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The integrated management of water and fertilizer has been widely applied for effectively utilizing limited rainwater resources in rainfed farming systems. However, the combined effect of straw mulching and urea blended with slow-release nitrogen fertilizer (SU) on rainfed maize has seldom been studied. A two-year field experiment (2016–2017) was conducted to evaluate the effects of various agronomic practices, i.e. wheat straw mulching over the entire soil surface (QSU), wheat straw mulching over the partial soil surface (DSU), and water-retaining agent (BSU) under two N application rates (N1: 120 kg ha−1 and N2: 180 kg ha−1) on rainfed maize in northwest China. The results showed that DSUN2 delayed leaf senescence, increased chlorophyll content and photosynthesis, promoted N uptake, and increased grain yield (GY) (by 19.34%-39.91% in 2016 and 11.00%-52.57% in 2017), water use efficiency (WUE) (by 14.35%-56.21% in 2016 and 8.87%-57.44% in 2017) and nitrogen use efficiency (NUE) (by 12.03%-31.82% in 2016 and 0.49%-9.34% in 2017). More soil water was retained by QSU, which significantly promoted maize growth, but decreased GY compared with DSU. In conclusion, DSUN2 was the most effective agricultural management practice for improving GY, WUE and NUE of rained maize in northwest China. [ABSTRACT FROM AUTHOR]

Optimising the management of water and fertilizer, and fully exploiting the positive effects of the coupling of water and fertilizer, are important ways of achieving high crop yields and promoting the sustainable development of water-efficient agriculture. The objective of this study was to investigate the coupling effects of different irrigation levels and different mixing ratios of slow-release nitrogen fertilizers on the physiological growth characteristics and yield of winter wheat in Guanzhong region under drip irrigation. In this study, field experiments were conducted in two winter wheat growing seasons, 2018–2019 and 2019–2020. The study included three irrigation levels: W1 (60% ETc, where ETc is the evapotranspiration of the crop), W2 (80% ETc), and W3 (100% ETc); and four N fertilizer treatments: U (100% urea), UNS1 (urea: slow-release N fertilizer = 1:1), UNS2 (urea: slow-release N fertilizer = 1:3) and SRF (100% slow-release N fertilizer). Compared to W1 and W2, W3 prolonged the winter wheat leaf functional period, increased leaf area index and net photosynthetic rate (P n), and promoted dry matter accumulation. The total N content of winter wheat decreased by 22.67% and 9.93% under W1 and W2 conditions, respectively. The nitrogen use efficiency (NUE) decreased by 5.87% and 1.97%, respectively, leading to a decrease in yield. Slow-release nitrogen fertilizer (SRF) and its mixture treatments (UNS1, UNS2) increased post-flowering nitrogen uptake in winter wheat compared to U. At the same irrigation level, water use efficiency (WUE) was increased by 34.03%, 13.35%, and 20.86% in the UNS2 treatment compared to U, UNS1, and SRF, respectively. W3UNS2 obtained the highest grain yield: 8026.32 kg hm−2 (2018–2019) and 8993.25 (2019–2020) kg hm−2, with a 9.85–68.24% yield increase compared to other treatments. Und4er the treatments of this study, yield, WUE, and NUE of winter wheat reached 90% of the maximum at irrigation levels of 82.04–91.83% ETc and 59.18–83.67% of slow-release N fertilizer in blended fertilizer. Under water stress conditions, UNS1 and UNS2 can mitigate the effects of water deficit on plant growth and stabilize grain yield. This study provides useful information for optimising water and nitrogen management decisions for winter wheat in semi-arid climatic regions, and contributes to the promotion of sustainable development of wheat production and water-efficient agriculture. • The two-year drip trial was conducted in a sheltered canopy in GuanZhong. • Field trial address in the coupling impacts of irrigation&fertilizer on winter wheat. • Recommended irrigation volumes and mixing ratios were obtained using modelling. • Blended slow-release nitrogen fertilizer can effectively mitigate the drought effects. • 100% ETc with U:SRF = 1:3 is the most recommended irrigation and fertilization option. [ABSTRACT FROM AUTHOR]

China has the largest apple-growing area and fresh fruit production in the world; however, water shortages and low fertilizer utilization rates have restricted agricultural development. It is a major challenge to obtain scientific and reasonable irrigation and fertilization systems for young apple trees in semi-arid regions of northern China. A 2-year field bucket experiment with four irrigation levels of W1 (75–90% Fs, where Fs is the field water holding capacity), W2 (65–80% Fs), W3 (55–70% Fs), and W4 (45–60% Fs), and three fertilizer levels of F1 (27-9-9 g N-P2O5-K2O), F2 (18-9-9 g N-P2O5-K2O), and F3 (9-9-9 g N-P2O5-K2O) was conducted in 2019 and 2020, so as to explore the effects of different water and fertilizer treatments on the growth and physiological characteristics of young apple trees. The results showed that the plant growth, leaf area, and dry matter of young apple trees at each growing period reached maximum values under F1W2, and they showed a positive linear relationship with relative chlorophyll content (SPAD), net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), water consumption, and water use efficiency (WUE). With the growth of young apple trees, water-fertilizer coupling could significantly increase the leaf SPAD of young apple trees. Pn, Tr, and Gs reached the maximum value under F1W1, and although they decreased under F1W2, the water use efficiency increased by 2.3–25.7% and 4.0–23.8% under F1W2 compared with other treatments in two years, respectively. The water consumption of young apple trees increased with the increase of irrigation and fertilizer, and both dry matter and water productivity reached the maximum value under F1W2, which increased by 0.8%, 14.6% in 2019, and 0.6%, 11.1% in 2020 compared with F1W1, while water consumption decreased by 12.2% and 9.4% in both years. In conclusion, F1W2 treatment (soil moisture was controlled at 65–80% of field water holding capacity, and N-P2O5-K2O was controlled at 27-9-9 g) was the best coupling mode of water and fertilizer for young apple trees in semi-arid areas of northern China. [ABSTRACT FROM AUTHOR]

In dryland agriculture, mulching methods and nitrogen application have been extensively adopted to improve water and nitrogen use efficiency and increase crop yield. However, there has been a scarcity of research on the combined effects of mulching types and nitrogen application on the growth and yield of soybean (Glycine max L.). In the present study, four nitrogen levels (N0: 0 kg N ha−1, N1: 60 kg N ha−1, N2: 120 kg N ha−1, N3: 180 kg N ha−1) and four mulching methods (NM: no mulching, SM: straw mulching, FM: film mulching, SFM: straw and film mulching) were set so as to evaluate the effects of mulching methods and nitrogen application on dry matter accumulation, grain yield, water-nitrogen use efficiency, and economic benefits of soybean in Northwest China from 2021 to 2022. The results show that the dry matter accumulation, yield formation, water and nitrogen use efficiency, and economic benefits of soybean were improved under different mulching methods (SM, FM, and SFM) and nitrogen applications (N1-N3), and that the effect is the best when the nitrogen application rate is N2 and the mulching method is FM. As such, a conclusion could be drawn that suitable nitrogen application (120 kg ha−1) combined with film mulching was beneficial for the utilization of rainwater resources and soybean production in the dryland of Northwest China. [ABSTRACT FROM AUTHOR]

The over-application of irrigation and chemical fertilization in the greenhouse vegetable production system (GVPS) in China can jeopardize fruit quality, compromise economic profit and waste resources. Seeking optimal water and fertilizer supply mode for GVPS is urgently required to improve resource use efficiency and economic benefit. A greenhouse experiment was conducted during four consecutive tomato growing seasons to investigate the combined effects of various irrigation levels and fertilization practices on yield, fruit quality, economic benefit, water use efficiency (WUE) and nitrogen use efficiency (NUE) of drip-fertigated tomato, and to obtain the optimal water and fertilizer supply practice by the principal component analysis (PCA). On the basis of full irrigation (W1: 100%ET c , ET c was the crop evapotranspiration), two deficit irrigation levels (W2: 75%ET c , W3: 50%ET c) were set. Except for the conventional fertilization practice used by local farmers (CC: chicken manures for basal application and chemical fertilizer for topdressing), four other fertilization practices were considered, including soluble organic fertilizers for topdressing (SO), soluble chemical fertilizers for topdressing (SC), both soluble organic and chemical fertilizers for topdressing (SOSC), and a control with no fertilizer application under full irrigation (CK). The results showed that SOSC obtained relatively high plant nitrogen uptake, net profit and WUE, and significantly improved tomato yield. Organic fertilizers addition reduced nitrate content in tomato fruits. Deficit irrigation promoted CC to obtain higher WUE than SC. According to the result of PCA, the comprehensive ranking of SOSC was first among the fertilization practices, regardless of irrigation levels and growing seasons. W1SOSC and W2SOSC were highly recommended for greenhouse tomato production in spring and autumn seasons, respectively. ● Drip irrigation and fertilization effects on yield and economic benefit of tomato were explored. ● Organic fertilizers addition reduced nitrate content in tomato fruits. ● The comprehensive ranking of soluble organic and chemical fertilizers for topdressing was first. ● Soluble organic and chemical fertilizers combined with full irrigation or 75% full irrigation was recommended. [ABSTRACT FROM AUTHOR]

Nitrogen (N), phosphorus (P) and potassium (K) are essential elements for crop growth. The absorption, accumulation process and distribution of these nutrients affect not only the growth and grain yield, but also the grain quality of wheat (Triticum aestivum L.). Various fertilization and irrigation practices can influence wheat growth as well as the absorption and utilization of nutrient elements. A four-season (2014–2018) experiment was conducted on drip-fertigated winter wheat on the Loess Plateau of China with three irrigation levels and three fertilization rates. Irrigation rates included normal irrigation (W1), mild deficit irrigation (W2) and more severe deficit irrigation (W3), while fertilization rates (N-P 2 O 5 -K 2 O) included F1 (175–117–150 kg ha−1), F2 (125–84–108 kg ha−1) and F3 (75–50–65 kg ha−1). The results showed that NPK uptake in aboveground biomass decreased as the water stress increased, but there was no significant difference between W1 and W2. When sufficient water and fertilizer were applied, the stem, leaf and rachis + glume obtained higher proportion of NP, while grain nitrogen and phosphorus harvest index (NHI and PHI) decreased. When the supply of water and fertilizer was insufficient, NHI and PHI increased, and the proportion of vegetative organs was relatively low. The average NPK requirement for 100 kg grain (GNR, GPR and GKR) varied 1.93–3.03, 0.37–0.41 and 2.26–2.93 kg over the four seasons. GNR and GKR increased with increasing irrigation and fertilization regimes. With the increase of irrigation amount, irrigation water use efficiency (IWUE) first increased and then decreased slightly, and the maximum IWUE occurred under W2. Yield and IWUE increased with the increase of fertilization rate, but there was no significant difference between F1 and F2. F2 obtained higher partial factor productivity than F1. F1 and F2 had no significant difference in protein content and protein yield, but they obtained significantly higher values than F3. Therefore, W2F2 was an efficient water and fertilizer management practice for drip-fertigated winter wheat, which promoted nutrients transfer to grains without significantly reducing grain yield and protein. • Drip fertigation effects on nutrient uptake and utilization of winter wheat were explored. • When sufficient water-fertilizer applied, grain nitrogen and phosphorus harvest index decreased. • Average NPK requirement for 100 kg grain were 1.93–3.03, 0.37–0.41 and 2.26–2.93 kg, respectively. • W2F2 promoted nutrients transfer to grains without significantly reducing yield. [ABSTRACT FROM AUTHOR]

Given water resources scarcity in Northwest China and the urgent need for the integration and optimization of scientific and technological resources in facility agriculture, this experiment explored the appropriate water and fertilizer management measures for greenhouse sweet pepper under fertilization in Northwest China. A two-year drip fertigation sweet pepper experiment was conducted in a solar greenhouse, with four irrigation levels (W 1 : 105% ET C , W 2 : 90% ET C , W 3 : 75% ET C , W 4 : 60% ET C) and four nitrogen levels (N 1 : 300 kg/ha, N 2 : 225 kg/ha, N 3 : 150 kg/ha, N 4 : 75 kg/ha). The results showed that above-ground dry matter accumulation (DMA), yield, harvest index (HI), and water use efficiency (WUE) of sweet pepper increased first and then decreased with the increase of irrigation/nitrogen amounts under the same nitrogen/irrigation levels. The partial factor productivity of nitrogen (PFPN) decreased significantly with the increase of nitrogen application rate, while it increased first and then decreased with the increase of irrigation level. The PFPN reached a peak at W 2 level, despite no significant difference between W 2 and W 3 levels. With the increase of nitrogen application rate, soluble sugar and vitamin C content increased first and then decreased with a maximum at N 3 level; nitrate content increased with the increase of nitrogen application rate, and there was no significant difference between N 4 and N 3 levels. The contents of soluble sugar and nitrate nitrogen decreased with the increase of irrigation amount, and they did not differ between W 1 and W 3 levels at N 3 level; the vitamin C content increased first and then decreased with the increase of irrigation amount, reaching the maximum in W 2 or W 3 treatments. Considering the shortage of water resources in the study area, the W 3 N 3 treatment (75% ET C , 150 kg/ha) could be recommended as the optimal drip fertigation strategy. Results showed that the optimal value of sweet pepper (the best confidence intervals of 85%) was achieved at the irrigation water and nitrogen amount of 78.2–80.8% ET C and 164.5–189.5 kg/ha, respectively. This study provides scientific basis for water and nitrogen management of high yield, quality, and benefit planting of facility sweet pepper in Northwest China. • Water and nitrogen had significant effects on sweet pepper harvest index. • Vitamin C increased first and then decreased with increase of water and nitrogen. • WUE decreased with the increase of irrigation amount. • The precise water and nitrogen application interval were determined. [ABSTRACT FROM AUTHOR]

• Full irrigation (100 %ET c) improved plant growth and yield of greenhouse tomato. • 75 %ET c obtained higher WUE and lower unmarketable yield. • 100 %ET c tended to shorten rapid growth period of aboveground biomass and improve maximum growth rate. • The lowest total water consumption occurred at the blooming and setting stage. Agriculture is the largest consumer of scarce water resources and irrigation serves as the sole source of water for greenhouse tomato production. It is an urgent task to seek an appropriate deficit irrigation strategy that is beneficial for high marketable yield, fruit quality, saving irrigation water and ultimately improving water use efficiency. A four-season experiment was conducted on drip-irrigated greenhouse tomato during Autumn 2015-Spring 2017 with three irrigation regimes, i.e., 100 %ET c (crop evapotranspiration) (W1), 75 %ET c (W2) and 50 %ET c (W3). The results showed that aboveground biomass, leaf area index (LAI), plant height and fruit yield increased with increasing irrigation amount. However, soluble solids, vitamin C and soluble sugar of tomato fruits were lowest under W1. W2 markedly reduced unmarketable fruits and more small-sized fruits were harvested at the late stage under W1. Through fitting the relationship between cumulative temperature and aboveground biomass using logistic equations, it was found that average duration of the rapid growth period (t d) and the time when growth rate reached the maximum value (t m) increased as irrigation amount decreased. Conversely, the maximum growth rate during the rapid growth period (v m) decreased with the increase of water deficit. The highest total water consumption (278.05 mm), lowest total yield water use efficiency (25.12 kg m−3) and marketable yield water use efficiency (22.87 kg m−3) were obtained under W1. The smallest total water consumption (27.01–50.75 mm) occurred at the blooming and setting stage. Based on the results of path analysis, aboveground biomass and average fruit weight were important indexes affecting yield positively. It is concluded that deficit drip irrigation with 75 %ET c has the potential of supporting tomato growth, improving marketable yield and WUE as a result of less unmarketable yield and bigger fruit size. [ABSTRACT FROM AUTHOR]