Benefits of Conservation Tillage

What is conservation tillage?

Currently, there is no universally accepted definition of conservation tillage, but one of the most widely accepted definitions is proposed by the Conservation Technology Information Center, which describes conservation tillage as “any tillage and planting system that covers 30% or more of the soil surface with crop residue, after planting, to reduce soil erosion by water” [1]. However, the natural environments and planting habits (or planting preferences) are diverse in different regions. I have reviewed the practices of conservation tillage in China, the United States, the United Kingdom, the European Union, and Sub-Saharan Africa [2]. You can find the most adopted operation of conservation tillage in the table below (Table 1). Moreover, I have also included the conservation tillage practice in India in this article (you can also see in Table 1), as India is one of the largest food producers around the world. In India, the major technique being adopted is no/reduced tillage[3,4]. Although we can find that the operation of conservation tillage varies for different countries, it is easy to see that no-tillage and retention of crop residues are the key techniques of conservation tillage.

Table 1 Technical Points of Conservation Tillage in Different Country/Region

Benefits of conservation tillage

According to the United Nations Convention to Combat Desertification (UNCCD), soil degradation and desertification have resulted in the abandonment of 30% of the world’s farmland over the past 40 years, while 52% of agricultural land is moderately to severely affected by soil degradation. In the current context of climate change, characterized by high temperatures, heavy rains, floods, and extreme weather events, has exacerbated this situation. In addition to crop species adaptation and losses caused by global warming and extreme weather conditions, climate change can also negatively impact soil health by damaging its structure and beneficial microorganisms as well as hindering animal growth. Conservation farming can serve as a potential solution for enhancing adaptation and resilience to climate change. Here are some benefits of conservation tillage:

• Reduce surface runoff

One symptom of climate change is abnormal precipitation distribution with continuous or heavy rainfall that hampers water infiltration leading to surface runoff or even floods. Conservation tillage practices can improve water infiltration capacity and alleviate surface water runoff.

• Increase soil water storage

Another consequence of climate change is drought. Rising temperatures coupled with prolonged droughts result in significant evaporation rates that disrupt the natural water cycle, particularly precipitation processes. Water scarcity during the growing season adversely affects both soil health and agricultural production outcomes. Conservation tillage techniques enhance soil’s ability to retain moisture thereby increasing overall water use efficiency.

• Enhance soil fertility

Heavy rainfall and windstorms caused by climate change are likely to erode topsoil and deplete soil nutrients, resulting in a decline in crop yield. Conservation tillage can enhance the availability of soil nutrition and organic matter, thereby securing soil fertility. Additionally, enzyme activity serves as another indicator of soil fertility. Conservation tillage can create a favorable environment for microorganisms, leading to increased enzyme activity and ultimately improving soil fertility.

• Improve soil structure

Given the current emergency situation, changes in soil structure are highly unstable [5]. Intensive farming practices with conventional tillage exacerbate soil disturbance, leading to compaction and physical damage to the structural integrity of the soil. Conservation tillage reduces such disturbances, resulting in decreased bulk density, increased porosity, and improved stability of soil aggregates.

• Control pests, disease, and weeds

Global warming and climate change create favorable conditions for pest infestations and weed growth, causing an increase in pest-related diseases as well as weed bursts. Conservation tillage enhances the richness and abundance of beneficial microorganisms in the soil ecosystem—especially natural enemies of pests—thus enabling effective pest control measures. Furthermore, conservation tillage can restrict weed growth by limiting their space for propagation.

• Achieve carbon sequestration

The agricultural sector is recognized as a major contributor to greenhouse gas emissions; however, it also holds great potential for mitigating the impacts of climate change. The largest organic carbon pool within terrestrial ecosystems is found within the soils themselves. Firstly, conservation tillage can achieve carbon sequestration through enhancing soil aggregate stability. Another method is placing soil organic carbon in the sub-soil horizons and incorporating it with biomass, as one of the important parts of conservation tillage is the retention of crop residues.

How can conservation tillage contribute more?

Although conservation tillage indeed has a lot of benefits, we acknowledge that there are some potential risks in performing conservation tillage. For example, there is evidence that the conservation tillage will cause a decline in crop yield at the beginning of conducting conservation tillage. Some cold regions may not be suitable for the full retention of crop residues. Therefore, I have two suggestions for farmers who want to carry out conservation tillage for the first time. First, conduct a trial in a small plot of your farmland. A second suggestion is performing conservation tillage with other sustainable agriculture practices, such as crop rotation, cover crop, or holistic gazing as I have found the evidence to support the combination of those practices can alleviate the potential negative impacts of conservation tillage.

Acknowledgment

This article is mainly based on my work during my volunteering at the Sustainable Agriculture Program of the Nature Conservancy (TNC). I sincerely appreciate the support of Dr. Ying Li, Dr. Dan Zhang, and Mr. Qianxi Yang.

References

[1] Tillage Type Definitions. Available online: https://www.ctic.org/resource_display/?id=322&title=Tillage+Type+Definitions

[2] Deng X, Yang Q, Zhang D, Dong S. Application of Conservation Tillage in China: A Method to Improve Climate Resilience. Agronomy. 2022; 12(7):1575. https://doi.org/10.3390/agronomy12071575

[3] Bhan S, Behera U.K. Conservation agriculture in India – Problems, prospects and policy issues. International Soil and Water Conservation Research. 2014; 2(4): 1-12. https://doi.org/10.1016/S2095-6339(15)30053-8

[4] Jayaraman, S., Sinha, N.K., Mohanty, M. et al. Conservation Tillage, Residue Management, and Crop Rotation Effects on Soil Major and Micro-nutrients in Semi-arid Vertisols of India. Journal of Soil Science and Plant Nutrition .2021; 21: 523–535. https://doi.org/10.1007/s42729-020-00380-1

[5] Hirmas, D.R., Giménez, D., Nemes, A. et al. Climate-induced changes in continental-scale soil macroporosity may intensify water cycle. Nature 561, 100–103 (2018). https://doi.org/10.1038/s41586-018-0463-x

Further Reading

Soil Conservation

How to apply conservation tillage to protect soil fertility