The purpose of this study was to know the controlling effects of water and nitrogen coupling on the yield, quality, and water-nitrogen utilization effectiveness of mountain apples under surge-root irrigation in the Loess Plateau. In order to optimize the water and nitrogen irrigation systems of superior quality and high yield, 7 years was selected for the mountain apple test material. The trial was designed with four tiers of irrigation, i.e., full irrigation (FI: 85–100% θ_f, where θ_f is the field capacity), light deficit irrigation (DI_L: 70–85% θ_f), moderate deficit irrigation (DI_M: 55–70% θ_f), and severe deficit irrigation (DI_S: 40–55% θ_f) and three tiers of nitrogen, i.e., high nitrogen (N_H: 600 kg ha^–1), medium nitrogen (N_M: 400 kg ha^–1), and low nitrogen (N_L: 200 kg ha^–1). The subjective weight attained by the analytic hierarchy methods and the objective weight achieved by the enhanced coefficient of variation method were examined to find the comprehensive weight based on the notion of game hypothesis. Then, the weighted technique for order of preference by similarity to the ideal solution (TOPSIS) process was utilized to comprehensively assess the yield, quality, and water-nitrogen use efficiency of the apples, and a binary quadratic regression model was created between the comprehensive evaluation index and water-nitrogen inputs. The results showed that the effects of irrigation and nitrogen levels on the fruit yield, irrigation water use efficiency (IWUE), total water use efficiency (TWUE), nitrogen partial factor productivity (NPFP), and quality of mountain apples were significant (P < 0.05). The apple yield and TWUE first improved and then diminished with an escalating quantity of water-nitrogen inputs, the IWUE diminished with a boost in the irrigation quantity, the NPFP dwindled when the nitrogen amount was increased. The best water and nitrogen inputs for apple yield, quality, or water-nitrogen use efficiency were dissimilar. The best comprehensive evaluation index was DI_LN_M treatment, and the worst comprehensive evaluation index was DI_SN_L treatment, based on the TOPSIS system. The interval of irrigation and nitrogen attained from the mathematic model ranged in 95–115 mm and 470–575 kg ha^–1, respectively. The outcome of this study may perhaps offer a theoretical basis for the scientific research of surge-root irrigation and the managing of mountain apple tree irrigation and fertilization in the Loess Plateau, China.

The effects of ploy (γ-glutamic acid) on spinach productivity and nitrogen use efficiency in North-West China | Lin Chen, Liangjun Fei, Zilu Wang, Mohamed Khaled Salahou, Le Liu, Yun Zhong, Zhiguang Dai | Agricultural Journals

This study analyzes the soil water infiltration characteristics under muddy water irrigation and bio-organic fertilizer conditions in the current context of muddy water irrigation rarely being used in agricultural production and in combination with the problems of water resource shortages and low soil fertility in arid and semi-arid regions. An indoor one-dimensional soil column infiltration device was used for studying the effects of four muddy water sediment concentration levels (ρ₀: 0; ρ₁: 4%; ρ₂: 8%; ρ₃: 12%) and four bio-organic fertilizer levels (FO₀: 0; FO₁: 2250 kg·hm⁻²; FO₂: 4500 kg·hm⁻²; sFO₃: 6750 kg·hm⁻²) on soil water infiltration, evaporation characteristics, and leaching loss. The results demonstrated that a higher muddy water sediment concentration and fertilization level resulted in a smaller wetting front distance and cumulative infiltration amount within the same time, but the infiltration reduction rate (η) gradually increased. The three infiltration models (Kostiakov, Philip, and Horton) were fitted, and it was discovered that all three had good fitting results (R² > 0.8), with the Kostiakov model displaying the best fit and the Horton model exhibiting the worst fit. The cumulative evaporation amount and evaporation time in muddy water irrigation and fertilization conditions was consistent with the Black and Rose evaporation models (R² > 0.9), the Black model was proved to be higher than the Rose model. In comparison to ρ₀, muddy water irrigation increased conductivity and total dissolved solids (TDS) in the leaching solution, but it reduced cumulative evaporation, soil moisture content, the uniformity coefficient of soil water distribution, and leaching solution volume. Compared with FO₀, the application of bio-organic fertilizer increased soil water content and reduced soil water evaporation while also reducing the leaching solution volume, conductivity, and TDS in the leaching solution. The results of this research can provide scientific reference for the efficient utilization of muddy water irrigation and the rational application of bio-organic fertilizer.