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Abstract: To investigate the effect of alternate drip irrigation on hydraulic conductivity and water-use efficiency of young pear tree, a field experiment was conducted with three drip irrigation methods, i.e. alternate drip irrigation (ADI, both sides of the root-zone irrigated alternatively), fixed drip irrigation (FDI, only one side of the root-zone irrigated), conventional drip irrigation (CDI, watering near the base of tree), and three irrigation levels, i.e. irrigation quantity of 20 (W1), 30 (W2) and 40mm (W3), respectively. Results show that compared to CDI, ADI reduced total hydraulic conductivity (root to leaf), soil evaporation, evapotranspiration, leaf area and total dry mass of young pear tree, but increased water-use efficiency (WUE ET ) and irrigation water-use efficiency (WUE I ) when the watering was reduced by 50% at W1, and it reduced soil evaporation, evapotranspiration, leaf area and total dry mass, but increased total hydraulic conductivity (root to leaf), WUE ET and WUE I when the watering was reduced by 25–33% at W2 and W3. However, FDI significantly decreased total hydraulic conductivity and total dry mass when compared to CDI. Thus ADI significantly increased total hydraulic conductivity due to its more evenly watering to the whole root-zone, which led to the increase of water-use efficiency when the watering was reduced by 25–33%. [Copyright &y& Elsevier]

Abstract: A pot experiment was conducted to investigate the effect of three drip irrigation methods (i.e. conventional drip irrigation (CDI), both sides of the root-zone irrigated with full watering, alternate drip irrigation (ADI), both sides of the root-zone irrigated alternatively with half of the full watering, and fixed drip irrigation (FDI), only one side of the root-zone irrigated with half of the full watering) on growth, physiology, root hydraulic conductance and water use of young apple tree under different nitrogen (N) or phosphorus (P) fertilization (i.e. CK (no fertilization), N1 (0.2gN/kg), N2 (0.4gN/kg), P1 (0.2gP2O5/kg) and P2 (0.4gP2O5/kg)). Results show that compared to CDI, ADI and FDI reduced mean root dry mass, daily transpiration, root hydraulic conductance (K r ), leaf photosynthesis rate, transpiration rate and stomatal conductance of young apple tree by 6.9 and 27.7, 29.3 and 45.0, 6.8 and 37.9, 2.5 and 4.8, 32.6 and 33.0, 22.1 and 22.3%, but increased leaf water use efficiency (WUE) by 31.3 and 29.8%, respectively when they saved irrigation water by 50%. Compared to the CK, N or P fertilization significantly increased K r , and K r was increased with the increased N or P fertilization level. There were parabolic correlations between K r and root dry mass, daily transpiration and stomatal conductance. Our results indicate that ADI reduced transpiration rate significantly, but it did not reduce photosynthesis rate and K r significantly, thus alternate drip irrigation improved WUE and the regulation ability of water balance in plants. [Copyright &y& Elsevier]

Panax notoginseng is an important medicinal crop in China. The high incidence of root rot in P. notoginseng during the rainy season has restricted the development of the industry. It is believed that frequent rainfall and a warm soil environment are important factors that promote root rot incidence. However, there is still a significant knowledge gap in the relationship between rainfall and root rot incidence. To understand the effects of rainfall and fertilizer on root exudates, the soil bacterial structure, and root rot in P. notoginseng, four treatments were chosen for both field and pot experiments. These treatments included DW (rain shelter and no fertilizer), RW (no rain shelter and no fertilizer), DWF (rain shelter and fertilizer), and RWF (no rain shelter and fertilizer). The results showed that both factors (rain shelter and fertilizer) significantly affected root rot incidence and several other parameters. Among them, the effect of a rain shelter is more significant than that of fertilizer, and the combination of the two further improves the effect. DW and DWF treatments significantly reduced the soil moisture, phenolic acid, and root rot incidence, while significantly increasing the soil temperature and enzyme activities compared to RW or RWF. Seven phenolic acids secreted by P. notoginseng roots were all positively correlated with root rot incidence. Root rot was also positively correlated with Planctomycetota, Acidobacteriota, and Gemmatimonadota and negatively correlated with Firmicutes, Proteobacteria, Patescibacteria, and Nitrospirota. DWF treatment decreased the soil moisture and the concentration of p-hydroxybenzoic acid, syringic acid, phthalic acid, and vanillic acid and promoted the growth of Firmicutes and Proteobacteria, leading to the lowest incidence of root rot. [ABSTRACT FROM AUTHOR]

Excessive water and fertilizer management strategy was main factor restricting high-quality production of edible Rose s. The objective of this study was therefore to explore a combination of micro-irrigation method and bio-organic fertilizer application amount suitable for high-quality production of edible Rose s. A two-year greenhouse experiment was conducted to investigate the effects micro-irrigation method and bio-organic fertilizer application on soil environment, photosynthetic characteristics, yield, and nutritional quality of edible Rose in 2019 and 2020. The experiment treatments consisted of three micro-irrigation methods [micro-sprinkler irrigation (SI), drip irrigation (DI), and micro-moistening irrigation (MI)] and four bio-organic fertilizer supplementation levels (0, 5000, 10000, and 15000 kg ha−1, labeled as BF 0 , BF L , BF M , and BF H). The results indicated that MIBF M significantly improved soil water content, soil organic matter, pH, and the number of bacteria, fungus, and actinomycetes in the edible Rose field among all treatments. The MIBF M could improve net photosynthetic rate and leaf instantaneous water use efficiency of edible Rose compared with MIBF H. The flower weight, average flower diameter, and edible Rose yield were larger in MIBF M than those of MIBF H in 2019 and 2020. The MIBF M improved total sugar, flavonoids, vitamin C, and total amino acids of edible Rose compared with MIBF H. According to analyzing the relationships between photosynthesis, soil environment, flower yield, and quality among all treatments, we found MIBF M promoted edible Rose production by improving soil environment. The membership function method was used to comprehensively evaluate the nutritional quality of edible Rose s, we recommended that the combination of micro-moistening irrigation (MI) combined with bio-organic fertilizer application amount (10000 kg ha−1) (BF M) would be an adaptive irrigation and fertilization management strategy for improving soil environment and edible Rose production in Southwest China. • The MIBF M could improve soil environment and edible Rose productivity. • The MIBF M improved soil water storage, soil nutrients and soil microorganism. • The MIBF M improved yield and nutritional quality of edible Rose. [ABSTRACT FROM AUTHOR]

• Micro-moistening irrigation (MM) significantly increased dry mass (DM) accumulation and water-fertilizer use efficiency of young mango tree. • Moderate fertilization rate (F M) had the highest leaf net photosynthetic rate (P n), hydraulic conductivity and healthy index (H i). • MMF M treatment was the suitable coupling mode of irrigation and fertilization management for young mango tree. Unsuitable irrigation and soil nutrient deficiency affect the normal physiology and growth of mango (Mangifera indica L.) of tropical fruit tree in Southwest China. To obtain optimal fertigation mode for mango, the effects of three micro-irrigation methods (i.e., micro-sprinkler irrigation (SI), drip irrigation (DI) and micro-moistening irrigation (MM)) on photosynthetic characteristics, hydraulic conductivity, growth and water-fertilizer use efficiency of young mango tree were investigated under four fertilization rates (i.e., 0 g plant−1 (F N), 9.3 g plant−1 (F L), 18.6 g plant−1 (F M) and 27.9 g plant−1 (F H), a compound water-soluble fertilizer) using a randomized block design experiment. The results indicated that DI and MM increased net photosynthetic rate (P n) by 17.50 and 28.95%, root hydraulic conductivity (K r) by 39.65 and 52.69%, shoot hydraulic conductivity (K sh) by 48.63 and 82.38%, total dry mass (DM) by 27.44 and 47.13%, water use efficiency (WUE ET) by 43.27 and 73.17%, fertilizer agronomic efficiency (FAE) by 45.92 and 95.41%, and partial factor productivity of fertilizer (PFP) by 33.96 and 54.44%, but reduced transpiration rate (T r) by 6.61 and 16.38%, leaf with petiole hydraulic conductivity (K l+p) by 13.11 and 30.32%, and water consumption (ET) by 10.38 and 14.85% when compared with SI. Compared with F N , enhancing fertilization rate significantly increased P n , T r , total hydraulic conductivity (root to leaf), total DM , healthy index (H i) and WUE ET , and their maximum values appeared in the F M. FAE firstly increased and then decreased, while PFP gradually reduced with the increase of fertilization rate. MMF M had the highest total DM and WUE ET , 2.32 and 2.58 times of SIF N (CK), and the largest FAE of 4.95 kg−1. Thus, MMF M (micro-moistening irrigation with moderate fertilization rate of 18.6 g plant−1) significantly promoted growth and improved water-fertilizer use efficiency of young mango tree, which was the best coupling mode of irrigation method and fertilization rate. [ABSTRACT FROM AUTHOR]