Low Carbon Technologies for Agriculture in Dryland: Brazilian Experience

Abstract

Anthropogenic activities have altered the atmospheric composition since the industrial era, especially with the increasing greenhouse gas emission due to fossil fuel combustion, cement production, and land-use change. The Brazilian semiarid, covering approximately 969.589 km 2 with 21 million people, region has 1.6 million agricultural establishments and 95% are classified as family farms. The typical agricultural systems are characterized by high grazing density, slash and burn practices, and fruits and legumes by irrigated monocultures. Consequently, soil degradation occurs due unsustainable soil management, decreasing soil carbon stock, and the biodiversity. The soil carbon depletion is also associated with saline, water, and thermal stresses. Saline, water, and thermal stresses in dryland, the impact of the land-use change associated with climate change, and few technological resources available for use in agricultural systems are the main reasons responsible for low productivity in the Brazilian semiarid region. Low-cost agricultural practices can contribute to build healthy and sustainable agroecosystems: among these, the selection of plant species tolerant to saline, water, and thermal stresses, the use of rhizobial inoculants, adoption of no-tillage, sowing green manure, and adoption of technologies to stock water to improve its efficiency and productivity.

Processos Pedogenéticos E Susceptibilidade Dos Solos À Degradação No Semiárido Brasileiro

“…Os sais em quase sua totalidade apresentam Na + em sua composição e, nos níveis encontrados nesses solos, podem interferir no crescimento da maioria das culturas, tendo em vista a ocorrência nos primeiros 12 cm do solo, zona de maior influência do sistema radicular. A principal fonte desses sais é o intemperismo de plagioclásios, presentes entre 30-40% da composição mineralógica dos horizontes subsuperficiais e do saprolito (BRASIL, 1971), associado às elevadas taxas de evapotranspiração de até 2200 mm/ano (GIONGO et al, 2018 As áreas com RLe no Seridó paraibano são geralmente extremamente erodidas, dado a quantidade expressiva de afloramentos rochosos, relevo variando de ondulado a montanhoso e vertentes amplas e convexas que atuam como dissipadoras dos fluxos de água (BRASIL, 1972). Essa forte declividade contribui para a ocorrência de horizonte A pouco espesso, que aliado a vegetação de caatinga hiperxerófila arbustiva aberta explicam os extremamente baixos teores de C orgânico em superfície (≤ 0,5%) (HAZELTON e MURPHY, 2017).…”

Clay and organic compost as quality conditioners of a sandy soil in the brazilian semiarid

“…Soils in arid and semiarid regions are highly vulnerable due to shortage and low levels of OM, which increases greenhouse gas emissions, impairs soil aggregation, favors nutrient leaching, and decreases water retention (RAMANKUTTY et al, 2018). In Brazil, Giongo et al (2018) described the limiting characteristics of the northeastern semiarid, such as low quantity and poorly distributed rainfall, high temperatures and variation in soil types, besides poor-C soils. The Brazilian northeastern semiarid is among the regions with the most vulnerable soils in view of climate change and projections of aridity intensification (VIEIRA et al, 2015), with serious socioeconomic and environmental implications, which compromise ecosystem services and food security, then becoming dependent on practices that improve soil quality.…”