Wednesday’s post from Professor Joern Fischer provided some background on agricultural intensification, benefits and pitfalls, and a movement toward “sustainability.” In particular, he noted how landscape scale adds complexity to intensifying practices, but also helps build resilience. Professor Norman Uphoff provides a concrete example, with a discussion of the experiences with the System of Rice Intensification (SRI) that has improved the efficiency and sustainability of rice (and increasingly, other crop) production around the world. There is considerable opportunity for these practices to be applied in an integrated landscape framework, and Professor Uphoff expands upon this notion.
‘Intensification’ in the agriculture context has usually referred to increasing the application of production inputs – especially inorganic fertilization and agrochemical crop protection, as well as irrigation water. This strategy has had some demonstrable successes in the past, but the economic costs of fossil-fuel-based inputs continue to rise, as do the adverse consequences of declining soil health and poorer water quality that result from the overuse of fertilizers and agrochemicals, as well as from heavy mechanical tillage.
Moreover, there are signs of diminishing returns to the currently favored input-based strategy for raising agricultural production. In China, the ratio of nitrogen fertilizer to kilograms of rice has dropped from 20:1 at the start of its Green Revolution to 5:1 or lower. Farmers have responded to this diminished marginal productivity by using still more fertilizer on their fields, further lowering the ratio, while adding to the problem of nitrate pollution in water supplies. Similarly in the U.S., despite a more than 10-fold increase in the applications of chemical insecticides between 1945 and 2000, the percent of crops that were lost to insect pests almost doubled, from 7 to 13%. Such changes suggest that the intensification associated with our ‘modern agriculture’ is due for revision.
Farmers in over 50 countries around the world have learned that there is another kind of intensification, one that can reduce, or even end, their dependence on agrochemical inputs for soil fertilization and for crop protection. The System of Rice Intensification (SRI), developed in Madagascar in the 1980s by Fr. Henri de Laulanié, SJ, involves an intensification of learning, labor, and management more than of purchased, external inputs – being more mental than material. SRI methods can increase grain yields by at least 20 to 50%, often by 100%, and sometimes even by several hundred percent, just by changing the way that existing resources, plants, soil, water, and nutrients are managed.
SRI enables farmers to make reductions in:
Seeds — by 80-90% — because plant populations are so drastically reduced, with wider spacing between plants;
Irrigation water — by 25-50% — because paddy fields are not kept continuously flooded;
Synthetic fertilizers — by 50-100% — because farmers rely as much as possible on organic matter for sustaining soil fertility, using compost or mulch made from rice straw and any other available vegetative biomass, and possibly farmyard manure if available,
Agrochemical biocides — by 50-100% — because crop plants raised with SRI management are inherently more resistant to pests and disease.
Plants grown through more efficient use of seeds, agrochemicals, irrigation water, and synthetic fertilizers are also more resistant to abiotic stresses – drought, storm damage, extreme temperatures – that are becoming more frequent with climate change. Plants raised according to SRI principles have larger, healthier root systems, and the soil is inhabited by additional and more beneficial, soil organisms.
In the last half dozen years, principles of SRI developed for rice have been extrapolated, with appropriate modifications, to increase the productivity when growing certain other crops. These principles include:
- Establish healthy plants early and carefully, nurturing their root potential.
- Reduce plant populations so each plant has more room to grow above- and below-ground, thereby capturing more nutrients and more sunlight.
- Enrich the soil with organic matter, keeping it well-aerated to support better growth of roots and aerobic soil biota.
- Apply water in ways that favor both plant-root and soil-microbial growth, avoiding inundate, anaerobic soil conditions as these are adverse for roots and beneficial soil organisms.
Through the System of Crop Intensification (SCI), wheat, finger millet, sugarcane, maize, tef, many legumes (kidney bean, soy bean, lentils, mung bean, etc.), and vegetables such as tomatoes, eggplant, and chilies – are showing that the agroecological principles and practices that promote more productive, healthier rice crops have even broader relevance.
So far, the focus of SRI and SCI work has been at field level. It is important to ask: How does this kind of intensification — reported on extensively on the SRI-Rice website – relate to improved management, productivity, and sustainability at the landscape level? Some opportunities and issues should be considered with regard to making innovations such as SRI and SCI successful and more broadly extendable at the landscape level.
1. To reduce both farmers’ costs of production and adverse environmental impacts when agricultural systems rely primarily on inorganic fertilizer (particularly synthetic nitrogen), it is important for farmers to have more access to biomass for making compost or for mulching. Within any landscape, there are usually considerable areas where biomass could be produced/grown with little opportunity cost and with little direct cost on non-arable land areas as a kind of ‘commons’ service.
Such areas could be designated or zoned for biomass production, e.g., for planting fast-growing leguminous trees that produce a lot of biomass with high N content with little labor requirement. Note that this measure would be good for improving soil fertility and enhancing agricultural sustainability for ANY AND ALL arable areas within a landscape, whether practicing SRI/SCI or other farming systems.
2. To make point #1 happen, there is a need for more and improved research, innovation and evaluation done on tools and implements for improved biomass management – for gathering, transporting, processing, and applying biomass – many of which are currently of antique design. Making the harvesting and use of biomass within a landscape more productive in terms of labor time and money expenditure, will also become more economic as the costs of chemical fertilizer continue to rise and as there is full-cost reckoning of chemical fertilizer use.
3. Within landscapes where SRI is practiced using irrigation facilities, the methods of alternate wetting and drying or minimum daily applications of water can enable individual farmers to reduce their water requirements by 25-50%, with higher yield and lower costs. But this may not add up to water saving on a command-area basis if there is no coordination among farmers.
To reduce the amounts of water that must be issued from reservoirs, diverted from rivers, or pumped from groundwater reserves, cooperation among water users such as through water user associations should be promoted to utilize irrigation water most efficiently. This could enable farmers to cultivate larger areas within their watershed as the water requirements per hectare are reduced.
4. In general, introducing reductions in the application of inorganic fertilizer and agrochemicals is beneficial on a landscape basis to reduce water pollution and soil degradation. This involves mobilizing the services of the soil biota to fix nitrogen, make more phosphorous more available, cycle nutrients, induce systemic resistance, etc. Synthetic chemical applications impede these natural processes. In general, agroecological crop management, of which SRI and SCI are good examples, will improve agricultural productivity and sustainability on a landscape basis.
Supporting Food Security in the 21st Century Through Resource-Conserving Increases in Agricultural Production – Agriculture and Food Security