近日，国际知名期刊《Field Crops Research》发表了一项关于农业生态系统养分管理的重要研究成果。该研究由沈阳农业大学水利学院陈涛涛教授课题组完成，题为“Unlocking potassium sustainability: Rice-crab co-culture system enhances potassium balance”（DOI：10.1016/j.fcr.2025.110289）。研究通过两年田间试验，系统量化了稻蟹共生系统中的钾素利用、平衡与经济效益，为发展可持续稻作农业提供了关键科学依据。博士研究生刘海霞为第一作者，刘光岩博士和陈涛涛教授为通讯作者。
钾是作物生长的必需元素，但中国约75%的稻田面临钾素缺乏。稻蟹共生作为一种生态集约化模式，其钾素利用与平衡机制尚不明确。研究团队在中国稻蟹共生主产区辽宁省开展试验，对比了水稻单作与稻蟹共生两种模式。研究发现，稻蟹共生系统显著提升了土壤钾素有效性。蟹类饲料成为系统重要的外源钾输入途径。饲料中的钾通过螃蟹摄食、未食残饵及排泄物逐步释放至土壤，形成“缓释钾源”，使稻蟹共作土壤交换性钾含量相比单作提高5.23–7.06%，同时螃蟹的掘穴、搅动等生物扰动行为显著改善了土壤结构，增加孔隙度，促进水分入渗和钾离子向20–40 cm土层迁移，使该层钾离子浓度提高了13.79–16.61%。尽管稻蟹共作系统的钾淋失量增加了14.43–24.49%，但其表观钾平衡和总钾平衡分别比单作系统高出13.51–15.77%和16.83–18.78%，表现出更强的钾素固持能力。研究揭示，蟹类活动和饲料投入是系统钾素循环的关键驱动因素。饲料成为系统重要的外部钾源，通过蟹类摄食、排泄及残饵分解，实现了钾素在系统中的缓释与再分布，优化了钾输入结构。偏最小二乘路径模型分析进一步证实，水稻地上部吸钾量和土壤有效钾是影响系统总钾平衡的最关键因素，二者均对总钾平衡产生消极影响。在经济收益方面，稻蟹共生在保证水稻产量与单作持平的同时，额外产出每公顷156–162公斤的河蟹，使净收入比单作系统显著提高17.26–21.76%，证明了该模式的经济可行性。
本项研究的创新之处在于，首次在系统水平上全面量化了稻蟹共生模式的钾素流动与平衡，明确了饲料投入和蟹类生物扰动在提升钾素可持续性中的核心作用。研究结果不仅为优化稻蟹共生系统的养分管理提供了定量框架，也为推动生态农业提供了重要的理论与实践依据。研究成果得到了国家自然科学基金面上项目（52379043）、辽宁省应用基础研究计划项目（2023030237-JH2/1016）和辽宁省“兴辽英才”项目（XLYC1902064）等资助。
Fig. 2 Dynamics in soil solution K+ and averaged soil solution K+ in the (a-c) 0–20 cm and (d–f) 20–40 cm soil layer under rice monoculture (RM) and rice-crab coculture (RC) during the whole rice growing seasons in 2022 and 2023, respectively. (g–h) Soil exchangeable K fluxes and (i) season-averaged soil exchangeable K under rice monoculture (RM), in the rice planting areas of rice-crab coculture and in the crab ditched areas of rice-crab coculture during the whole rice growth season. *, **, ***, and ns indicate significance at P<0.05, P<0.01, P<0.001, and not significant, respectively.
Fig. 3 Cumulative K leaching under rice monoculture (RM) and rice-crab coculture (RC) at basal fertilization period (BF), tillering fertilization period (TF), panicle fertilization period (PF) and the whole rice growth season (Whole) in (a) 2022 and (b) 2023. *, **, and ns indicate significance at P<0.05, P<0.01, and not significant, respectively.
Fig. 4 K uptake under rice monoculture, in rice planting areas in rice-crab coculture and under rice-crab coculture in (a) 2022 and (b) 2023. *, **, and ns indicate significance at P<0.05, P<0.01, and not significant, respectively.
Fig. 5 (a–b) Apparent K balance, (c–d) soil K balance, and (e–f) total K balance under rice monoculture (RM) and rice-crab coculture (RC) during 2022 and 2023. *, **, and ns indicate significance at P<0.05, P<0.01, and not significant, respectively.
Fig. 6 (a) Partial least-squares path model (PLS-PM) was used to assess the relative strengths of direct relationship among K input (irrigation, precipitation, K fertilizer and artificial feed), soil available K (soil solution K and exchangeable K), K leaching, crab K accumulation, aboveground K uptake and total K balance. R2 donates the proportion of variance explained. Values adjacent to arrows represent standardized path coefficients, and the “+” “－” indicate positive and negative effects, respectively. The goodness-of-fit (GoF) index, used to evaluate the overall performance of the model, was 0.57. (b) Standardized total effects of each variable on total K balance derived from the PLS-PM. (c) Relative importance of variables (soil solution K, exchangeable K irrigation, K leaching, crab K accumulation, aboveground K uptake, irrigation, precipitation, K fertilizer and artificial feed) in influencing total K balance. * and ** indicate significance at P<0.05 and P<0.01, respectively.
DOI: 10.1016/j.fcr.2025.110289
