ABSTRACT. Management systems that include trees tend to provide higher amounts of plant biomass to the soil, contributing to the increase in carbon (C) and nitrogen (N) stocks. This study simulated C and N stocks and their compartments in a crop-livestock-forest integration system in the edafoclimatic conditions of the Maranhão Cerrado using the Century 4.5 model. The evaluated areas were native Cerrado vegetation (NV) and crop-livestock-forest integration (CLFI). The calibration process gradually modified the model parameters to better fit the simulated and observed soil C and N stocks. The best fit between the data was obtained after changes in the main parameters (DEC3(2), DEC4, and DEC5) that controlled the rate of decomposition of soil organic matter. C and N stocks increased by 14% and 15%, respectively, over 14 years after replacing NV with CLFI. The slow compartment of C presented greater sensitivity to changes in management, with an increase of 47% compared with that of NV. The active compartment increased by 31% and the passive compartment remained constant for over 14 years. Future scenarios, where pasture was maintained between the eucalyptus trees and the scenario that allowed the soybean, corn, and Brachiaria rotation between the trees, were more effective, accumulating approximately 37 Mg C ha-1. The continuous contribution of residues from the trees and pasture increased C and N stocks in the long-term in the slow fraction, where the total organic carbon increased from 32 to 36 Mg ha-1 when NV was replaced with CLFI. The model predicted the C and N stocks with accuracies ranging from 1 to 11% of the observed values. ABSTRACT (C (N croplivestockforest crop livestock forest 45 4 5 4. (NV CLFI . (CLFI) DEC32, DEC32 DEC DEC3 2 , (DEC3(2) DEC4 DEC5 matter 15 15% respectively management 47 31 scenarios soybean corn effective 3 ha1. ha1 ha 1. longterm long term fraction ha- 11 values (CLFI (DEC3(2 (DEC3( (DEC3 (DEC

ABSTRACT Diversifying pastures with forage legumes may reduce nitrogen fertilization due to biological N fixation. This study aimed to quantify forage accumulation rate and macronutrients extraction and to identify the best intercropping combination between butterfly pea (Clitoria ternatea) – a legume, and three warm-season forage grasses of different growth habits (signalgrass – Urochloa decumbunes, Guinea grass - Mega thyrsus maximus, and bermudagrass Cynodon dactylon). Treatments consisted of mixes of perennial herbaceous legume, butterfly pea (twining stem), with grasses, signalgrass (decumbent stem) and Guinea grass (erect stem), and bermudagrass (stoloniferous/rhizomatous). The experiment was arranged in a randomized complete block design, with three treatments and three replications. There was interaction between the intercropping combinations and cutting cycles for forage accumulation rate (FAR) and N, P, K, Ca, Mg, and S uptake. Phosphorus and K uptake was reduced from the second cycle onwards, except for the signalgrass-butterfly pea intercropping, whose reduction was only from the third cycle. Conversely, the signalgrass-butterfly pea and bermudagrass-butterfly pea intercropping did not differ from each other in relation to total N concentration in soil, but the signalgrass-butterfly pea intercropping showed total N concentration in soil higher than that of Guinea grass-butterfly pea intercropping. A higher predominance of the N-NH4+ form was observed in the soil. Grass-legume intercropping increased the demand for nutrients, which makes it indispensable to verify the export of macronutrients to know when to supply these nutrients removed from the soil solution. fixation Clitoria ternatea legume warmseason warm season decumbunes maximus dactylon. dactylon . dactylon) twining stem, stem , decumbent erect stoloniferous/rhizomatous. stoloniferousrhizomatous stoloniferous/rhizomatous stoloniferous rhizomatous (stoloniferous/rhizomatous) design replications FAR (FAR P Ca Mg onwards signalgrassbutterfly Conversely bermudagrassbutterfly grassbutterfly NNH4+ NNH4 NNH NH4+ NH4 NH N-NH4 Grasslegume Grass solution (stoloniferous/rhizomatous N-NH

ABSTRACT Soil fertility evaluation is important for adopting conservation management and adequate nutrient supply. The objective of this study was to identify critical levels and soil fertility classes using the boundary line method for rainfed crops (corn, cowpea and sabiá [Mimosa caesalpiniifolia]) in the Brazilian semi-arid region. A database of 226 soil fertility analyses of samples from the 0.00-0.20 m soil layer, and corn, cowpea and sabiá yields from Ceará State was used to generate interpretation classes (at 80 and 95 % of maximum yield). In a scatter plot, soil nutrient concentrations (x-axis) and relative crop yields (y-axis) were correlated, and the border points fitted to a quadratic model. Proposed interpretation classes were classified as very low, low, adequate, high and very high, except for Na+, whose adequate class was considered tolerable. Generated models showed coefficients of determination (R2) for the chemical properties ranging from 0.54 to 0.92. Based on the interpretation classes, the critical level was determined as 6.3 for pH, 10.8 g dm-3 for OM, 20.9 mg dm-3 for P, 81 mg dm-3 for K, 55 mmolc dm-3 for Ca2+, 24 mmolc dm-3 for Mg2+ and 8 mg dm-3 for S-SO42-. Interpretation classes for soils with high-activity clay in the Brazilian semi-arid region were superior to those in the reference literature. Boundary line method established fertility classes and critical levels for soil chemical properties in more than one crop, using the concept of relative yield. supply corn (corn Mimosa caesalpiniifolia caesalpiniifolia] semiarid semi arid 22 0.000.20 000020 0.00 0.20 0 00 20 0.00-0.2 layer at 9 yield . yield) plot xaxis x axis (x-axis yaxis y (y-axis correlated model low Na Na+ tolerable R2 R (R2 054 54 0.5 092 92 0.92 63 6 3 6. pH 108 10 10. dm3 dm dm- OM 209 20. P K 5 Ca2 Ca Ca2+ 2 Mg2 Mg SSO42. SSO42 SSO S SO42 SO S-SO42- highactivity activity literature 000 0.000.2 00002 0.0 020 0.2 0.00-0. (R 05 0. 09 0.9 1 SSO4 SO4 S-SO42 0.000. 0000 02 0.00-0 S-SO4 0.000 0.00- S-SO

Resumo O fósforo (P) é um dos principais nutrientes capazes de aumentar a produtividade de gramíneas tropicais. A definição de doses de P pode contribuir para aumentar a produção de forragem em pastagens cultivadas. Todavia não se conhece a eficiência na resposta de diferentes genótipos de capim-corrente (Urochloa mosambicensis (Hack.) Dandy) a doses de P. Este estudo objetivou quantificar a resposta de genótipos de capim-corrente a níveis de adubação com P e classificá-los segundo a sua eficiência e responsividade. O experimento foi conduzido em vasos, em condições controladas, no delineamento inteiramente casualizado, num esquema fatorial 2 x 9, com cinco repetições. Os fatores consistiram de doses equivalentes de P de 10 e 90 kg ha-1 de P2O5 (superfosfato triplo) e oito genótipos de U. mosambicensis (UmCO1 (2), UmCO-2 (2), UmCO-4 (1), UmCO-8 (1), UmCO-11 (2), UmCO-12 (2), UmCO-13 (2) e UmCO-14 (2)), além da testemunha Urochloa brizantha syn. Brachiaria brizantha cv. BRS Piatã. Cada unidade experimental foi constituída de um vaso. Foram avaliados atributos biométricos e rendimento de massa seca ao longo de quatro ciclos de corte. Não houve efeito da interação entre adubação x genótipos para as variáveis avaliadas. Entretanto, a maior dose do fertilizante incrementou o rendimento de massa seca e densidade populacional de perfilhos em todos os genótipos e cortes avaliados. O genótipo UmCO-4 (1) e a cultivar BRS Piatã revelaram-se responsivos e eficientes no uso de P. A maior dose de P promoveu maior produção de massa seca e maior número de perfilhos em todos os genótipos de U. mosambicensis. (P tropicais cultivadas capimcorrente capim corrente Hack. Hack (Hack. Dandy classificálos classificá los responsividade vasos controladas casualizado 9 repetições 1 ha1 ha ha- PO P2O superfosfato triplo U UmCO1 UmCO (UmCO 2, , UmCO2 UmCO- UmCO4 4 1, UmCO8 8 UmCO11 11 UmCO-1 UmCO12 12 UmCO13 13 (2 UmCO14 14 (2)) syn cv vaso corte avaliadas Entretanto (1 revelaramse revelaram (Hack (

Abstract Phosphorus (P) is one of the main nutrients capable of increasing yields of tropical grasses. The definition of adequate P fertilizer rates can contribute to improving forage production of pastures. However, the efficiency in the response of different genotypes of Urochloa mosambicensis (Hack.) Dandy (Bushveld herringbone grass) to P fertilizer rates is not known. This study aimed to quantify the response of U. mosambicensis genotypes to P fertilizer levels and classify the genotypes as to efficiency and responsiveness. The experiment was carried out in pots, under controlled conditions, in a completely randomized design, in a 2 x 9 factorial with five replications. The factors consisted of equivalent P rates of 10 and 90 kg ha-1 of P2O5 (triple superphosphate) and eight genotypes of U. mosambicensis (UmCO-1 (2), UmCO-2 (2), UmCO-4 (1), UmCO-8 (1), UmCO-11 (2), UmCO-12 (2), UmCO-13 (2) and UmCO-14 (2)), in addition to a control, Urochloa brizantha syn. Brachiaria brizantha cv. BRS Piatã. Each experimental unit consisted of one pot. Biometric attributes and dry mass yield were evaluated over four cutting cycles. There was no effect of the P fertilization x genotypes interaction for the variables evaluated. However, the highest fertilizer rate increased dry mass yield and tiller population density in all genotypes and cuttings evaluated. The genotype UmCO-4 (1) and the cultivar BRS Piatã proved to be responsive to and efficient in P use. The highest P rate promoted greatest production of dry mass and greatest number of tillers in all genotypes of U. mosambicensis. (P grasses pastures However Hack. Hack (Hack. Bushveld grass known U responsiveness pots conditions design replications 1 ha1 ha ha- PO O P2O triple superphosphate UmCO1 UmCO (UmCO- 2, , UmCO2 UmCO- UmCO4 4 1, UmCO8 8 UmCO11 11 UmCO-1 UmCO12 12 UmCO13 13 (2 UmCO14 14 (2)) control syn cv pot cycles (1 use (Hack (UmCO (

ABSTRACT. This study was performed to investigate the effects of composted tannery sludge (CTS) on the physical properties of tropical sandy soil after seven years of CTS application. CTS was applied to a Fluvisol at five rates (0.0, 2.5, 5.0, 10.0, and 20.0 Mg ha-1) in experimental plots (sized 20 m2) with four replications. Water infiltration into the soil was determined in the field with the concentric-ring infiltrometer method. Bulk density, total porosity, macroporosity, and microporosity were determined in the soil samples. The permanent CTS application altered the physical properties of the soil and led to a decrease in bulk density. The total porosity, microporosity and macroporosity values in the CTS-applied soil ranged from 44.1-51.7, 34.6-39.4, and 9.1-12.8%, respectively. Water-infiltration rates were significantly influenced by CTS. The cumulative infiltrated water in the soil varied from 21.3-34.7 cm. The basic infiltration rate was lower in the unamended soil and increased with an increase in the rate of CTS application. This study confirmed that the physical soil parameters improved after the permanent CTS application. Therefore, this application may be a suitable strategy for improving physical soil properties over time. ABSTRACT (CTS 0.0, 00 0 (0.0 25 2 5 2.5 50 5.0 100 10 10.0 200 20. ha1 ha 1 ha-1 sized m2 m replications concentricring concentric ring method density porosity samples CTSapplied 44.151.7, 441517 44.1 51.7, 44 51 7 44.1-51.7 34.639.4, 346394 34.6 39.4, 34 6 39 4 34.6-39.4 9.112.8%, 91128 9.1 12.8%, 9 12 8 9.1-12.8% respectively Waterinfiltration 21.334.7 213347 21.3 34.7 21 3 21.3-34. cm Therefore time 0.0 (0. 2. 5. 10. ha- 151 44.151.7 44151 441 44. 517 51.7 44.1-51. 639 34.639.4 34639 346 34. 394 39.4 34.6-39. 112 9.112.8% 9112 91 9. 128 12.8% 9.1-12.8 334 21.334. 21334 213 21. 347 21.3-34 0. (0 15 44.151. 4415 51. 44.1-51 63 34.639. 3463 39. 34.6-39 11 9.112.8 911 12.8 9.1-12. 33 21.334 2133 21.3-3 ( 44.151 44.1-5 34.639 34.6-3 9.112. 12. 9.1-12 21.33 21.3- 44.15 44.1- 34.63 34.6- 9.112 9.1-1 9.11 9.1-

RESUMO: A verminose em pequenos ruminantes é uma doença que pode inviabilizar a atividade rural. Embora o sucesso no controle dos nematóides gastrointestinais de pequenos ruminantes dependa da adoção associada de diferentes estratégias e tecnologias, ainda é possível notar a escolha, por parte de alguns ovinocaprinocultores, pelo tratamento exclusivamente baseado na administração de anti-helmínticos aos animais. Contudo, é no ambiente que encontramos um elevado número de formas imaturas de nematóides gastrointestinais. Objetivou-se com o presente trabalho avaliar quatro resíduos agroindustriais como adubo no controle dos nematóides gastrointestinais de pequenos ruminantes, em estádio de vida livre. Casca de caranguejo, manipueira, biochar e organomineral foram os resíduos empregados nos vasos com capacidade média de 5,0 kg de solo, onde foi cultivado o capim Massai (Megathyrsus maximus cv. Massai). Após corte de uniformização do capim, os vasos foram contaminados utilizando-se fezes de ovinos portadores de infecção natural multiespecífica por nematóides gastrointestinais. E, na sequência, os resíduos foram aplicados individualmente no solo, na quantidade de 50 mL/vaso para o resíduo líquido e 50 g/vaso para os sólidos. O tratamento com a manipueira foi o que apresentou o menor número de larvas infectantes de terceiro estádio (L3) recuperado do capim (202,44 L3.kg MS-1) quando comparado com os tratamentos utilizando organomineral (823,89 L3.kg MS-1) e biochar (689,34 L3.kg MS-1). Contudo, não houve diferença estatística significativa (P < 0,05) entre os quatro tratamentos testados quando comparado ao grupo controle. Os resíduos agroindustriais podem ser utilizados como adubos orgânicos, mas não vão auxiliar no controle dos nematóides gastrintestinais dos ovinos. RESUMO rural tecnologias escolha ovinocaprinocultores antihelmínticos anti helmínticos animais Contudo Objetivouse Objetivou se livre caranguejo 5 0 5, solo Megathyrsus cv Massai. . Massai) utilizandose E sequência mLvaso mL vaso gvaso g sólidos L3 L (L3 202,44 20244 202 44 (202,4 L3kg Lkg MS1 MS 1 MS-1 823,89 82389 823 89 (823,8 689,34 68934 689 34 (689,3 MS1. P 0,05 005 05 orgânicos (L 202,4 2024 20 4 (202, MS- 823,8 8238 82 8 (823, 689,3 6893 68 3 (689, 0,0 00 202, 2 (202 823, (823 689, 6 (689 0, (20 (82 (68 (2 (8 (6 (

ABSTRACT: Verminosis in small ruminants can render rural activity impractical, which is still controlled through the administration of anthelmintics. The present study evaluated four agro-industrial residues as fertilizer in the control of GIN of small ruminants in the free-living stage. Crab shell, manipueira, biochar, and organomineral residues were used in pots (5.0 kg of soil) and cultivated with Massai grass (Megathyrsus maximum cv. Massai). Further, the pots were contaminated with feces from sheep carrying a natural multispecific infection by GIN. Next, the residues were applied individually to the soil, with 50 mL/pot for liquid and 50 g/pot for solid residues. Treatment with manipueira showed the lowest number of L3.kg MS-1 recovered from the grass (202.44), when compared with treatments using organomineral (823.89) and biochar (689.34). However, there was no statistically significant difference (P < 0.05) between the four treatments as compared to the control group. These agro-industrial residues can be used as organic fertilizers; however, these will not help in the control of GIN in sheep. ABSTRACT impractical anthelmintics agroindustrial agro industrial freeliving free living stage shell 5.0 5 0 (5. soil Megathyrsus cv Massai. . Massai) Further Next mLpot mL pot gpot g L3kg Lkg L3 L MS1 MS 1 MS- 202.44, 20244 202.44 , 202 44 (202.44) 823.89 82389 823 89 (823.89 689.34. 68934 689.34 689 34 (689.34) However P 0.05 005 05 group fertilizers however 5. (5 2024 202.4 20 4 (202.44 823.8 8238 82 8 (823.8 6893 689.3 68 3 (689.34 0.0 00 ( 202. 2 (202.4 823. (823. 689. 6 (689.3 0. (202. (823 (689. (202 (82 (689 (20 (8 (68 (2 (6

ABSTRACT. This study aimed to evaluate the nutrition of commercial soybean crops in an agricultural frontier region using the diagnosis and recommendation integrated system (DRIS) and compositional nutrient diagnosis (CND) methods, as well as identify sufficiency ranges. The study was performed by collecting leaf samples (third trifoliate leaf without petiole) at flowering from commercial soybean crops in the states of Piauí and Maranhão, Brazil, and evaluating the crop yield by analyzing macro- and micronutrients in the plant tissue of 98 samples. The DRIS and CND methods were applied based on the cataloged data, followed by the generation of norms, analysis of relationships between yield and nutrients (selecting high-yield crops by the cumulative function of the data), generation of sufficiency ranges, and comparison of methods. The relationships obtained by the DRIS and CND indices with the yield and nutrients were significant, indicating that both methods can be employed for the evaluation of leaf nutrients in soybean. The sufficiency ranges from the DRIS and CND methods presented superior nutrient ranges in relation to the values proposed in the literature for macronutrients, except for nitrogen, and greater range amplitudes for micronutrients. ABSTRACT (DRIS (CND third petiole Maranhão Brazil macro 9 data norms selecting highyield high , data) significant macronutrients nitrogen

ABSTRACT Agroforestry systems have the potential to increase soil organic matter, with effects on soil carbon and nitrogen contents, but information on the application of these systems in semi-arid regions is still scarce. This study aimed to analyze soil carbon and nitrogen stocks in the conversion of native forest from the Caatinga Biome into integrated agriculture systems in the Brazilian semi-arid region. We evaluated the following management systems in the Haplic Inceptisol (Cambissolo Háplico eutrófico): (1) Intercropping area, cultivated with corn and Massai grass; (2) Caatinga (natural vegetation); (3) AFS10: agroforestry system with native woody forest rows occupying 33 % and agriculture occupying 66 % of the total area; and (4) AFS20: agroforestry system presenting inverse proportions of AFS10. The agroforestry systems were intercropped with sorghum or millet, pigeon pea and Massai grass. We collected disturbed and undisturbed soil samples at the layers of 0.00-0.10; 0.10-0.20; 0.20-0.40, 0.40-0.60 and 0.60-1.00 m for analysis of carbon (SOC), nitrogen (N), soil bulk density, and calculation of SOC and N stocks and C/N ratio, two years after the conversion of natural vegetation to the agricultural area (intercropping) and agroforestry system (AFS10 and AFS20). We applied principal component and cluster analysis to explore the data, and confidence interval to compare the means of accumulated SOC and N stocks up to 1 m soil depth. No differences exist for the properties analysed in superficial layers (0.00-0.10 and 0.10-0.20 m), regardless of land-use systems. AFS20 increase the SOC content and, consequently, SOC stock, in subsurface layers; on the other hand, intercropping increases N content and N stock. AFS20 presented higher accumulated SOC stocks up to 1.00 m (114.97 Mg ha-1). Agroforestry systems management is an alternative for increasing carbon sequestration under the conversion from Caatinga to agricultural areas. matter contents semiarid semi arid scarce region Cambissolo eutrófico eutrófico) (1 grass 2 (2 vegetation) 3 (3 AFS10 AFS 6 4 (4 millet 0.000.10 000010 0.00 0.10 0 00 10 0.00-0.10 0.100.20 010020 0.20 20 0.200.40, 020040 0.40, 40 0.20-0.40 0.400.60 040060 0.40 0.60 60 0.40-0.6 0.601.00 060100 0.60-1.0 SOC, , (SOC) N, (N) density CN C ratio (intercropping (AFS1 AFS20. . AFS20) data depth (0.00-0.1 0.10-0.2 m, m) landuse land use AFS2 consequently stock hand 100 1.0 114.97 11497 114 97 (114.9 ha1. ha1 ha ha-1) areas ( AFS1 000 0.000.1 00001 0.0 010 0.1 0.00-0.1 0.100.2 01002 020 0.2 200 0.200.40 02004 040 0.20-0.4 400 0.400.6 04006 0.4 060 0.6 0.40-0. 601 0.601.0 06010 0.60-1. (SOC (N (AFS (0.00-0. 0.10-0. 1. 114.9 1149 11 9 (114. ha-1 0.000. 0000 0. 01 0.00-0. 0.100. 0100 02 0.200.4 0200 04 0.20-0. 0.400. 0400 06 0.40-0 0.601. 0601 0.60-1 (0.00-0 0.10-0 114. (114 ha- 0.000 0.00-0 0.100 0.200. 0.20-0 0.400 0.40- 0.601 0.60- (0.00- 0.10- (11 0.00- 0.200 0.20- (0.00 (0.0 (0. (0

RESUMO O objetivo foi avaliar o desempenho produtivo e a exportação de nutrientes do consórcio de milho com gramíneas forrageiras tolerantes ao estresse hídrico. O experimento foi delineado em blocos casualizados em esquema fatorial 2x2x2+1 (duas espécies de gramíneas forrageiras – Massai e Buffel; dois métodos de semeadura – no sulco e a lanço; e duas épocas de semeadura – antecipada e simultânea; e monocultivo de milho como um controle adicional), com três repetições. O consórcio milho+forragem promoveu maior competição por recursos, principalmente água, limitando a absorção de N, síntese de clorofila e produção de biomassa pelo milho para condições semiáridas. A semeadura precoce deu vantagem competitiva às plantas forrageiras, favorecendo seu estabelecimento antes ou imediatamente após a semeadura do milho. Assim, a semeadura simultânea de gramíneas forrageiras em ambiente semiárido é uma opção mais adequada, considerando a importância de garantir altos teores de clorofila e, consequentemente, alta atividade fotossintética nas plantas de milho para garantir a capacidade de síntese de biomassa.Massai consorciado com milho apresenta maior potencial para produção de biomassa do que Buffel em condições semiáridas.Milho+Buffel resulta em maior exportação de macronutrientes pelo milho, enquanto milho+Massai resulta em maior exportação de macronutrientes pela biomassa forrageira total em ambiente semiárido.A escolha da espécie forrageira e sua época de semeadura em relação ao milho são os principais determinantes do sucesso do consórcio no semiárido. hídrico 2x2x21 xx 2x2x2 1 x 2x2x2+ lanço adicional, adicional , adicional) repetições milhoforragem forragem recursos água N semiáridas Assim adequada consequentemente biomassaMassai semiáridasMilhoBuffel Milho milhoMassai semiáridoA 2x2x

ABSTRACT The aim was to evaluate the productive performance and nutrient export of maize intercropped with drought-tolerant forage grasses. The experimental design was a randomized blocks in a 2x2x2+1 factorial scheme (two forage grasses species – Massai and Buffel; two forage sowing methods - in the furrow and broadcast; and two forage sowing times - anticipated and simultaneous; and monoculture maize as an additional control), with three replicates. The maize+forage intercropping promoted greater competition for resources, especially water, limiting N uptake, chlorophyll synthesis, and biomass production by maize under semiarid conditions. Early sowing gave forage plants a competitive advantage, favoring forage establishment before or immediately after the sowing of maize. Thus, the simultaneous sowing of forage grasses in a semiarid environment is a more appropriate option considering the importance of high levels of chlorophyll to ensure high photosynthetic activity in maize plants and greater capacity of biomass synthesis. Massai intercropped with maize exhibits a greaterpotential for biomass production than Buffel under semiarid conditions. Maize+Buffel result in highest macronutrient export by maize, while maize+Massai result in highest macronutrient exports by total forage biomass under a semiarid environment. The choice of the forage species and its sowing time in relation to maize are the main determinants of successful intercropping systems under semiarid conditions. droughttolerant drought tolerant 2x2x21 xx 2x2x2 1 x 2x2x2+ broadcast control, control , control) replicates maizeforage resources water uptake synthesis conditions advantage Thus MaizeBuffel Maize maizeMassai 2x2x

RESUMO: Os sistemas integrados de produção agropecuária possuem potencial de incrementar a matéria orgânica, com reflexos nas concentrações de carbono e de nitrogênio no solo. O objetivo do trabalho foi avaliar estoques de carbono e nitrogênio e seus compartimentos em um Argissolo Amarelo Distrocoeso típico sob plantio direto e integração lavoura-pecuária no Leste maranhense. Os manejos avaliados foram: sistema de plantio direto em sucessão há 14 anos (soja/milheto), três áreas com diferentes históricos de sucessão com a adoção do sistema integração lavoura-pecuária (ILP), sendo dois, quatro e oito anos, além de uma área de Cerrado nativo. Foram coletadas amostras de solo nas profundidades de 0,00-0,10; 0,10-0,20; 0,20-0,30; 0,30-0,50 metros para análise de teores e estoques totais de carbono (C) e de seus compartimentos (físico e químico), nitrogênio (N) e da biomassa microbiana do solo e respiração basal. Os resultados revelam maior teor e estoque de C e N nas áreas com ILP. A substância húmica predominante foi a humina e maiores concentrações do carbono associado a minerais estiveram presentes na área sob ILP mais recente (dois e quatro anos). A adoção da ILP, mesmo que recente, proporciona incrementos imediatos nas concentrações de C e suas frações em função do emprego de forrageiras. O plantio direto há 14anos e ILP há oito anos são sistemas com maior índice de manejo do C, como, também, apresentam maior atividade biológica do solo, devido à maiores estabilidade destes sistemas.

ABSTRACT: Integrated agricultural production systems have the potential to increase organic matter content, which is reflected in the soil carbon (C) and nitrogen (N) concentrations. Here, we evaluated the C and N stocks and its compartments in a typical distro cohesive yellow Ultisol under the no-till (NT) and crop-livestock integration (CLI) systems, in eastern Maranhão. Five areas with different management strategies were evaluated, more specifically, one area was managed under the NT system in succession for 14 years (soybean/millet), three areas had different CLI system adoption histories (i.e., CLI was adopted 2, 4, or 8 years prior to sample collection); and finally, one area consisted of native Cerrado (savannah) vegetation. Soil samples were collected at depths of 0-0.10, 0.10-0.20, 0.20-0.30, and 0.30-0.50 m,to analyze the content and total stocks of carbon (C) and its compartments (physical and chemical), N content, soil microbial biomass, and basal respiration. Results revealed higher content and stock of C and N in areas with CLI. The principal humic substance reported was humin, and higher concentrations of C associated with minerals were present in areas under more recent CLI adoption (2 and 4 years). We demonstrated that the adoption of CLI, even if recent, leads to immediate increases in the concentrations of C and its fractions as a result of using forage crops. NT for 14 years and CLI for 8 years exhibited higher levels of C management and higher soil biological activity due to the greater stability of these systems.

RESUMO Objetivou-se avaliar os parâmetros fisiológicos, as características produtivas, estruturais e composição química de Megathyrsus maximus (syn. Panicum maximum) cultivares BRS Massai e BRS Tamani submetidas à diferentes períodos de diferimento e momentos de utilização. Utilizou-se o delineamento de blocos completos casualizados, em esquema fatorial 2 x 2 x 3, sendo duas cultivares de gramíneas (capim-massai e capim-tamani), dois períodos de diferimento (período chuvoso e transição chuvoso-seco) e três tempos de vedação (40, 80 e 120 dias). Ambas as cultivares tiveram maior taxa de transpiração foliar quando utilizadas aos 40 dias de diferimento (0,63 μmol/m2/s). Observou-se que a cultivar BRS Massai apresentou a maior taxa fotossintética (1,10 μmol/m²/s), taxa de produção e acúmulo de forragem quando utilizada aos 40 dias de diferimento (P<0,05). Por outo lado, houve maior eficiência no uso da água durante o período de transição nos pastos vedados por 80 e 120 dias (64,60 e 62,30 kg de MS/ha/mm, respectivamente). Observou-se redução (P<0,05) dos nutrientes digestíveis totais (NDT) e proteína bruta (PB) com o aumento no tempo de vedação das pastagens. De modo geral o diferimento no período de transição possibilita a utilização da forragem sem maiores perdas produtivas e nutritivas até os 80 dias de vedação para a cultivar BRS Tamani e até os 40 dias para a BRS Massai.

ABSTRACT This study aimed to evaluate the physiological parameters, the productive characteristics, structural and chemical composition of Megathyrsus maximus (syn. Panicum maximum) cultivars BRS Massai and BRS Tamani submitted to different periods of deferment and moments of use. The experimental design was randomized complete block design in a factorial scheme 2 x 2 x 3, being two grass cultivars (Massai grass and Tamani grass), two deferment periods (rainy season and dry-rainy transition) and three sealing times (40, 80 and 120 days). Both cultivars had higher leaf transpiration rate when used for 40 days of deferment (0.63 μmol/m2/s). It was observed that the cultivar BRS Massai presented higher photosynthetic rate (P<0.05) to 40 days of deferment (1.10 μmol/m2/s), higher rate of production and forage accumulation when used for 40 days. On another side, there was a greater efficiency in the use of water during the period of transition in the pastures sealed for 80 and 120 days (64.60 and 62.30 kg DM/ha/mm, respectively). A reduction (P<0.05) of total digestible nutrients (TDN) and crude protein (CP) was observed with the increase in pasture sealing time. In general, the deferment in the transition period allows the use of forage without greater productive and nutrient losses up to 80 days of sealing for the cultivar BRS Tamani and up to 40 days for BRS Massai.

ABSTRACT The implementation of integrated agricultural production systems is considered a promising strategy for sustainable agricultural intensification in Brazil. This study aimed to evaluate the effects of different monoculture and integrated production systems on the microbiological attributes and organic carbon of soil from the Cerrado region in Piauí, Brazil. Soil samples were collected from the 0.0-0.10-m layer in the following systems: no-tillage (PD), pasture (PAS), exclusive eucalyptus cultivation (CEE), integrated livestock-forest system (IPF) and a native Cerrado (CN) area, which was used as reference. Total organic carbon (TOC) and nitrogen (NT) contents, microbial biomass carbon (CMIC), microbial respiration (MR), microbial quotient (qMIC), metabolic quotient (qCO2), as well as the activities of the hydrolysis of fluorescein diacetate (FDA), acid phosphatase, β-glucosidase and urease enzymes were evaluated. High TOC contents were found in the CEE, IPF and PAS systems, and high CMIC and qMIC values were found in the CN and CEE systems. The variables MR, qCO2 and enzymatic activity varied as a function of the management systems. The IPF and CEE systems caused improvements in the soil attributes, with increases in organic carbon and microbial biomass. The IPF integrated production system promoted improvements in the microbiological indicators of soil quality and was considered an environmentally sustainable agricultural production system. The transition from CN to agricultural areas caused changes in the soil microbiological indicators, which were perceived several years after anthropogenic intervention, indicating that even with the adoption of conservation systems, it was not possible to reestablish the soil microbial biomass.

RESUMO O objetivo deste estudo foi avaliar as características químicas de um processo contínuo de compostagem aeróbia com aeração passiva com material de alimentação proveniente da produção e abate de pequenos ruminantes, realizado com diferentes níveis de umidade. O processo de compostagem foi realizado em celas de tijolos, com resíduos sólidos (esterco e partes de carcaça) do abate de cabras e ovelhas, juntamente com capim-elefante seco picado e aparas de árvores. Os tratamentos empregaram três teores de umidade nas pilhas (30, 50 e 70%) e intervalos de tempo (0, 30, 60 e 120 dias) de avaliação do material compostado, com três repetições. As variáveis avaliadas foram os atributos químicos do composto gerado. O processo de compostagem aumentou as concentrações dos elementos Ca, Mg, S, Cu, Fe, Mn e Zn e reduziu o pH, o teor de lignina e a razão lignina/nitrogênio. O N, P e B apresentaram maior teor com 111, 61 e 94 dias, respectivamente. O K não teve sua concentração alterada. O teor de água de 70% produziu os maiores teores de N e menor razão lignina/N. Ao final do processo de compostagem, em 120 dias, houve aumento dos teores de N, P, Ca, Mg, S, B, Cu, Fe, Mn, Zn e condutividade elétrica em 33,7; 6,3; 17,5; 16,3; 666; 22; 31,3; 49,7; 30,4: 29,4 e 16,1%, respectivamente. E houve decréscimo nos valores de pH e lignina em 8,4 e 27,2%, respectivamente.

ABSTRACT The aim of this study was to assess the chemical characteristics of a continuous aerobic composting process with passive aeration of feed material from the production and slaughter of small ruminants at different moisture levels. The composting process was performed in a brick barn with solid residues (manure and carcass parts) from the slaughter of goats and sheep along with chopped dry elephant grass and tree trimmings. The treatments employed three moisture contents (30, 50, and 70% water) and four sample collections at timed intervals (0, 30, 60, and 120 days), with three repetitions. The variables evaluated were the chemical attributes of the generated compost. The compositing process increased the concentrations of the elements Ca, Mg, S, Cu, Fe, Mn, and Zn and reduced the pH, lignin, and lignin/nitrogen ratio. The levels of N, P, and B increased up to 111, 61, and 94 days, respectively, whereas no change in the K content occurred. At the end of the process at 120 days, the contents of N, P, Ca, Mg, S, B, Cu, Fe, Mn, Zn, and electrical conductivity were increased by 33.7, 6.3, 17.5, 16.3, 666, 22, 31.3, 49.7, 30.4, 29.4 and 16.1%, respectively. The pH and lignin values decreased by 8.4 and 27.2%, respectively.

RESUMO Objetivou-se avaliar, por meio de análise multivariada de dados, quais resíduos de leguminosas arbóreas tem melhor potencial fertilizante para culturas agrícolas no semiárido nordestino brasileiro. O experimento foi conduzido em vasos, em delineamento aleatorizado em blocos, com sete tratamentos e quatro repetições. Para constituir os tratamentos utilizaram-se resíduos de sabiá, jurema-preta e gliricídia; além de duas partes da planta: folhas e folhas mais galhos. Os vasos foram preenchidos com 8,0 dm3 de solo e os resíduos foram adicionados na forma de massa verde, correspondendo a 73,0 g de massa seca por vaso. Sementes de milho foram semeadas e aos 65 dias após adição dos resíduos avaliou-se atributos químicos do solo, crescimento e teores de nutrientes das plantas. Os dados foram estudados por meio das análises de componentes principais, agrupamento, função discriminante canônica e teste de comparação de médias a partir da varável canônica 1. Resíduos de gliricídia influenciaram positivamente K e Mg do solo, bem como altura, diâmetro do caule, número de folhas e teores foliares de P, N e Mg em plantas de milho. Estes resíduos apresentaram maior dissimilaridade e separação em relação ao tratamento controle e proporcionaram médias estatisticamente superiores aos demais tratamentos. Folhas de jurema-preta influenciaram positivamente Ca, N e COT do solo, bem como teores foliares de K e Ca e matéria seca total do milho. A análise estatística multivariada permitiu identificar potenciais distintos entre resíduos de leguminosas para uso como fertilizante na cultura do milho, sendo a espécie gliricídia a que apresenta maior potencial.

ABSTRACT The objective of this study was to evaluate, through multivariate data analysis, which tree legume residues have the best fertilizer potential for agricultural crops in the semi-arid region of northeastern Brazil. The experiment was conducted in pots, in a randomized block design, with seven treatments and four replicates. Treatments consisted of residues of Sabiá, Jurema Preta and Gliricidia, besides two parts of the plant: leaves and leaves + branches. The pots were filled with 8.0 dm3 of soil and the residues were added in the form of green mass, corresponding to 73.0 g of dry mass per pot. Maize seeds were sown and, at 65 days after addition of the residues, soil chemical attributes, growth and nutrient contents in the plants were evaluated. The data were studied through principal component analysis, clustering analysis, canonical discriminant function analysis and means comparison test from canonical variable 1. Gliricidia residues positively influenced soil K and Mg contents, as well as height, stem diameter, number of leaves and leaf contents of P, N and Mg in maize plants. These residues showed greater dissimilarity and separation compared to the control treatment and led to statistically higher means compared to the other treatments. Jurema Preta leaves positively influenced soil Ca, N and TOC, as well as leaf contents of K and Ca and total dry mass of maize. Multivariate statistical analysis made it possible to identify distinct potentials among legume residues for use as fertilizer in maize crop, and Gliricidia is the species with highest potential.

ABSTRACT The conservation tillage systems is based on the surface protection by crop residue and reduced soil disturbance. These two principles can favor the soil quality and promote sustainable agricultural systems. The study was developed with the objective of measure soil microbial biomass, soil basal respiration, enzymatic activity and soybean yield in conservation systems cultivated with cover crops species in the Northeastern Cerrado. The experiment was carried out in 2016/2017 and 2017/2018 cropping seasons, performed in a randomized blocks design. The treatments were soil tillage systems allocated in the main plots: no-tillage (NT) and minimum tillage (MT) and the cover crops were allocated in the subplots: Pennisetum glaucum (millet), Urochloa ruziziensis (brachiaria), Crotalaria spectabilis (C. spectabilis), Crotalaria ochroleuca (C. ochroleuca), Pennisetum glaucum + Crotalaria spectabilis (millet + C. spectabilis) and spontaneous plants with three replicates. The evaluated variables were dry mass (DM) production and nutrient accumulation in cover crops; soil biological properties, namely microbial biomass carbon and nitrogen (MBC and MBN, respectively), respiration, metabolic quotient (qCO2), dehydrogenase enzymatic activity (DH), fluorescein diacetate (FDA); and soybean yield. The higher production of dry mass and nutrient cycling occurs with the intercropping millet + C. spectabilis and single millet. The highest soybean yield occurs in succession to C. ochroleuca and intercropping of the millet + C. spectabilis. Cover crops in conservation systems improve soil microbial quality and increase soybean yield.