Opoku Akwasi, Ogunleye Anuoluwapo M, Solomon Juan K Q, Payne William A
Department of Agriculture, Veterinary & Rangeland Sciences, University of Nevada, Reno, NV, 89557, USA.
Environmental Sciences & Health Graduate Program, University of Nevada, Reno, NV, 89557, USA.
Heliyon. 2024 Oct 18;10(20):e39600. doi: 10.1016/j.heliyon.2024.e39600. eCollection 2024 Oct 30.
Cover cropping is a soil restorative strategy that can save degraded soils and offer additional benefits relative to the traditional fallow-based practice in semi-arid cropping systems. This study aimed to (i) quantify the above (shoot)- and belowground (root) biomass production, nutritive value, and tissue carbon and nitrogen concentrations from different annual cool-season cover crop systems, and (ii) determine their effects on soil organic carbon, total nitrogen, soil respiration, and soil microbial population biomass in a semi-arid environment. Treatments used were monocultures of annual ryegrass ( Lam.), oat ( L.), faba bean ( L.), yellow sweetclover [ (L.) Lam], winter pea ( L.), two three-species mixtures (Mix 1: annual ryegrass + faba bean + yellow sweetclover and Mix 2: Oat + faba bean + winter pea), and a fallow laid out in a randomized complete block design with three replications. Averaged across years, Mix 2 produced greater shoot biomass (9714 kg DM ha; SE = 699) than all other cover crop systems except, the monoculture of oat (7970 kg DM ha; SE = 699). The plant tissue C/N ratio of the mixtures and monoculture legumes was mostly similar (range = 19.4-29.1). Overall, legumes produced superior relative feed value (RFV; 112-161) compared to grass monocultures and mixtures (RFV; 80-95). Soil gram-negative bacteria biomass was greatest under the yellow sweetclover monoculture. Based on the results of this study, the mixed cover crop systems (Mix 1 and Mix 2) offered a better chance of fulfilling the dual role of soil health improvement and feed quality for livestock in this semi-arid environment.
覆盖作物种植是一种土壤修复策略，相对于半干旱种植系统中基于传统休耕的做法，它可以拯救退化土壤并带来额外益处。本研究旨在：（i）量化不同一年生冷季覆盖作物系统地上（茎）和地下（根）生物量产量、营养价值以及组织碳和氮浓度；（ii）确定它们对半干旱环境中土壤有机碳、总氮、土壤呼吸和土壤微生物种群生物量的影响。所采用的处理方式包括一年生黑麦草（Lolium）、燕麦（Avena）、蚕豆（Vicia）、黄花草木樨（Melilotus）、冬豌豆（Pisum）的单作，两种三种作物的混合物（混合物1：一年生黑麦草 + 蚕豆 + 黄花草木樨；混合物2：燕麦 + 蚕豆 + 冬豌豆），以及休耕，采用随机完全区组设计，重复三次。多年平均来看，混合物2产生的地上生物量（9714千克干物质/公顷；标准误 = 699）高于除燕麦单作（7970千克干物质/公顷；标准误 = 699）之外的所有其他覆盖作物系统。混合物和单作豆科植物的植物组织碳氮比大多相似（范围 = 19.4 - 29.1）。总体而言，与禾本科单作和混合物（相对饲用价值；80 - 95）相比，豆科植物产生的相对饲用价值更高（112 - 161）。黄花草木樨单作下土壤革兰氏阴性菌生物量最大。基于本研究结果，混合覆盖作物系统（混合物1和混合物2）在这种半干旱环境中更有机会实现改善土壤健康和提高牲畜饲料质量的双重作用。
