Evaluation of the Inhibiting Effect of Copper Oxideon Root Growth and Density in the Vicinity of Subsurface Irrigation Nozzles

Due to the population growth and the increase in global demand for food security, the correct use of water and soil resources, especially in arid and semi-arid regions, is necessary and inevitable. Providing water sources in agricultural and garden lands by clay irrigation method has been customary in arid and semi-arid regions of Iran for a long time. However, the development of this method has not received much attention due to the invasion of the roots into the clay nozzles and the clogging of the pores caused by the growth of algae, fungi, and bacteria. One of the main goals of this article is to provide a practical solution to combat root invasion towards the wall of clay subsurface irrigation nozzles (porous clay capsules). This research seeks to investigate the effect of copper oxide added to the porous clay capsule wall in inhibiting root invasion.

This research aims to reduce the density and distribution of roots in the vicinity of porous clay capsules, by investigating the effect of copper oxide on the wall of the clay nozzle as an inhibitor of root movement in the form of a completely randomized design with 4 treatments with zero concentrations (control). 1000ppm, 5000ppm and 10000ppm copper) in 3 replications in the research greenhouse of Tarbiat Modares University in 1401 on sweet pepper variety 302. In this experiment, the volume, length and dry weight of root, fresh weight of leaf and stem, dry weight of leaf and stem and ratio of dry weight of leaf/root were measured at the end of vegetative growth stage of the bell pepper plant.

The results showed that copper levels did not have a significant effect on the volume and length of the bell pepper plant's root, but it had a significant effect on the dry weight of the root. The highest root dry weight (3.27 grams) was obtained at the probability level of 5% corresponding to the level of 10000 ppm of copper sulfate. Also, the results of the investigation of the root distribution system showed that the distribution of the root distribution in the control treatment was the same in all directions, while in the 10000 ppm copper sulfate treatment, this distribution was severely limited around the wall of the clay nozzles, so that the most the root accumulation around the nozzles was related to the control treatment and the lowest root accumulation was visible in the 10000 ppm treatment. The results showed that the highest development of the root system around the nozzles was related to the control treatment and the lowest was observed in the 10000 ppm treatment in the control treatment, the porous clay capsule were heavily invaded by plant roots and the roots completely surrounded the porous clay capsules. Therefore, adding copper sulfate to the wall of the porous clay capsule and fixing it in its pores as copper oxide has had positive effects in inhibiting the invasion of plant roots into clay nozzles.