Integrated Crop-livestock Systems Research Articles

Case study analysis of innovative producers toward sustainable integrated crop-livestock systems: trajectory, achievements, and thought process

Integrated crop-livestock systems (ICLS) are more complex to properly manage than specialized farming systems due to multiple interactions between crops, livestock, and grassland. Despite individual and structural barriers to adopting sustainable ICLS, some innovative producers have successfully conducted integrated production practices. In this context, a research gap exists in understanding the motivations and incentives for transitioning to such systems. This study aims to address ICLS adoption barriers by analyzing the trajectory, achievements, and thought processes of 15 producers practicing ICLS. Our objectives were to (1) highlight producers’ perceptions of ICLS levers and barriers and (2) identify turning point factors that enabled producers to overcome the barriers. We used a unique set of cases in three continental regions (southern Brazil, the northern Great Plains region in the United States, and southern France) and conducted semi-structured interviews. Interviewees emphasized that ICLS imply dealing with barriers ranging from mindset change to operational adaptations, but they also emphasized the rewarding nature of ICLS when properly managed. All their trajectories had important turning points, such as programs or initiatives, human influence, and broader social and economic reasons that resulted in shifts in their production practices and thought processes. The cases also highlighted that integrating crops and livestock positively impacted family producers’ business outcomes, soil health, and livelihood options. Still, individual barriers, including operational management, and structural barriers, including stakeholder awareness and commitment, must be overcome. Encouraging initiatives that offer a systemic approach and promote knowledge exchange can address part of ICLS adoption barriers. Initiatives must embrace a broader innovation ecosystem, having extension teams in close contact with researchers and stakeholders to assist producers in providing support for a more sophisticated level of management that ICLS require. Overall, we found commonalities in consciousness and proactiveness in remarkable cases that could inspire broader sustainability transitions.

Dairy cattle grazing compacts soil surface without reducing subsequent crop yield

Integrated crop-livestock systems are being increasingly used to intensify food production and make it more sustainable. On the other hand, most studies have focused on extensive systems. This paper analyzed the effects of different managements on soil and plants in an intensive integrated system for milk production. An experiment of management systems was installed in southern Brazil, Rio Grande do Sul, on a Latossolo Vermelho (Oxisol), in 2015 to evaluate: rotational grazing of dairy cows in the winter; rotational grazing of dairy cows in winter followed by soil chiseling; and ungrazed area (control). Soil physical properties and yields of crops were evaluated. Trampling by dairy cows increased soil bulk density by 24 % (0.0-0.05 m), but did not influence yields of subsequent soybean or maize. Chiseling reduced the bulk density of the uppermost layer by 19 %, but did not affect the yields of subsequent crops. It was concluded that in years with abundant water, dairy cattle grazing in an integrated crop-livestock system in Southern Brazil compacts the soil surface, but does not compromise the soil physical processes related to the growth and development of subsequent crops.

Mapping Integrated Crop–Livestock Systems Using Fused Sentinel-2 and PlanetScope Time Series and Deep Learning

Mapping Integrated Crop–Livestock Systems Using Fused Sentinel-2 and PlanetScope Time Series and Deep Learning

Crop, livestock, and forestry integration to reconcile soil health, food production, and climate change mitigation in the Brazilian Cerrado: A review

Integrated crop–livestock (ICL) and crop–livestock–forestry (ICLF) systems have been widely adopted in the Brazilian Cerrado. In this study, we gathered the publications regarding the effects of the ICL and ICLF systems on soil health, plant and animal production, and carbon (C) balance and then synthesized them in comparable terms, aiming to evaluate the sustainability of these systems in a broader and comprehensive approach. On the basis of the evidence from 65 peer-reviewed publications, it was observed that adopting integrated systems can improve soil health in the Brazilian Cerrado. With a few exceptions, positive effects on chemical, physical, and biological indicators of soil health were observed in most of the studies that comprised our data. Accordingly, the results showed that the ICL and ICLF systems can improve plant yield and animal production, but special attention regarding the grazing regime and tree management (e.g., spacing, pruning, and thinning) is required. Moreover, soil C accumulation fully offsets soil N2O emissions, underscoring the feasibility of using the ICL and ICLF systems for decreasing the C footprint of agricultural commodities in this region. The research assembled in this review has undoubtedly advanced our knowledge regarding integrated systems in the Brazilian Cerrado. However, there are still significant knowledge gaps that should be addressed, such as their effects on soil physics and biology. Despite these shortcomings, our literature review demonstrates that the ICL and ICLF systems are essential strategies to intensify agricultural production in the Brazilian Cerrado while ensuring sustainability.

Soil management shapes bacterial and archaeal communities in soybean rhizosphere: Comparison of no-tillage and integrated crop-livestock systems

Sustainable agricultural systems play a crucial role in improving soil properties and enhancing crop yields. Particularly for soybean, a vital agricultural commodity, no-tillage (NT) and integrated crop-livestock (ICL) systems have been employed in tropical regions. Despite the recognized benefits of using NT and ICL, there is a significant knowledge gap regarding their impact on the rhizosphere microbiome of soybean. Therefore, this field study aimed to explore and compare the responses of the bacterial and archaeal communities within the soybean rhizosphere in both NT and ICL systems. To address this objective, in addition to sampling the soybean rhizosphere, we collected samples from the bulk soil in the NT area and the rhizospheres of grass (Urochloa brizantha) and corn (Zea mays L.) in the ICL system, covering the typical land use in this region. The results revealed distinct bacterial and archaeal communities in the soybean rhizosphere under NT and ICL. Specifically, the ICL system enriched the soybean rhizosphere with KD4_96 (score 3), Vicinamibacteraceae (score 3), Candidatus Nitrocosmicus (score 2.5), and Methylobacterium (score 2.5). In contrast, NT led to an enrichment of Solirubrobacter (score 3), Amycolatopsis (score 2.8), Sphingomonas (score 2.8), and Nitrososphaeraceae (score 2.5). Microbial community interactions exhibited greater complexity in the soybean rhizosphere under NT (676 nodes and 7095 edges). Notably, both bacterial and archaeal communities in the soybean rhizosphere under NT and ICL demonstrated potential functionality in nitrogen fixation. Thus, this study showed that NT and ICL promoted different responses of bacterial and archaeal communities within the soybean rhizosphere which, can influence the plant's performance.

Stock of Carbon and Soil Organic Fractions in No-Tillage and Crop–Livestock Integration Systems

Soil use and management practices influence the quantity and quality of soil organic matter (SOM). From this perspective, the objective of this work was to evaluate the carbon stock and SOM fractions in a no-tillage (NT) and crop–livestock integration (CL) system in the Cerrado biome. The treatments were divided into four areas, subdivided into an area under NT with 11 years of cultivation, two areas under CL with 5 or 10 years of cultivation, and an area of native vegetation (NV). Undisturbed and disturbed soil (Ferralsols) samples were collected in layers 0.0–0.1, 0.1–0.2, 0.2–0.4, and 0.4–0.6 m for the evaluations of soil properties, including bulk density, weighted mean diameter, clay content, carbon stock, carbon stock of light and mineral fractions, humification rate, and carbon management index. The results obtained suggest that the environments with the highest conservation of the physical properties of the soil are those that contain the highest levels of stable C. The main mechanism for C protection in the systems evaluated was mainly associated with physical protection, promoted by soil aggregates, capable of keeping C protected, and mitigation of C into the atmosphere. The values of the carbon management index in the agriculture areas were >100, indicating that these production systems could approach the soil quality of the native vegetation reference system.

Enhancing soil quality and grain yields through fertilization strategies in integrated crop-livestock system under no-till in Brazilian Cerrado

The study aimed to evaluate the effects of P and K fertilization strategies with and without N-fertilization on soil quality and crop yields in integrated crop-livestock system (ICLS) in the Brazilian Cerrado. The treatments included various fertilization strategies, such as applying P and K during either the cropping phase (conventional fertilization) or the pasture phase (system fertilization), with or without N-fertilization during the pasture phase. Soil samples were collected two years after the experiment was initiated from the 0–10 cm layer, and soybean yields were determined at the end of the crop cycle. Soil carbon (C) stocks remained largely unaffected by the different fertilization strategies. However, soil nitrogen (N) stocks, as well as C and N within the microbial biomass, were lower when conventional fertilization and 0 kg ha−1 of N were used in pastures compared to other treatments. Enzyme activity also decreased with conventional fertilization and 0 kg ha−1 of N in pastures. Scores for Nutrient Cycling and Nutrient Storage were higher with 100 kg ha−1 compared to 0 kg ha−1 of N in the case of conventional fertilization, marking an increase of 22% and 18% for Nutrient Cycling and Nutrient Storage, respectively. For soil function associated with Nutrient Supply, there was no difference between the treatments. Within the 0 kg ha−1 of N group, system fertilization was 12% and 24% higher compared to conventional fertilization. The soil quality index (SQIFERTBIO) was higher with 100 kg ha−1 (0.83) compared to 0 kg ha−1 of N (0.77), showing an 8% increase. Soybean yield was 3% higher with system fertilization and 7% higher with 100 kg ha−1 of N, compared to conventional fertilization with 0 kg ha−1 of N. In conclusion, even in the short term, adopting a system fertilization strategy and applying N-fertilization in pastures benefits soybean yields in ICLS under no-till.

Crop-livestock integration influenced soil profile organic carbon and hydro-physical properties in converted grasslands to row crops

Integrated crop-livestock systems (ICLS) can mitigate the impacts of cropping intensification by improving soil organic carbon (SOC) and associated hydro-physical properties. This study was conducted on three on-farm long-term (≥30 years) sites (Site 1, 2, and 3) and one short-term (4 years) experimental site (Site 4) to compare the SOC and hydro-physical properties to a depth of 40 cm for an intensive-cropland (CL), a native-grassland (NG) and cropland managed with ICLS. Data showed higher SOC, soil water retention (SWR), macroporosity, available water capacity (AWC), and saturated hydraulic conductivity (Ksat) for the NG than the CL indicating the degradation of soil physical quality because of intensive agriculture. However, for sites 1 and 2, the ICLS had 27% and 46% more SOC than the CL in the 0–10 cm depth. In addition, the ICLS decreased bulk density (ρb) (sites 1 and 3) and increased the Ksat (sites 1, 2, and 3) at 0–10 cm depth as compared to the CL. No differences in SOC or hydro-physical properties were observed for the short-term ICLS (site 4) when compared to the CL. The impacts of ICLS were most prominent at the surface soil (0–10 cm) and no difference was observed for the deeper soil. The AWC showed a linear increase with the increase in SOC, however, soils under ICLS and CL showed a higher increase in AWC with an increase in SOC as compared to the NG. This study highlighted the negative impacts of grassland to cropland conversion and suggested the implementation of ICLS to improve organic carbon and other associated hydro-physical properties of soils.

Innovation in crop rotations for sustainable integrated crop-livestock systems: The case of a typical semi-arid Mediterranean area

Integrated organic crop-livestock systems represent a sustainability model on which many environmental, economic and social expectations have been placed, especially in some areas with limited availability of natural resources. In recent years, among the fodder crops in rotation on organic livestock farms, conditions have been created for the emergence of soya (Glycine hispida, M.), also due to the coupled aid granted by the Common Agricultural Policy (CAP). A generalised spread of soybean, however, may generate unsustainable production patterns, especially in Mediterranean areas characterised by limited irrigation and weed management issues. With respect to the above, the research assessed the holistic sustainability of using field beans (Vicia faba, L.) in rotation for fodder purposes. To this end, a technical-economic and environmental analysis was carried out with economic balances and Life Cycle Assessment (LCA), through which a number of synthetic efficiency indices were developed. The results demonstrate the validity of the agronomic choice in achieving environmental efficiency, but also the importance of soil management and reducing the livestock load per unit area in order to simultaneously maintain economic and social efficiency levels.

Temporal evaluation of soil chemical quality using VNIR and XRF spectroscopies

New soil sensing technologies, such as visible and near-infrared diffuse reflectance spectroscopy (VNIR) and X-ray fluorescence spectroscopy (XRF), emerged as alternatives to low-cost, rapid, and environmental-friendly soil analyses. Studies involving the prediction of integrated soil quality indices using individual and combined soil sensing techniques have not been conducted yet on tropical soils, especially regarding the temporal stability of models' performance. This study evaluated tropical soils to give insight into the potential of using individual and combined VNIR and XRF sensors to predict the Soil Chemical Quality Index (SCQI) and its sub-functions (Nutrient Availability, Acidity/Al Toxicity, and Nutrient Storage and Cycling). Furthermore, the temporal stability of these models' performance and a spiking strategy to mitigate performance loss throughout crop seasons were assessed. We conducted this study using 924 soil samples collected over three years (2018, 2019, and 2022) in a field managed with an integrated crop-livestock system (200 ha) in a Brazilian tropical area. We determined the SCQI and its sub-functions for each sample from 15 soil quality indicators. Soil samples were scanned with VNIR (350–2500 nm) and XRF (0–35 kV) spectrometers. VNIR spectroscopy predicted the SCQI, Nutrient Availability, and Nutrient Storage and Cycling with satisfactory accuracy (models classified as good, good, and excellent, respectively), outperforming the XRF technique and the fusion approach. The prediction performance of SCQI and its sub-functions does not show temporal stability. However, the performance loss can be mitigated using the spiking strategy, i.e., using new data from subsequent seasons to recalibrate the global model.

Machine learning algorithms applied to weed management in integrated crop-livestock systems: a systematic literature review

Machine learning algorithms applied to weed management in integrated crop-livestock systems: a systematic literature review

Integrated crop‐livestock versus conventional systems: Effects on the chemical and physical characteristics of an Oxisol

AbstractStudies have reported improvements in soil quality in integrated crop‐livestock systems (ICLS) when compared to conventional systems. The hypothesis of this study was that ICLS improve Oxisol quality due to the use of intercropping, adding pasture and cattle to the systems. The aim of the study was to evaluate the chemical and physical characteristics of an Oxisol and pasture production in the integrated system versus conventional system. We compared two conventional systems: crop system (maize grain production) and livestock system (beef cattle on single pasture) and, four ICLS: maize plus Marandu palisade grass sown simultaneously without herbicide (ICLS‐1); maize plus Marandu palisade grass sown simultaneously with herbicide (ICLS‐2); maize plus Marandu palisade grass in lagged sowing (ICLS‐3); and maize plus Marandu palisade grass sown simultaneously in maize rows and inter‐rows with herbicide (ICLS‐4). A randomized block design with six treatments and three replicates was used. The results suggest improvements in soil quality, including soil organic carbon (ICLS‐4), total nitrogen, and nitrogen stocks (ICLS‐1, ICLS‐2, and ICLS‐4). The intercropping technique influenced pasture production and soil quality during the implementation of integrated systems. The lowest soil strength was obtained for the crop system compared to systems with grazing animals but there were no changes in the soil physical characteristics that could compromise the production system.

Grazing effect on different forage species in yield of soybean-pasture succession

Integrated crop-livestock systems play a crucial hole on sustainable intensification due simultaneous increase the land use efficiency and minimize nutrient leaching due an intensification of nutrient cycling. However, these benefits depend on a good planning and management of the production system. The main objective of this study was to investigate biomass composition, soybean yield and beef cattle performance using three distinct forage cultivars within two cropping systems: Integrated Crop-Livestock System (ICLS) and the Pure Crop System (CS). The three forage cultivars used were: Urochloa ruziziensis, Urochloa brizantha cv. Xaraés, and Megathyrsus maximus cv. BRS Quênia. The experimental area was split into 24 plots, with each plot assigned one of the cropping systems and a specific forage cultivar. The ICLS involved soybean cultivation during spring-summer followed by cattle grazing during the autumn-winter. Conversely, the CS functioned as a pure crop system, utilizing soybean cultivation alongside forage as a cover crop. Soybean yield did not differ between ICLS and CS, neither between forage cultivars (4110 ± 627.0 kg ha−1). Animal performance did not differ between forage cultivars, resulting in average daily gain equals to 0.538 ± 0.316 kg of BW day−1. Animal production per area also was not affected by forage cultivars, yielding 145.0 ± 56.8 kg of BW ha−1. For comparison between systems, beef cattle production was converted in soybean equivalent based on commodities values. ICLS proportionated an increment of 624 ± 135 kg ha−1 per year of soybean equivalent yield, representing 15% increase in land use efficiency compared to the CS system. Therefore, beef cattle grazing in off-season of cash crops can enhance the sustainable intensification of food production. The forage species choice seems not be a paramount question for this model of ICLS.

Optimizing the Nitrogen Use Efficiency in Vegetable Crops

Nitrogen (N) is the most limiting nutrient for the production of vegetable crops, but anthropogenic sources pose risks due to its transformation into several reactive forms and movement throughout the environment. The bulk of the N research to date to improve Nitrogen Use Efficiency (NUE) has followed a reductionist factorial approach focused on synthetic N application rates and crop growth response, under monocultures. The increased adoption of diversified cropping systems, organic N sources, and alternative management practices makes it more challenging to unravel N form transformation, movement, and crop uptake dynamics, in time and space. Here, based on a selected review of the recent literature, we propose a holistic approach of nutrient management to highlight key management and production variables as well as multilevel cropping system, genetic, environmental, ecological, and socioeconomic interactions to improve the N cycle and NUE. The best management strategies to improve NUE include both organic and inorganic N rate calibration studies, germplasm selection, crop rotations, identification of nutrient x nutrient interactions, and pest and water management. Agroecological practices that may improve NUE include vegetational diversification in time and space, integrated crop–livestock systems, conservation tillage, organic amendment inputs, legume-based cropping systems, as well as a landscape approach to nutrient management.

Understanding the Relations between Soil Biochemical Properties and N2O Emissions in a Long-Term Integrated Crop–Livestock System

Edaphoclimatic conditions influence nitrous oxide (N2O) emissions from agricultural systems where soil biochemical properties play a key role. This study addressed cumulative N2O emissions and their relations with soil biochemical properties in a long-term experiment (26 years) with integrated crop–livestock farming systems fertilized with two P and K rates. The farming systems consisted of continuous crops fertilized with half of the recommended P and K rates (CCF1), continuous crops at the recommended P and K rates (CCF2), an integrated crop–livestock system with half of the recommended P and K rates (ICLF1), and an integrated crop–livestock at the recommended P and K rates (ICLF2). The ICLF2 may have promoted the greatest entry of carbon into the soil and positively influenced the soil’s biochemical properties. Total carbon (TC) was highest in ICLF2 in both growing seasons. The particulate and mineral-associated fractions in 2016 and 2017, respectively, and the microbial biomass fraction in the two growing seasons were also very high. Acid phosphatase and arylsulfatase in ICLF1 and ICLF2 were highest in 2016. The soil properties correlated with cumulative N2O emissions were TC, total nitrogen (TN), particulate nitrogen (PN), available nitrogen (AN), mineral-associated organic carbon (MAC), and microbial biomass carbon (MBC). The results indicated that ICLF2 induces an accumulation of more stable organic matter (OM) fractions that are unavailable to the microbiota in the short term and result in lower N2O emissions.

Should we consider integrated crop–livestock systems for ecosystem services, carbon sequestration, and agricultural resilience to climate change?

AbstractContemporary agricultural systems can be generalized as highly specialized operations that are fueled by mechanization; supplied with external nutrients to maximize production; crops protected by petrochemicals to fight against weed, disease, and insect pressures; and livestock protected by therapeutics to ward off virus and bacterial infections when managed in confinement. Such specialized systems have led to low levels of diversity, elevated environmental risks from contamination, loss of soil organic matter, ecological instability, and limited adaptability to climate change. More diversified farming systems are possible, but research required to characterize them in a holistic manner as an alternative to contemporary, specialized systems remains challenging to fund and sustain over time, primarily because they require more labor, management skills, and accessible markets to achieve additional ecological, environmental, and social goals. We share some perspectives as to (1) how specialized systems became the norm and (2) what changes could be made to reverse some ecological risks and environmental declines associated with specialization, acknowledging there is no panacea. Strong evidence exists for perennial forages to restore soil organic carbon (C) and nitrogen, but system‐level analyses of the net balance in greenhouse gas emissions remain to be characterized in the myriad of potential integrated crop–livestock systems that might be deployed across the diversity of edaphic, environmental, and socio‐economic conditions. We suggest there are abundant opportunities for more sustainable agricultural production to sequester soil organic C, reduce greenhouse gas emissions, and develop more climate‐resilient agricultural systems that will be needed in a future dominated by climate change issues.

Soil carbon dynamics in integrated agricultural systems in Minas Gerais state, Brazil: A meta-analysis

The state of Minas Gerais, Brazil, has one of the highest rates of carbon dioxide emission in the country with a large part of these emissions attributed to extensive livestock on degraded pastures. Integrated agricultural production systems are considered a promising strategy to alleviate the negative impacts on soil caused by agriculture (e.g., soil carbon losses via CO2 emissions) while keeping food production. However, the extent to which integrated systems [i.e., integrated crop-livestock (ICL) and integrated crop-livestock-forestry (ICLF)] can contribute to counterbalance soil organic carbon (SOC) losses is limited. Here, through a meta-analysis, we provide a regional-scale assessment of changes in SOC stocks associated with the adoption of ICL and ICLF systems in Minas Gerais state, Brazil. Additionally, we further investigated how SOC dynamics in these systems are affected by distinct soil (e.g., texture, depth) and climatic (e.g., temperature, precipitation) variables. Our results indicate that both ICL and ICLF systems resulted in SOC accrual after their implementation, at average rates of 1.09 and 1.21 Mg ha−1 yr−1, respectivelly. The age of the system affected SOC stocks only in the ICLF system, particularly between 4 and 8 years, in which SOC stocks increased at an average rate of 1.3 Mg ha−1 yr−1. While SOC stocks decreased in clay-sandy soils under ICLF systems, they increased in clay loam soils (1.06 Mg ha−1 yr−1). No clear trend was observed for ICL systems regarding soil texture. Positive effects of precipitation on SOC stocks in ICLF and ICL systems were observed only between 880 and 1000 and 1500–1700 mm, respectively. Clear effects of temperature on SOC stocks were observed only between 22 and 25 °C in ICLF systems. Soil depth had no significant effect on the rate of SOC stock change in the systems evaluated. Although the observed results help to better understand how integrated agricultural systems can affect SOC dynamics, the lack of detailed information in the studies used in our meta-analysis limits statically comparisons. However, our results indicate clear trends that ICLF and ICL systems can contribute to increasing SOC sequestration, and which climate and soil characteristics might be considered to maximize the efficiency of these systems in increasing SOC across Minas Gerais state, Brazil.

Confinamento e semiconfinamento de cordeiras em um sistema integrado de produção: impactos na produção, infecção por nematódeos gastrointestinais e em variáveis sanguíneas

ABSTRACT: This trial evaluated the production performance, gastrointestinal nematode infection (GIN), and selected blood analytes, in Corriedale lambs during the finishing phase in an integrated crop-livestock system (ICLS) with 2 stocking rates. Fifty-two Corriedale lambs were divided into 4 groups: a semi confinement system with a low stocking rate (T1) for 70 days; a semi confinement system with a high stocking rate (T2) for 70 days; confinement for 28 days, followed by semi confinement with a low stocking rate (T3) for 42 days; and confinement for 28 days, followed by semi confinement with a high stocking rate (T4) for 42 days. Body weight, dry matter intake, blood collection, and faecal analysis of nematode eggs were performed for each animal. The stocking rates did not influence body weight gain for the semiconfined lambs (T1 and T2) or for the confined/semiconfined lambs (T3 and T4). All treatments had lower EPG counts at the end of the experimental period. The nematode genera identified during the experiment trial were Haemonchus and Trichostrongylus. There were no significant differences (P > 0.05) for packed cell volume, total plasma protein, and eosinophil means between treatments. These results suggested that the confinement followed by semi confinement in an ICLS, was an option for lamb production during the finishing phase which could be useful in reducing GIN without affecting the production performance.

Sobressemeadura de pastos anuais de verão na cultura da soja para suprir a escassez de foragem outonal

ABSTRACT: In integrated crop-livestock systems, overseeding annual summer pastures over grain crops can reduce forage shortages in autumn without altering grain production. This study evaluated the influence of pearl millet (Pennisetumglaucum L.) and sudangrass (Sorghum Sudanese) overseeded on a soybean (Glycine Max) crop or no-tillage seeding after soybean harvest on productive aspects of pasture. The experimental design was a randomized block with treatments in a 2 × 2 factorial arrangement (pearl millet or sudangrass, overseeding in the full seed stage (R6) of soybean crops or seeding them in a no-tillage system after soybean harvest) in two agricultural years. Pasture height, plant stand, tiller density, and forage production were higher in the first crop year. The overseeding strategy resulted in higher pasture height and foraged production in the first crop year and higher pasture utilization for the next two crop years. Under the no-tillage strategy, the plants stand more elevated in the first crop year, resulting in a higher tiller density in the second crop year. Pasture height, utilization period, and forage production did not differ among the forage species. Pearl millet had a more elevated plant stand, while sudangrass had a higher tiller density. Annual summer pasture overseeding of soybean crops increases the pasture utilization period and forage production in autumn.

Grazing intensity and nitrogen fertilization timing to increase soil organic carbon stock and nitrogen in integrated crop-livestock systems

ABSTRACT Integrated crop-livestock systems (ICLS) foster synergistic relationships to increase nitrogen (N) cycling and soil organic carbon (SOC) accrual in agricultural setups. This study evaluated how the grazing intensity and N fertilization (rates and timing) affect both SOC and N fractions, and soil organic matter chemical composition in an ICLS managed under no-tillage in an Oxisol, six years after initiation. The ICLS was compared to a nearby pasture (PA) and a native forest (NF). The treatments consisted of two grazing intensities: Low Sward Height (LH) and High Sward Height (HH) were maintained with high and low stocking rates, respectively. The HH varied between 0.20 and 0.60 m, and LH between 0.10 and 0.30 m according to the plant forage species throughout the experiment. Fertilization using 200 kg ha -1 N-urea, not splitting up, was conducted at two timings, either at the winter pasture establishment (autumn), about 35 days after sowing or during the summer cash crop cycle (spring). Total N amount per year, including both phases, pasture and cash crop was the same for all treatments. The SOC and N contents were assessed in soil and particulate organic matter (POM), while carbon (C) and N stocks were specifically determined in the soil. Soil organic matter composition was characterized by FTIR. The combination of HH and N fertilization during the pasture phase increased the content of C from 36.1 to 39.9 ± 0.7 g C kg -1 and of N from 2.7 to 3.2 ± 0.1 g N kg -1 . The SOC stocks varied from 37.3 to 41.1 ± 0.7 Mg C ha -1 , and the N stocks from 2.1 to 3.3 ± 0.1 Mg N ha -1 at 0.0-0.10 m soil layer. The SOC content of the POM and the soil organic matter chemical composition determined by FTIR were mainly affected by the grazing intensity. The HH led to an increased in C content within the POM fraction, reaching values of 51.6 ± 1 and 49.2 g C kg -1 , respectively to N crop fertilization and N pasture fertilization. Land-use changed how organic functional groups were stored in soil organic matter fractions. The NF had a greater abundance of aliphatic and phenol in the MAOM, while pasture and ICLS systems had greater aliphatic in the POM fraction. In ICLS, SOC accrual was positively associated with more recalcitrant organic functional groups of phenol, aromatic, and carbonyl C-O. The HH increases SOC accrual, while N-fertilization on pasture ensures adequate nutrition of plants and animals during the winter ICLS phase, at the same time as providing greater residual N for subsequent cash crops through enhanced catalyzed by ruminants. Therefore, grazing and fertilization management strategies should be considered to promote sustainable agriculture intensification with ICLS.