Tommi Segabinazzi

Efeito do pisoteio bovino em algumas propriedades físicas do solo de várzea

The objetive of the work was to evaluate effects of bovine stepping on the physical proprieties of a lowland soil where a mixture of winter pastures were grown. The plant species were italian ryegrass (Lolium multiflorum), white clover (Trifolium repens) and birdsfoot trefoil (Lotus corniculatus). The soil is classified as an albaqualf, previously leveled with a 0,06% gradient. The experimental design was a randomized block in which each plot measured 0,5ha forming six experimental units under continuous grazzing. The soil treatments were the occasions in which the samplimg were taken; T1 = just before entrance of the animals, T2 = immediately after their exit and T3 = six months later. The animals were 8-10 months old calves with an initial load of 480kg/ha-1 of live load and the residual pasture mass was about 1000kg/ha-1. Animal stepping caused an increase on soil density and a reduction in total porosity. An increase on soil density occurred at the first 5cm soil depth. Six months with no stepping were not sufficient for plant roots to decrease soil compactation.

Manejo da adubação do arroz irrigado em sistema pré-germinado na produtividade e perda de nutrientes através da água de drenagem inicial

The experiment was conducted aiming to evaluate the effects of fertilization management in the pregerminated system, on grain yield and nutrient loss through early drain discharge. The treatments were: T1- Control (without fertilization); T2- fertilization 20 days before sowing without incorporation; T3- fertilization 20 days before sowing with fertilizer incorporation; T4- fertilization 05 days before sowing without incorporation; T5- fertilization 05 days before sowing with fertilizer incorporation; T6- fertilizer application 10 days after sowing; T7- fertilizer application 25 days after sowing. Grain yield was not affected by the different fertilization management procedures. The fertilizer applied 05 days before sowing promoted the highest nutrients loss, especially potassium. However, recorded loss values were within the range allowed by current legislation.

Produção de forragem e rentabilidade da recria de novilhos de corte em área de várzea

O experimento foi realizado em 2000 (Ano 1) e 2001 (Ano 2), em varzea sistematizada, com o objetivo de comparar o uso de doses de adubacao nitrogenada em cobertura, associadas a niveis de suplementacao energetica, sobre os teores de proteina bruta, digestibilidade in vitro da materia orgânica e producao de forragem, producao animal e rentabilidade. Os tratamentos aplicados no Ano 1 foram: novilhos em pastagem cultivada de azevem (Lolium multiflorum Lam.) + 300 kg/ha de nitrogenio (N), recebendo suplementacao com grao de milho moido a 0,8% do peso vivo (PV)/dia (300N+0,8S); novilhos em pastagem de azevem + 200 kg/ha de N, recebendo suplementacao com grao de milho moido a 0,4% do PV/dia (200N+0,4S); e novilhos em pastagem de azevem + 100 kg/ha de N, sem suplementacao (100N+0,0S). No Ano 2: novilhos em pastagem de azevem + 230 kg/ha de N, recebendo suplementacao com grao de milho moido a 1,0% do PV/dia (230N+1,0S); novilhos em pastagem de azevem + 155 kg/ha de N, recebendo suplementacao com grao de milho moido a 0,5% do PV/dia (155N+0,5S); novilhos em pastagem de azevem + 80 kg/ha de N, sem suplementacao (80N+0,0S). Foram utilizados novilhos de corte em pastagem sob lotacao continua e carga variavel. A taxa de acumulo de massa seca nao diferiu entre os niveis de N e de suplementacao utilizados. O ganho de peso animal por hectare foi maior quando se utilizaram as maiores doses de N e suplementacao. A menor utilizacao de N e a ausencia de suplementacao em 2000 ocasionaram a maior renda liquida. Em 2001, qualquer nivel de insumo utilizado apresentou renda liquida negativa. O aumento das doses de adubacao nitrogenada em cobertura, associado a diferentes niveis de suplementacao energetica, embora tenha proporcionado acrescimo na taxa de lotacao, nao afetou a taxa de producao de massa seca e a qualidade da forragem, resultando em menor renda liquida.

Manejo dos fertilizantes fosfatados e potássicos em arroz irrigado no sistema pré-germinado

In pregerminated rice system, initial water drainage promotes nutrient losses, depending on fertilizer management, leading to environmental problems. During the 2000/01 and 2003/04 growing seasons experiments were conducted at Universidade Federal de Santa Maria aiming to evaluate the effect of phosphorus and potassium fertilizer application methods on nutrient losses and pregerminated rice grain yield. The treatments were seven phosphorus and potassium fertilization methods combining application time and incorporated or not incorporated. Phosphorus and nitrogen concentration measured at initial water drainage were not affected by time or method of fertilizer application. The average of phosphorus and nitrogen were 0.07 and 0.81 mg L-1 respectively. However, less potassium runoff was verified in the treatments where the fertilizer was applied 10 and 30 days after sowing as well as on the check treatment. The treatments tested did not affect the rice agronomic traits. Rice yield was not affected by the phosphorus and potassium fertilization timing and method of application, but when the permanent flooding is not kept on the phosphorus and potassium application need to be done after the initial drainage to reduce potassium losses.