Moore Elizabeth A, Norton Urszula
Department of Plant Sciences, Department 3354, University of Wyoming, Laramie, WY, United States of America.
Program in Ecology, University of Wyoming, Laramie, WY, United States of America.
PLoS One. 2024 Aug 1;19(8):e0306567. doi: 10.1371/journal.pone.0306567. eCollection 2024.
Winter wheat (Triticum aestivum, L.) production in the semi-arid US Northern High Plains (NHP) is challenged by frequent droughts and water-limited, low fertility soils. Composted cattle manure (compost) and cover crops (CC) are known to provide agroecosystem services such as improved soil health, and in the CC case, increased plant diversity, and competition with weedy species. The main concern of planting CC in winter wheat fallow rotation in regions that are more productive than the NHP, however, is the soil moisture depletion. It is unknown however, whether addition of CC to compost-amended soils in the NHP will improve soil properties and agroecosystem health without compromising already low soil water content. The main objective of this study was to assess the effects of four CC treatments amended with compost (45 Mg ha-1) or inorganic fertilizer (IF) (.09 Mg ha-1 mono-ammonium phosphate, 11-52-0 and 1.2 Mg ha-1ammonium sulfate, 21-0-0) on the presence of weeds, soil and plant total carbon (C), nitrogen (N), and biological dinitrogen (N2) fixation (BNF). Mycorrhizal Mix (MM), Nitrogen Fixer Mix (NF), Soil Building Mix (SB), a monoculture of phacelia (Phacelia tanacetifolia Benth L.) (PH), and a no CC control (no CC) were grown in native soil kept at 7% soil moisture in a greenhouse for a period of nine weeks. When amended with compost, MM was the most beneficial (48 g m-2 BNF and 1.7% soil C increase). SB had the highest germination, aboveground biomass, and decreased weed biomass by 60%. It also demonstrated the second highest amount of BNF (40 g m-2) and soil C increase by 1.5%. On contrary, IF hindered BNF by almost 70% in all legume-containing CC treatments and reduced soil C by 15%.
美国半干旱的北部高平原（NHP）地区的冬小麦（Triticum aestivum, L.）生产面临频繁干旱以及水分有限、土壤肥力低的挑战。已知堆肥牛粪（堆肥）和覆盖作物（CC）能提供农业生态系统服务，如改善土壤健康，就覆盖作物而言，还能增加植物多样性并与杂草物种竞争。然而，在比NHP地区生产力更高的地区，冬小麦休耕轮作中种植覆盖作物的主要担忧是土壤水分消耗。然而，在NHP地区，向施用堆肥的土壤中添加覆盖作物是否会在不影响本就较低的土壤含水量的情况下改善土壤性质和农业生态系统健康尚不清楚。本研究的主要目的是评估四种用堆肥（45 Mg ha-1）或无机肥料（IF）（0.09 Mg ha-1磷酸一铵，11 - 52 - 0和1.2 Mg ha-1硫酸铵，21 - 0 - 0）改良的覆盖作物处理对杂草存在情况、土壤和植物总碳（C）、氮（N）以及生物固氮（BNF）的影响。菌根混合物（MM）、固氮混合物（NF）、土壤改良混合物（SB）、单一品种的天蓝苜蓿（Phacelia tanacetifolia Benth L.）（PH）以及无覆盖作物对照（无CC）在温室中保持7%土壤湿度的原生土壤中种植9周。用堆肥改良时，MM最有益（生物固氮量为48 g m-2，土壤碳增加1.7%）。SB发芽率最高、地上生物量最高，杂草生物量减少了60%。它还表现出第二高的生物固氮量（40 g m-2），土壤碳增加1.5%。相反，在所有含豆科植物的覆盖作物处理中，无机肥料使生物固氮减少了近70%，土壤碳减少了15%。
