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The combined effects of soil waterlogging and compaction are important concerns in crop production. Two field experiments were performed over two seasons to examine the effects of soil waterlogging and high bulk density (BD) on the performance of winter wheat in terms of its agronomic and physiological traits. Trial 1 applied soil waterlogging at different stages (started at tillering, jointing, booting and anthesis). Trial 2 was conducted with soil waterlogging and compaction that created BD of the topsoil (1.6 g cm −3 ). Results from trial 1 showed that the tillering stage was the most waterlogging-sensitive period. A 12% lower grain yield caused by waterlogging was primarily reflected in reductions in spike numbers. Waterlogging at jointing and booting stages reduced grain weight through decreased dry matter translocation. Results from the field trial 2 showed that soil compaction decreased grain yield by 4.8%, and waterlogging aggravated this reduction by 20.7% and 22.4% when fields were waterlogged for 2 weeks (WL 2w ) and 4 weeks (WL 4w ), respectively. A reduction in spike number from fewer tillers at stem elongation stage was the main reason for grain yield loss. Soil compaction combined with waterlogging duration did not affect root weight, but soil compaction reduced above ground biomass and root weight after the jointing stage. Furthermore, waterlogging accelerated leaf senescence, especially under compacted conditions, which significantly decreased photosynthetic capacity, resulting in a lower maximal PSII photochemical efficiency (F v /F m ), apparent electron transport rate (ETR), effective quantum yield of photosystem II (ΦPSII) and photochemical quenching (qP). Root weight was positively related to the total above ground biomass; whereas the final grain yield was not linearly related to the shoot weight. SPAD value correlated positively with yield and PSII parameters (F v /F m , F v /F 0 ). The study concluded that the tillering stage was most susceptible to waterlogging, and soil compaction combined with waterlogging at tillering stage had a larger harmful effect on root and shoot growth during or after waterlogging. SPAD readings may be a good surrogate for photosynthetic activity under waterlogging and compaction conditions. [ABSTRACT FROM AUTHOR]

The effects of climate warming on wheat yields vary geographically under different warming scenarios. Such variations reflect real climatic differences and our insufficient understanding of how physiological processes respond to warming conditions. In this study, a 16-year trial comprising three crop production systems (CPSs) and a 5-year trial including seven cultivars were conducted in the Sichuan Basin of China to investigate the effects of climate warming on the phenological development, grain yield (GY), dry matter (DM) accumulation and translocation of wheat. The three CPSs included conventional rotary tillage with residue removal for both rice and wheat (CPS1), conventional rotary tillage with the wheat residue incorporated for the rice following zero tillage with residue-mulching for wheat (CPS2), and zero tillage and residue-mulching employed for both wheat and rice (CPS3). The wheat cultivars used in this study were all spring-type wheat, and the trials were planted from 26 to 30 October each year, irrigation was applied only at the seeding and topdressing stages and in amounts less than 20 mm. The results showed that mean of daily mean temperature from November to March (MT Nov-Mar) and November to April (MT Nov-Apr) significantly increased by 0.0964 °C yr-1 and 0.0947 °C yr-1 from 2004 to 2020, respectively. This warming caused earlier flowering and significantly decreased mean temperature from anthesis to maturity (P ost AT mean) by 0.091 °C yr-1. However, grain number m-2 was unaffected by this warming. Cooler and longer grain-gilling periods (GFP) lead to larger grain sinks and allow more preanthesis assimilates to be transported to the grain, resulting in increased individual grain weight and harvest index under all CPSs and all cultivars. There were no significant differences in sensitivities of GY and DM related trait responses to temperature change between CPSs or between cultivars. Averaged over all CPSs, GY increased 741.9 kg ha-1 with each 1 °C increases in MT Nov-Apr. The increase in yield was mainly attributable to increase in grain weights while grain number m-2 was maintained. In addition, the MT Nov-Apr values in the Sichuan Basin were predicted to reach 14.7 °C and 16.5 °C by the end of this century under the SSP245 and SSP585 climate change scenarios, respectively. When the CO 2 concentration was fixed at 350 ppm, the Agricultural Production Systems SIMulator (APSIM) model showed that the increasing MT Nov-Apr values significantly increased the GY under the SSP245 scenario, but the GY was initially positively and then negatively affected under the SSP585 scenario. These results lay the foundation for developing adaptation strategies to address future climate change in climates like that of Sichuan Basin and ensure wheat supplies. • An increasing MT Nov-Apr strongly advanced the anthesis date and increased the GY by 742 kg ha-1 °C-1 in the Sichuan Basin. • High GY obtained from high MT Nov-Apr because of earlier flowering and cooler GFP induced larger grain sinks, DMt and CPAG. • Under SSP245 scenario from 2021 to 2100, increasing MT Nov-Apr values are expected to increase the wheat yield using APSIM. • No significant differences in slopes of GY response to temperature change was detected between CPSs or between cultivars. [ABSTRACT FROM AUTHOR]

• Pea prominently increased maize yield under 0P treatment. • Pea significantly increased wheat yield, biomass, P uptake, the inorganic Pi. • P applied during the maize season barely affected subsequently grown wheat. • P applied during wheat season prominent enhanced agronomic traits and P uptake. Relay strip intercropping systems have the advantage of increasing land yield, but there are few studies on how pre-crops affect the grain yield and phosphorus (P) use of subsequent crops in such systems. Field experiments were carried out for four consecutive years, covering two complete cycles of the crop sequence, to evaluate the effects of pre-crops on crop yield, P uptake, and topsoil P balance of maize and wheat. Three pre-crops were used, i.e. fallow, pea, and rutabaga planted with two P levels with (+P) and without (0P) P fertilizer applied to maize and/or the wheat season. Pea significantly improved grain yield in cycle 1 and grain yield, biomass and P uptake of subsequently grown maize in cycle 2, compared with fallow, and P fertilizer application had no effect on maize yield, P uptake and above-ground biomass in cycle 1, but significantly improved yield and P uptake in cycle 2. Regarding the subsequently grown wheat, on average, pea significantly increased the wheat average yield by 11.57 % and 4.27 % under the 0P and + P treatment, respectively; and rutabaga had 5.22 % and 6.40 % higher wheat average yield than under the same conditions of fallow. Pea prominently improved the above-ground biomass, P uptake; soil Olsen-P in the 0–20-cm soil profile, and the inorganic Pi fraction concentration after two consecutive cycles, with a significant positive correlation between Olsen-P and most Pi fractions. Rutabaga prominently improved above-ground biomass and P uptake. The above parameters performed better under pea than rutabaga. P fertilizer application during the maize season barely affected the growth or P uptake of subsequently grown wheat, P applied during the wheat season, however, significantly enhanced agronomic traits and P uptake, and this effect was more pronounced under pea. We therefore conclude that pea as pre-crop is instrumental for subsequent maize and wheat production, and provides more benefits for farmers. [ABSTRACT FROM AUTHOR]

• N deficiency significantly affected GY and N utilization-related traits. • SDCs showed advantages over NSCs in GY, DM accumulation, and NUtE under N deficiency. • High-yielding SDCs is associated with the low GPC and high NUtE. Synthetic hexaploid wheat-derived cultivars (SDCs) show substantially improved yield potential compared with that of nonsynthetic-derived cultivars (NSCs) developed by conventional breeding. However, the relationship between the high-yielding traits of SDCs and nitrogen (N) use efficiency, especially their performance under N deficiency, is unclear. A field experiment was conducted in two successive seasons examining the responses of six genotypes (three SDCs and three NSCs) under two N treatments: N+ (N sufficiency, N nutrition index ≥ 1) and N− (N deficiency, N nutrition index < 1). N deficiency had a significantly negative effect on grain yield (GY) and yield-related traits. Compared with that of NSCs, SDCs showed 14% (N+) and 16% (N−) higher GY. This yield gain was mainly attributable to the higher total dry matter (DM) and post-anthesis DM accumulation of SDCs under both N treatments. On average, SDCs showed higher chlorophyll content than NSCs in the three upper leaves from 0 to 32 days post-anthesis, which was highly positively correlated with GY under both N treatments. Total and fertilizer N accumulation were significantly decreased under N deficiency. Compared with that of NSCs, SDCs showed lower grain protein concentrations under both N treatments, which was negatively correlated with GY. In addition, SDCs showed significantly higher N use efficiency and N utilization efficiency (NUtE) than NSCs, and a positive correlation was detected between NUtE and GY. The results indicated that SDCs show advantages over NSCs in GY, DM accumulation, and NUtE under N deficiency, and thus cultivation of SDCs shows potential to reduce N waste and environmental contamination. [ABSTRACT FROM AUTHOR]