Impact of Aerated Drip Irrigation and Nitrogen Application on Soil Properties, Soil Bacterial Communities and Agronomic Traits of Cucumber in a Greenhouse System

Abstract

Root hypoxia stress and soil nutrient turnover have been related to reduced crop productivity. Aerated drip irrigation (ADI) can effectively enhance crop productivity and yield. However, the response of the soil bacterial community to different irrigation water dissolved oxygen (DO) concentrations remains elusive due to the extreme sensitivity of microorganisms to environmental variations. We investigated the effects of aerated irrigation with different concentrations of DO on soil properties and agronomic performance of cucumber, as well as the contribution of the bacterial community. We performed experiments on cucumber cultivation in Shouguang, China, including different irrigation methods (ADI: O2–10 and O3–20 mg L−1, non-aerated groundwater: O1–5 mg L−1) and nitrogen (N) application rates: 240 and 360 kg N ha−1. ADI (particularly O2) significantly improved soil properties, root growth, cucumber yields, and irrigation water use efficiency (IWUE), and appropriate DO concentrations reduced N fertilizer application and increased crop yields. Furthermore, these changes were associated with bacterial community diversity, aerobic bacteria abundance, and consolidated bacterial population stability within the network module. Environmental factors such as soil respiration rate (Rs), DO, and NO3−-N have significant effects on bacterial communities. The FAPROTAX results demonstrated enhanced nitrification (Nitrospira) and aerobic nitrite oxidation by soil bacteria under ADI, promoting the accumulation of effective soil N and improved soil fertility and crop yield. Appropriate DO concentration is conducive to the involvement of soil bacterial communities in regulating soil properties and cucumber growth performance, which are vital for the sustainable development of facility agriculture.

Effects of Intercropping and Nitrogen Application on Soil Fertility and Microbial Communities in Peanut Rhizosphere Soil

“…Thus, the present study revealed some differences relative to prior reports with respect to the characteristics of monocropping and intercropping systems, while also providing new details regarding the effects of different levels of nitrogen application under these conditions. Bradyrhizobium is capable of utilizing plant-derived carbohydrates to exchange fixed nitrogen, whereas Nitrospira bacteria with nitrifying activity are capable of converting soil ammonia nitrogen into nitrate nitrogen to maintain soil nitrogen cycling [55,56]. As nitrogen fertilizer levels rose, Bradyrhizobium abundance under monocropping conditions declined, while Nitrospira abundance increased and decreased in the monocropping and intercropping systems, respectively.…”

Effects of Aerated Drip Irrigation on the Soil Nitrogen Distribution, Crop Growth, and Yield of Chili Peppers

“…Aerated drip irrigation (ADI) technology delivers micro-nano bubble water through the SDI system to the root zone to a certain extent, alleviating the problem of root anoxia caused by conventional SDI. Some studies have shown that aerated irrigation significantly affects the inter-root soil oxygen environment of crops, enhancing soil permeability, improving soil enzyme activity and the activities of soil microorganisms [ 13 , 14 ], promoting the aerobic respiration of the crop root system [ 15 ], and increasing crop yields and fruit quality [ 16 ]. Soil aeration increases the crop yield and improves the quality of cucumber, potato, zucchini, and rice [ 11 ].…”