Each month, the conservation ag group at Cornell University offers an analysis of the latest scientific papers dealing with conservation agriculture research from around the world. For this on-going web series, our editors will be selecting several research papers from the Cornell list that will be of special interest to North American no-tillers, strip-tillers and cover croppers.

Further adoption of conservation tillage can increase maize yields in the western US Corn Belt. 

Cambron, T.W., Deines, J.M., Lopez, B., Patel, R., Liang, S-Z. & Lobell, D.B. 2024. Environmental Research Letters. 19 (5) Article 054040.

Cornell Conservation Agriculture Group (soilhealth.org)'s insight:

This paper looks at maize yield impacts conservation tillage (CA) from satellite data from 4 States of the US Corn Belt from 2008-2020. Data was obtained from several thousand fields with differences in climate, soil quality and irrigation status. Their results show overall that long-term adoption of CA increased rainfed maize yields by almost 10% in the area covered. When analyzing the variables, the increase in maize yields were associated with improved water infiltration and retention. But many fields that could benefit from no-till have not adopted yet. They can now strengthen the reasons and areas suitable for benefits from CA. Benefits can be obtained without negative crop yields in most cases. They did say in the paper that NT combined with cover crops amplified the benefits.

A new theory for soil health 

Harris, J.A., Evans, D.L. & Mooney, S.J. 2022. European Journal of Soil Science. 73 (4) Article e13292.

Cornell Conservation Agriculture Group (soilhealth.org)'s insight:

This is an interesting paper discussing the term "Soil Health". They say this is a term for soils that has gained interest by government and land managers but the academic community has struggled to rationalize its use and wider benefit. This is a 2022 paper but since one of the main benefits of CA is to improve soil properties or health, I have included this paper in this month's newsletter. They conclude that "We suggest a broad programme of research to identify dynamic emergent properties, especially resilience, in order to determine soil health."

Weed communities after decades of mineral fertilization and tillage treatments in a corn–soybean rotation. 

Simard, M-J. & Ziadi, N. 2024. Weed Technology. 38 Article e5.

Cornell Conservation Agriculture Group (soilhealth.org)'s insight:

This study, initiated in Canada in 1992, evaluated the effect of 25 years of N and P fertilizer application and tillage (Moldboard vs No-till) on density, biomass and composition of weeds before and after herbicide application in maize (2016) and Soybean (2017). It also evaluated the same treatments 6 years later in maize (2022). comparing  weeds found in 2004 all weed variables increased and there were more grassy weeds in both tillage treatments. No fertilization effect was observed on any weed variables, including composition, except for increased biomass when left to grow all season after crop planting. No till had higher density and biomass of both annuals and perennials before herbicide application but only reduced yield in soybean.

Changes in Soil Microbial Parameters after Herbicide Application in Soils under Conventional Tillage and Non-Tillage. 

Douibi,M., Carpio, M.J., Rodriguez-Cruz, M.S., Sanchez-Martin, M.J. & Marin-Benito, J.M. 2024. Processes. 12 (4) Article 827.

Cornell Conservation Agriculture Group (soilhealth.org)'s insight:

This article evaluates the changes in microbial activity in time after applying3 herbicides to 2 different soils (S1) and (S2) under conventional tillage and no-tillage under field conditions. Various soil biological measures were determined after 1, 34, and 153 days. Without any herbicide all microbial activity was higher under NT than CT with similar or higher values for S1 compared to S2. With herbicides, decrease in microbial activity was greater in CT than NT. It is suggested that this was because the herbicides were adsorbed in the mulch in NT.