The Effect of Four Irrigation Methods on the Damage of Weeds, Two-Spotted Spider Mite (Tetranychus urticae Koch) and Bacterial Blight Disease in Chitti Bean (Phaseolus vulgaris L.)

IntroductionBeans are one of the cheap and important sources of high-quality vegetable protein, which is present in the diet of many people in developing countries and completes the cereal protein. Bean seeds have almost as much energy per unit weight as cereal seeds, and their protein content varies from 20-25% (about twice that of cereal). With 8-14% protein content, bean straw is very suitable fodder for livestock. The production of vegetable protein of grains has several advantages over animal protein in terms of cost and consumer health. Among other features of this plant, we can point to the ability to coexist with air nitrogen-fixing bacteria and their role in productivity, as well as strengthening and improving the physical properties of the soil. Through the ability of nitrogen fixation in these plants, placing them in rotation helps the stability of agricultural systems. At present, the largest area of bean cultivation is in the form of traditional cultivation and bean irrigation is also in the form of flooding. In this production method, more than 15,000 cubic meters of water is consumed. This amount of water consumption, along with the lack of proper productivity of other factors in production, has caused beans to be one of the least efficient products in terms of water consumption efficiency. Materials and MethodsIn order to investigate the effect of four irrigation methods on the damage of weeds, two-spotted spider mite (Tetranychus urticae Koch) and bacterial blight disease in chitti bean (Phaseolus vulgaris L.), a research study was conducted in 2022 and 2023 at the Bean Research and Education Center in Khomein, Iran. Despite employing a field with uniform conditions, the study was designed as a multi-location (regional) experiment using a randomized complete block design with three replications. The irrigation methods were categorized into four treatment levels: classical sprinkler irrigation, New-fit sprinkler irrigation, rain flat irrigation, and drip tape irrigation. Different types of chitti bean cultivars with three growth habits were randomly sown in these locations. Results and DiscussionThe experimental results showed that the irrigation method had a significant effect on seed germination percentage and bean plant height. The highest and lowest seed germination percentage and plant height were associated with drip tape irrigation and classical sprinkler irrigation, respectively. Also, the type of irrigation significantly impacted weed density, total biomass of weeds, the intensity of two spotted spider mite infestation, and bacterial blight disease. The highest weed density and biomass were observed in the New-fit and classical sprinkler irrigation methods, and the classical sprinkler irrigation exhibited the highest incidence of bacterial blight disease, too. Conversely, the lowest values for these parameters were obtained with the drip tape irrigation method. However, the highest damage caused by two spotted spider mite was observed in the drip tape irrigation method, while the lowest damage by two spotted spider mite was present in the classical sprinkler irrigation method. Furthermore, both irrigation method and bean cultivar significantly affected bean grain yield. The highest grain yield (293.6 g.m-2) was associated with drip tape irrigation, while the lowest yield (225.4 g.m-2) was observed in the classical sprinkler irrigation treatment. Among the different bean cultivars, the highest grain yield (274.1 g.m-2) was obtained from the Kousha cultivar. One of the important solutions in achieving the goals of reducing water consumption and increasing the efficiency of water consumption in bean cultivation is the implementation of pressurized irrigation instead of conventional cultivation. Pressure irrigation methods in planting beans reduce water consumption to a great extent and increase the efficiency of water consumption. The two main methods of irrigation under pressure in the country are the drip tape method and the fixed classical sprinkler with a movable sprinkler, each of which has its own advantages and disadvantages. In addition to the positive aspects of increasing yield, drip tape irrigation method in bean planting will help to further reduce water consumption. ConclusionsIn general, the experiment results demonstrated that drip tape irrigation not only increased seed germination percentage and plant height in different bean cultivars, but also led to higher grain yield compared to other irrigation methods. Additionally, the presence of weeds and bacterial blight disease were reduced in the drip tape irrigation method.