Diversification Of Crop Rotations Research Articles

Diversification of crop rotations and soil carbon balance: impact assessment based on national-scale monitoring data

A successful crop rotation choice is key to the profitability and sustainability of farm management and may simultaneously have an impact on soil organic carbon (SOC) content. In this study, we estimated how changes in crop rotations affected SOC balance in Finland between 2009 and 2018, using geospatial data and Bayesian modeling. The area designated for perennial-dominated and diverse cereal rotations increased over the study period. Perennial grassland rotation was found to have a positive impact on SOC balance, while rotations dominated by annual crops did not differ in their impacts on SOC content. At the national scale, changes in Finnish crop rotations resulted in an estimated annual mitigation of the loss of SOC content by 1336 Mg C year−1 in mineral soils and reduced the carbon dioxide emissions of organic soils by 10,475 Mg C year−1. The combined effect of these two contributions is 11,811 Mg C year−1, with an 80% probability interval of (−6600; 30,300) Mg C year−1. While the overall impact of changes in crop rotations on SOC is relatively small, a continued change to more diverse and perennial-dominated crop rotations may have other agronomic and environmental benefits, e.g. on resilience and biodiversity.

Effect of short-term perennial leys on life cycle environmental performance of cropping systems: An assessment based on data from a long-term field experiment

Modern agriculture’s dependence on the intensive use of inputs, such as chemical fertiliser and pesticides, leads to high environmental impacts and, possibly, vulnerability in food security, since most of these inputs are imported from other countries. This calls for more sustainable and resilient agricultural practices. Diversification of crop rotations, e.g. by including perennial leys, enhances provision of ecosystem services, leading to healthier crops and increased yields. Perennial crops also increase soil organic carbon (SOC) stocks, which is interesting from a global warming mitigation perspective. In addition, legume-rich leys can utilise atmospheric nitrogen (N) through symbiotic association with N2-fixing bacteria. However, few studies have evaluated the effects of short-term perennial leys in rotation on cropping system performance over long periods and under different conditions. In this study, we used data from three sites in a long-term experiment in Sweden (initiated in the 1960 s), in combination with Life Cycle Assessment methodology, to assess the environmental and yield effect of including ley in crop rotations. Two N fertiliser regimes (High, Low) in combination with three six-year crop rotations, consisting of either i) two-year mixed grass-legume ley, ii) two-year pure grass ley or iii) annual crops without ley, were compared. Environmental impacts (climate impact, energy resource depletion, eutrophication potential) of the different combinations were quantified per kg harvested crop (expressed in cereal units, CU) and per hectare. The lowest environmental impact, at all sites, was found for the crop rotation with two-year mixed ley under the Low N regime. On average, this combination resulted in 329 g lower GHG emissions per kg CU than the crop rotation without ley and Low N, primarily due to lower input of chemical N fertiliser, which reduced the impact from fertiliser production and soil N2O emissions. Comparison of mean SOC change over the study period revealed reduced SOC stocks for all rotations and all sites, especially in the rotation without ley. Therefore, including short-term perennial leys, especially leys containing legume species, in crop rotations can be a useful tool in meeting policy targets on reducing the environmental impacts of agriculture, and in reducing the dependence on purchased agricultural commodities. However, despite the potential benefits of rotational leys, the market demand for the produced ley biomass may be insufficient. Hence, incentives to increase demand are necessary to promote large-scale adoption, for example, for use in bioenergy production and feed.

Evaluation of different weed management strategies including non‐chemical tools and cinmethylin for control of multiple herbicide‐resistant Alopecurus myosuroides

AbstractThe development of resistance in Alopecurus myosuroides populations to different herbicide active ingredients in Europe exacerbates efforts toward its chemical control. In Europe, cinmethylin provides an additional mode of action for the control of A. myosuroides. The objective of this study was to evaluate three resistance weed management (RWM) strategies, including cinmethylin and other pre‐emergence herbicides, for the control of multiple herbicide–resistant A. myosuroides. The RWM strategies used in this study differed in the extent of preventive cultural practices (tillage, crop rotation, sowing date and stale seedbed). Two field trials were conducted at sites with ACCase‐ and ALS‐resistant A. myosuroides biotypes in Germany between 2017 and 2020. Cinmethylin was included in the herbicide regime for A. myosuroides control. The combination of initial inversion tillage, delayed sowing, crop rotation diversification, and stale seedbed reduced the density of A. myosuroides bup to 90% compared to a strategy with pre‐emergence herbicides used as main components in control. At both sites, the amount of viable A. myosuroides seeds in the soil seed bank was reduced by over 90% after a 3‐year trial period in plots with initial inversion tillage. Molecular analyses revealed that the omission of ACCase and ALS inhibitors did not reduce the proportion of resistant A. myosuroides biotypes. Long‐term control of resistant A. myosuroides must be based on a combination of cultural practices that reduce the soil seed bank and suppress the occurrence of A. myosuroides and the use of still‐effective active ingredients for preventing the renewed entry of seeds into the soil.

Yield, soil Nitrogen content and weed control in six years of conservation agriculture on-farm field trials in Southwest Germany

Conservation Agriculture (CA) is a farming system that aims to protect soil resources by promoting minimum soil disturbance in combination with the maintenance of a permanent soil cover, and diversification of crop rotation. The aim of this study was to investigate the effects of no-till and shallow conservation tillage using a chisel plough and rotor tiller on loamy soils with high clay contents in combination with cover crop mixtures in rotations with at least three different crops. Crop yield, soil Nitrogen content and weed coverage were the main parameters measured. Experiments were performed in an on-farm approach in southwest Germany on 18 farms and two research stations over a period of 6 years. Yields of cereals, oilseed rape, maize, soybean and peas were slightly lower under no-tillage with 5.8–7.3 Mg grain yield equivalents ha−1 than under conservation tillage with 6.3–7.8 Mg grain yield equivalents ha−1. Cover cropping did not affect crop yields. Tillage and cover cropping had no influence on weed control in the subsequent main crop. Soil nitrate contents before winter in November were on average 11 kg N ha −1 lower in the cover crop treatments compared to the plots without cover crops. This study shows that CA with minimum tillage had slight advantages compared to the no-till system under Southwest Germany farming conditions.

Editorial: crop diversification, a key pillar for the agroecological transition

The spatial and temporal diversification of cropping systems is a way to reduce the dependency of 14 agricultural systems on synthetic inputs and limit their environmental impacts by promoting the 15 expression of ecosystem services (Tamburini et al. 2020; Kremen et al. 2012). The options to 16 diversify cropping systems are numerous going through the diversification of crop rotations with 17 legumes and other crops, the association of species with intercropping (with annual or perennial 18 crops), agroforestry and the introduction of multiservice cover crops during fallow periods (Hufnagel 19 et al. 2020

Resilient soybean and maize production under a varying climate in the semi-arid and sub-humid Chaco

Food security and economic stability of many developing countries rely on the resilience of major crops to climatic variability and climatic anomalies. Since climate change forecasts predict an increasing frequency and intensity of climatic disturbances, the need to increase our knowledge about the influence of climate variability on crop productivity is especially acute for areas with fragile environments such as the semi-arid and sub-humid Chaco in South America. We used climate records from recent decades and crop growth models to: (i) identify the main climatic variables that have influenced the productivity of soybean and maize which are major crops cultivated in the area and (ii) to assess the impact of inter-annual variability of climate variables on the productivity of soybean and maize. Simulated soybean and maize grain yields indicated that farmers in Chaco should be aware of the high interannual variability in the productivity of these crops. Farmers face a different risk cropping maize and soybean depending on the location. The productivity of soybean was below production costs in 10–13% of the studied years while the corresponding values for maize were 11–14%. Diversification of crop rotations is therefore key to enhance resilience and to increase the likelihood of harnessing favorable growing conditions. Management strategies intended to conserve soil water are of paramount importance, especially for soybean where anomalies in the precipitation during the first four months after sowing was the predictor that explained the highest amount of variance in grain yield (r = 0.58). To mitigate the effect of temperature, which essentially is a factor out of direct control of the farmer, the main practice that arose from our study is delaying planting dates (e.g., towards late January) to avoid the occurrence of high temperatures during the critical stages of the crop.

Long‐term effect of tillage and straw retention in conservation agriculture systems on soil carbon storage

AbstractThe main principles of conservationagriculture (CA) are minimal soil disturbance, permanent soil cover, diversification of crop rotations, and retention of crop residues. Tillage has been implicated with increased soil organic C (SOC) mineralization, but recently this has been contested. Residue retention and cover crops result in higher soil C inputs and are therefore expected to increase SOC. This study aimed to evaluate the effect of 17 yr of residue retention (with and without) and tillage (plowing and no‐till) on soil C storage on two Danish sandy loam soils with different clay and SOC content under cool temperate humid climate conditions. Straw retention reduced bulk density at both sites. It also increased the C concentration with 0.47 mg C g–1 dry soil on average from 2002 to 2019, and SOC stocks in 2019 with 23 tonnes C ha–1, on average, at the site with higher initial SOC content. The effect of straw retention on soil C was higher when the soil was plowed, and no significant effect was observed in no‐till soils. Straw retention did not significantly affect C concentration at the site with low initial SOC. Tillage altered the C distribution in the soil profile, so that the C concentration in the upper layer (0–25 cm) was higher in the no‐till soils, but did not significantly increase total C concentration in deeper layers (0–50 cm). Use of no‐till and straw retention did not consistently affect crop yield across site‐years, but the interannual variability was large, obscuring possible differences in yields.

Crop Yield and Essential Oil Composition of Two Thymus vulgaris Chemotypes along Three Years of Organic Cultivation in a Hilly Area of Central Italy.

Thymus vulgaris L. is one of the most commonly used medicinal and aromatic plants (MAPs), owing to a range of therapeutic properties of its essential oil. Plant growth, biomass yield, essential oil content and composition are influenced by chemotype, environmental conditions, cultivation techniques and vegetative development. Since in MAPs cultivation special attention is paid on high quality of raw material, the adoption of sustainable agriculture methods is of pivotal importance. Therefore, we evaluated the agronomic and qualitative performances of two Thymus vulgaris L. chemotypes, organically cultivated under the Mediterranean climate of hilly lands of central Italy for three consecutive years (2017–2019). Along the trial, total above-ground dry biomass significantly increased from the 1st to 3rd year after planting and large variations in the main biological, biometric and productive traits were observed between the two chemotypes. The ‘thymol’ chemotype EO obviously showed thymol as the major constituent (51.26–49.87%) followed by γ-terpinene and p-cymene. The ‘linalool’ chemotype EO showed high percentages of oxygenated monoterpenes (about 90%) with linalool (75%), linalyl acetate (8.15%) and b-caryophyllene (3.2%) as main constituents. This study highlighted that T. vulgaris can be successfully organically grown in the hilly lands of Tuscany, with interesting biomass and essential oil yields, even though the plants were in the initial years of crop establishment (start in 2017). The introduction of this species into organic cultivation systems could contribute to obtain high-quality raw material, as well as to enhance crop rotation diversification, which is of pivotal importance in the management of organic farms.

Long-term crop rotation diversification enhances maize drought resistance through soil organic matter

Climate change adaptation requires building agricultural system resilience to warmer, drier climates. Increasing temporal plant diversity through crop rotation diversification increases yields of some crops under drought, but its potential to enhance crop drought resistance and the underlying mechanisms remain unclear. We conducted a drought manipulation experiment using rainout shelters embedded within a 36-year crop rotation diversity and no-till experiment in a temperate climate and measured a suite of soil and crop developmental and eco-physiological traits in the field and laboratory. We show that diversifying maize-soybean rotations with small grain cereals and cover crops mitigated maize water stress at the leaf and canopy scales and reduced yield losses to drought by 17.1 ± 6.1%, while no-till did not affect maize drought resistance. Path analysis showed a strong correlation between soil organic matter and lower maize water stress despite no significant differences in soil organic matter between rotations or tillage treatments. This positive relationship between soil organic matter and maize water status was not mediated by higher soil water retention or infiltration as often hypothesized, nor differential depth of root water uptake as measured with stable isotopes, suggesting that other mechanisms are at play. Crop rotation diversification is an underappreciated drought management tool to adapt crop production to climate change through managing for soil organic matter.

Influence of various elements from cultivation technology on the buckwheat yield

Buckwheat is a very valuable food crop, widely in demand not only in Russia, but also in the world agri-food market. Buckwheat belongs to pseudo-grain culture and is therefore of particular interest for crop rotation diversification and is suitable for organic farming. Scientists have long faced the question about the reasons for obtaining low yields of buckwheat grain with the high biological yield potential. We can talk about two groups of reasons that reduce crop productivity: the first are agrotechnical, the second are biological. Agronomic reasons are sowing buckwheat after bad and clogged previous crops, often after spring plowing, insufficient weed control before sowing, insufficient mineral nutrition, untimely sowing, poor plant care, lack of pollinators, large losses of grain during harvesting. The biological causes include dimorphism of flowers. The purpose of this work is to determine the influence of growth stimulant, fertilizer and previous crops on the buckwheat yield in Siberia. The role of adding ammonium nitrate and the use of the growth stimulant «Zerebra Agro» in the productivity formation of this crop was studied, as well as the influence of previous crops on its yield value. Six varieties of buckwheat were used as the object of research. Analysis of influence indicators in our studies revealed that buckwheat yield depends by 19% on its previous crops, by 12% on the means of intensification, by 29% on the interaction between the previous crops and means of intensification and by 39 % on unaccounted factors.

Can no‐till restore soil organic carbon to levels under natural vegetation in a subtropical and tropical Typic Quartzipisamment?

AbstractSandy soils are widely distributed in Brazil and occur in most states. However, they have serious limitations for agricultural use due to low natural fertility, low water retention capacity, low resilience, and high susceptibility to erosion. Management of these soils through a no‐till (NT) system following its basic principles (i.e., elimination of plowing, diversification of crop rotation, retention of crop residues, and maintenance of permanent soil cover) is a practice that can restore the soil organic carbon (SOC) stock, and restore productivity and economic viability of these soils. We hypothesized that: (a) we can recover the carbon (C) stock in Typic Quartzipisamment in subtropical and tropical climates to the level of native vegetation; (b) the adoption of NT during the initial phase, in conjunction with intensive cropping systems with high plant biomass input, is an efficient strategy to recover SOC in Typic Quartzipisamment soils; and (c) long‐term NT (over 20 years—the maintenance phase), and low/medium input of plant biomass, is an efficient strategy for SOC recovery in Typic Quartzipisamment soils. Thus, the present study aimed at assessment of the recovery of SOC stocks in soil profile (0–1.0 m depth) in a Typic Quartzipisamment in subtropical and tropical climates, in comparison with the neighboring soil under native vegetation (NV). The sites selected for this study are located in two Brazilian grain‐producing regions: (a) Manoel Viana City—Rio Grande do Sul State (MV—site 1) that represents the subtropical climate condition, and (b) Luiz Eduardo Magalhães City—Bahia State (LEM—site 2), which represents the tropical climate. Soil samples were collected from soil profile for 0–1.0 m depth. At site 1, the predominant crop rotation over the years was wheat/soybean/oats + forage turnip/soybean. At site 2, the crop rotation includes cultivation in two periods designated as the crop and off‐seasons, and the succession consisted of soybean/Brachiaria/cotton/millet/soybean/maize‐Brachiaria. In both sites, soils under the neighboring NV were also sampled. SOC content was determined by the dry combustion method using an elemental C and N analyzer. Soil C stock was calculated based on the equivalent soil mass. Approximately 31 and 23% of the SOC stock was stored in the surface at 0–0.20 m, compared with 69 and 77% in 0.20–1.0 m layer of a Typic Quartzipisamment with high and low/medium input of crop residues, respectively. The Typic Quartzipisamment with low/medium input of crop residues fully recovered the stock of C in the surface soil layer (0–0.05 m). The Typic Quartzipisamment with high input of crop residues fully recovered the stock of C in the cultivated (0–0.20 m) and also in deeper soil layers (0–0.40 m). Thus, adoption of NT associated with intensification of cultivation systems and high addition of biomass‐C is an effective strategy for C restoration in a Typic Quartzipisamment, while also playing a crucial role in restoring ecosystem productivity, soil quality, and environment.

Adoption by adaptation: moving from Conservation Agriculture to conservation practices

ABSTRACT Conservation Agriculture (CA) is a Sustainable Agricultural Intensification strategy based on minimum soil disturbance, permanent soil coverage by living or dead biomass, and diversification of crop rotations. We reviewed the literature on benefits, trade-offs, adoption and adaptation of CA in sub-Saharan Africa (SSA). While CA can improve soils and sustain crop yields, benefits are inconsistent and there are trade-offs with crop residue use, weeds and insect pests, labour demands and short-term yield penalties. Adoption rates by smallholders in sub-Saharan Africa are generally low. We hypothesize that underlying adoption constraints are 1) the magnitude of transformation of management practices required from farmers moving to CA, 2) the multiple inherent trade-offs associated with CA practices and 3) the incompatibility of CA practices to local conditions. We suggest CA adoption in SSA could be improved by focusing the promotion of CA to environments where it best fits, or by facilitating smallholders’ adaptation of the practices of CA to respond to their conditions and constraints. We, therefore, propose to move from Conservation Agriculture to Conservation Practices by: (A) identifying and overcoming locally important CA trade-offs through adaptations and complementary practices, and (B) finding farm-specific optimal combinations of practices in terms of feasibility and benefits.

Potential of indicators to unveil the hidden side of cropping system classification: Differences and similarities in cropping practices between conventional, no-till and organic systems

To compare different cropping systems, it is crucial to describe explicitly the associated cropping practices. A set of 31 indicators and six composite indexes addressing farm structure, crop diversification, soil disturbance, organic matter inputs, nitrogen fertilisation, crop protection, and yield was used to describe 59 winter wheat fields belonging to conventional, no-till and organic systems, in Switzerland. The aim of this study was to investigate the complementarity and redundancy of the indicators and their potential to characterise these cropping systems. In general, weak correlations were observed between the studied indicators, showing the importance of using a set of indicators to fully characterise cropping practices. The complex indicators were often correlated with simpler ones, but it cannot be excluded that they can prove to be more useful in different contexts. Retaining a combination of simple and complex indicators to obtain a broad picture of cropping practices is thus recommended. The indicators highlighted differences but also similarities between the three systems. For example, the input of organic matter and crop rotation diversification were similar between the three systems. In contrast, total nitrogen fertilisation (lower for organic systems) and soil disturbance (lower for no-till systems) were different. A high within-system variability was observed for some indicators, suggesting that using quantitative indicators rather than simple classifications based on a general description of the systems allows a better characterisation of these systems. Overall, the use of indicators has the potential to improve our understanding of the influence of cropping practices on the soil and environment.

Carbon Dioxide Emission and Soil Sequestration for the French Agro-Food System: Present and Prospective Scenarios

France is a major agricultural power, characterized by a high degree of regional specialization, either in stockless cash crop farming, exporting most of its intensive cereal production, or in intensive livestock farming highly dependent on foreign feed imports. This agricultural model is characterized by wide nutrient and carbon cycle opening and severe environmental pollution. Based on the nutrient accounting GRAFS model, two contrasted scenarios for the French agricultural system at the 2050 horizon have recently been designed and evaluated for their capacity to meet both the national population's food demand and environmental standards in terms of water pollution. The first scenario (O/S, for opening and specialization) assumes the continuation of the current trends of intensification, specialization, and opening to international markets. The second one (A/R/D, for autonomy, reconnection, and demitarian diet) assumes a radical change toward organic farming with diversification of crop rotations, reconnection of crop and livestock farming, and reduction of the proportion of animal proteins in the human diet. Herein we calculate the budget of CO2 emissions and C sequestration in soils of these two scenarios compared with the current situation of the French agro-food system, by coupling the GRAFS and AMG models. These simulations reveal that the overall CO2 emissions balance of the O/S scenario is far higher than those of the A/R/D, namely because of the emissions associated with mineral fertilizer manufacture, and imported feed and mechanization of land management requiring a large amount of fossil fuel. As the organic carbon content of the soil is known to be highly path-dependent (in the sense that it is the inheritance of previous land use practices), we tested the effect of two rates of implementation of the two scenarios and evaluated the response time of the C soil store, which is of the order of two decades or more. This reveals that after about two-three decades following the implementation of a scenario, an equilibrium is reached with no more net soil C emission nor sequestration.

Crop rotation, tillage system, and precipitation regime effects on soil carbon stocks over 1 to 30 years in Saskatchewan, Canada

For both agronomic and environmental purposes, it is relevant to assess the effect of various land management practices on soil organic carbon (SOC). In the North American Great Plains, fallowing was used to increase soil water storage and production of succeeding crops. In addition, tillage was done to prepare seed beds and to control weeds. But these management practices led to important SOC losses, mainly due to increased mineralization with tillage and reduced plant C inputs with fallowing. In recent years, reduction of fallowing, use of minimum and no-tillage management practices and diversification of crop rotations with the inclusion of pulse crops have been studied. But the results are variable according to soil and climatic situations. In addition, long-term data are not always available. In this context, the objective of the present work was to assess over time the effects of cropping systems involving the use of various tillage management, the presence or absence of fallowing (1981–2011), and the presence or absence of pulse crops (1997–2011) on plant C inputs and SOC stocks along a 0–30 cm silt loam soil profile at Swift Current, SK. First changes between SOC stocks were apparent five years after the start of the experiment involving changed crop systems and mainly in the surface 0–7.5 cm soil layer instead of 0–15 cm or 0–30 cm soil profiles. This study confirmed the accumulation of SOC under continuous wheat systems in comparison to fallow-wheat rotations, probably related to larger C inputs in the continuous wheat systems. Although the effect of tillage was quite scattered in time, it seemed to be more pronounced in the fallow-wheat rotations than in the continuous wheat systems, with higher SOC stocks with no tillage. Then, the replacement of fallow phase by pulse crops offered promising potential to rebuild SOC stock after fallow-wheat rotations, even if its efficacy might depend on the initial SOC content and/or its combination with a tillage reduction. Finally, even if a kind of equilibrium could set after changes from a traditional fallow wheat rotation, the SOC dynamics might be highly influenced by precipitation regime and all the carbon accumulated for decades could be lost in few years (less than five in this study). Indeed, in this semi-arid prairie, the increase of the apparent decomposition with precipitation exceeded that of the plant biomass C inputs.

Pressures on soil functions from soil management in Germany. A foresight review

Global trends in demand for biomass-based food, feed, energy, and fiber call for a sustainable intensification of agricultural production. From the perspective of sustaining soil functions, this implies the integration of soil productivity with the other soil functions and services, namely carbon sequestration, water purification and retention, and nutrient and matter cycling as well as biodiversity. Soil management is the key to this integration. The proper anticipation of future opportunities and challenges for sustainable soil management requires an analysis of drivers and trends affecting soil management. Here, we review drivers and trends of soil management and their relevance for soil functions taking Germany as an example of industrialized agricultural systems with low yield gaps. We analyzed socio-economic, biophysical and technological drivers and identified two types of future management changes: (1) Quantitative changes, i.e., more or less of the same input factors, such as fertilizers, as part of a moderate intensification. (2) Qualitative changes: There, we found the strongest signals for the following practices: higher precision and lightweight machines triggered by information and communication technology (ICT) and robotics; diversification of crop rotations, including the integration of lignocellulosic crops; inoculation with biota; and new crop varieties. Positive practices may be reinforced by a behavioral trend towards sustainable soil management, driven by increasing awareness, knowledge, and consumer demand. They offer opportunities for relieving mechanical pressures from weight and contact stress, chemical pressures from pesticides and fertilizers and promoting soil biodiversity without compromising the soil’s production function. We also found threats, such as increased removal of organic residues and potentially harmful organisms. This foresight study is the first to delineate opportunities and challenges for sustainable soil management and intensification. It informs researchers who intend to improve the knowledge base for reinforcement of positive and mitigation of negative trends of soil management.

Integrating Historic Agronomic and Policy Lessons with New Technologies to Drive Farmer Decisions for Farm and Climate: The Case of Inland Pacific Northwestern U.S.

Climate-friendly best management practices for mitigating and adapting to climate change (cfBMPs) include changes in crop rotation, soil management and resource use. Determined largely by precipitation gradients, specific agroecological systems in the inland Pacific Northwestern U.S. (iPNW) feature different practices across the region. Historically, these farming systems have been economically productive, but at the cost of high soil erosion rates and organic matter depletion, making them win-lose situations. Agronomic, sociological, political and economic drivers all influence cropping system innovations. Integrated, holistic conservation systems also need to be identified to address climate change by integrating cfBMPs that provide win-win benefits for farmer and environment. We conclude that systems featuring short-term improvements in farm economics, market diversification, resource efficiency and soil health will be most readily adopted by farmers, thereby simultaneously addressing longer term challenges including climate change. Specific ‘win-win scenarios’ are designed for different iPNW production zones delineated by water availability. The cfBMPs include reduced tillage and residue management, organic carbon (C) recycling, precision nitrogen (N) management and crop rotation diversification and intensification. Current plant breeding technologies have provided new cultivars of canola and pea that can diversify system agronomics and markets. These agronomic improvements require associated shifts in prescriptive, precision N and weed management. The integrated cfBMP systems we describe have the potential for reducing system-wide greenhouse gas (GHG) emissions by increasing soil C storage, N use efficiency (NUE) and by production of biofuels. Novel systems, even if they are economically competitive, can come with increased financial risk to producers, necessitating government support (e.g., subsidized crop insurance) to promote adoption. Other conservation- and climate change-targeted farm policies can also improve adoption. Ultimately, farmers must meet their economic and legacy goals to assure longer-term adoption of mature cfBMP for iPNW production systems.

Enhancing planned and associated biodiversity in French farming systems

AbstractIn a context of global change involving uncertainty in agricultural production, agroecological systems need to reduce their dependency on inputs and increase their resilience. Biodiversity-based techniques are promising, as they provide production services based on biological processes. Tracking farmer practices is an original approach aiming at identifying and analysing alternative systems and supporting the development of these techniques. We studied, for the first time, the on-farm implementation of six biodiversity-based techniques: (i) agroecological infrastructures, (ii) cropped varietal mixtures, (iii) agroforestry, (iv) intercropping, (v) cover cropping and (vi) crop rotation diversification. We first analysed the combinations of these techniques in a large sample of 194 French farmers. A multiple correspondence analysis followed by a hierarchical cluster analysis on principal components resulted in groups of farms with different combinations of these techniques. Then, deeper interviews were conducted with 29 farmers across three regions to analyse the various methods of applying the techniques in the context of their farm and to identify the conditions for their successful implementation. Taking advantage of this large and rare sample of almost 200 interviewed farmers, we identified six different groups of farms. From farms applying mainly cover cropping to comply with European regulations to much diversified farms implying the redesign of the farming system, we support the idea that different strategies of implementation of such biodiversity-based techniques co-exist. The in-depth interviews demonstrated that the level of diversification is related to farm characteristics and four factors mainly favoured the development of such techniques on farms: (1) available labour force and (2) specialised machinery (internal factors) as well as (3) access to market opportunities and (4) the exchange of knowledge through networking (external factors). Surprisingly, the conservation agriculture farmers of our sample did not apply significantly more biodiversity-based techniques. However, our results indicated that organic farmers applied significantly more of these techniques. Our results suggest that enhancing knowledge exchange through networks would favour the broader application of such techniques. It could also be relevant to gather farmers, industries and public authorities to favour the emergence of market opportunities.

An economic analysis of integrated crop-livestock systems in Iowa, U.S.A.

Diversified cropping systems integrated with livestock production can provide substantial soil conservation and water quality benefits, yet farmers in the U.S. Corn Belt have shifted toward greater specialization of farming systems in recent decades. The purpose of this study was to evaluate the economic feasibility of re-integrating crops and livestock in farming systems of the U.S. Corn Belt. Using data on farming practices and yields from a long-term cropping systems experiment, we calculated annual revenue and costs of four farming systems–a simple corn-soybean rotation with and without cattle (2-yr cash and 2-yr integrated, respectively) and a diversified corn-soybean-oat/alfalfa-alfalfa rotation with and without cattle (4-yr cash and 4-yr integrated, respectively). Our analysis was conducted for a 405-ha parcel in central Iowa over the period of 2008 to 2015. To maximize the use of harvested crops, cattle enterprises differed for the 2- and 4-yr rotations: yearlings were finished using a diet of mostly concentrate feeds for the 2-yr integrated system and calves were backgrounded and finished using a diet of forages and concentrates for the 4-yr integrated system. We found that mean annual returns to land and management were similar among all four farming systems ($790ha−1 averaged across the four systems). The integrated systems exhibited greater variability among years in returns to land and management than the cash systems. In addition, total costs excluding land and management were four- to nine-fold greater for the integrated crop-livestock systems than for the cash crop systems. Labor requirements increased with crop rotation diversification by 59% (4-yr cash vs. 2-yr cash) and with integration of cattle by 217% (2-yr integrated vs. 2-yr cash) or 232% (4-yr integrated vs. 2-yr cash). We concluded that diversified crop rotations with or without cattle are profitable farming systems in Iowa, but require greater capital and labor inputs than the dominant 2-yr cash grain system.

Impact of Energy Crop Rotation Design on Multiple Aspects of Resource Efficiency

AbstractBiogas production can cause environmental problems due to a biased alignment of one energy crop used as a feedstock, e.g., maize in Germany. Diversification of crop rotations and resource‐efficient management can be the key to sustainable crop management. Four crop rotations on eight sites across Germany were evaluated in terms of their resource efficiency (area use, energy, and economic efficiency) to derive options. Analysis revealed high variation in all indicators under review, with a high variance explanation by the interaction between crop rotation and regional characteristics. Furthermore, results indicate that high area‐specific methane yields do not equate to high energy efficiency. Crop management adaptation is a useful tool for optimizing resource efficiency.