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A high-quality canopy architecture is central to obtaining high crop yields. A field experiment was carried out at the Wuqiao Experimental Station from 2015 to 2019 under four irrigation schemes (W0, no irrigation after sowing; W1, 75 mm irrigation at jointing stage; W2, 75 mm irrigation at jointing and anthesis stages, respectively; W3, 75 mm irrigation at tillering, jointing and anthesis stages, respectively) to investigate the canopy structure, canopy apparent photosynthesis (CAP), canopy temperature (CT), yield and water use efficiency (WUE). The results showed that increasing irrigation times improved the leaf area index (LAI), non-leaf area index (NLAI) and light interception (LI) of the spike and total canopy but decreased the canopy temperature (CT) after anthesis. The CAP in the W3 treatment was consistently lower than that in the W1 treatment, suggesting lower effective utilization of light energy under the W3 treatment. Increasing irrigation times improved wheat yield, but the W2 treatment had no significant difference in yield compared to the W3 treatment. In addition, the W1 and W2 treatments had higher WUEs. The CT, organ temperature and LI were closely positively associated with each other, but they were all strongly negatively related to the yield. Overall, the W2 treatment was the best irrigation scheme for constructing a reasonable canopy architecture for winter wheat, obtaining more efficient water use and yield in the North China Plain (NCP). CT and organ temperature can be used as proxy parameters to estimate the canopy structure. [ABSTRACT FROM AUTHOR]

Selecting more water‐efficient wheat (Triticum aestivum L.) varieties that are suited to no seasonal irrigation is an important way to improve water use efficiency (WUE) in the North China Plain (NCP). The goal of this study was to assess the yield and WUE of wheat, maize (Zea mays L.), and rotation, and to determine the traits of high‐WUE wheat varieties and clarify the mechanism for increasing WUE. Experiments were conducted during the 2012–2016 seasons using 10 common winter wheat varieties under no seasonal irrigation (W0) or two irrigation events (W2, irrigation at jointing and anthesis). No seasonal irrigation treatment decreased wheat and rotation yield, and improved maize yield and WUE of maize and rotation. No seasonal irrigation treatment decreased 150‐mm irrigation amount, reduced soil water content in 0–2‐m soil depth at wheat maturity and 1–2‐m depth after maize harvest, and extended the maize grain filling stage. Compared with the wheat genotype with the lowest WUE ('Nongda 211'), under W0 condition, the genotype with the highest WUE, 'Nongda 5133,' could improve rotation yield and WUE by 10.7 and 10.9%, respectively. The WUE of wheat had a strong positive association with yield across the genotypes. High‐WUE varieties had a higher leaf area index at anthesis and higher late‐season photosynthesis rate and/or delayed canopy senescence under W0. This study indicated that W0 in wheat growing season could improve maize yield, narrow the rotation yield gap with W2 treatment, and improve wheat and rotation WUE by combining with high‐WUE wheat varieties. [ABSTRACT FROM AUTHOR]

Favorable crop population architecture is the foundation for obtaining high crop yields and water productivity (WP) under limited irrigation. A field experiment was conducted at Wuqiao Experimental Station from 2015 to 2018 using the 'Nongda399′ wheat variety under the four seeding density and three irrigation schemes to explore the population architecture, canopy apparent photosynthesis (CAP), organ contribution, yield, and WP of winter wheat (Triticum aestivum L.). Compared with conventional high-yield cultivation (SD1W3), the water-saving cultivation (SD3W1) obtained a comparable yield meanwhile improved the WP in the range of 14.2–39.2%. The non-significant change in the yield under SD3W1 was primarily due to the increasing seeding density under W1 irrigation treatment, which improved the spike number and grains per unit area, especially the main stem spike, and had no significant effect on the thousand kernel weight (TKW). Increases in grain yield was generally caused by increases in CAP by constructing a reasonable canopy architecture with higher leaf area index (LAI) and non-leaf area index (NLAI) of the total canopy and upper strata, especially the spike area index (SAI) of the upper strata. Therefore, more light was intercepted by spikes, which improved the contribution of spike photosynthesis to yield. Increasing the seeding density also improved the assimilate remobilization contribution (RC) of pre-anthesis and decreased the post-anthesis leaf photosynthesis contribution to yield. Increasing the seeding density under limited irrigation improved the root length density (RLD), especially in 120–200 cm soil layer, which increased the absorption and use of deep soil moisture and improved WP. Overall, when sowing time from October 10–20, the appropriate seeding density of approximately 525–600 plants m−2 with 75 mm of irrigation at the jointing stage was the best cultivation practice for saving water and obtaining a comparable yield and a high water productivity of winter wheat in the North China Plain (NCP). • Increasing the seeding density improved the spike area index of the upper strata. • Higher seeding density improved the contribution of spike photosynthesis to yield. • Higher seeding density improved the contribution of remobilization before anthesis. • Increasing the seeding density improved the root length density in the deeper soil layers. • Increasing the seeding density under limited irrigation improved the yield and water productivity. [ABSTRACT FROM AUTHOR]

• The maximum number of floret primordia was hardly affected by treatments. • Florets that have started abortion can not become fertile florets. • Anthers development determines the number of fertile florets. • Nitrogen application accelerated the rates of floret development and hence increased the number of fertile florets. The dynamics of floret initiation/abortion has been explored widely; however, the mechanisms of increasing floret fertility at anthesis in wheat production remain unclear. In this study, morphological and physiological responses of florets per spikelet and per spike to nitrogen and irrigation treatments in the field were investigated. Each spikelet produced the maximum number of living floret primordia (MFP) and showed no difference between treatments at the W7.5 stage; this ability was hardly affected by treatments. We firstly found that gradually abortive florets during W8.5-W10 stages were delayed due to improving assimilates availability in the spike instead of the 4th-5th inthernode; in fact, these florets would be aborted completely and never become fertile florets. Notably, we found that those florets in which the anther turned green (value ≥ 97) at W7.5 always became fertile, and their number showed a significant positive relationship with number of fertile florets (NFF) at W10. Collectively, more available assimilates in spike accelerated anther turning green during period of early floret development, maintained their development normally and becoming fertile florets, but did not make florets that initiate abortion become fertile florets and increase the MFP. [ABSTRACT FROM AUTHOR]

• A water-saving method considering winter wheat-summer maize rotation was investigated. • New method saved 1126 m3 ha−1 of water with comparable rotation yield to the current irrigation management. • Increased maize yield compensated the elimination in wheat yield. • Higher received precipitation in maize while not temperature explained increased yield. Water scarcity in the North China Plain (NCP) is threatening irrigation of predominant winter wheat-summer maize rotation and thus rotation yield. To maximally reduce irrigation input while maintaining relatively high yield is urgently needed and an enduring challenge. Here we present an innovative practice that considers the water use of the entire rotation system, i.e., application of presowing irrigation to reach 85% of the field capacity for wheat (W0) compared with the common practice of applying twice more irrigation with each 750 m3 ha−1 during the wheat season (W2). After sowing maize, 750 m3 ha−1 irrigation was applied for both practices. The main hypothesis was that reducing wheat irrigation would lead to lower water content in the soil, which would in turn preserve more rain in the maize season, and that earlier maturity of wheat caused by reduced irrigation would advance earlier maize-sowing to utilize more radiation and thermal inputs resulting in higher maize yield which would compensate for decreased wheat yield. From 2012 to 2016, the 0–200 cm soil water contents, as well the yield and its components, were monitored at key growth stages of wheat and maize. There was consistently lower water content under W0 than under W2 from flowering to maturity of wheat making 4–5 days earlier maturity under the W0 practice, and led to a higher accumulated temperature of maize relative to the W2 practice. The grain yields of wheat, maize and rotation were 6694 to 9218 kg ha−1, 7284 to 12,843 kg ha−1, 16,336 to 20,605 kg ha−1, respectively. The temperature accumulated after silking well explained the interannual variation in maize yield. In contrast to temperature, rainfall during the maize season explained the yield difference between two practices. The maize yield was 6.4% higher under the W0 practice than under the W2 practice, in a year with sufficient rainfall, above 451 mm, and this trend was unpronounced under rare drought stress, below 250 mm of rainfall, leading to a 7.5% lower yield. The average yield of the four rotation rounds under W0 was equal to that under W2. Nevertheless, the W0 practice significantly increased the water use efficiency under rotation by 12.9%. On average, the irrigated amount in each rotation under W0 was significantly reduced by 1126 m3 ha−1 relative to W2. Therefore, the W0 practice is a simple and promising water management strategy for addressing shortages of water and labor while maintaining relatively high rotation yield in the NCP. [ABSTRACT FROM AUTHOR]

• Compared to TI120, MI120 and MI150 significantly increased grain yield and WUE. • MI90 ensured grain yield by significantly improving thousand grain weight. • Except for MI60, MI treatments significantly delayed the senescence of flag leaf during grain filling. • MI treatments ensured the water supply in the mainly root distribution zone of wheat. • MI with reducing irrigation promoted water consumption of the deep soil profile. It's very important to guarantee the wheat production and improve water productivity in the North China Plain (NCP). In order to reduce irrigation and ensure the crop production in the NCP, a two-year field experiment of winter wheat was conducted in 2016–2018 using micro-sprinkling irrigation including different irrigation amount treatments (60 mm, MI60; 90 mm, MI90; 120 mm, MI120; and 150 mm, MI150), and the local traditional water-saving and productive flooding irrigation method (TI120) was as a control. The grain yield (GY), dry matter accumulation (DM), root system distribution and water utilization were investigated. The results showed that, the GY of MI60 decreased by 5.1–13.4% compared with TI120; GY of MI90 was comparable with TI120, while that of MI120 and MI150 increased significantly. The higher GY in micro-sprinkling treatments was mainly due to the significant increase of 1,000-grain weight (TGW), which was the result of the significant delay of the senescence in flag leaves during grain filling and then the increase in the post-anthesis DM. In addition, the roots mainly distributed in the 0−60 cm soil profile, and micro-sprinkling ensured the soil water supply in this areas at the critical growth stages; what's more, micro-sprinkling with reducing irrigation treatments significantly promoted the growth of root system to the deep soil layer, which improved the absorption and utilization of moisture stored in soil. Compared with TI120, the same irrigation amount treatment under micro-sprinkling (MI120) significantly increased water use efficiency (WUE) due to higher GY and lower seasonal evapotranspiration (ET); the 125% irrigation amount treatment (MI150) increased WUE due to higher GY and comparable ET; the 75% irrigation amount treatment (MI90) obtained the similar WUE to TI120; the 50% irrigation amount treatment (MI60) got similar or lower WUE to TI120. Overall, suitable reduction of irrigation amount under micro-sprinkling (MI90) can ensure the grain yield of winter wheat and efficient utilization of irrigation water in the NCP. [ABSTRACT FROM AUTHOR]