Changes in Agroecosystem Structure and Function Along a Chronosequence of Taungya System in Chiapas, Mexico

Abstract

The shifting cultivation system was widely used in the past; however in recent times it is no longer sustainable. In Mexico, a group of Mayan farmers established Taungya system (Ixim'te) as alternative to shifting cultivation. The system consists of the rotational association of crops with cultivated and spontaneous timber trees. The aim was to evaluate the changes in ecological structure and functions, and economic value along a chronosequence of 2 to 13 years. Twenty farmer's plots were selected. In each plot, structure, function and economic indicators were evaluated. Along the chronosequence cultivated trees (Cedrela odorata, Swietenia macrophyla, Tabebuia rosea, Cordia alliodora and Enterolobium cyclocarpum) mixed with crops and spontaneous trees, forming a sort of diverse garden containing 75 plant species. Tree diameter, tree height, total biomass, carbon stock, timber volume, timber value and present value significantly increased along the chronosequence. Two harvests of maize and beans were obtained yearly. According to interviews in the early years maize and beans yielded about 2400 kg and 600 kg ha -1 , respectively, maize was reduced with each crop cycle at a rate of approximately 280 kg ha -1 yr -1 , no reductions for bean yield were reported. The number of woody species per 500 m 2 -sampling area showed a minimum of 4 species on the first years and a maximum of 34 species on the last years. At years 11-13 carbon aboveground stock averaged 45.4 Mg C ha -1 and stored 3.9 Mg C ha -1 Year -1 . The timber volume reached 110.7 m 3 ha -1 ; the timber value was estimated in 4261.7 USD ha -1 and the present value in 5665.7 USD ha -1. Most of the plots presented low levels of soil nitrogen and phosphorus. The studied system increased in complexity, productivity, carbon stocks, and economic value. However, this system may require inputs in organic matter in order to restore soil nitrogen and phosphorus.

How to quantify the impacts of diversification on sustainability? A review of indicators in coffee systems

“…More diversified systems were also reported to enhance the provision of multiple ecosystem services (Figure 5). The positive effects were especially strong for the ecosystem services: climate regulation, soil erosion control, pest control and carbon sequestration (Figure 5), which is in line with other studies that report benefits of diversification strategies (McDaniel et al 2014;Soto-Pinto and Armijo-Florentino 2014;Gomes et al 2016;Dainese et al 2019;Tamburini et al 2020). For instance, higher plant diversity can benefit trophic interactions among insects, leading to higher presence of natural enemies and increased pest control (Wan et al 2020).…”

Carbon Stocks in Organic Coffee Systems in Chiapas, Mexico

“…Organic coffee polyculture showed similar carbon stocks to low tropical forests in Guatemala (Schmitt-Harsh et al, 2012), medium semi-humid forest in Mexico (Orihuela-Belmonte et al, 2013), and other high covered agroforestry systems in Mexico, such as improved fallows, Taungya, and silvopastoral systems (Soto-Pinto et al, 2010;Soto-Pinto & Armijo-Florentino, 2014). Thus, the organic management could be much more important to increase not only the carbon in shade vegetation, but significantly, in the soil; litter deposition, humus content in the first soil layer, and the role of shade vegetation to preserve soil and carbon content are of paramount importance at landscape and global scales (Soto-Pinto et al, 2010;Häger, 2012;Palm et al, 2014).…”

“…Agroforestry systems play an important role in mitigating climate change due to their potential in carbon sequestration (Hutchinson et al, 2007;Idol et al, 2011;Soto-Pinto & Armijo-Florentino, 2014). It was previously mentioned that agroforestry systems, especially those with high tree and cover densities can store significant amounts of carbon, depending on the agro-climatic zone, physiographic conditions, vegetation characteristics, system complexity and management (Schroeder, 1994;Kotto-Same et al, 1997;Beer et al, 1998;Albrecht & Kandji, 2003;Montagnini & Nair, 2004;Roshetko et al, 2007;Roncal-Garcia et al, 2008;Tscharntke et al, 2011).…”

Contributions of Agroforestry Systems to Food Provisioning of Peasant Households: Conflicts and Synergies in Chiapas, Mexico

“…AFS have undergone simplification of structure and agrobiodiversity, as shown by the dominance of some plant genera, shade species, and uses as well as a reduction in the number of strata, tree densities and coffee plant densities, as previously reported for coffee and cocoa agroforests, homegardens, and milpas (Moguel and Toledo, 1999;Belchier et al, 2005;Soto-Pinto et al, 2013;Soto-Pinto et al, 2014Benítez et al, 2020;Escobar-Colmenares et al, 2021;López Cruz et al, 2021), which demonstrates similarities between food forests and anthropized forests (Moguel and Toledo, 1999;Belchier et al, 2005;Ford and Nigh, 2009;Van Dooren et al, 2018). All these AFS are within forest environments and have often been established as part of these ecosystems.…”

“…Collectively, these agroecosystems make up a complex agricultural matrix that supports habitat for biodiversity and human life, while supporting a myriad of environmental services, including soil health (Dollinger and Jose, 2018), pest and disease control (Wemheuer et al, 2020), microclimate regulation (Lin, 2010;Carvalho et al, 2021), carbon sequestration (Soto-Pinto and Armijo-Florentino, 2014;Cerda et al, 2020), hurricane and landslide protection (Lin, 2007), aesthetic values (Purba et al, 2020), nutrition (Falkowski et al, 2019), and other social and economic values (Bello et al, 2019).…”