineral fertilization treatment were used. The four treatments were replicated four times. The results of the 1 st year experiment showed that the different amounts of MF-OMWW used had no significant effect on soil properties. Maize yield, kernel moisture and fat content were not significantly influenced by the different treatments, whereas kernel protein, starch, fiber and ash content were significantly affected. Considering all quality and quantity parameters studied, the treatment with only mineral fertilizer N application gave similar results with the only MF-OMWW treatment, indicating the potential of mineral fertilizer full substitution by MF-OMWW, under the conditions of our study