ABSTRACT The objective of this study was to monitor the temporal variation in penetration resistance (PR) after soil saturation under different management systems in three areas of the Cerrado biome: two in no-till systems (NT with 3 and 10 years of implementation) and one of crop-livestock integration (CL with 9 years of implementation) with soybean/forage succession. Four transects were delimited in each area. The delimited area was saturated and the PR measurements were performed daily for 11 days at 10 transect points, up to 0.40 m of depth. Soil moisture was determined with PR measurements, soil hydraulic conductivity, and organic carbon. PR values were more significant in the 0.10 - 0.20 m layer than in the 0.0 - 0.10 and 0.20 - 0.40 m layers. The NT-3 area showed a lower PR value (1.65 MPa) than the area under NT-10 and CL-9, with 2.48 and 2.69 MPa, respectively. Thus, critical soil moisture values, that is, soil moisture values most susceptible to soil compaction were determined. Thus, in the NT-3 area, the critical moisture was 0.20 kg kg-1, in the NT-10, ranged from 0.19 - 0.20 kg kg-1, and in the CL-9, between 0.23 and 0.20 kg kg-1. Monitoring soil moisture can prevent management operations from restricting root growth. (PR biome notill no till NT 1 implementation croplivestock crop livestock CL soybeanforage soybean forage succession points 040 0 40 0.4 depth conductivity carbon 010 0.1 020 20 0.2 00 0. layers NT3 NT- 1.65 165 65 (1.6 MPa NT10 NT-1 CL9, CL9 9, CL-9 248 2 48 2.4 269 69 2.6 respectively Thus is kg1, kg1 1, kg-1 NT10, 10, 019 19 023 23 kg1. 1. growth 04 4 01 02 1.6 16 6 (1. NT1 CL- 24 2. 26 kg- (1 (

ABSTRACT A long-term experiment (2013 to 2017) of treated sewage effluent (TSE) levels via fertigation in a humid tropical region was installed in Jaboticabal, state of São Paulo, Southeast of Brazil, to evaluate the impact of TSE on soil fertility and the potential for salinization and heavy metal contamination of an Oxisol. The area was cultivated with Urochloa brizantha under the application of four TSE levels at the irrigation depth (0, 11, 60, and 100% TSE) during the four years of the experiment. The TSE chemical composition was monitored throughout the experimental period. The heavy metal levels and soil fertility were evaluated in the 0-0.10 and 0.10-0.20 m layers at the end of the four years of the experiment. Fertigation using TSE did not increase the concentration of potentially toxic elements (As, Cd, Cu, Hg, Mo, Ni, Pb, Se, and Zn) in the soil due to their low concentration in the effluent. A higher Na concentration was also observed at high TSE levels (60 and 100%). However, the sodium adsorption rate in the TSE was low, generating no potential for soil salinization and sodification. Fertigation with TSE levels increased soil fertility, increasing by more than 10% the P content and base saturation in the soil compared to control. According to the chemical attributes evaluated in the soil and effluent, this long-term study showed that TSE application via fertigation in humid tropical regions on clayey soils cultivated with forage grasses is recommended.

RESUMO. O alto consumo de água na agricultura irrigada e falta de fontes alternativas de água tornar a reutilização da água de esgoto uma opção altamente promissora nesta atividade. Este trabalho teve como objetivo avaliar o rendimento e a qualidade da forrageira Brachiaria brizantha cv. Marandu fertirrigada com águas residuais de efluente de esgoto tratado (EET) e fertilizante mineral, nos anos de 2013 e 2014, em Jaboticabal, Estado de São Paulo, Brasil. A lâmina homogênea da água foi aplicada por um sistema de irrigação por aspersão em linha tripla, mas sob aplicação gradual EET, usando os seguintes EET e água proporções: E5 = 1,0; E4 = 0,87; E3 = 0,6; E2 = 0,31, E1 = 0,11 e E0 = 0,0. O rendimento anual de biomassa aumentou com aplicação EET, variando 31,3-47,4 Mg ha-1 em 2013 e 25,7-56,9 Mg ha-1 em 2014, para E1 e E5, respectivamente. Houve sazonalidade na produção de forrageira, com os valores mais elevados no verão (35,9 a 44,7%) e primavera (35,7 a 38,4%) e as mais baixas durante a temporada de outono-inverno (19,6 a 25,7%). Apesar das altas doses de nitrogênio (1.132 kg ha-1), o rendimento máximo de forragem não foi alcançado, de modo que novos aumentos de nitrogênio ainda possam melhorar o rendimento. As baixas produtividades no outono-inverno foram compensadas pela melhor qualidade da forrageira em proteína bruta (PB) e fibra em detergente neutro (FDN).

ABSTRACT. The high consumption of water in irrigated agriculture and lack of alternative water sources make reusing sewage water a highly promising option for irrigation. This paper is aimed at evaluating Brachiaria brizantha cv. Marandu forage quality and yield when fertigated with treated sewage wastewater (TSW) and mineral fertilizer, in the 2013 and 2014 crop years in Jaboticabal, São Paulo State, Brazil. A homogeneous water depth was applied using a triple-line sprinkling irrigation system under a gradual TSW application, using the following TSW and water ratios: E5 = 1.0; E4 = 0.87; E3 = 0.6; E2 = 0.31, E1 = 0.11, and E0 = 0.0. Annual biomass yield increased with the TSW application, ranging from 31.3 to 47.4 Mg ha-1 in 2013 and from 25.7 to 56.9 Mg ha-1 in 2014, for E1 and E5, respectively. Forage yield had marked seasonality, with the highest values in summer (35.9 to 44.7%) and spring (35.7 to 38.4%) and the lowest ones during the fall-winter seasons (19.6 to 25.7%). Despite the high nitrogen rates (1,132 kg ha-1), maximum forage yield was not achieved, hence further nitrogen increments would still enhance yield. Forage improved quality has counterbalanced the low fall-winter yields in terms of crude protein (CP) and neutral detergent fibre (NDF).