Spring low-temperature stress (LTS) has become a major limiting factor for the development of high yield, quality and efficiency in wheat production. It not only affects the function of wheat leaves and the development of spikes but also impacts stem lodging resistance, and may experience elevated risk of stem lodging. This study conducted a field pot experiment to assess the effect of phosphorus fertilizer application mode on wheat stem lodging resistance under spring LTS. Two wheat varieties, Yannong19 (YN19, cold-tolerant variety) and Xinmai26 (XM26, cold-sensitive variety) used as the experiment material. Two phosphorus fertilizer application models including traditional phosphorus application (TPA) and optimized phosphorus application (OPA) were employed. Temperature treatment was conducted at 15 degrees C (CK) and -4 degrees C (LT) in a controlled phytotron. Our results showed that spring LTS decreased the stem wall thickness and internode fullness, and altered stem anatomical structure and chemical composition, resulting in a decrease in wheat stem mechanical strength and lodging resistant index. Compared with TPA, the OPA increased the stem wall thickness and internode fullness. The thickness of the stem mechanic tissue layer and parenchymatous tissue, and the area of the large vascular bundle and small vascular bundle were increased by the OPA, which alleviated the damage to stem cell walls caused by spring LTS. At the same time, the OPA also increased the contents of lignin, cellulose, and soluble sugar, improving the C/N ratio in wheat stem. Due to the improved stem morphological characteristics, anatomical structure, and chemical compositions, the wheat stem exhibited enhanced lodging resistance, which increased the lodging resistant index of the 2nd and 3rd internodes of YN19 and XM26 by 27.27%, 11.63% and 14.15%, 15.73% at the dough stage compared with TPA under spring LTS. Meanwhile, OPA could not only alleviate the yield loss caused by spring LTS, but also increase the grain yield without spring LTS. This study indicated that OPA enhances wheat stem lodging resistance under spring LTS, and would be meaningful and practical for improving wheat resistance to low-temperature stress.
Optimizing canopy spacing configuration can enhance resources utilization, supporting robust growth and dry matter production, while mitigating the risk of lodging and improving crop yield and quality. However, research specifically addressing optimal canopy spacing configurations for foxtail millet remains limited. Over a two-year period, a field experiment in the North China Plain assessed the impacts of four-row spacing configurations (T0: 40 + 40 cm; T1: 30 + 50 cm; T2: 20 + 60 cm; T3: 10 + 70 cm), to investigate the effects of row spacing configuration on lodging resistance, canopy spatial configuration, stem characteristics, yield, and water productivity (WP) of foxtail millet, aiming to elucidate the underlying regulatory mechanisms. Row spacing configurations significantly influenced lodging resistance, yield, and WP. Under T1, improvements were observed in stem morphology and mechanical properties, particularly in the 2nd-6th basal internodes (I2-I6). The light interception rate in T1 at wide rows in the middle canopy (30-90 cm aboveground) increased by 97.89 %, compared to T0. Partial least squares-structural equation modeling revealed that improved light interception in wide rows in the middle canopy contributed to a rise in diameter and dry plumpness of I2. This, in turn, promoted greater breaking resistance of I2 and tensile resistance, ultimately reducing the lodging likelihood. Simultaneously, the decrease in lodging resulted in higher yield and WP at yield level of foxtail millet. Therefore, T1 demonstrated the lowest lodging rate (67.34 %-91.92 % lower than T0), and the highest yield and WP at yield level (4.10 %-8.03 % and 20.79 %-22.46 % higher than T0). Optimizing canopy spacing configuration is essential for cultivating high-yielding and water-efficient foxtail millet populations. The results indicated that the 30 + 50 cm row spacing configuration improves light distribution in the middle canopy, enhancing lodging resistance and consequently increasing both yield and WP. This research offers a theoretical foundation for foxtail millet breeding and agronomic practices to achieve lower lodging rate, higher yields, and enhanced WP in the North China Plain.
Addressing the negative impacts of lodging on crops is a global topic, but it is not clear whether and how straw and its derivatives positively affect the lodging resistance, yield, and quality of spring maize in rainfed areas. Therefore, a field experiment with three organic amendments, straw (at 9000 kg ha(-1)), cattle manure (at 7140 kg ha(-1)), and biogas residue (at 6554.52 kg ha(-1)), was set up in a typical rainfed area with film mulching. The results showed that straw and its derivatives significantly improved the mechanical properties of the third internode by improving the cellulose and lignin contents and their related synthase activities, which resulted in a significant increase in the stalk lodging-resistant index by 3.65 similar to 7.23% (P < 0.05); contributed to a deeper and longer root system that significantly improved root pulling force by 1.41 similar to 4.75%, further enhancing the positive correlation between root in the secondary zone and root lodging resistance; and improved the 1000- kernel weight, content of crude fat and crude protein by constructing a lush above-ground population, which significantly increased the grain yield by 5.95 similar to 13.22%. Among them, the performance of biogas residue fermented by both anaerobic and composting was better than that of other treatments, which provided an informative organic solution for synchronizing the spring maize lodging resistance and yield increase.