Plot Diversification

Lead Organization:

Centro Internacional de Agricultura Tropical

Community of Practice:



Bolivia and Peru




Agricultural intensification associated with population growth, market forces and cultural shifts in land management (among other factors) has led to declining soil fertility and agricultural productivity in much of the Andean highlands and represents a growing threat to the livelihoods and well-being of farming communities throughout the region. While agricultural systems in the Andean region are generally more diversified than farming systems in other parts of the world and have a longer history of apparently sustainable management, this trend is changing rapidly. Hence, it is imperative to identify alternative forms of management that address soil fertility loss and the changing needs of Andean farmers. Climate change further emphasizes the importance of developing robust agricultural systems that can help small farmers adapt to more variable weather conditions while mitigating some the root causes of climate change.

Within the context of the Andes, fallows represent a common strategy to restore soil fertility and function and are in many ways emblematic of traditional low-intensity agriculture in the region. Shortening fallow cycles associated with land use intensification now impedes the restorative capacity of this phase, with important implications for long-term soil fertility and rangeland forage production. The services provided by fallows are often indirect and difficult to estimate; thus farmers and researchers generally pay less attention to fallows than to other phases of the cropping cycle. The project proposes to focus on developing more intensive, but sustainable fallow systems via a more active management of the fallow stage with a focus on low-cost fertility inputs and plant species assemblages that are more productive and better able to restore soil fertility. Similarly, it plans to work at the farm or landscape scale supporting planned diversification and more holistic management of all farmscape components (i.e., agricultural plots and non-production areas).

During the inception phase, the project sharpened its approach and strengthened its operative capacity. The project team explored community social and biophysical contexts and existing management practices related to fallows and cropping, identified several excellent research contacts, and became aware of existing research on species for forage availability and rangeland intervention. The project will continue to study the drivers and real constraints of current management practices in fallow-based systems, that were examined in the inception phase of this project, and will work closely with farmers and technicians to explore opportunities for fallow improvement in a local context. The research will benefit farmers directly by building local capacity for research and innovation, while providing new options for restoring soil fertility and improving other services offered by fallow stages (e.g., forage production). At the same time, a detailed assessment of production and ecosystem services (including biodiversity conservation) will provide local governments and development organizations with vital information for guiding investment and policy decisions in the region.

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Grant Aims:

  • Increased knowledge on improved soil fertility through forage management for various contexts and gender-differentiated economic purposes.
  • Improved forage resources, and reduced environmental degradation from adoption of improved fallow systems.
  • Increased ability for farmer innovation and research around soil fertility.
  • Diversified farms and landscapes that contribute to greater profits, income stability and the provision of ecosystem goods and services.
  • Better informed policy decisions and investment in more sustainable farming practices.
  • Improved regional coordination and capacity for soil fertility management research and farmer engagement.

Outputs and Outcomes:

  • A first round of experimentation on forage best bets in 60 farmer field plots across three communities in Bolivia (1) and Peru (2) showed striking differences between sites in terms of productivity (OxC). For example, legumes such as vetch and red clover don’t appear to perform well at higher elevations in the Peruvian sites.  Also, as expected, annuals produced considerably more biomass in the first year relative to perennials; however, the longer-term (i.e., multi-year) impact of this needs to be explored. Follow-up workshops indicated that farmers (8 men and 12 women) like the highly productive annuals, but generally supported the idea of combining annuals with perennials to ensure continued production beyond the first year. While some important generalities exist, it is important to note that there was high variability between plots (farms), in terms of which species mixtures perform best as well as the magnitude of biomass production. This suggests that site specific recommendations could prove highly valuable for determining which improved fallow/forage options are best suited (if any) to a particular site.
  • In a semi controlled field environment in Quilcas, Peru, a pot study was undertaken to screen 70 potential forage/fallow plants using two soils representative of Quilcas and Castillapata. There was more than 20-fold variability in total biomass production (above and below ground).  Some varieties of Vicia (vetch) and Festulolium performed well in both soils tested, many species seems to greatly prefer one soil over another, with the Castillapata soil generally yielding better (likely due to improved infiltration and higher pH).
  • Initial results from participatory mapping for landscape assessment in three communities in three countries reveal that there are distinct gradients in land use intensity associated with changing altitude and land ownership.
  • Groups of farmers in two Peruvian high Andean communities helped to select promising treatments of grass/legume forage mixtures as options for seeding at the initiation of fallows, including combinations of vetch/oat annual mixtures, Andean lupine, and short-cycle perennial grasses and grass/legume mixtures. These were tested in 56 farmer experiments for their role in providing better soil cover and enhance forage supplies early in the fallow period, as well as enhancing nitrogen (N) fixation benefits.
  • Within the middle zone of one Peruvian highland community with shortened fallows (18 farmer experiments), seeded fallows produced more forage biomass of higher quality early in fallow periods compared to an unseeded control (between 80 and 360% increase). These sites represent a context which can derive benefit from more rapid soil cover and increased forage production.  Total N and available P (phosphorus) in soil positively affected the productivity of these forage/fallow options, indicating that manuring or fertilizing these fallows could have a beneficial effect.
  • Within the middle zone of one Peruvian highland community with shortened fallows (18 farmer experiments), seeded fallows produced more forage biomass of higher quality early in fallow periods compared to an unseeded control, the proportion of legumes in trial biomass was related to total N and P uptake, suggesting that where legumes can become successfully established in forage/fallow land uses, they can play important roles in increasing N and P availability throughout the rotation, by contributing residues higher in N and P.  There are resulting tradeoffs for soil fertility between P export from soils in forage and off-farm export (P mining of soils) when using a legume-based fallow strategy, especially if manure is not returned to soils. legumes crops showed different adaptation to soil pH, with treatments containing lupin being more productive at lower levels of soil pH than treatments containing common vetch. (p< 0.05).
  • Within the middle zone of one highland community with shortened fallows (18 farmer experiments), all seeded treatments had superior nutritional and decomposition quality of forage (higher NIR-measured Crude protein and total digestible nutrients, lower lignin content) compared to the unseeded fallow (p< 0.05).
  • Within the middle zone of one highland community with shortened fallows (18 farmer experiments), soil cover at 70 days post seeding increased from a mean of 53% cover in the control to 71% cover across the different seeded fallows (p<0.05), showing the potential for seeding of fallows to better protect soils from erosion at the initiation of resting phases, even if the fallow were used to supply forage. In contrast at a separate set of high-elevation sites (33 sites between two communities) cover was lower in the seeded plots than the controls at 70 days post planting.  However, vetch/oats mixtures and vetch/oats+ perennials were still able to outyield the unseeded plots by between 23% and 70%.  Here as in the middle zone, soil P fertility predicted higher growth of the forage/fallow covers. The difference between mid-elevation and high-elevation sites demonstrates interactions between the tested innovations and existing fallow practices at different elevations, as well as slow growth of seeded covers at high elevation that led to lower mid-season cover.
  • Evaluations of forage and fallow options in community workshops in Peru showed a strong cost-benefit analysis of labor costs to establish forage and fallows and the importance of forage production. Dialogue in workshops also indicated appreciation for the labor-saving and improved performance associated with establishing perennial forages together with annual crops and mixing legumes and grasses and sensitization to the needs of ameliorating soil pH and soil fertility and sustaining soil organic matter.
  • As a result of seeing trial results and with collaboration from Grupo Yanapai in Peru, the local project partner, a community seeded several large areas to intercrops of lupine with oats, ryegrass, and clover in different combinations, in order to expand the results to a larger scale and test the use of lupine at a high elevation site.
  • Results from sampling the chemical, physical and biological properties of soil of 14 different land use areas within a landscape in Ecuador, Central Peru, and Central Bolivia show that the different land uses displayed significant differences among the 3 variables. These variables are tightly linked so that changing one will likely effect the other two. In terms of specific land use results from sampling these, higher levels of soil organic matter, available P and high N were found at higher elevations. Demonstrating the importance of less management of high-elevation less zones. In terms of soil biodiversity, forested systems exhibit the highest diversity of soil macrofauna, while high elevation pastures were the richest in terms of ground cover vegetation. As expected, degraded pastures in Peru were lowest in terms of soil C storage, macrofauna activity, and vegetation cover suggesting that these soils offer little in terms of ecosystem services or productive potential.
  • Forest plantations (eucalyptus and alder), that were largely established on such degraded areas some 15-20 years ago, now offer relatively fertile soils (alder forests in particular) suggesting a means to recuperate a range of ecosystem services and land for cultivation.