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【Objective】 Water and nitrogen are integrative in their impacts on root uptake of water and nutrients from soil. The purpose of this paper is to screen for optimal combination of irrigation and nitrogen fertilization for sustaining summer maize production in north of Henan province. 【Method】 A 3-year experiment designed in randomized block was conducted from 2017 to 2019 in a maize field. It compared three irrigation schedules: rainfed (A1), irrigation twice (A2), and irrigation three times (A3) during growing season of the crop; for each irrigation treatment, there were two nitrogen fertilizations: applying 70%, 20% and 10% of the fertilizer as basal fertilization, at small trumpet and filling stage respectively (B1), applying 60%, 25% and 15% of the fertilizer as basal, at small trumpet and filling stage respectively (B2). During the experiment, we measured water and nitrogen use efficiency, as well as the grain yield. 【Result】 Irrigation amount and nitrogen fertilization in separation affected yield, water use efficiency (WUE) and irrigation water use efficiency (IWUE), as well as partial productivity of the nitrogen (NPFP) far more significantly than their combination. The impact of the treatments on yield, WUE and NPFP in 2017 and 2019 was ranked in the order of A3B2 > A2B2 > A3B1 > A2B1 > A1B2 > A1B1. In 2018, their impact on yield and NPFP was ranked in the order of A3B2 > A3B1 > A2B2 > A2B1 > A1B2 > A1B1 in 2018, and on WUE the ranking was A3B2 > A3B1 > A2B2 > A1B2 > A1B1 > A2B1. There were no significant differences in yield, WUE and NPFP between A3B1 and A2B2. A3B2 gave the highest yield, WUE and NPFP consistently over the three years, increasing by 20.2%~39.6%, 4.8%~10.9% and 20.2%~39.6%, respectively, compared with A1B2. During the experimental period, IWUE decreased as the irrigation frequency increased. The yield and NPFP of A2B2 were 11.3%~21.1% and 11.3%~21.2% higher than those of A1B2. 【Conclusion】 A3B2 was optimal for increasing yield while A2B2 was optimal for improving water use efficiency for maize production in northern Henan province.

Subsoiling and straw mulching are two techniques that conserve soil water and improve the sustainability of agricultural production. However, the benefits to soil sustainability of combining subsoiling with straw mulching under intensive rotation between wheat and maize remain uncertain. We conducted a field experiment to determine the long‐term impacts of conventional tillage with straw mulching (CS), and subsoiling with straw mulching (SS), on soil macropore characteristics (>160 μm), soil aggregate characteristics, and soil hydraulic parameters at 0–100 cm depths. Results indicate that SS increased the mean macropore number (66.9%), macroporosity (93.5%), pore circularity (3.5%), field moisture capacity (11.8%), saturated moisture content (21.4%), available soil moisture content (24.1%), and the saturated hydraulic conductivity (39.3%) in the shallowest 50 cm of soil, and total organic carbon content (34.5%) and soil labile organic carbon (20.2%) in the shallowest 30 cm of soil, compared to CS. Compared with CS, SS was more effective at increasing the proportion of aggregates larger than 0.25 mm in the top 20 cm of soil and decreasing the proportion of aggregates smaller than 0.25 mm in the top 30 cm of soil. Correlations between soil organic carbon and various soil physical properties under different practices suggest that SS has larger causative effects on soil physical properties than CS. Therefore, SS is recommended over CS. [ABSTRACT FROM AUTHOR]

Reductions in soil productivity and soil water retention capacity, and water scarcity during crop growth, may occur due to long-term suboptimal tillage and fertilization practices. Therefore, the application of appropriate tillage (subsoiling) and fertilization (organic fertilizer) practices is important for improving soil structure, water conservation and soil productivity. We hypothesize that subsoiling tillage combined with organic fertilizer has a better effect than subsoiling or organic fertilizer alone. A field experiment in Henan, China, has been conducted since 2011 to explore the effects of subsoiling and organic fertilizer, in combination, on winter wheat (Triticum aestivum L.) farming. We studied the effects of conventional tillage (CT), subsoiling (S), organic fertilizer (OF), and organic fertilizer combined with subsoiling (S+OF) treatments on dry matter accumulation (DM), water consumption (ET), water use efficiency (WUE) at different growth stages, yield, and water production efficiency (WPE) of winter wheat over 3 years (2016–2017, 2017–2018, 2018–2019). We also analyzed the soil structure, soil organic carbon, soil microbial biomass carbon and nitrogen, and soil enzymes in 2019. The results indicate that compared with CT, the S, OF and S+OF treatments increased the proportion of >0.25 mm aggregates, and S+OF especially led to increased soil organic carbon, soil microbial biomass carbon and nitrogen, soil enzyme activity (sucrase, cellulose, and urease). S+OF treatment was most effective in reducing ET, and increasing DM and WUE during the entire growth period of wheat. S+OF treatment also increased the total dry matter accumulation (Total DM) and total water use efficiency (total WUE) by 18.6–32.0% and 36.6–42.7%, respectively, during these 3 years. Wheat yield and WPE under S+OF treatment increased by 11.6–28.6% and 26.8–43.6%, respectively, in these 3 years. Therefore, S+OF in combination was found to be superior to S or OF alone, which in turn yielded better results than the CT. [ABSTRACT FROM AUTHOR]

Root water uptake is strongly influenced by the morphology and anatomical structure of roots, which are regulated by nitrogen forms and environmental stimuli. To further illustrate the roles of different nitrogen forms on root water uptake under osmotic stress, a split-root system was supplied with different nitrogen forms and osmotic stress simulated by adding 10% (w/v) polyethylene glycol (PEG, 6000). The local effects of nitrogen form and osmotic stress on root morphology, anatomical structure, root lignin content, and water uptake rate were investigated. Under osmotic stress conditions, ammonium markedly promoted the formation and elongation of the lateral root, whereas a significant decrease in numbers of lateral roots was observed under local nitrate supply. Under nitrate supply in split-root systems, osmotic stress significantly promoted root cell death and more aerenchyma formation, as well as accelerated the lignification of the root. However, osmotic stress had no negative effect on the root anatomical structure under ammonium supply. The root water uptake rate was significantly higher in split-root supplied with ammonium than nitrate under osmotic stress conditions. In conclusion, the high water uptake ability in local ammonium supply was associated with the more lateral roots development and the lower cell death, aerenchyma formation and lignification under osmotic stress. • Osmotic stress promoted lateral root development with local ammonium supplied. • Osmotic stress significantly induced aerenchyma formation in local nitrate supply. • Exceeded aerenchyma formation obviously restrict water uptake. • Ammonium could maintain a higher water uptake and increase drought resistance. [ABSTRACT FROM AUTHOR]

Previously, we demonstrated that drought resistance in rice seedlings was increased by ammonium (NH 4 + ) treatment, but not by nitrate (NO 3 − ) treatment, and that the change was associated with root development. To study the effects of different forms of nitrogen on water uptake and root growth under drought conditions, we subjected two rice cultivars (cv. ‘Shanyou 63’ hybrid indica and cv. ‘Yangdao 6’ indica , China) to polyethylene glycol-induced drought stress in a glasshouse using hydroponic culture. Under drought conditions, NH 4 + significantly stimulated root growth compared to NO 3 − , as indicated by the root length, surface area, volume, and numbers of lateral roots and root tips. Drought stress decreased the root elongation rate in both cultivars when they were supplied with NO 3 − , while the rate was unaffected in the presence of NH 4 + . Drought stress significantly increased root protoplast water permeability, root hydraulic conductivity, and the expression of root aquaporin (AQP) plasma intrinsic protein (PIP) genes in rice plants supplied with NH 4 + ; these changes were not observed in plants supplied with NO 3 − . Additionally, ethylene, which is involved in the regulation of root growth, accumulated in rice roots supplied with NO 3 − under conditions of drought stress. We conclude that the increase in AQP expression and/or activity enhanced the root water uptake ability and the drought tolerance of rice plants supplied with NH 4 + . [ABSTRACT FROM AUTHOR]

In order to find out the appropriate measures for soil water preservation and wheat yield increase, a three–year field experiment was conducted in Yuzhou Experimental Station of Water Saving Agriculture in the west of Henan Province, China, during the growing seasons of 2014–2015, 2015–2016 and 2016–2017 to study the effects of different tillage modes and soil mulching measures on dynamics of soil moisture and temperature, photosynthetic characteristics and yield of winter wheat ( Triticum aestivum L .). The results showed that straw coverage and film mulching measures under the conventional tillage and no tillage modes increased soil moisture by 4.4%–27.3%,13.4%–41.8% and 6.2%–46.7%, 2.4%–80.2%, respectively. The treatments of soil surface coverage measures under both conventional tillage and no tillage modes at tillering stage increased the temperature of soil layer at 10 cm and 15 cm depth by 9.1%–18.2% and 10.0%–40.0% in 2014–2015, while mulching measures under the conventional tillage obviously increased soil temperature at wintering stage but decreased soil temperature at booting and mature stages in 2016–2017. However, mulching measures under no tillage mode reduced soil temperature in shallower layer during seedling establishment stage in the three–year period of 2014–2017. Moreover, the two mulching measures raised net photosynthetic rate (Pn) and water use efficiency (WUE) of functional leaves under the conventional tillage mode and reduced transpiration rate (Tr) at the filling stage. Except straw coverage measures under no tillage in 2015–2016, the combination of mulching measures under no tillage reduced Pn, Tr and WUE of wheat leaves at filling stage as compared to those without mulching measures. Under the conventional tillage mode, straw coverage increased wheat yield by 6.4%–9.3%, mainly due to the increase in the number of grains per panicle. Under no tillage mode, both straw coverage and mulching measures reduced wheat yield to different extents and film mulching measures was more effective than straw coverage. The combination of conventional tillage and straw mulching resulted in a yield of 8425.9–8888.9 kg hm −2 , so this combination was recommended as the optimal treatment under the conditions set in this study. [ABSTRACT FROM AUTHOR]

Tillage combined with straw mulching is an effective water-saving agricultural strategy in eastern Central China. A two-year field experiment with four treatments, including conventional tillage (CT), conventional tillage with straw mulching (CT+S), no-tillage (NT) and no-tillage with straw mulching (NT+S), was conducted on semihydromorphic soil. The objective was to investigate how tillage with straw mulching affected the soil temperature, water consumption, photosynthetic rate (Pn), grain yield, soil temperature use efficiency (TUE) and water productivity (WP) in a winter wheat-summer maize rotation system. The results indicated that straw mulching tended to increase the soil temperature before the wheat regreening stage and decrease the soil temperature during the following wheat growing season and throughout the maize growing season. Compared with CT, the soil effective accumulated temperature (EAT) under the NT+S treatment significantly decreased by 4.8% but the annual ET increased by 4.3% in the winter wheat–summer maize rotation system. The Pn and transpiration rate (Tr) at the anthesis stage of wheat under the NT+S treatment increased by 15.2% and 15.6%, respectively, and the leaf water use efficiency (LWUE) during the growing season of maize increased by 11.3% as compared with that under CT treatment. Wheat yields decreased in the order of NT+S, NT, CT and CT+S during both experimental years, and the average yield of maize under the NT+S treatment increased by 27.2% compared with that under CT. Additionally, WP values under the NT+S treatment during both the wheat and maize seasons were 7.0% and 21.8% higher than those of the CT treatment (p < 0.05), respectively. The annual yield, TUE and WP values under the NT+S treatment were much higher than those under the other treatments. Therefore, NT+S treatment has a positive effect on yield and hydrothermal resource utilization in semihydromorphic soil in eastern Central China. • NT+S improved annual crop yield by 19.5% compared to conventional tillage. • NT+S increased hydrothermal resources utilization in this rotation system. • NT+S enhanced LWUE of the wheat and maize in eastern central China. [ABSTRACT FROM AUTHOR]

Introduction: Inappropriate residue and nutrient management leads to soil degradation and the decline of soil quality and water storage capacity., Methods: An ongoing field experiment has been conducted since 2011 to investigate the effects of straw mulching (SM), and straw mulching combined with organic fertilizer (SM+O), on winter wheat yield, including a control treatment (CK, no straw). We studied the effects of these treatments on soil microbial biomass nitrogen and carbon, soil enzyme activity in 2019, photosynthetic parameters, evapotranspiration (ET), water use efficiency (WUE), and yields over five consecutive years (2015-2019). We also analyzed the soil organic carbon, soil structure, field capacity, and saturated hydraulic conductivity in 2015 and 2019., Results: Results indicate that compared with CK, SM and SM+O treatments increased the proportion of >0.25mm aggregates, soil organic carbon, field capacity, and saturated hydraulic conductivity, but decreased the soil bulk density. In addition, the SM and SM+O treatments also increased soil microbial biomass nitrogen and carbon, the activity of soil enzymes, and decreased the carbon-nitrogen ratio of microbial biomass. Therefore, SM and SM+O treatments both increased the leaf water use efficiency (LWUE) and photosynthetic rate (Pn), and improved the yields and water use efficiency (WUE) of winter wheat. The combination SM (4.5 t/ha)+O (0.75 t/ha) was more effective than SM alone, and both treatments were superior to the control., Conclusion: Based on the results of this study, SM+O is recommended as the most effective cultivation practice., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yang, Liu, Wu, Zhang, Gao, Zhang and Tang.)

Introduction: Water scarcity and seasonal drought are major constraints on agricultural development globally. Super absorbent polymer (SAP) is a good amendment that can improve soil structure, increase soil water retention, and promote crop growth even with less soil moisture. We hypothesize that long term application of SAP has a better effect on soil organic carbon, soil enzyme activity, photosynthetic characteristics, yield, and water and nitrogen use than short term application., Methods: A long term field experiment with different application rates (0 (CK), 15 (L), 30 (M), 45 (H) kg ha -1 ) of SAP was conducted at the Yuzhou water conservation agriculture base of the Henan Academy of Agricultural Sciences from 2011 to 2019., Results and Discussion: The results indicate that applying SAP increases > 0.25 mm aggregates and decreased<0.25 mm aggregates in the soil after one year (2011) and 9 years (2019) of application. In addition, soil organic carbon, soil microbial biomass carbon, soil sucrase and cellulase activities, soil water consumption, water consumption, net photosynthetic rate (Pn), leaf water use efficiency (LWUE) of wheat and yield, all increased after SAP application. SAP also boosts water use efficiency and nitrogen use efficiency. Correlation analyses show that SAP promotes the growth of wheat, and improves the utilization rate of soil water and nutrients by improving the soil structure and increasing soil organic carbon and microbial enzyme activity., Conclusion: Based on our research, SAP treatment at a dosage of 45 kg ha -1 is most effective and is thus recommended., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yang, Zhang, Wu, Gao, Lu and Tang.)

Ethylene increases root cortical aerenchyma formation in maize (Zea mays L.), rice (Oryza sativa L.) and other species. To further investigate the effects of nitrate, ammonium and water stress on ethylene production and aerenchyma formation in roots, two lowland rice cultivars (Shanyou 63, hybrid indica, and Yangdao 6, inbred indica) were cultured hydroponically with 10% (w/v) polyethylene glycol to simulate water stress. Water stress decreased shoot biomass, stomatal conductivity and leaf water potential in cultivars fed with nitrate but not with ammonium. Water stress induced more aerenchyma formation in cultivars fed with nitrate rather than ammonium, and increased cortical aerenchyma was found in Yangdao 6. Endogenous ethylene production by roots increased significantly under water stress in plants fed with nitrate rather than ammonium. Exogenous ethylene stimulated root cortical aerenchyma formation. Expression of the ethylene biosynthesis gene 1-aminocyclo-propane-1-carboxylic acid (ACC) synthase (ACS5) was greater in roots fed with nitrate rather than ammonium in the presence and absence of water stress. The expression of ethylene signalling pathway genes involved in programmed cell death (lesion-simulating disease (L.S.D.)1.1 and L.S.D.2; enhanced disease susceptibility (EDS) and phytoalexin-deficient (PAD4)) were regulated by the N form and water stress. In plants of cultivars fed with ammonium, L.S.D.1.1 expression increased under water stress, whereas L.S.D.2, EDS and PAD4 expression decreased. In conclusion, nitrate increases ethylene production and cortical aerenchyma formation in roots of water-stressed lowland rice. However, ammonium increased L.S.D.1.1 expression in water-stressed roots, and decreased ACS5, EDS and PAD4 expression, which would inhibit ethylene production and aerenchyma formation.