Table 1 Alternative management practices that can aid in breaking the cycle of long-term inappropriate farming methods, with their benefits and trade-offs
From: Agricultural practices can threaten soil resilience through changing feedback loops
Practice | Alternative practice | Benefits | Trade-offs | References |
|---|---|---|---|---|
Tillage | Zero or no tillage | • Soil physical structure is maintained, including micro and macro porosity • Function of underground biota retained (e.g., mycorrhiza, nematodes) • Increase biodiversity • Tillage erosion reduced | • Increased weed pressure • Increased soil moisture can delay germination • Incorporation of organic fertilisers not always possible (although slurry injection is an option) and can lead to nitrogen losses via atmosphere • Benefits might vary over time (i.e., the seasonality effect on species and duration of the practice impact) • Temporary yield reduction • Soil texture and climate can influence crop productivity under zero tillage | Soil biota16 Biodiversity86 Tillage erosion19 Soil texture and climate effects87 |
Reduced tillage (tillage depth, intensity, frequency or spatial coverage is reduced) | • Density and diversity of soil micro and meso-fauna increased • Allows soil incorporation of organic inputs | • Organic matter gains can be lost following a tillage event and will take time to build up again • Potential yield reduction | Soil biota16 Yield reductions85 | |
Use of organic fertilisers | • Can improve and valorise re-use of food, crop and livestock by-products • Organic fertilisers can increase soil organic matter content, soil water holding capacity • Reduces nutrient losses to environment associated with wasting by-products | • Uncertainty around and variability of nutritional composition, therefore challenging to optimise crop nutrition • Availability, transport and cost can be an issue • Potential source of contamination (e.g., heavy metals) | Benefits88 Trade-offs89 Contamination90 | |
Legume inclusion or rotation | • Reduces nitrogen fertiliser requirement • Legume yield may be greater under conditions that companion crops may decline under (e.g., ryegrass and clover leys at temperatures > 25°) • Legumes can have a legacy effect, increasing soil nitrogen supply for the next crop | • Biological nitrogen fixation capacity less in cooler climates | Increased sward yields and zero N fertiliser51 | |
Plant breeding (targeting nitrification inhibition or phosphorus and nitrogen-efficient plants) | • Increased nutrient efficiency reduces requirements for nitrogen and phosphorus fertilisers • Reduced emissions of nitrogen and phosphorus to the wider environment | • Availability of suitable varieties • Reduction in diversity/genetic erosion | Biological nitrification inhibition91 P utilisation efficiency92 | |
Apply nitrogen cycle inhibitors with the fertiliser | • Can improve crop nitrogen use efficiency • Reduces nitrogen emissions to air and water • Provides opportunity to reduce nitrogen application rate | • Effectiveness is dependent on local management and environmental conditions • Availability and cost can be an issue | Yield increase and effectiveness93 Yield increase and reduce fertilizer rate94 | |
Pesticides | Plant breeding | Reduces need for pesticides and environmental impacts associated with pesticide use | Resistant varieties might be difficult to access for some growers | Benefits and trade-offs95 |
Integrated pest management | • Can reduce the amount and variety of pesticides used • Cost savings made by reducing chemical inputs | Requires grower knowledge/understanding, including identification of different pests and understanding of their life cycle | Benefits and trade-offs95 | |
Plastic mulching | Use truly biodegradable plastic with non-toxic compounds | • Provide micro-climate benefits without toxicity of plastic contamination | • Availability and price of materials | Benefits and trade-offs96 |
Irrigation | Use mulches | • Mulches can reduce evaporation from the soil surface | • Plastic mulches can lead to soil contamination | See SI5 |
Increase soil organic matter | • Increases macro-aggregation in highly weathered soils | • Difficult to achieve without external organic material inputs in highly weathered soils | Benefits and trade-offs97 | |
Plant breeding for drought/salt-tolerant varieties | • Improves crop tolerance to drought/salt and reduces the need for other mitigative strategies | • Geographic and economic access to new varieties, • Legislative barriers for genetic editing, which vary by country and region | Benefits and trade-offs98 | |
Use of salt-tolerant rhizobacteria | • Potential to support plant growth and survival under saline conditions | • Plant response not consistent across varying global regions | Benefits and trade-offs70 | |
Flooding of paddy fields | Alternate wetting and drying cycles | • Alternate wetting and drying can increase water use efficiency and reduce GHG emissions | • Possible yield penalty for alternate wetting and drying • Good alternate wetting and drying management is time-consuming and variable between fields • Alternate wetting and drying can lead to increased mineralisation of soil organic carbon • Good weed management is essential for alternate wetting and drying practices | Benefits and trade-offs99 |
Straw management | • Improved straw management can reduce greenhouse gas emissions and maintain organic carbon input | Straw management100 | ||
Plant breeding for nutrient use efficiency | • High NUE varieties are higher yielding with the same nutrient input | • High NUE varieties may have lower nutritional value | ||
Grazing intensive grassland | Diverse herbal leys, including N-fixing species | • Deep-rooting herbal leys improve soil porosity, aggregate stability, and topsoil and subsoil carbon storage; this in turn enhances water infiltration and nutrient cycling • Improved drought resistance | • Introduction of new herbal leys requires destruction of the previous crop via tillage and/or herbicides • Challenges with broadleaf weed control | Soil porosity101 Soil aggregates102 Soil carbon103 Drought resistance & trade-offs104 |
Controlled grazing systems (mob or rotational grazing) | • Rotational grazing has potential for higher pasture carrying capacity • Rotational grazing can increase soil carbon content | • Mis-managed rotational grazing can result in compromised forage quality and therefore impair livestock performance • Requires more infrastructure and labour • Risk of poaching caused by high stocking densities on small paddocks in wet conditions | Benefits105 Trade-offs104 | |
Grazing rangelands | Reduce stocking rates | • Adopting low and/or flexible stocking rates can help reduce land erodibility and limit accelerated erosion | • Reduction of grazing pressure or complete abandonment can lead to shrub encroachment | Benefits106 Trade-offs107 |
Control grazing with herding | • Adaptive grazing strategies, which include controlled herding, can regenerate depleted soil and maintain plant integrity | • Implementing controlled grazing systems may involve upfront costs for infrastructure such as fencing and water systems | Benefits108 Trade-offs106 | |
Introduce pastures for nomadic grazing | • Yield of cultivated forage is substantially greater than that of the natural grassland | • Rapid degradation of re-established plant communities on bare-land due to poor management or poor soil structure and composition | Benefits and trade-offs109 | |
Forest clearing and burning, followed by fallow | Increase the length of the fallow period | • Better biogeochemical starting conditions • Can support increases in the functional diversity of fallow area | • Greater land area needed to produce a similar yield | |
Introduce high-yielding crop varieties | • Higher yields • Improved economic and social outcomes | • Cost and difficulty of accessing remote places • Introduction of commodity crops can increase deforestation via a rebound effect. • Modern varieties may require greater nutrient inputs, which may lead to clearing of primary forest. | Higher yields111 Rebound effect112 High yields, economic and social outcomes, and nutrient demands113 | |
Introduce fertilizers | • Higher yields | • Cost and difficulty of accessing remote places | Nutrient demands113 | |
Agroforestry | • Multiple products produced (e.g., timber, fuel, fibre, feed, pharmaceuticals, alley/surrounding ground crops) • Co-benefits (shade, pollinators, habitat for game, soil nutrient fixation) • Improved economic and social outcomes | • Finding good rotation • Competition with crop • Unwanted impacts of tree species on local hydrology |
