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In Brazil, to conserve soil and water, the adoption of a complete array of conservation agriculture technologies in conjunction with contour farming and agricultural terraces is necessary. However, there is little knowledge about the awareness and adoption level of conservationist practices by farmers. In this context, the objective of the study, which took place in a watershed containing agricultural areas dominated by annual crops, was to verify farmers’ perception and adoption level of soil and water conservation practices and the relationship between their adoption level of conservation practices and their socioeconomic characteristics. For this purpose, a survey was carried out with farmers in the Rio Vermelho watershed in southern Brazil. It was found that the majority of farmers have adequate awareness about the use of soil and water conservation practices. Maintaining productivity was identified as the main reason to conserve soil and water, while reducing production costs and controlling erosion stood out as secondary reasons. Agricultural terraces and no-tillage were the most adopted practices by farmers. No-tillage was implemented by approximately 78.3% of landowners and 50% of tenants. However, only 26.8% of farmers adopted conservation agriculture. Overall, most farmers adopt conservationist practices, but in a partial manner, which may not be sufficient to ensure soil and water conservation. Awareness of soil and water conservation needs to be further improved. RESUMO No Brasil para conservar o solo e a água faz-se necessário a adoção do pacote tecnológico da agricultura conservacionista, em conjunto com o plantio em nível e o uso dos terraços agrícolas. Porém pouco se sabe sobre a percepção e o nível de adoção dessas práticas pelos agricultores. Neste contexto, o objetivo do estudo foi verificar a percepção e o nível de adoção de práticas de conservação do solo e da água por agricultores, em áreas agrícolas com culturas anuais, o objetivo do estudo foi verificar a percepção e o nível de adoção de práticas de conservação do solo e da água por agricultores, em áreas agrícolas com culturas anuais, em uma bacia hidrográfica; além de analisar a relação entre a adoção destas práticas e as características socioeconômicas destes agricultores. Para tanto, foi realizada uma pesquisa do tipo survey junto a agricultores da bacia hidrográfica do Rio Vermelho, no sul do Brasil. Com base nos resultados, verificou-se que a grande maioria dos agricultores tem percepção adequada acerca do uso das práticas de conservação do solo e da água. A manutenção da produtividade foi apontada como principal motivo para se conservar o solo e a água, enquanto que a redução de custo de produção e o controle da erosão aparecem como motivos secundários. O uso dos terraços agrícolas e o plantio direto foram as práticas mais adotadas pelos agricultores, e a rotação de culturas foi a menos adotada. Cerca de 78,3% dos proprietários de terra e 50% dos arrendatários adotaram o plantio direto. Porém, apenas 26,8% dos agricultores adotaram a agricultura conservacionista. No geral, verificou-se que a maioria dos agricultores adota medidas conservacionistas, mas de forma parcial, que podem não ser suficientes para garantir a conservação do solo e a da água. A conscientização sobre a conservação do solo e da água precisa ser melhorada.

Quantifying infiltration and surface runoff at the hillslope scale is indispensable for soil conservation studies. However, the spatial and temporal variability of infiltration imposes a major constraint on surface runoff estimation. Point infiltration values do not fully express the complexity of the surface runoff in the landscape. Considering the need to improve the estimation of runoff volume from infiltration data, this study aimed to measure the apparent infiltration at hillslope-scale and compare it with two methods of infiltration estimative derived from point information. The study was carried out in six hydrological monitoring units paired. A set of hyetographs and hydrographs allowed the determination of apparent infiltration [Formula: see text] to each monitoring unit as a function of precipitation rate P. The measured [Formula: see text] values were used: (1) to evaluate the efficiency of the different land management in increasing infiltration; and (2) to evaluate the efficiency of two methods of hillslope-scale infiltration estimation based on point data: (a) derived from concentric rings method ([Formula: see text]), and (b) derived from a physically-based modeling ([Formula: see text]). Regarding the differences in land managements, terraces proved to be the most efficient land management practice, followed by phytomass addition. Regarding the methods, for precipitation rates greater than 40 [Formula: see text] the point infiltration-based [Formula: see text] underestimates apparent infiltration [Formula: see text] with PBIAS ranging from [Formula: see text] to [Formula: see text]. Even so, [Formula: see text] proved efficient in representing [Formula: see text] at less intense rainfall events. Nonetheless, the point infiltration-based method [Formula: see text] properly represented [Formula: see text] to all rainfall intensities (Nash-Sutcliffe coefficient [Formula: see text]).

No-tillage (NT) is a practice that has been used for >30 years and is used as the main soil conservation strategy in South America. However, recent studies have demonstrated soil erosion problems in agricultural fields in southern Brazil related to soybean monoculture, low phytomass production by crops and an absence of runoff control. This study describes the erosion and hydrological response of chisel ploughing and crop rotation intensification in a NT traditionally managed without crop rotation on a Nitisol on an agricultural hillslope in southern Brazil. The water and soil losses were monitored in natural hillslope (Macroplots) approximately 90 m in length and 6000 m2 in area and with a rectilinear plane curvature and a slope of 9%. The treatments tested were as follows: i) NT without crop rotation (NTnocr), ii) chisel ploughing in NT without crop rotation (CH + NTnocr), iii) NT with crop rotation (NTcr), and iv) chisel ploughing in NT with crop rotation (CH + NTcr). Monitoring was performed in the period from July 2015 to June 2016, during which 9 significant rainfall events occurred at different intensities and accumulated volumes. The monitoring results indicated that NTnocr is insufficient to control soil erosion, even during low-intensity events. The crop rotation intensification in NT with increased phytomass production by crops reduced runoff only by 18% and soil losses by up to 84%. Care in relation to chisel ploughing was evidenced by a 2.4-fold increase in NTcr soil losses associated with soil mobilization due to chiseling and high-intensity events. In conclusion, the results revealed that the isolated adoption of NT is insufficient to control runoff, even under crop rotation intensification. This result clearly indicates that complementary conservation practices are necessary to control runoff and all its associated processes, from soil erosion and nutrient and pesticide mobilization to water resources, to improve the definition of conservation agriculture.

No-till (NT) is a soil management system designed to protect soil resources from water erosion and provide numerous benefits compared to conventional tillage through the increase of organic matter inputs into the soil. However, NT in isolation is not sufficient to control erosion processes caused by an excessive production of surface runoff. This study evaluated soil losses on agricultural hillslopes under no-till characterized by contrasted water, soil, and crop management conditions. To this end, water and soil losses were monitored between 2014 and 2018 at two scales, including four macroplots (0.6 ha; 27 events) and two paired zero-order catchments (2.4 ha; 63 events). The resulting dataset covered a wide range of rainfall conditions that occurred in contrasted soil, crop, and runoff management conditions. Hyetographs, hydrographs, and sedigraphs were constructed, and these data were used to evaluate the impact of management on sediment yields, including that of terraces, scarification, and phytomass on sediment yield. The installation of terraces reduced sediment yield by 58.7%, mainly through surface runoff control. Crop management including an increased phytomass input efficiently controlled soil losses (63%), although it did not reduce runoff volume and peak flow. In contrast, scarification had no impact on runoff and soil losses. The current research demonstrated the need to combine the installation of terraces and leaving a high amount of phytomass on the soil to control surface runoff and erosion and reduce sediment yield. The current research therefore reinforces the relevance of the monitoring strategy conducted at the scale of macroplots and zero-order catchments to evaluate the impact of contrasted water, soil, and crop management methods and select the most effective conservation agriculture practices.

International audience; No-till (NT) is a conservation system that improves the hydrological regime of agricultural slopes by providing greater surface protection and benefits to the physical and hydrological properties of soils. However, the isolated use of NT is not enough to control runoff and its associated degradation processes. Therefore, this study aimed to evaluate the runoff of agricultural slopes under NT under different runoff control conditions by monitoring 63 rainfall events in two 2.4-ha zero-order catchments and 27 rainfall events in four 0.6-ha macroplots. The catchments are paired and similar in terms of the type of soil and relief, but different regarding the presence of terraces. The macroplots have different soil and crop management systems. By using monitoring techniques, the hyetographs and hydrographs revealed the influence of the different types of management on the catchments and macroplots and allowed rainfall characteristics, runoff volume, runoff coefficients, water infiltration, peak runoff, response times, and curve number to be analyzed. The terraces positively affected the NT and controlled runoff and related variables, in addition to infiltration significantly increasing and runoff reducing in the terraced catchment. All the hydrological information assessed pointed to the positive effects provided by the presence of the terraces. The results in the macroplots showed that high amounts of phytomass and/or chiseling do not control runoff and its correlated variables in medium and high magnitude events. The study concludes by underlining the need for additional measures to control runoff (terraces), even in areas under NT and with high phytomass production. Additionally, the study emphasizes the importance of monitoring at the catchment scale to better understand the hydrological behavior of agricultural areas and provide the necessary parameters to effectively control runoff.

No-till is considered an efficient soil and water conservation practice when accompanied by crop species diversification and overland flow control. However, the last twenty years in south Brazil, farmers under no-till abandoned crop diversification and others soil conservation practice. As a consequence, severe erosion process have been observed caused by overland flow. The overland flow has been intensified due to a combination of problems such as soil compaction and poor surface residues. Understanding the formation and propagation of overland flow when the no-till is submitted to different agronomic conditions and practices mechanics as terraces is crucial for the improvement of conservationist agriculture, since many associated problems have caused environmental and economic damage. Unfortunately, there is currently a lack of information about the surface runoff processes occurring under no-till, which is essential to define the best water management practices. The objective of this study was to determine parameters related to surface runoff under different conditions of no-till, specifically regarding the amount of biomass, mechanical scarification and presence of terraces. The study was performed at the hillslope scale in southern Brazil characterized by a deep, clay and weathered soil under no-till. Two zero order catchments (2.4ha) and four hillslopes runoff plots (0.5ha) were monitored during natural rainfall from 2014 to 2018. These catchments and runoff plots are paired and have different soil management to test their respective effects on infiltration and overland flow. In the catchments the presence of terraces was evaluated and in the runoff plot the amount of biomass and mechanical scarification was evaluated. Precipitation was measured with pluviographs and overland flow was carried out automatically on H flumes with sensor pressures. A set of 63 rainfall-runoff events were monitored at the outlet of zero order catchments (2,4ha) and 27 events were observed in the along the runoff plots (0.5ha). From these events, we derived information reflecting the influence of mechanical scarification, of terraces and of biomass. The variables derived for each management mode were: Runoff coefficient (RC), Peak water discharge (PWD), Curve Number (CN), Sediment Yield (SY) and apparent infiltration (AI). In catchments, the main results demonstrate a, influence of terraces on overland flow control, where the reduction reached 50% for RC, 12% for CN, and 60% for PWD, and 70% for SSC. Furthermore, infiltration increased by 11%. In runoff plots, the influence of increasing biomass with scarification the reduction was 16% for RC, 5% for CN, 6.3% for PWD and 6% for SSC. In runoff plots, the influence of increasing biomass without scarification the reduction was 27% for RC, 5.4% for CN, 13% for PWD and 81% for SSC. The results demonstrated that the presence of terraces mitigated the overland flow; however, despite the positive effect of amount of biomass and mechanical scarification, its performance is of less impact. This set of original results will provide the data to quantify the impact of different management conditions and will assist the local managers in the planning of conservationist practices adapted to the conditions observed in Southern Brazil.

Soil degradation is a widespread problem and currently one of the biggest challenges in modern-day agriculture. The partial adoption of conservation agriculture, such as no-till management, does not provide adequate erosion control, and the hydrology dynamics on hillslopes under no-till management remain poorly quantified. This study examines the hydrology of agricultural hillslopes under no-till management, with and without terraces in southern Brazil. Water and soil losses were measured in two paired, zero-order catchments (2.4 ha) under no-till cultivation, with and without broad-based retention terraces. Rainfall, surface runoff, and suspended sediment concentrations were monitored during major rainfall events. Analysis of hydrographs and sedigraphs was used to derive the peak flow, runoff duration, and sediment yield values and the hysteresis between surface runoff and the suspended sediment concentration during different seasons. The results show higher soil and water losses in the catchment without terraces. Terracing reduced peak flow rates by 79%, sediment yield from 0.44 to 0.16 t ha−1, and the total surface runoff from 3943 (126 mm) to 855 m3 (36 mm) during 31 events over 16 months. The no-till system without terraces was unable to adequately control surface runoff and soil erosion. Surface runoff and sediment yield were higher under no-till without terraces than under no-till with terraces. The difference in terms of surface runoff volume and sediment yield indicates an important difference in the hydrology and soil erosion in the catchment without terraces, which is represented by high-surface-runoff coefficient values observed during the rainfall-runoff events. The short lag time and steep rising limb of the hydrographs indicate high-surface-runoff responsivity to rainfall in no-till without terraces.

International audience; No-tillage is a soil management practice that results in reduced soil losses when compared to conventional tillage systems. However, when this practice is overly simplified, it may lead, over the years, to higher levels of soil loss than expected. In this context, this study sought to compare the rates of long-term soil redistribution on three hillslopes used for grain production under different soil management on deep weathered soils (Ferralsols) in southern Brazil. Soil samples were collected along three transects in different hillslopes characterized by either no-tillage or conventional tillage. Cs-137 inventories were used to estimate the soil redistribution rates based on Mass Balance Model - 2. The results indicate that along the three slopes and during the last five decades, changes in soil management impacted the patterns of soil erosion in the landscape, showing the occurrence of significant soil loss in the upper and backslope segments, and deposition in the lower parts of the three hillslopes studied. Even with no-tillage, erosion has continued to occur, although at lower rates when compared to conventional tillage. The use of the $^{137}$Cs marker associated with the Mass Balance Model - 2 (MBM - 2) conversion model provided an effective tool for estimating soil redistribution rates under different management systems. Although the introduction of no-tillage in the last 28 years has reduced erosion rates, these processes remain significant and the implementation of additional runoff and/or erosion control practices is recommended in order to keep erosion rates at sustainable levels.