Moreira Silvino G, Hoogenboom Gerrit, Nunes Marcio R, Martin-Ryals Ana D, Sanchez Pedro A
Departamento de Agricultura, Universidade Federal de Lavras, Av. Doutor Silvio Menicucci 1001, CEP 37200-000 Lavras, Minas Gerais, Brazil; University of Florida, Global Food Systems Institute, Gainesville, FL 32611, USA.
University of Florida, Global Food Systems Institute, Gainesville, FL 32611, USA; University of Florida, Department of Agricultural and Biological Engineering, Gainesville, FL 32611, USA.
Sci Total Environ. 2023 Jun 25;879:163031. doi: 10.1016/j.scitotenv.2023.163031. Epub 2023 Mar 25.
World food production must increase in the coming years with minimal environmental impact for food and nutrition security. Circular Agriculture has emerged as an approach to minimize non-renewable resource depletion and encourage by-product reuse. The goal of this study was to evaluate Circular Agriculture as a tool to increase food production and N recovery. The assessment was conducted for two Brazilian farms (Farm 1; Farm 2) with Oxisols under no-till and a diversified cropping system, including five species of grain, three cover crop species, and sweet potato. Both farms implemented an annual two-crop rotation and an integrated crop-livestock system with beef cattle confined for 2-years. Grain and forage from the fields, leftovers from silos, and crop residues were used as cattle feed. Grain yield was 4.8 and 4.5 t ha for soybean, 12.5 and 12.1 t ha for maize, and 2.6 and 2.4 t ha for common bean, for Farm 1 and Farm 2, respectively, which is higher than the national average. The animals gained 1.2 kg day of live weight. Farm 1 exported 246 kg ha year of N in grains, tubers, and animals, while 216 kg ha year was added as fertilizer and N to cattle. Farm 2 exported 224 kg ha year in grain and animals, while 215 kg ha year was added as fertilizer and N to cattle. Circular practices, i.e., no-till, crop rotation, year-round soil covered, maize intercropped with brachiaria ruziziensis, biological N fixation, and crop-livestock integration, increased crop yield and decreased N application by 14.7 % (Farm 1) and 4.3 % (Farm 2). 85 % of the N consumed by the confined animals was excreted and converted into organic compost. Overall, circular practices associated with adequate crop management allowed recovering high rate of applied N, reducing environmental impacts, and increasing food production with lower production costs.
未来几年，世界粮食产量必须增加，同时对粮食和营养安全的环境影响降至最低。循环农业已成为一种尽量减少不可再生资源消耗并鼓励副产品再利用的方法。本研究的目的是评估循环农业作为增加粮食产量和氮素回收的工具。对巴西的两个农场（农场1；农场2）进行了评估，这两个农场的土壤为氧化土，采用免耕和多样化种植系统，包括五种谷物、三种覆盖作物和红薯。两个农场都实行了每年两季作物轮作和农牧结合系统，肉牛圈养两年。田间的谷物和草料、筒仓中的剩余物以及作物残渣都用作牛的饲料。农场1和农场2的大豆产量分别为4.8吨/公顷和4.5吨/公顷，玉米产量分别为12.5吨/公顷和12.1吨/公顷，普通豆产量分别为2.6吨/公顷和2.4吨/公顷，均高于全国平均水平。动物日增重1.2千克。农场1每年在谷物、块茎和动物中输出246千克/公顷的氮，同时向牛添加216千克/公顷的肥料和氮。农场2每年在谷物和动物中输出224千克/公顷，同时向牛添加215千克/公顷的肥料和氮。免耕、作物轮作、全年土壤覆盖、玉米与鲁氏臂形草间作、生物固氮和农牧结合等循环做法提高了作物产量，农场1和农场2的氮肥施用量分别减少了14.7%和4.3%。圈养动物消耗的氮中有85%被排泄出来并转化为有机堆肥。总体而言，与适当作物管理相关的循环做法能够实现较高的施氮回收率，减少环境影响，并以较低的生产成本增加粮食产量。
