No-till Implementation Research Articles

Farmer typologies integrating latent and observed characteristics: Insights for soil and water conservation outreach

One of the fundamental rules of effective communication is to “know your audience.” When engaging farmers in conservation in the U.S. and elsewhere where their participation is voluntary, communication should start with the fundamental recognition that farmers are heterogeneous in many ways; their attitudes, values, and motivations, as well as their farms’ biophysical and economic characteristics, can influence their behaviors. Previous typology research in Iowa, USA using data from a panel survey of farmers, revealed heterogeneity by identifying four types of farmers—Conservationists, Deliberative, Productivists, and Traditionalists—based on latent class analysis of variables measuring varied dimensions of awareness, attitudes, beliefs, perceived motivations, and barriers to practice adoption. The study presented in this article advances the typology by associating observable variables from the same survey (e.g., farmer demographics, farm enterprises, participation in conservation programs, adoption of conservation practices) with the four farmer types. The Conservationist type was the most educated and indicated a high intention of adopting cover crops. The Deliberative type tended not to have a conservation plan with the U.S. Department of Agriculture Natural Resources Conservation Service. The Productivist farmer farmed the most land, rented and owned, and had the highest no-till implementation in land size and percentage of the group. The Traditionalist type rented the least amount of land. We expect outreach professionals, watershed coordinators, and conservation practitioners can use observable characteristics to segment the farmer population and improve conservation messages by tailoring them to the specific farmer types, leading to a higher return on investment in terms of money, time, and goodwill.

Does the duration of no-till implementation influence depth distribution of soil organic carbon, hydro-physical properties, and computed tomography-derived macropore characteristics?

No-till (NT) is a sustainable alternative to conventional-till (CT), however, the impacts of NT and its duration on the depth distribution of soil organic carbon (SOC), physical and hydrological parameters are less studied. Therefore, the objective of this study was to evaluate the changes in soil hydro-physical properties and X-ray computed tomography (XCT)-derived macropore characteristics to a depth of 40 cm as influenced by the duration [short-(5-yr) and long-(30 yr) term] of NT practice on a previously conventionally-tilled (CT) soil. The treatments included: CT, initiated in 1991; long-term NT (LTNT),1991; and short-term NT (STNT), 2016 established on silty clay loam soil (Udic Haplustolls). Four replicated intact soil cores were collected from each treatment at 0–10, 10–20, 20–30, and 30–40 cm depths. Data showed that the LTNT stored 23% more SOC stock in the 0–40 cm depth as compared to the CT. The LTNT also increased the total nitrogen (TN) stock, soil water retention (SWR), plant available water (PAW) content, and saturated hydraulic conductivity (Ksat) to the depth of 40 cm as compared to the CT. The LTNT increased the XCT-derived soil macroporosity [pores with > 500 µm equivalent cylindrical diameter (ECD)] and pore connectivity up to 20 cm than the CT. However, the STNT implementation increased the SWR at − 0.6, − 5, and − 30 kPa, pore connectivity, and Ksat only for the 0–10 cm depth than the CT. In addition, PAW showed a high correlation with SOC content [Pearson correlation coefficient (δ) = 0.71], and Ksat was highly correlated with the modulus of XCT-derived Euler-Poincaré characteristic (a measure of local connectivity; δ = 0.61). The study highlighted that pore connectivity and Ksat in surface soil (0–10 cm) were most responsive to the implementation of NT on a previously tilled soil. Data suggest that a longer duration of NT implementation was required to improve the SOC and soil hydro-physical parameters to a deeper soil profile (0–40 cm). Therefore, we conclude that the conversion of tilled soil to NT practice has beneficial effects, depending upon the duration of NT implementation, in enhancing the SOC and hydro-physical conditions, which may help in storing more water in deeper soil for enhanced production.

A comprehensive modeling framework to evaluate soil erosion by water and tillage

Soil erosion is significantly increased and accelerated by unsustainable agricultural activities, resulting in one of the major threats to soil health and water quality worldwide. Quantifying soil erosion under different conservation practices is important for watershed management and a framework that can capture the spatio-temporal dynamics of soil erosion by water is required. In this paper, a modeling framework that coupled physically based models, Water Erosion Prediction Project (WEPP) and MIKE SHE/MIKE 11, was presented. Daily soil loss at a grid-scale resolution was determined using WEPP and the transport processes were simulated using a generic advection dispersion equation in MIKE SHE/MIKE 11 models. The framework facilitated the physical simulation of sediment production at the field scale and transport processes across the watershed. The coupled model was tested using an intensively managed agricultural watershed in Illinois. The impacts of no-till practice on both sediment production and sediment yield were evaluated using scenario-based simulations with different fractions of no-till and conventional tillage combinations. The results showed that if no-till were implemented for all fields throughout the watershed, 76% and 72% reductions in total soil loss and sediment yield, respectively, can be achieved. In addition, if no-till practice were implemented in the most vulnerable areas to sediment production across the watershed, a 40% no-till implementation can achieve almost the same reduction as 100% no-till implementation. Based on the simulation results, the impacts of no-till practice are more prominent if implemented where it is most needed.

Long‐term research avoids spurious and misleading trends in sustainability attributes of no‐till

Agricultural management recommendations based on short-term studies can produce findings inconsistent with long-term reality. Here, we test the long-term environmental sustainability and profitability of continuous no-till agriculture on yield, soil water availability, and N2 O fluxes. Using a moving window approach, we investigate the development and stability of several attributes of continuous no-till as compared to conventional till agriculture over a 29-year period at a site in the upper Midwest, US. Over a decade is needed to detect the consistent effects of no-till. Both crop yield and soil water availability required 15years or longer to generate patterns consistent with 29-year trends. Only marginal trends for N2 O fluxes appeared in this period. Relative profitability analysis suggests that after initial implementation, 86% of periods between 10 and 29years recuperated the initial expense of no-till implementation, with the probability of higher relative profit increasing with longevity. Importantly, statistically significant but misleading short-term trends appeared in more than 20% of the periods examined. Results underscore the importance of decadal and longer studies for revealing consistent dynamics and emergent outcomes of no-till agriculture, shown to be beneficial in the long term.

The Current State and Future Directions of Organic No-Till Farming with Cover Crops in Canada, with Case Study Support

Eliminating regular tillage practices in agriculture has numerous ecological benefits that correspond to the intentions of organic agriculture; yet, more tillage is conducted in organic agriculture than in conventional agriculture. Organic systems face more management challenges to avoid tillage. This paper identifies factors to consider when implementing no-till practices particularly in organic agronomic and vegetable crop agriculture and describes techniques to address these factors. In some cases, future research is recommended to effectively address the current limitations. The format includes a literature review of organic no-till (OrgNT) research and two case studies of Ontario organic farmers that highlight no-till challenges and practices to overcome these challenges. Cover crops require significant consideration because they are the alternative to herbicides and fertilizers to manage weeds and provide nutrients in the OrgNT system. Equipment requirements have also proven to be unique in OrgNT systems. In the future, it is recommended that researchers involve organic farmers closely in studies on no-till implementation, so that the farmers’ concerns are effectively addressed, and research is guided by possibilities recognized by the practitioners.

The adaptive capacity of maize-based conservation agriculture systems to climate stress in tropical and subtropical environments: A meta-regression of yields

Conservation agriculture is widely promoted across sub-Saharan Africa as a sustainable farming practice that enhances adaptive capacity to climate change. The interactions between climate stress, management, and soil are critical to understanding the adaptive capacity of conservation agriculture. Yet conservation agriculture syntheses to date have largely neglected climate, especially the effects of extreme heat.For the sub-tropics and tropics, we use meta-regression, in combination with global soil and climate datasets, to test four hypotheses: (1) that relative yield performance of conservation agriculture improves with increasing drought and temperature stress; (2) that the effects of moisture and temperature stress exposure interact; (3) that the effects of moisture and temperature stress are modified by soil texture; and (4) that crop diversification, fertilizer application rate, or the time since no-till implementation will enhance conservation agriculture performance under climate stress.Our results support the hypothesis that the relative maize yield performance of conservation agriculture improves with increasing drought severity or exposure to high temperatures. Further, there is an interaction of moisture and heat stress on conservation agriculture performance and their combined effect is both non-additive and modified by soil clay content, supporting our second and third hypotheses. Finally, we found only limited support for our fourth hypothesis as (1) increasing nitrogen application rates did not improve the relative performance of conservation agriculture under high heat stress; (2) crop diversification did not notably improve conservation agriculture performance, but did increase its stability with heat stress; and (3) a statistically robust effect of the time since no-till implementation was not evident.Our meta-regression supports the narrative that conservation agriculture enhances the adaptive capacity of maize production in sub-Saharan Africa under drought and/or heat stress. However, in very wet seasons and on clay-rich soils, conservation agriculture yields less compared to conventional practices.

Cover crops affect the soil chemical properties under no-till system

The purpose of this study was to assess the changes in soil chemical properties affected by the cover crops cultivated in crop rotation in short-term of no-till implementation under Rhodic Hapludox soil. This research was carried out from October 2010 to February 2014. The experiment was set up in completely randomized blocks in a factorial design with eight treatments (cover crops) and three soil depths (0-5, 5-10 and 10-20 cm) with four repetitions. The cover crops were: fall-winter maize (T1), intercropping fall-winter maize with B. ruziziensis (T2), intercropping fall-winter maize with B. brizantha cv. Marandu (T3), intercropping fall-winter maize with Crotalaria spectabilis (T4), B. ruziziensis (T5), B. brizantha cv. Marandu (T6), Pennisetum glaucum L. (T7) and fallow (T8). The T6 and T7 affected exchangeable Mg +2 , it was observed higher exchangeable Mg +2 in T6 (2.39 cmolc dm -3 ) and T7 (2.43 cmolc dm -3 ) in comparison to T1. The phosphorus content showed interactive effect between cover crops and soil depth. In the comparison among the depths, the P contents were higher in 5-10 cm, which showed improvement of 24.6% and 25.2% in comparison to 0-5 and 10-20 cm layers, respectively. The cover crops evaluated in this research affected the exchangeable Mg +2 and K + , as well as Mg +2 and K + saturation. The P content changed in response of cover crops, which was important to observe that this nutrient may increase the content with adoption of cover crops in no-till system. The species used in this research might be recommended to integrate a crop rotation system with the possibility of increasing P availability in topsoil depth in no-till system.

When does no-till yield more? A global meta-analysis

No-till agriculture represents a relatively widely adopted management system that aims to reduce soil erosion, decrease input costs, and sustain long-term crop productivity. However, its impacts on crop yields are variable, and an improved understanding of the factors limiting productivity is needed to support evidence-based management decisions. We conducted a global meta-analysis to evaluate the influence of various crop and environmental variables on no-till relative to conventional tillage yields using data obtained from peer-reviewed publications (678 studies with 6005 paired observations, representing 50 crops and 63 countries). Side-by-side yield comparisons were restricted to studies comparing conventional tillage to no-till practices in the absence of other cropping system modifications. Crop category was the most important factor influencing the overall yield response to no-till followed by aridity index, residue management, no-till duration, and N rate. No-till yields matched conventional tillage yields for oilseed, cotton, and legume crop categories. Among cereals, the negative impacts of no-till were smallest for wheat (−2.6%) and largest for rice (−7.5%) and maize (−7.6%). No-till performed best under rainfed conditions in dry climates, with yields often being equal to or higher than conventional tillage practices. Yields in the first 1–2 years following no-till implementation declined for all crops except oilseeds and cotton, but matched conventional tillage yields after 3–10 years except for maize and wheat in humid climates. Overall, no-till yields were reduced by 12% without N fertilizer addition and 4% with inorganic N addition. Our study highlights factors contributing to and/or decreasing no-till yield gaps and suggests that improved targeting and adaptation, possibly including additional system modifications, are necessary to optimize no-till performance and contribute to food production goals. In addition, our results provide a basis for conducting trade-off analyses to support the development of no-till crop management and international development strategies based on available scientific evidence.