Effect of Five Different Rest Periods on Tiller Regrowth of Ryegrass

Five rest periods were imposed from April to May on a mixed pasture of two ryegrass (Lolium multiflorum Lam.) varieties and white clover (Trifolium repens L.). The rest period starting dates were: April 4, April 18, May 2, May 16, and May 30, for rest periods 1, 2, 3, 4, and 5, respectively. The total area allocated to the experiment was 1.1 ha, which was divided into 22 pastures. The experimental design used was a split-plot. Rest period was assigned to the main plot, grass to the subplot and legume to the subsubplot. The pastures were “mob-grazed” by cattle from 1 to 4 days to a prescribed residue level. The number of tillers per 0.25 m2 decreased linearly with advanced rest periods, at rates of approximately 40 tillers/0.25 m2/week. The percentage of tillers with seed heads increased linearly with advanced rest periods. The percentage of tillers with ripe seeds increased with later rest periods and reached 98% by rest period 5. The decrease in length of seed head probably was responsible for the decrease in seed weight/tiller. However, estimates indicated that because of the increase in percentage of tillers with ripe seeds with later rest periods about 100, 83, and 103 kg/ha of ripe seeds were produced in rest period 3, 4, and 5, respectively. This amount of seed produced is more than enough for a self-reestablishment of the pasture for the following winter

Onde posicionar sensores de umidade e de tensão de água do solo próximo da planta para um manejo mais eficiente da água de irrigação.

A irrigação eficiente é aquela com menor consumo de energia e menor perda de água, contribuindo na maior conservação dos recursos hídricos, por ser aplicada no momento correto, isto é, aquele em que a umidade do solo começa a comprometer a absorção de água pela planta. Essa irrigação eficiente requer também a reposição correta da água perdida pelas plantas desde a última irrigação.bitstream/item/118884/1/CircularTecnica-109-Onde-posicionar-sensores.pd

Allelopathic Influence of \u3ci\u3eEragrostis curvula\u3c/i\u3e Water Extract on Seed Germination and Seedling Growth of Two Other Species

Weeping lovegrass (Eragrostis curvula Schrad. Nees) is a very agressive tropical species and does not grow well with other species. This study was set up to investigate the allelopathic effect of various extract concentrations of weeping lovegrass on seed germination of white clover (Trifolium repens L.) and bentgrass (Agrostis stolonifera L.) and the seedling development of white clover. Labotatory and growth chamber studies were conducted. Extract concentrations of 13.6, 27.2, 40.8, 54.4, and 62.0 g/100mL of water were studied. Treatments were arranged in a completely ramdomized design with three replications. The allelopathic effect of weeping lovegrass was significant (P \u3c 0.01) on white clover andbentgrass. White clover was affected by lower extract concentration than bentgrass. The seedling growth of white clover was reduced when compared with the control (P \u3c 0.01) for root growth and (P \u3c 0.04) for whole plant. The osmotic potential also affected (P \u3c 0.01) seed germination of white clover. For the highest concentrated solution there was a decrease of 20% on the seed germination of white clover due to the water potential

Coulomb and quantum oscillator problems in conical spaces with arbitrary dimensions

The Schr\"odinger equations for the Coulomb and the Harmonic oscillator potentials are solved in the cosmic-string conical space-time. The spherical harmonics with angular deficit are introduced. The algebraic construction of the harmonic oscillator eigenfunctions is performed through the introduction of non-local ladder operators. By exploiting the hidden symmetry of the two-dimensional harmonic oscillator the eigenvalues for the angular momentum operators in three dimensions are reproduced. A generalization for N-dimensions is performed for both Coulomb and harmonic oscillator problems in angular deficit space-times. It is thus established the connection among the states and energies of both problems in these topologically non-trivial space-times.Comment: 15 page