Abstract:
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%.
摘要:
冬小麦(普通小麦,L.)半干旱的美国北部高地平原(NHP)的生产受到频繁干旱和水资源限制的挑战,低肥力土壤。众所周知,堆肥牛粪(堆肥)和覆盖作物(CC)可以提供农业生态系统服务,例如改善土壤健康,在CC案例中,增加植物多样性,与杂草物种的竞争。在冬小麦休耕轮作中种植CC的主要关注点是在比NHP生产率更高的地区,然而,是土壤水分的枯竭。然而,它是未知的,在NHP的堆肥改良土壤中添加CC是否会改善土壤特性和农业生态系统健康,而不会损害已经很低的土壤水分含量。这项研究的主要目的是评估用堆肥(45Mgha-1)或无机肥料(IF)(.09Mgha-1磷酸一铵,11-52-0和1.2Mgha-1硫酸铵,21-0-0)对杂草的存在,土壤和植物总碳(C),氮(N),和生物氮气(N2)固定(BNF)。菌根混合物(MM),氮气固定器混合物(NF),土层混合料(SB),Phacelia(PhaceliatanetifoliaBenthL.)的单一培养物(PH),并且无CC对照(无CC)在温室中保持在7%土壤湿度的天然土壤中生长9周。当用堆肥修改时,MM是最有益的(48gm-2BNF和1.7%的土壤C增加)。SB的发芽率最高,地上生物量,杂草生物量减少了60%。它还证明了第二高的BNF量(40gm-2)和土壤C增加了1.5%。相反,在所有含豆类的CC处理中,IF使BNF受阻近70%,并使土壤C降低15%。