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The injudicious use of water and fertilizer to maximize crop yield not only leads to environmental pollution, but also causes enormous economic losses. For this reason, we investigated the effect of nitrogen (N) (N0 (0), N60 (60 kg ha−1), and N120 (120 kg ha−1)) at different irrigation levels (I0 (0), I1200 (budding 600 m3 ha−1 + kernel 600 m3 ha−1), and I1800 (budding 900 m3 ha−1 + kernel 900 m3 ha−1)) on oilseed flax in the Loess Plateau of China in 2019 and 2020. The objective was to establish appropriate irrigation and fertilizer management strategies that enhance the grain yield (GY) of oilseed flax and maximize water and N productivity. The results demonstrated that irrigation and N application and their coupling effects promoted dry matter accumulation (DMA) and non-structural carbohydrate (NSC) synthesis, and increased the GY of oilseed flax. The contents of NSC in various organs of flax were closely related to grain yield and yield components. Higher NSC in stems was conducive to increased sink capacity (effective capsule number per plant (EC) and thousand kernel weight (TKW)), and the coupling of irrigation and N affected GY by promoting NSC synthesis. Higher GY was obtained by the interaction of irrigation and N fertilizer, with the increase rate ranging from 15.84% to 35.40%. Additionally, in the increased yield of oilseed flax, 39.70–78.06%, 14.49–54.11%, and −10.6–24.93% were contributed by the application of irrigation and nitrogen and the interaction of irrigation and nitrogen (I × N), respectively. Irrigation was the main factor for increasing the GY of oilseed flax. In addition, different climatic conditions changed the contribution of irrigation and N and their interaction to yield increase in oilseed flax. Drought and low temperature induced soluble sugar (SS) and starch (ST) synthesis to resist an unfavorable environment, respectively. The structural equation model showed that the key factors to increasing the GY of oilseed flax by irrigation and nitrogen fertilization were the differential increases in DMA, EC, and TKW. The increases in EC and TKW were attributed to the promotion of DMA and NSC synthesis in oilseed flax organs by irrigation, nitrogen fertilization, and their coupling effects. The I1200N60 treatment obtained higher water use efficiency (WUE) and N partial factor productivity (NPFP) due to lower actual evapotranspiration (ETa) and lower N application rate. Therefore, the strategy of 1200 m3 ha−1 irrigation and 60 kg ha−1 N application is recommended for oilseed flax in semi-arid and similar areas to achieve high grain yield and efficient use of resources. [ABSTRACT FROM AUTHOR]

Various crop rotation patterns can result in differences in nutrient consumption and the accumulation of toxic substances in the soil, indirectly impacting the soil environment and its nutrient supply capacity. Implementing optimized crop planting practices is beneficial for maintaining the favorable physical and chemical properties of farmland soil in the arid area of northwestern China. This study aimed to establish a crop rotation pattern to improve key enzyme activities and soil nitrogen conversion efficiency, as well as understand the underlying mechanism for enhancing nitrogen supply capacity. A field experiment was conducted to study the effect of four flax planting patterns, which included 13 crop rotation patterns with different crop frequencies: 100% Flax (Cont F), 50% Flax (I) (WFPF, FPFW, PFWF, FWFP), 50% Flax (II) (FWPF, WPFF, PFFW, FFWP), 25% Flax (WPWF, PWFW, WFWP, FWPW), on the key enzyme activities and the rate of soil nitrogen conversion, as well as the nitrogen supply capacity. Here, F, P, and W represent oilseed flax, potato, and wheat, respectively. The results indicated that the wheat stubble significantly increased the intensity of soil ammonification and denitrification before planting. Additionally, the activity levels of soil nitrate reductase and nitrite reductase under wheat stubble were significantly increased by 66.67% to 104.55%, while soil urease activity significantly decreased by 27.27–133.33% under wheat stubble compared to other stubbles. After harvest, the activities of soil nitrate reductase and nitrite reductase under the wheat stubble decreased significantly, and the intensity of soil ammonification, nitrification, and denitrification reduced significantly by 7.83–27.72%. The WFWP and FWFP treatments led to a significant increase in soil nitrogen fixation intensity under various crop rotations after harvest and significantly increased the levels of inorganic nitrogen in the soil before the planting of the next crop. This study suggests that the long-term rotation planting patterns WFWP and FWFP can significantly enhance the key enzyme activities of soil nitrogen conversion and significantly improve soil nitrogen conversion before crop sowing. This may increase the rate of soil nitrogen transfer and raise the available nitrogen content of the soil. These findings are crucial for reducing soil nitrogen loss and improving soil nitrogen nutrient supply capacity in dry areas of the Loess Plateau of China. [ABSTRACT FROM AUTHOR]

Organic fertilizers are an important source of nutrients for improving farmland fertility. To explore high-yield, efficient and green production technology for oilseed flax in dryland agricultural areas, a field split plot experiment was conducted in the semi-arid area of the Loess Plateau in northwest China from April to August in 2020 and 2021. The study compared and analyzed the effects of different nutrient sources and their application rates on water consumption characteristics, grain yield and water use efficiency of oilseed flax. The main plots were fertilizer types (sheep manure, chicken manure and chemical fertilizer), while the subplots were fertilizer application rates (sheep manure: S1-12,500 kg·hm−2 and S2-25,000 kg·hm−2; chicken manure: C1-5800 kg·hm−2 and C2-11,600 kg·hm−2; chemical fertilizer: F1-N 112.5 kg·hm−2, P 75 kg·hm−2, K 67.5 kg·hm−2 and F2-N 225 kg·hm−2, P2O5 150 kg·hm−2, K2O 135 kg·hm−2). The results showed that compared with chemical fertilizers, organic fertilizers significantly increased the soil water storage capacity of the 0–160 cm soil layer during the whole growth period of oilseed flax and significantly reduced water consumption. During two growing seasons, the application of 25,000 kg·hm−2 sheep manure significantly reduced water consumption during the seedling-bud period and green fruit period-maturity period of oilseed flax by 16.13% and 23.19% compared with CK, respectively. Thousand-grain weight, yield and water use efficiency were significantly increased by 14.70%, 48.32% and 61.29%, respectively. These results indicate that the application of 25,000 kg·hm−2 sheep manure can significantly increase soil water storage capacity of the 0–160 cm soil layer, reduce water consumption during the whole growth period of oilseed flax and thus improve grain yield and water use efficiency of oilseed flax. It is a suitable fertilization technology for the high-yield, efficient and green production of oilseed flax in the semi-arid areas of northwest Loess Plateau. [ABSTRACT FROM AUTHOR]

Introduction: Phosphorus nutrition and hormone concentration both affect crop yield formation. Ascertaining the interaction of phosphorus and GA 3 has a synergistic effect on the grain yield and phosphorus utilization efficiency of oilseed flax in dryland. It is extremely important for improving grain yield and phosphorus utilization efficiency., Methods: A field experiment was conducted in 2019 and 2020 at the Dingxi Oil Crops Test Station to investigated the effects of phosphorus, gibberellin (GA 3 ), and their interaction on the grain yield and phosphorus-utilization efficiency of oilseed flax plants. Phosphorus fertilizer was applied at three levels (0, 67.5, 135 kg P 2 O 5 ·ha -1 ) and GA 3 was also sprayed at three concentrations (0, 15, and 30 mg·L -1 )., Results: The results showed that application of 67.5 kg P 2 O 5 ·ha -1 reduced leaves acid phosphatase (ACPase) activity, but increased phosphorus accumulation throughout the growth period, the 1000-kernel weight (TKW), and the number of grains per capsule. Spraying GA 3 significantly increased the leaves ACPase activity, phosphorus accumulation after anthesis and its contribution to grain, phosphorus-utilization efficiency, the number of capsules per plant, and TKW. The phosphorus accumulation at the anthesis, kernel, and maturity stages under the treatment of fertilizing 67.5 kg P 2 O 5 ·ha -1 and spraying 30 mg·L -1 GA 3 were increased by 56.06%, 73.51%, and 62.17%, respectively, compared with the control (no phosphorus, no GA 3 ). And the phosphorus accumulation after anthesis and its contribution to grain also increased. 67.5 kg P 2 O 5 ·ha -1 combined with 30 mg·L -1 GA 3 and 135 kg P 2 O 5 ·ha -1 combined with 15 mg·L -1 GA 3 both significantly increased grain yield of oilseed flax, reaching 1696 kg·ha -1 and 1716 kg·ha -1 across two years, respectively. And there was no significant difference between them. However, the former treatment significant increased the apparent utilization rate, agronomic utilization rate, and partial productivity of phosphorus. The interaction between phosphorus and GA 3 was significant for grain yield., Conclusion: Therefore, the application of 67.5 kg P 2 O 5 ·ha -1 in combination with 30 mg·L -1 GA 3 is an effective fertilization approach for enhancing oilseed flax growth and grain yield in the experiment region and other similar areas., 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 © 2024 Wang, Cao, Gao, Wu, Niu, Yan, Wang, Cui, Wen, Xu, Wang and Ma.)