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The incidence and prevalence of inflammatory bowel disease (IBD), namely Crohn's disease and ulcerative colitis, have increased in Latin America over the past few decades. Although incidence is accelerating in some countries in the region, other areas in Latin America are already transitioning into the next epidemiological stage—ie, compounding prevalence—with a similar epidemiological profile to the western world. Consequently, more attention must be given to the diagnosis and management of IBD in Latin America. In this Review, we provide an overview of epidemiology, potential local environmental risk factors, challenges in the management of IBD, and limitations due to the heterogenity of health-care systems, both public and private, in Latin America. Unresolved issues in the region include inadequate access to diagnostic resources, biological therapies, tight disease monitoring (including treat to target therapy, surveillance and prevention of complications, drug monitoring), and specialised IBD surgery. Local guidelines are an important effort to overcome barriers in IBD management. Advancements in long-term health-care policies will be important to promote early diagnosis, access to new treatments, and improvements in research in Latin America. These improvements will not only affect overall health care but will also lead to optimal prioritisation of IBD-related costs and resources and enhance the quality of life of people with IBD in Latin America.

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Core IdeasEnhanced‐efficiency fertilizers reduced N2O compared with anhydrous ammonia in two of three years.SuperU reduced both area‐ and yield‐scaled N2O emissions in two of three years.Soil inorganic N concentrations were not correlated with daily N2O fluxes.Fertilizers ESN, SuperU, and UAN + nitrapyrin did not increase yield or grain N recovery efficiency. Balancing efforts to mitigate nitrous oxide (N2O) emissions from crop production while increasing grain yields is an important challenge for agriculture. The objectives of this study were to assess N2O emissions, soil inorganic nitrogen (N) concentrations, grain yield, and grain N content for three enhanced‐efficiency nitrogen fertilizers (EENFs) compared with anhydrous ammonia in a rainfed corn system in Illinois over 3 yr (2015–2017). Treatments included a control (check) and four N sources applied at 202 kg N ha−1: injected anhydrous ammonia, stabilized urea containing urease and nitrification inhibitors (SuperU, Agrotain International), polymer‐coated urea (ESN, Agrium Advanced Technologies), and injected urea‐ammonium nitrate (UAN) + nitrapyrin. Significant reductions in N2O emissions were observed for several EENFs compared with anhydrous ammonia, but results were not consistent across treatments and years. SuperU reduced area‐ and yield‐scaled N2O emissions in two of three study years compared with anhydrous ammonia, while ESN had no N2O mitigation benefit. Injected UAN + nitrapyrin had the highest emissions in the first year but significantly decreased emissions in the second 2 yr. No treatment significantly improved yield or grain N content compared with anhydrous ammonia. In light of efforts to broadly promote EENFs in the US Midwest, these results demonstrate there is some promise for N2O mitigation, but the lack of clear crop productivity benefits combined with inconsistent N2O mitigation effects do not support the conclusion that EENFs inherently improve agronomic and environmental outcomes.

Soil organic C (SOC) is significantly affected by changes in climate that control the physical, chemical, and biological processes in the soil. Simulating the impacts of future climate on SOC is challenging due to the limited availability of soil and climate variables required to properly simulate future SOC dynamics. The main objective of this study was to develop a modeling framework to quantify the impacts of future climate on SOC dynamics. The framework was developed for the Model for Nitrogen and Carbon in Agro‐Ecosystems (MONICA) using the data collected from three University of Illinois Crop Science Research Centers. Projected precipitation and air temperature, collected from 32 global circulation models, were used to estimate the climate variables and cropping operation schedules required as inputs in MONICA. Six corn (Zea mays L.)–soybean [Glycine max(L.) Merr.] rotation scenarios were considered in the simulations. Results showed that the total SOC in the upper 30 cm of the soil was expected to decrease from 43 to 70% in 2015 to 2075, with an uncertainty range of 13 to 16% due to the variation in climate prediction. The SOC in corn–soybean rotation schemes did not vary significantly from that of continuous corn scheme. The ability of a model to simulate realistic results depends significantly on the reliability of input data used to parameterize the model. A methodology that comprehensively estimates the impacts of future climatic conditions on SOC allows for realistic model results that can be used as a basis for environmental options, leading to a sustainable agro‐production system. Long‐term changes in SOC due to future climatic conditions were simulated.The impacts of climate projections on SOC from 32 global circulation models were evaluated.We studied the effects of corn–soybean rotations on SOC under changing climate.We made a modeling framework to asses SOC dynamics under scenario‐based climate projections.

Recent research in Illinois suggests that yield increase in corn (Zea maysL.) and soybean [Glycine max. (L.) Merr.] with strip‐till (ST) vs. no‐till (NT) could be explained by differences in root characteristics and enhanced nutrient uptake in ST. However, the effect of these tillage practices on soil properties remains unclear. Our objective was to evaluate the impact of NT and ST on soil organic matter (SOM), penetration resistance (PR), bulk density (BD), water aggregate stability (WAS), and infiltration rate (INF) from selected treatments of a larger study established in 2007 with two adjacent fields in a corn–soybean rotation. The effect of tillage (NT, ST) on soil properties at four different positions relative to the crop‐row and at four successive depths was measured during the corn phase in 2012 and 2013. Averaged across crop‐row positions relative to NT, ST increased SOM by 8.6% (3.5 vs. 3.8% SOM), reduced BD by 4% to 1.35 g cm−3and reduced PR by 18% to 0.94 MPa. There were no differences or inconsistent responses to tillage for WAS and INF indicating additional years are likely needed to determine whether these soil properties can be influenced with NT and ST. Consistent repeated planting over the same position in the field created substantial differences in soil properties in relation to position from the crop‐row. We showed that previously observed improved nutrient uptake efficiency and yields in ST compared with NT is related, at least in part, to improved properties of the soil with ST.

Recent increases in corn (Zea maysL.) production in the U.S. Corn Belt have necessitated the conversion of rotations to continuous corn, and an increase in the frequency of tillage. The objective of this study was to assess the effect of rotation and tillage on soil physical and chemical properties in soils typical of Illinois. Sequences of continuous corn (CCC), 2‐yr corn–soybean [Glycine max(L.) Merr.] (CS) rotation, 3‐yr corn–soybean–wheat (Triticum aestivumL.) (CSW) rotation, and continuous soybean (SSS) were split into conventional tillage (CT) and no‐till (NT) subplots at two Illinois sites. After 15 yr, bulk density (BD) under NT was 2.4% greater than under CT. Water aggregate stability (WAS) was 0.84 kg kg−1under NT compared to 0.81 kg kg−1under CT. Similarly, soil organic carbon (SOC) and total nitrogen (TN) were greater under NT than under CT with SOC values for 0 to 60 cm of 96.0 and 91.0 Mg ha−1and TN values of 8.87 and 8.40 Mg ha−1for NT and CT, respectively. Rotations affected WAS, TN, and K levels with WAS being greatest for the CSW rotation at 0.87 kg kg−1, decreasing with more soybean years (CS, 0.82 kg kg−1and SSS, 0.79 kg kg−1). A similar pattern was detected for TN and exchangeable K. Results indicated that while the use of NT improved soil quality, long‐term implementation of continuous corn had similar soil quality parameters to those found under a corn–soybean rotation.

During transition to organic production, various strategies can be implemented to enhance soil health, including the soil property of disease suppressiveness. We previously found increased levels of diseases caused by biotrophic pathogens associated with manure application, but manure also suppressed diseases caused by necrotrophic pathogens. In an extension of that study we evaluated soils from different cropping system and organic amendment treated plots using a bioassay of suppressiveness to two soilborne diseases, Rhizoctonia root rot and sudden death syndrome (SDS) of soybean [Glycine max(L.) Merr.]. Also, the soil population levels of Pseudomonadaceae were assessed for their suitability as an indicator of disease suppressiveness. Levels of soil suppression of both Rhizoctonia root rot and SDS were found to be associated with specific cropping systems, but the associations were not consistent from year to year. There were no associations between organic amendment treatments and disease suppression in the bioassay studies. However, there was an overall increase in soil suppressiveness to Rhizoctonia solaniduring the 3 yr of transition, regardless of cropping system or organic amendment treatments. In contrast, there was an overall decrease in suppressiveness to Fusarium virguliformeduring the transition. There was no significant effect of cropping system or organic amendment treatments on the levels of Pseudomonadaceae, indicating that this was not a good predictor of general suppression in this study. While specific treatments were not found to consistently impact soil suppressiveness, the overall increase in suppressiveness to R. solaniduring the 3‐yr transition did show the value of the transition process.

Organic inputs have been suggested to have either suppressive or conducive effects on levels of plant diseases. In this study, we compared effects of organic matter amendments and transitional cropping systems on plant diseases during the transition from conventional to organic agricultural production and 2 yr following. During the 3‐yr transition, organic amendments included raw dairy manure, composted dairy manure, and non‐amended treatment superimposed on three cropping systems (perennial pasture, cash grain crops, and vegetable crops). Two years of post‐transition crops included tomato (Lycopersicon esculentumMill.) and bell pepper (Capsicum annuumL. var. annuum) in the first year and soybean [Glycine max(L.) Merr.] in the second. During transition, raw manure amendments resulted in higher levels of diseases caused by some biotrophic pathogens, including rusts in corn (Zea maysL.) and orchardgrass (Dactylis glomerataL.). However, raw manure applications were also found to suppress some diseases caused by necrotrophic pathogens, including anthracnose and Septoria leaf spot in tomato. Manure applications promoted higher soybean yields. Powdery mildew of cucurbits (Curbubita moschataDuchesne) was suppressed by composted manure. After transition, tomato plants grown in plots previously under the vegetable system had the highest levels of anthracnose, and soybean grown in plots previously in the pasture system had the highest levels of bacterial pustule, despite the fact that these same plots produced the highest yields in soybean. Yield benefits resulting from applications of raw manure to a pasture transition system may be attractive for farmers, but disease management strategies will need to be considered to prevent increased disease levels.

Expansion of the agricultural frontier over marginal soils leaves a significant environmental imprint on the southern semiarid region of the Argentina pampas. A chronosequence of anthropogenic soils in a cultivated area was investigated to determine the role of human actions on the development of a highly compacted horizon below the plow layer observed during a detailed soil survey in Villarino County. A model area of 300 ha (6 × 0.5 km) representative of the county soilscapes was used to (i) characterize the main physical, chemical, and morphological features of the soils in the chronosequence, and (ii) discuss taxonomical issues that can be improved on to facilitate information transfer. Based on our observations, we propose a new diagnostic feature to classify these soils according to USDA Soil Taxonomyguidelines placed at a taxonomical level above series. Our investigation confirmed that soil morphology is modified within 27 yr of cultivation. Tillage leads to the development of a noncemented plowpan immediately below the Ap, here called ACd, with distinctive morphological features. The ACd is compact and massive with extremely hard rupture resistance when dried. Cultivation‐induced alterations were considered important enough to classify the soils into unique soil series. Given the widespread environmental and financial costs and implications of soil compaction, and the genetic connotations of the plowpan, we propose the densipanas a diagnostic horizon and a new class densicto be use at the family level. Advantages of its use will lead to increased utility and precision in published soil maps and improved communication and understanding among stakeholders.

Phosphorus fertilizer is frequently fall‐applied for corn (Zea maysL.). Diammonium‐(DAP) or monoammonium‐phosphates (MAP) are the preferred P fertilizers and the N in MAP and DAP is assumed to be available for corn. Our objective was to evaluate the effect of application time on availability of ammoniated‐phosphate N to the crop in two different environments. In a laboratory study, MAP and DAP at rates of 70 and 140 mg N kg−1soil were incubated at either 80 or 120% field capacity (FC). Nitrification proceeded rapidly in all treatments, but nitrate levels fell to near zero by 8 wk at 120% FC while remaining above 50% after 16 wk at 80% FC. In a 3‐yr study at Waseca, MN and Urbana, IL with a factorial combination of three N sources [DAP, MAP, ammonium‐sulfate (AMS)], two application times (fall, spring), and two N rates (45, 90 kg N ha−1), N rate and application time, but not N source, affected grain yield and inorganic soil‐N concentrations. Yields were 0.71 and 0.37 Mg ha−1greater for spring than fall applications at Urbana and Waseca, respectively. Late May soil‐N recovery ranged from 31 to 35 and 90 to 100% for fall and spring applications, respectively. It thus appears that only about one‐third of N applied in the fall as ammoniated phosphates at typical rates is available to the next year's corn crop in Corn Belt mollisols. Colder, drier fall to spring conditions may increase this proportion, while warmer, wetter conditions would be expected to lower availability.

The cation exchange capacity (CEC) and specific surface properties were investigated in four particle-size fractions < 50 μm from three loess (one Kastanozem and two Phaeozems), a holocene (Fluvisol) and a basalt soil (Nitisol) before and after destruction of organic matter. Particle-size fractions were separated by sedimentation after chemical and physical dispersion of the soil samples. Illite, amorphous minerals, mixed layers, smectite and kaolinite were the predominant clay minerals. They were detected in all size fractions. The CEC increased with increasing organic matter contents and this effect was more pronounced in coarser fractions. The organic matter content per unit surface area was two or three times larger in coarse silt than in clay, irrespective of the soil type.