Water availability in sandy soil influences soybean yield under palisadegrass straw in non-irrigated integrated livestock system

Crop-livestock integration (CLI) is a management system that has been developed for a variety of soil and climatic conditions, which combined with the no-tillage system (NTS), has many variations in Brazil, particularly regarding grazing intensity. The objective of this study was to assess the effects of different grazing intensities and soybean (Glycine max L.) crops on carbon (Cst) and nitrogen (Nst) stocks, light organic matter (LOM), root content of the LOM (RLOM), and remaining phosphorus (Prem) in an Oxisol under CLI. The treatments consisted of three different heights (0.25 m [P25], 0.35 m [P35], and 0.45 m [P45]) of pasture grown in a CLI system. Two control areas, an area without grazing (AWG) and a native vegetation area of the Cerrado biome (NCA), which were adjacent to the experimental area, were compared with the cultivated areas. Soil samples were collected from 0.00-0.05, 0.05-0.10, and 0.10-0.20 m beneath each area in a completely randomized design with six replications. Soil characteristics were evaluated in the post-pasture cycle period (PP) and the post-soybean crop period (PC), which coincided with the wet and dry seasons, respectively. The NCA had more LOM in the 0.00-0.05 m layer during the PC and the 0.05-0.10 m layer during both the PP and the PC, C in the LOM in the 0.00-0.20 m layer during the PP and the PC, N in the LOM in the 0.00-0.05 m layer in the PC and the 0.05-0.10 m layer in the PP and the PC, and Cst in the 0.00-0.20 m layer in the PP and the PC than the cultivated areas, but a lower soil density (SD) and Prem in the 0.00-0.20 m layer during both the PP and the PC. Treatment P35 had more Nst in the PC and RLOM in the PP than the other cultivated treatments and the AWG. The absence of grazing in the AWG decreased the SD from the PP to the PC, while the treatments with different grazing intensities had similar values throughout this period. Our results suggest that production could be intensified under light and moderate grazing intensities in the CLI system.

Grazing intensities affect weed seedling emergence and the seed bank in an integrated crop–livestock system

Ryegrass early sowing into soybean to mitigate nitrous oxide emissions in a subtropical integrated crop-livestock system

Soil carbon indices as affected by 10 years of integrated crop–livestock production with different pasture grazing intensities in Southern Brazil

Pasture grazing intensity and presence or absence of cattle dung input and its relationships to soybean nutrition and yield in integrated crop–livestock systems under no-till

A presença de animais em áreas de lavoura pode alterar a estrutura física do solo, sendo que a intensidade de pastejo contribui para esse resultado. Este trabalho objetivou avaliar os atributos físicos do solo e a produtividade de soja e braquiária, em sistema integrado de produção agropecuária, sob plantio direto. Os tratamentos foram distribuídos em blocos casualizados, com três repetições, e consistiram de diferentes alturas de manejo do pasto (0,25 m, 0,35 m e 0,45 m) e uma área sem pastejo. Foi determinada a biomassa seca da parte aérea e raiz da soja e braquiária e a produtividade da soja. Amostras de solo foram coletadas nas camadas de 0-5 cm, 5-10 cm e 10-20 cm de profundidade, sendo determinados os seguintes atributos físicos: densidade, porosidade total, macroporosidade, microporosidade, resistência à penetração e diâmetro médio ponderado de agregados. As intensidades de pastejo não interferiram na densidade do solo em nenhuma das camadas. Houve redução da porosidade total após o segundo ciclo de pastejo, na camada de 0-5 cm. O diâmetro médio ponderado de agregados foi menor nas áreas pastejadas nas camadas de 0-5 cm e 10-20 cm e verificou-se aumento da resistência mecânica à penetração em todas as camadas, principalmente para o pastejo a 0,25 m de altura. A quantidade de biomassa seca total (soja + braquiária) e biomassa seca da parte aérea da braquiária foram menores nas áreas pastejadas, no entanto, a produtividade da soja não foi influenciada pelos ciclos de pastejo.

The aim of this study was to evaluate some morphogenetic and structural characteristics to explain variations in forage accumulation of Alexandergrass (Urochloa (Syn. Brachiaria) plantaginea) under continuous stocking method. The experimental treatments consisted of four grazing heights (10, 20, 30, and 40 cm), allocated to experimental units following a randomized block design with three replicates. The following variables were analyzed: leaf appearance, elongation, and senescence rates, leaf lamina length, number of leaves per tiller, leaf area index (LAI), and forage accumulation rate. Data were submitted to analysis of variance and means were compared by Student's t-test (P≤0.05). The main results were: i) different grazing heights had different tissue flows; ii) grazing heights between 30-40 cm showed the highest LAI, and produced similar values; iii) forage accumulation rate increased according to grazing height increments, but did not change above 30 cm. In conclusion, Alexandergrass pastures under continuous stocking should not be maintained at grazing heights lower than 30 cm if the objective is to maximize forage production.

The identification of the labile and recalcitrant forms of soil organic matter (SOM) allows to rapidly define, or even predict if the management used favors increments or losses of carbon in the soil. Thus, the objective of this work was to assess the effects of different grazing intensities and soybean crops on the oxidizable and granulometric fractions of the SOM in a crop-livestock integration combined with no-tillage system (CLI-NTS), established in 2009 in the Goiás Federal University. The treatments consisted of three different pasture heights (0.25 m P25; 0.35 m P35; 0.45 m P45), and areas without grazing (AWG), and a native vegetation area of the Cerrado biome (NCA), adjacent to the experimental area, was evaluated as references and compared with the cultivated areas. Soil samples (Oxisol - USDA; typic distroferric Red Latosol - SiBCS) were collected in the layers 0.00-0.05; 0.05-0.10 0.10-0.20 and 0.20-0.40 m of each area, and arranged in a completely randomized experimental design with six replications. The soil total carbon was quantified (TC) by dry combustion. The SOM granulometry and oxidizable SOM were fractionated into particulate carbon (OCp), carbon bond with minerals (OCm) and four oxidizable fractions with increasing degrees of recalcitrance (F1 < F2 < F3 < F4). These soil attributes were evaluated at two different times, representing the post-pasture cycle (PP) and post-soybean crop (PC) periods. The lower contents of total soil carbon (TC) were found in the F1 and F3 fractions of the area without grazing, suggesting that the crop-livestock integration increases the organic matter content in the soil surface layer regardless of the pasture height. The areas without grazing and with different pasture heights in CLI had similar contents of OCp and OCm due to the experiment short time of implementation (3 years). The fractionation of the oxidizable SOM was more sensitive in differentiating the treatments, showing that the higher intensity of grazing used (P25) provided a better balance of carbon accumulation between the SOM labile and recalcitrant fractions.

Structural soil quality and system fertilization efficiency in integrated crop-livestock system

Forms and balance of soil potassium from a long-term integrated crop-livestock system in a subtropical Oxisol

A ciclagem e balanço de nutrientes em sistemas de integração lavoura-pecuária (ILP) são processos que envolvem o componente solo, a planta e o animal, além da fertilização, em que o manejo dos animais, por alterar as condições bióticas e abióticas do solo, altera a velocidade de decomposição dos resíduos. Objetivou-se avaliar a ciclagem e o balanço de K em sistema ILP sob semeadura direta, em função da intensidade de pastejo por bovinos em pastagem, no inverno, e sua relação com a produtividade de soja, cultivada no verão. O experimento foi iniciado em maio de 2001 em Latossolo Vermelho distroférrico, em área que vinha sendo cultivada em semeadura direta desde 1991. Os tratamentos constaram de intensidades de pastejo contínuo, por bovinos jovens, em mistura de azevém + aveia-preta, representados por alturas do pasto: 10, 20, 30 e 40 cm e sem pastejo (testemunha), distribuídos num delineamento experimental de blocos ao acaso, com três repetições, em que se avaliou um ciclo pastagem/soja (safra 2007/08). Na ciclagem, foram considerados os teores de K na pastagem, na soja e nos animais e, no balanço desse nutriente, na lavoura e no solo, foram considerados os seus teores no solo e as entradas, como fertilizante e saídas, nos grãos de soja e no tecido animal. A ciclagem do K aumentou com o aumento da intensidade de pastejo, e o seu balanço no sistema, apesar de negativo, com maior déficit nas áreas com maior intensidade de pastejo, não influenciou a produtividade da soja.

Grazing livestock in integrated crop-livestock systems can cause impacts in the subsequent crop cycle. Aiming to investigate how grazing could affect soybean, the 9th crop cycle of a pasture/soybean rotation was assessed. Treatments were grazing intensities (10, 20, 30 and 40 cm of sward height) applied since 2001 in a mixed of oat and annual ryegrass; and an additional no grazing area as control. Treatments were arranged in a completely randomized block design with three replicates. Grazing affected soybean population and the mass of individual nodules (P 0.05). Soybean yield showed differences among treatments, but no difference was found between grazed and non-grazed areas. Grazing intensities impact the coverage and frequency of weeds (P>0.05). In conclusion, grazing intensity impacts different parameters of soybean yield and development, but only the grazing intensity of 10 cm can jeopardize the succeeding soybean crop.

The purpose of this work is to present the results of fi eld studies on the effectiveness of applying different primary tillage systems for soybean cultivation in the Forest-Steppe zone of Ukraine and the infl uence of agrometeorological conditions during the growing season on biological grain yield. Methods. The studies were conducted using four primary tillage systems: traditional (A1), conservative (A2), mulching (A3), and no-till (A4). Soybean cultivation technology in the experiments was traditional for the research area, except for the studied factors. The effectiveness of the tillage systems was determined by assessing the biological yield of soybean and its structure. Biological grain yield was determined from sample sheaves collected in triplicate for each variant. The main elements of yield structure for each variant were identifi ed during the analysis of the sample sheaves. Statistical data processing was performed using correlation analysis. Agrometeorological conditions during the soybean growing season were assessed using data from the Bila Tserkva weather station. Results. Among the studied primary tillage systems for soybean cultivation, the traditional system with plowing showed the highest biological grain yield. Replacing moldboard plowing (traditional system) and deep loosening (conservative system) with shallow tillage negatively affected the biological yield. The average biological soybean grain yield over the research years was 2.76 t/ha, ranging from a minimum of 1.82 t/ha (2018, no-till system) to a maximum of 3.88 t/ha (2021, traditional primary tillage system). During the research period, a signifi cant increase in average daily temperatures was observed in all summer months: June increased by 2.0 ºC, July by 1.1 ºC, and August by 2.0 ºC. Correlation analysis indicated that changes in average daily temperatures are refl ected in soybean biological grain yields. The strength of the relationship depends on the soybean growth and development phase and the primary tillage system used in the cultivation technology. Over the past ten years, the amount of atmospheric precipitation and its distribution have signifi cantly changed, especially in the summer months, as indicated by the trend line and comparison with actual data from the previous thirty years of observations: the average precipitation sum for June decreased by 23.2 mm, for July by 19.4 mm, and for August by 34.4 mm. Conclusions. The biological yield of soybean grain is related to the year’s conditions (r = 0.418) and the primary tillage system (r = 0.404): a decrease in tillage depth and the abandonment of moldboard plowing lead to a reduction in the biological grain yield formed by soybean phytocenoses. Changes in average daily temperatures are refl ected in soybean biological grain yields. The strength of the relationship depends on the soybean growth and development phase and the primary tillage system used in the cultivation technology. An increase in temperature in May (emergence – early branching phase) and August (grain fi lling – ripening phase) negatively affects the biological soybean grain yield, as evidenced by correlation coeffi cients of r = –0.370 and r = –0.303, respectively. There is a moderate direct correlation (r = 0.343) between biological yield and the average daily air temperature in June, and a weak direct correlation (r = 0.111) between biological soybean grain yield and the average daily air temperature in July. According to correlation analysis data, the amount of atmospheric precipitation during the vegetative development of soybean (May – June) practically does not affect the biological grain yield.

The research investigating the effects of different grazing intensities on greenhouse gas emissions within typical steppe ecosystems aids in formulating effective management strategies for these ecosystems. Furthermore, it plays a vital role in developing approaches to reduce greenhouse gas emissions. To investigate the effects of different grazing intensities on greenhouse gas emissions in typical steppe ecosystems, four treatments were established： no grazing （CK）, light grazing （LG）, moderate grazing, and heavy grazing （HG）. The greenhouse gas emission fluxes were measured using the static dark chamber infrared spectroscopy method. The results showed that： ① Significant seasonal changes exist in ecosystem respiration and CH4 emission flux. Compared with the CK treatment, the HG treatment significantly reduced the total ecosystem respiration emission by 31.43%, while the total CH4 emission was not significant among all treatments. Compared with the LG treatment, the HG treatment significantly reduced the total N2O emission by 94.03% （P <0.05）. ② A significant linear correlation exists between the values of ecosystem respiration pairs and soil temperature （P <0.001）, and there was a significant linear relationship between ecosystem respiration and soil water content under the CK and HG treatments （P <0.05）, mainly related to soil temperature. Except for the LG treatment, the CH4 emission fluxes of the other treatments showed a quadratic correlation with soil temperature, and the CH4 emission fluxes of all treatments were linearly correlated with soil water content and were mainly correlated with soil water content （P <0.01）. A significant linear correlation exists between N2O emission flux and soil temperature in the LG treatment （P <0.05）. ③ Compared with that in CK, the HG treatment significantly decreased soil water content, soil total carbon, soil total nitrogen, vegetation aboveground biomass, and litter, and significantly increased soil temperature and soil bulk density （P <0.05）. Heavy grazing reduced the total greenhouse gas emissions and total vegetation biomass. Although it reduced the carbon emissions of the grassland ecosystem, it was not conducive to maintaining the ecological balance of grassland. This study can provide reference data and theoretical support for evaluating the effects of grazing on the source-sink functions of grassland ecosystems.

Among integrated crop–livestock systems, forage succession is an advantageous strategy for the use of pasture to feed cattle in periods of low rainfall, as well as for the generation of biomass for the no-till system for the next crop. Different species have different abilities to accumulate nutrients in their biomass, which are then released into the soil through the decomposition of crop residues. This study aimed to evaluate soybean yield in an integrated crop–livestock system in comparison to soybean–maize succession system through the production, decomposition and nutrient accumulation in the biomass. The experiment had a randomized block design with four replicates. The treatments were three cropping systems: integrated crop–livestock with Paiaguas palisadegrass (Brachiaria brizantha cv. BRS Paiaguas), integrated crop–livestock with Tamani guinea grass (Panicum maximum cv. BRS Tamani) and maize grown in succession to soybean. The results showed that the use of the integrated crop–livestock system in the form of forage succession provided greater soil cover and nutrient cycling as a result of the better utilization of the animal's excreta, than the cropping of maize in succession and resulted in higher soybean productivity, thus contributing to agricultural sustainability. Paiaguas palisadegrass and Tamani guinea grass showed a C:N ratio greater than 30:1, indicating slow decomposition of plant residues. The forages accumulated amounts of nutrients in their biomass that met the soybean demand, resulting in higher grain yield.