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No‐till, crop diversity and integrated crop–livestock systems are proposed managements to increase agriculture sustainability in the rice paddies of the Southern Brazilian lowlands and avoid degradation in the region. Because soil is considered a key medium in which management modifications can be measured, our study aimed to evaluate soil‐quality impacts by measuring carbon and nitrogen stocks and microbial activity 18 months after the adoption of different paddy‐farming systems in an Albaqualf soil of Southern Brazil. The treatments consisted of five paddy‐farming systems with a range of vegetation diversity (both in time and in space) and grazing seasons. In addition, a reference area (i.e. native forest) was sampled for comparison. We verified that soil quality was affected over the short term through the adoption of no‐till, crop diversity and integrated grazing practices. However, during the study period, only the system with low anthropic and/or mechanical intervention and high plant diversity differed from the traditional paddy land‐use approach in Brazil in terms of soil‐quality effects. This system achieved a carbon management index of 49 (approximately half that of the native forest) and had the highest enzymatic activity (similar to native forest). These outcomes were primarily due to an increase in the particulate organic matter fraction of the soil carbon stock (4·6 Mg ha−1 more than in rice monocropping). To evaluate changes in soil quality over the long term, additional studies are required. Copyright © 2016 John Wiley & Sons, Ltd.

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The use of gypsum to improve the root environment in tropical soils in the southeastern and central-western regions of Brazil is a widespread practice with well-established recommendation criteria. However, only recently gypsum began to be used on subtropical soils in South of Brazil, so available knowledge of its effect on crop yield is incipient and mainly for soils under no-till (NT) systems. Avaiable studies span a wide range of responses, from a substantial increase to a slight reduction in crop yield. Also, the specific conditions leading to a favorable effect of gypsum application on crop yield are yet to be accurately identified. The primary objectives of this study were to examine previously reported results to assess the likelihood of a crop response to gypsum and to develop useful recommendation criteria for gypsum application to subtropical soils under NT in Brazil. For this purpose, we examined the results of a total of 73 growing seasons, reported in 20 different scientific publications that assessed grain yield as a function of gypsum rates. Four different scenarios were examined, by the occurrence or not of high subsurface acidity (viz., Al saturation >20 % and/or exchangeable Ca <0.5 cmol c dm-3 in the 0.20-0.40 m soil layer) and of water deficiency during the crop cycle. Based on the results, for grasses, 10 % Al saturation and/or 3 cmol c dm-3 exchangeable Ca in the soil subsurface layer (0.20-0.40 m) is more suitable than the current recommendation (Al saturation of 20 % and/or 0.5 cmol c dm-3 Ca) for subtropical NT soils in Brazil. Also, applying gypsum to NT soils with low subsurface acidity (Al saturation <10 %) and with an adequate Ca content (>3 cmol c dm-3) failed to increase crop yield, irrespective of the soil water status. Under these conditions, high gypsum rates (6-15 Mg ha-1) may even reduce grain yield, possibly by inducing K and Mg deficiency. On the other hand, applying gypsum to soils with high subsurface acidity increased yield by 16 % in corn (87 % of cases) and by 19 % in winter cereals (83 % of cases), whether or not the soil was water-deficient. By contrast, soybean yield was only increased by gypsum applied in the simultaneous presence of high soil subsurface acidity and water deficiency (average increase 27 %, 100 % of cases).

Integrated crop-livestock systems (ICLS) associated with crop rotation and soil conservation management cause numerous changes in nutrient fluxes and soil biochemical dynamics. In this sense, there is a gap in the impact of integrated production systems on nutrient dynamics and soil microbial activity in lowlands. In this context, this work had the objective of evaluating the nutrient availability and the activity of extracellular enzymes in a Gleyic Luvic Planosol under ICLS. The experiment has five paddy-farming systems with a range of crop diversity (both in time and space) and

This paper aims to discuss the impact of the introduction of pastures and grazing animals in agricultural systems. For the purposes of this manuscript, we focus on within-farm integrated crop-livestock systems (ICLS), typical of Southern Brazil. These ICLS are designed to create and enhance the synergisms and emergent properties have arisen from agricultural areas where livestock activities are integrated with crops. We show that the introduction of the crop component will affect less the preceding condition than the introduction of the livestock component. While the introduction of crops in pastoral systems represents increasing diversity of the plant component, the introduction of animals would represent the entry of new flows and interactions within the system. Thus, given the new complexity levels achieved from the introduction of grazing, the probability of arising emergent properties is theoretically much higher. However, grazing management is vital in determining the success or failure of such initiative. The grazing intensity practiced during the pasture phase would affect the canopy structure and the forage availability to animals. In adequate and moderate grazing intensities, it is possible to affirm that livestock combined with crops (ICLS) has a potential positive impact. As important as the improvements that grazing animals can generate to the soil-plant components, the economic resilience remarkably increases when pasture rotations are introduced compared with purely agriculture systems, particularly in climate-risk situations. Thus, the integration of the pastoral component can enhance the sustainable intensification of food production, but it modifies simple, pure agricultural systems into more complex and knowledge-demanding production systems.

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Integrated crop-livestock systems (ICLSs) appear as a good alternative to increase nutrient use efficiency (NUE) in rice (Oryza sativa L.) through the improvement in nutrient cycling and soil chemical attributes in paddy fields. The objective of this study was to evaluate the impact of an ICLS on soil chemical attributes and on the fertilization requirement of N, P, and K by flooded rice in the Brazilian subtropical region. Nutritional status, yield, and NUE of flooded rice were evaluated by fertilization trials through rice response to different fertilization rates of N, P, and K. Soil chemical attributes were evaluated at the beginning of the experiment and 30 mo later.Different fertilization rates were applied in two systems: (a) a conventional system (CS), based on intensive tillage, rice monocropping and winter fallow, and (b) ICLS, characterized by no-tillage and winter cattle grazing in annual ryegrass (Lolium multiflorum Lam.) pasture. Rice shoot accumulation of N, P, and K was greater under CS than ICLS at all fertilization levels. On the other hand, higher rice yields were observed under ICLS at almost every fertilization level, suggesting higher NUE than CS. In addition, rice yield was increased by 40% by fertilization of P and K under CS, whereas no response was observed under ICLS. These benefits were possibly related to greater nutrient cycling and greater synchronism between rice's nutrient uptake and nutrient release of the soil. Our results indicate that the adoption of ICLS ensures greater NUE becoming a system less dependent on external inputs.Abbreviations: CEC, cation exchange capacity; CS, conventional system; ICLS, integrated crop-livestock system; NUE, nutrient use efficiency; SOM, soil organic matter.