Effects of conservation agriculture on physicochemical soil health in 20 maize‐based trials in different agro‐ecological regions across Mexico

Abstract

Maize (Zea mays L.) is Mexico's primary staple food, but the Country's degrading soils and climate variability limit its productivity. Conservation agriculture (CA), a management technique that combines minimal tillage, permanent soil cover, and crop diversification, could reduce soil degradation and help improve soil health. There is however a lack of information about the effects of CA on soil health in the diverse agroecological conditions in Mexico. This study reports results of a field trial network established to adapt CA to Mexico's diverse cropping systems and local conditions.Physicochemical soil health, also referred to as soil quality, was studied in 20 trials in agro-ecologies ranging from handplanted traditional systems to intensive irrigated systems, initiated between 1991 and 2016. Soil in CA was compared to the local conventional practice (CP), which commonly involves tillage, residue removal, and continuous maize production. Across the sites, organic matter and nitrates were higher in the top (0-5 cm) layer of soil and soil aggregate stability was greater under CA than under CPs. For other soil health parameters, such as nutrient content, pH or penetration resistance, the effects of management varied widely across sites and soil types

Disaggregating the Value of Conservation Agriculture to Inform Smallholder Transition to Sustainable Farming: A Mexican Case Study

“…Input data points were drawn from several sources to populate the IAT. Price and cost data, production input levels, labour requirements, and family expenses were derived from a combination of baseline survey reports of households located in the target communities [52,53,64], databases [44,65], government historical records [38,66], research literature [4,5,8,12,13,25,[34][35][36][37], unpublished data [67][68][69], as well as local expert input from CIMMYT researchers. Validation of the modelled baseline scenario relative to the actual historical baseline was conducted via expert and stakeholder assessment of the system represented, as well as through relevant literature and data review.…”

“…The exception was NT, due to mixed trial results and the reported yield gains mostly occurring in hybrid maize. While it is difficult to define the stepwise increment of yield since it depends on multiple and complex factors-including water availability, soil health, and agronomic management [37]-a 10-year incremental yield boost of 15-30% for maize, 10-20% for sorghum, and 15% for legumes was assumed in this study, based on average figures found in unpublished or preliminary field data from Guanajuato (ciclo PV, 2019). There were also annual yield gains of up to 3.0% and 1.5% pa in maize and sorghum/beans, respectively [75].…”

“…There were also annual yield gains of up to 3.0% and 1.5% pa in maize and sorghum/beans, respectively [75]. For reference, significant improvements in maize yields of up to about 50% have been observed in long-term CA field experiments under rain-fed conditions across central Mexico [12,37].…”

“…For this study we used a case study within central Mexico, a dry-climate region with high potential for CA implementation outcomes [11]. For three decades, CA has been variously adapted to and promoted in Mexico's prevailing maize-based agriculture sector in an effort to increase productivity [4,5,8,12,13,25,[34][35][36][37]. One goal of the efforts is to improve the national average maize yield of 2.9 t/ha [38], significantly lower than the world's average of 5.1 t/ha [39], thereby contributing to the country's agricultural selfsufficiency and national food security [40].…”

Permanent Bed Width Has Little Effect on Crop Yield under Rainfed and Irrigated Conditions across Central Mexico

“…This highlights the importance of adopting production systems that help adapt to the impact of climate change on agriculture, such as conservation agriculture, which is a production system based on three principles: minimum tillage, permanent soil cover, and crop diversification [2]. Several studies have demonstrated the benefits of conservation agriculture, such as improvements in the physical, chemical, and biological properties of soil [3][4][5], which can lead to higher and more stable crop yields and increased profitability of production systems [6][7][8]. Although conservation agriculture has been shown to be a climate-smart production system, applicable to a wide range of environments, the practice should be adapted to the conditions of each region, depending on the climate, soil conditions, and production system [9].…”