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The growth status of mango (Mangifera indica L.) seedlings directly affects the yield and quality of mango, but there are few reports on water management at the growth stage of mango seedlings. The objective of this study was to identify an optimal water-saving irrigation method for mango seedlings. Taking surface drip irrigation as the control (CK), the effects of alternate infiltration irrigation (AII) on the photosynthetic characteristics, growth, and irrigation water use efficiency (IWUE) of mango seedlings were studied. The AII systems used three irrigation levels: 90% (AII90), 70% (AII70), and 50% (AII50) of the irrigation quota of CK. The results indicated that compared with CK, AII70 and AII50 increased the average leaf water use efficiency by 10.54% and 11.77%, respectively. However, compared with CK, AII50 decreased the average stomatal conductance and transpiration rate by 13.89% and 13.76%, respectively. There was a significant linear relationship between dry mass increment and net photosynthetic rate. The dynamic TOPSIS method indicated that AII70 provided optimal comprehensive photosynthetic benefits. The incremental dry mass and IWUE of AII70 were significantly higher than those of the other treatments. Therefore, we recommend applying a moderate water deficit through alternate infiltration irrigation (AII70) for water management in mango seedling cultivation. [ABSTRACT FROM AUTHOR]

Reasonable water and light management technology can improve economic benefits, coffee yield, and quality. We used cluster analysis and principal component analysis to evaluate and optimize the water and light management technology with high coffee yield, quality, and economic benefits in a subtropical monsoon climate region of China. The experiment was arranged in a randomized complete block design with two factors (3 irrigation levels × 4 shade cultivation treatments) replicated four times during 2016–2017. The irrigation levels consisted of full irrigation (FI) and two deficit irrigations (DI L : 75% FI, DI S : 50% FI). The shade cultivation treatments consisted of no shade cultivation (S0) and three shade cultivation modes (S L : intercropping with four lines of coffee and one line of banana; S M : intercropping with three lines of coffee and one line of banana; S S : intercropping with two lines of coffee and one line of banana). The results showed that the effects of irrigation level and shade cultivation mode on growth, crop yield, most of the photosynthetic characteristics, and nutritional quality were significant (p < 0.05). Regression analysis showed that the leaf radiation use efficiency (RUE) showed a significant negative exponential relation or logistic-curve variation with photosynthetically active radiation (PAR). The bean yield increased with an increase of the shade degree when water was seriously deficient, whereas it first increased and then decreased with an increase of the shade degree under FI and DI L . Based on both cluster analysis and principal component analysis, the FIS S treatment resulted in the highest comprehensive quality of coffee, followed by the FIS M treatment; the DI S S0 treatment obtained the lowest quality. Compared with the FIS0 treatment, the FIS M treatment increased the 2-year average bean yield and net income by 15.0 and 28.5%, respectively, whereas the FIS S treatment decreased these by 17.8 and 8.7%, respectively. To summarize, FIS S treatment significantly improved the nutritional quality of coffee, and FIS M treatment significantly increased the dry bean yield and economic benefits of coffee. The results of the study could provide a theoretical basis for water-saving irrigation and shade cultivation management of coffee in a subtropical monsoon climate region of China. [ABSTRACT FROM AUTHOR]

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 (DIL: 70–85% θ f ), moderate deficit irrigation (DIM: 55–70% θ f ), and severe deficit irrigation (DIS: 40–55% θ f ) and three tiers of nitrogen, i.e., high nitrogen (NH: 600 kg ha–1), medium nitrogen (NM: 400 kg ha–1), and low nitrogen (NL: 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 DILNM treatment, and the worst comprehensive evaluation index was DISNL 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. [ABSTRACT FROM AUTHOR]

Soil water and nutrients are the two important factors affecting vegetative growth and the reproduction of greenhouse tomatoes (Solanum lycopersicum L.), but the effect of the interaction between irrigation and nitrogen (N) rates on fruit yield, root characteristics and N uptake have not yet been studied. Tomatoes were irrigated at 100% (W1), 80% (W2), and 60% (W3) of reference crop evapotranspiration (ET0) and N fertilizer was supplied at 240 kg N ha−1 (N240), 180 kg N ha−1 (N180), and 120 kg N ha−1 (N120) under drip fertigation in 2015 and 2016. In 2015, the fruit yield of the irrigation and N rates varied from 54.1 to 75.9 t ha−1. In 2016 (where the total irrigation amount was higher than in 2015), the fruit yield varied from 55.6 to 78.7 t ha−1. The average fruit yield in W1 was 17.8% and 21.4% higher than W3, in 2015 and 2016 respectively. The mean root weight density in N240 was 13.4% and 10.7% lower than N180, in 2015 and 2016, respectively. Averaging the irrigation levels, the total dry-matter production in N180 and N120 was, respectively, 1.4% and 13.2% lower than N240 in 2015. With the application of the irrigation and N fertilizer rates, plant N uptake increased from 28.7 to 94% in 2015 and from 14 to 92.3% in 2016. The water use efficiency (WUE) of the irrigation and N rates varied from 25.4 to 37.2 kg m−3 and from 20.8 to 36 kg m−3 in 2016. The partial factor productivity of the N fertilizer (PFPN) varied from 274.6 to 529.3 kg kg−1 and from 260.1 to 592.1 kg kg−1 in 2016 with the irrigation and N fertilizer rates. We conclude that the effect of irrigation and N rates on fruit yield, dry-matter production and N uptake significantly changes with the root characteristics. Considering the trade-off among the plant N uptake, WUE and PFPN, W2N180 may give a satisfactory fruit yield for greenhouse tomato in north-west China. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the interactions between irrigation and fertilizer treatments on soil NO3--N content and vertical distribution under drip fertigation in greenhouse tomatoes. Randomized block design with three replications and the treatments consisting of three levels of irrigation and three levels of N fertilizer were used. Three irrigation levels were W1 (100%  ET0), W2 (75%  ET0), and W3 (50%  ET0) and fertilizer levels were F1 (N240–P2O5120–K2O150 kg hm−2), F2 (N180–P2O590–K2O112.5 kg hm−2), and F3 (N120–P2O560–K2O75 kg hm−2). The result demonstrates that dynamics of soil NO3--N and its response to drip fertigation and levels of N moved toward the fore soil moist, and the average soil NO3--N content with W3 treatment was 1.23 times higher than that of the W1 treatment in 0–60 cm at 43 days after transplanting. The negative correlation between N use efficiency and levels of fertilizer N and the N recovery efficiency was increased with increases of N fertilizer application. The fertilizer nitrogen rate greatly significantly influenced soil NO3--N content. Avoiding N leaching through controlled matching N fertilizer application and controlled irrigation to tomato N demand is the key to maintain crop yield and improve N use efficiency. [ABSTRACT FROM AUTHOR]

To investigate the effects of alternate partial root-zone irrigation (APRI) and water deficit at different growth stages on maize growth, physiological characteristics, the grain yield, and the water use efficiency (WUE), a pot experiment was conducted under a mobile automatic rain shelter. There were two irrigation methods, i.e., conventional irrigation (CI) and APRI; two irrigation levels, i.e., mild deficit irrigation (W1, 55%~70% FC, where FC is the field capacity) and serious deficit irrigation (W2, 40%~55% FC); and two deficit stages, i.e., the seedling (S) and milking stage (M). Sufficient irrigation (W0: 70%~85% FC) was applied throughout the growing season of maize as the control treatment (CK). The results indicated that APRI and CI decreased the total water consumption (ET) by 34.7% and 23.8% compared to CK, respectively. In comparison to CK, APRI and CI increased the yield-based water use efficiency (WUEY) by 41% and 7.7%, respectively. APRI increased the irrigation water efficiency (IWUE) and biomass-based water use efficiency (WUEB) by 8.8% and 25.5% compared to CK, respectively. Additionally, ASW1 had a similar grain yield to CK and the largest harvest index (HI). However, the chlorophyll and carotenoid contents were significantly reduced by 13.7% and 23.1% under CI, and by 11.3% and 20.3% under APRI, compared to CK, respectively. Deficit irrigation at the milking stage produced a longer tip length, resulting in a lower grain yield. Based on the entropy weight method and the technique for order preference by similarity to an ideal solution (TOPSIS) method, multi-objective optimization was obtained when mild deficit irrigation (55%~70% FC) occurred at the seedling stage under APRI. [ABSTRACT FROM AUTHOR]

• Water, N and year significantly affect dry matter accumulation, fruit yield, quality, water and N productivity. • The Entropy Weight-TOPSIS method was adopted to achieve the multi-objective optimization of water and N fertilizer. • I80N360 (80% ET 0 - 360 kg N ha−1) is the ideal water and N management strategy for greenhouse cherry tomato. In the context of climate-change and shortage of fresh water resources, improving agricultural productivity has become a major challenge globally, especially in China with large population. In this study, the purpose was to achieve the optimal combination of water and nitrogen (N) rates for greenhouse cherry tomato based on fruit yield, quality, net income and water-N productivity. Herein, during 2019–2021, three irrigation levels (I100: 100% ET 0 ; I80: 80% ET 0 ; I60: 60% ET 0 , where ET 0 was the reference evapotranspiration) and five N rates (450, 360, 270, 180 and 0 kg N ha−1, defined by N450, N360, N270, N180 and N0, respectively) with 15 treatments were set up. The 3-year ANOVA analysis indicated that irrigation, N fertilizer and year had significant effects on dry matter accumulation, fruit yield, quality, water and N productivity of greenhouse cherry tomato. Both the highest fruit yield (56.72 t ha−1, average of 3-year) and net income (60.8 × 104 CNY ha−1) were occurred under I80N360 treatment, though peak N partial factor productivity (PFPN, 294.88 kg−1) was observed under I80N180 treatment. The combined application of water and N fertilizer increased water productivity (WP) by 15.64% (average of 3-year) compared to I60N0 treatment, with I80N360 and I60N270 treatments having the highest WP. N fertilizer addition significantly increased fruit yield and WP irrespective of irrigation level, but the differences between N360 and N450 treatments were not significant in 80% ET 0 and 100% ET 0 irrigation level treatments, and between N270, N360 and N450 treatments in 60% ET 0 irrigation level treatments. Nevertheless, PFPN decreased significantly as the N rate increased. In addition, fruit quality could be improved at some extent under deficit irrigation relative to full irrigation regardless of N rate. More specifically, compared with the full irrigation treatment (I100), the I80 treatment increased the content of total soluble solid (TSS) by an average of 6.68%, soluble sugar (SS) by 11.96%, organic acid (OA) by 4.91%, sugar acid ratio (SAR) by 11.28%, vitamin C (VC) by 14.55%, lycopene by 30.06% and firmness by 7.60%; meanwhile, the I60 treatment increased TSS by an average of 11.17%, SS by 18.60%, OA by 12.04%, SAR by 10.02%, VC by 27.55%, lycopene by -7.93% and firmness by 13.14%, respectively. The increase of N rate largely increased TSS, SS, SAR, VC and lycopene, while these indicators decreased when N rate exceeded a threshold. Nevertheless, OA and firmness increased with increasing N rate, while firmness showed a slight decrease when N rate increased from N360 to N450 treatment. Generally, in a greenhouse cherry tomato production agroecosystem, the optimal amount of N fertilizer applied for each indicator varies with the availability of irrigation water. Furthermore, the Entropy-Weight TOPSIS method was adopted and the results indicated that the optimization of irrigation and N fertilizer supply schedule (I80N360 treatment: 80% ET 0 –360 kg N ha−1) was conducive to increase fruit yield, net income and water-N productivity whilst maintaining fruit quality in greenhouse cherry tomato cultivation. [ABSTRACT FROM AUTHOR]

The knowledge of seasonal nutrient demand is necessary for maximizing potato yield and resources use efficiency under drip fertigation, and it also can effectively mitigate the risk of nutrient leaching caused by excessive fertilization. To explore the coupling effects of irrigation level and fertilization rate on drip-fertigated potato growth, nutrient accumulation and determine the multi-objective optimal irrigation and fertilization regimes, a two-year (2018 and 2019) field experiment was conducted in the sandy regions of northern China. The experiments included three irrigation levels (I 60 , 60% ET C ; I 80 , 80% ET C and I 100 , 100% ET C , where ETc is the crop evapotranspiration) and five fertilization rates (N 0 P 0 K 0 , 0 kg ha−1; N 1 P 1 K 1 , 100–17.5–124.5 kg ha−1; N 2 P 2 K 2 , 150–26.2–186.7 kg ha−1; N 3 P 3 K 3 , 200–34.9–248.9 kg ha−1 and N 4 P 4 K 4 , 250–43.7–311.2 kg ha−1, where the ratio of N, P and K was 1:0.17:1.24). The results showed that N, P and K accumulated rapidly from 42th to 95th, 50th to 96th and 46th to 91th days after sowing, respectively. For producing 1000 kg tuber yield, the required amounts of N, P and K were 1.97–4.16 kg, 0.55–0.81 kg and 4.83–7.65 kg, respectively. The uptakes of N, P and K in 1000 kg tubers across all treatments were 1:0.18–0.34:1.61–2.59, with the average N:P:K ratio of 1:0.23:2.05. Besides, irrigation level, fertilization rate and their interaction had significant effects on potato leaf area index, biomass, N, P and K accumulation. Deficit irrigation reduced seasonal LAI, biomass, N, P and K accumulation, tuber yield and apparent fertilizer recovery (AFR), but increased water productivity. High fertilization rate was conducive to promoting nutrient absorption, plant growth and improving tuber yield, while it reduced the unit nutrient productivity. The AFR increased first and then decreased with the increase of fertilization rate. To simultaneously achieve high potato yield and resources use efficiency, a multi-objective optimization model was established using the binary quadratic regression analysis between tuber yield, net income, water productivity, AFR and water–fertilizer regimes, which showed that tuber yield, net income, water productivity, and AFR could obtained ≥ 90% of their maximum values simultaneously when the irrigation interval was 204–262 mm and fertilization (N-P-K) interval ranged from 200–24–248 to 247–42–306 kg ha−1. The findings can provide useful information for optimizing irrigation and fertilization regimes in sandy regions of northern China. ● Nutrient uptake process under virous drip fertigation combinations was explored. ● Water and fertilization had significant effects on nutrient accumulation and yield. ● 1.97–4.16 kg N, 0.55–0.81 kg P and 4.83–7.65 kg K were needed to produce 1 t tuber. ● Interval of fertigation was put forward through a multi-objective optimization model. [ABSTRACT FROM AUTHOR]

Water shortage, excessive fertilization and improper variety selection have seriously restricted the sustainable development of potato in Northwest China. Two-year field experiments were conducted in 2021 and 2022 to explore the effects of irrigation amount and fertilizer application rate on the growth, yield, nutrient uptake, quality, water, and fertilizer use efficiency, soil enzyme activity and economic benefits of different potato varieties. Three irrigation levels were W1 (100% crop evapotranspiration (ET C)), W2 (80% ET C) and W3 (60% ET C). Three fertilization rates were F1 (240 kg N ha−1), F2 (180 kg N ha−1) and F3 (120 kg N ha−1). Three locally grown potato cultivars were V1 (Feiurita), V2 (Longshu 7), and V3 (Qingshu 9). The results showed that irrigation amount, fertilization rate and potato variety significantly influenced tuber yield, commercial tubers, maximum tubers, tuber weight, reduced sugar content, irrigation water productivity (WP I), partial fertilizer productivity (PFP), soil catalase activity (SCA), total income, net income, and input-output ratio. The chlorophyll content, net photosynthetic rate, dry matter accumulation, maximum tuber weight, starch content, vitamin C content, and crude protein content increased with the increase of irrigation amount. With the increase of fertilizer application rate, chlorophyll content, net photosynthetic rate, dry matter accumulation, tuber yield, plant nitrogen (N), phosphorus (P), potassium (K) absorption, starch content, crude protein content, vitamin C content, WP I , soil enzyme activity and net income increased first and then tended to stabilize or even decline. On average, the tuber yield, starch content, crude protein content, vitamin C content, WP I and net income of F2 were 19.3% (6.9%), 1.6% (1.6%), 8.8% (10.4%), 3.8% (10.5%) and 21.1% (7.8%), 34.6% (14.9%) higher than those of F1 in 2021 (2022), respectively. In two years, the average potato yield, WP I , PFP and SCA of V3 treatment were 13.1%, 14.5%, 16.4% and 4.8% higher than those of V2 treatment, respectively. Among all treatments, T5 (W2F2V3) had the highest tuber yield, commercial tuber yield, total P accumulation, crude protein content, SCA, soil alkaline phosphatase activity (SPA), soil sucrase activity (SSA) and net income, and the lowest reducing sugar content. Plant accumulation of N, P and K was closely related to tuber yield, and potato tuber yield showed a significant positive correlation with SCA and SSA. Based on the comprehensive differential combination evaluation model, considering potato growth and development, yield, quality, water, and fertilizer use efficiency and economic benefits, T5 treatment was the best treatment. After comprehensive evaluation, the optimal irrigation and fertilizer ranges were 270–290 mm and 167 kg N ha−1 to 193 kg N ha−1, respectively. The present study provides a basis for evaluating and selecting better management practices for effective irrigation and fertilization management of the best potato varieties in Northwest China. • Irrigation and fertilization had significant effects on soil catalase activity. • Maximum crude protein content was achieved under medium fertilization. • Starch content was significantly correlated with soil enzyme activity. • Varieties had significant effects on potato WP I and PFP. [ABSTRACT FROM AUTHOR]

The scarcity of irrigation water has now become the main constraint for crop production globally. Potato growth in arid and semiarid regions is facing increasing challenges due to water deficit. Potato productivity is generally influenced by water and fertilizer, and the requirements for these factors vary depending on the soil type and potato variety. Field experiments were conducted during 2019–2020 to select the suitable potato varieties with the best combination of irrigation and fertilization levels. The three irrigation amounts were W1 (100% crop evapotranspiration (ET C)), W2 (80% ET C) and W3 (60% ET C). The three fertilizer rates were F1 (N–P 2 O 5 –K 2 O, 240–120–300 kg ha−1), F2 (180–90–225 kg ha−1) and F3 (120–60–150 kg ha−1). The three locally cultivated potato varieties were V1 (Feiurita), V2 (Xiapoti), and V3 (Yushu 4). The results showed that irrigation amount, fertilizer amount and potato variety had significant effects on potato growth, yield, quality and water and fertilizer productivity. The average potato yield and irrigation water use efficiency (IWUE) in Feiurita were 12.5% (11.9%) and 14.2% (13.3%) higher than those in Xiapoti in 2019 (2020), respectively. On average, the tuber yield and partial factor productivity (PFP) in W1 were 27.8% (35%) and 26.8% (34.7%) higher than those in W3 in 2019 (2020), respectively. Tuber yield, IWUE and polyphenol oxidase activity (POA) were most subject to irrigation amount, followed by potato variety and fertilizer rate. Potato tuber yield was significantly correlated with soil available potassium, soil actinomycete quantity, soil catalase activity, and soil sucrase activity (SSA). The W2F3V1 treatment had the highest PFP, starch content, reducing sugar content, and vitamin C content (VC), and the tuber yield and crude protein content were relatively high. The W3F2V1 treatment had the highest IWUE and vitamin C, and the starch content and POA were relatively high. Among them, the soil actinomycete quantity, soil cellulose decomposition bacteria quantity (SCDBQ), soil catalase activity, soil urease activity (SUA), and SSA in the W2F3V1 and W3F2V1 treatments were moderate. The W2F3V1 and W3F2V1 treatments are recommended as the best water and fertilizer management in sandy loam soils in Northwest China. • Tuber yield was most subject to irrigation, followed by variety and fertilizer • Soil pH and soil conductivity significantly affected vitamin C content • Increasing irrigation amount can reduce soil actinomyces and increase sucrase • Soil cellulose decomposition bacteria significantly affected reducing sugar [ABSTRACT FROM AUTHOR]

As a cash crop, potato plays an important role in the economic development and ensuring food security. Reasonable management of irrigation and fertilization can promote the uptake of water and nutrients by potato, thereby improving the tuber yield and quality, and reducing fertilizer residues in the soil. A four-year field experiment was carried out to explore the effects of different irrigation amounts and fertilization rates on potato yield, economic benefit, tuber quality, water productivity (WP) and fertilizer use efficiency (FUE), and soil nutrient residues during 2016–2019. Multi-objective optimization of irrigation amount and fertilization rate was conducted based on data in 2018 and 2019 using the Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation methods. In 2016 and 2017, three irrigation levels (W 1 , 60% ET C ; W 2 , 80% ET C and W 3 , 100% ET C) and three fertilization (N-P-K) rates (F 1 , 100–17.5–124.5 kg/ha; F 2 , 150–26.2–186.7 kg/ha and F 3 , 200–34.9–248.9 kg/ha) were applied. The highest tuber yield was obtained under F 3 in 2016 and 2017. Two fertilization rates (F 0 , 0 kg/ha and F 4 , 250–43.7–311.2 kg/ha) were further considered in 2018 and 2019. Results showed that the highest tuber yield, net income, WP, dry matter and the residues accumulation of nitrate nitrogen, available phosphorus, and available potassium were obtained under F 4 in 2018 and 2019. However, the differences in tuber yield, net income and WP between F 3 and F 4 were not significant under W 3. Deficit irrigation reduced tuber yield, ET, net income, shoot dry matter, tuber dry matter, LAI, relative chlorophyll content, starch and vitamin C content and FUE, and increased the residues of nutrient in the soil and reducing sugar content. Besides, W 1 showed the highest irrigation water productivity, but the starch and vitamin C content of W 3 F 2 were largest. The highest FUE was obtained under W 3 F 3 (56.33% in 2018 and 53.33% in 2019). Increasing fertilization rate decreased the fertilizer partial factor productivity and sink/source. Based on the economic benefit, tuber quality, WP and FUE and soil environmental benefit, the multi-objective optimization was evaluated by the Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation methods. When the irrigation amount was 100% ET C (W 3) and the fertilization rate (N-P-K) was 200–34.9–248.9 kg/ha (F 3), the multi-objective optimization was obtained. The results can provide a theoretical basis for the optimization of water and fertilizer regimes of potato in northern China and other regions with similar environments. • Optimization of water and fertilizer management of drip-fertigated potato were studied. • Deficit irrigation reduced tuber yield, quality and FUE. • Quality and FUE increased first and then decreased as the rate of fertilizer increased. • The best strategy of irrigation and fertilization was put forward based on AHP-FCE. [ABSTRACT FROM AUTHOR]