The agricultural potential of Latosols of the Brazilian Cerrado region is high, but when intensively cultivated under inappropriate management systems, the porosity can be seriously reduced, leading to rapid soil degradation. Consequently, accelerated erosion and sedimentation of springs and creeks have been observed. Therefore, the objective of this study was to evaluate structural changes of Latosols in Rio Verde, Goiás, based on the Least Limiting Water Range (LLWR), and relationships between LLWR and other physical properties. Soil samples were collected from the B horizons of five oxidic Latosols representing the textural variability of the Latosols of the Cerrado biome. LLWR and other soil physical properties were determined at various soil compaction degrees induced by uniaxial compression. Soil compaction caused effects varying from enhanced plant growth due to higher water retention, to severe restriction of edaphic functions. Also, inverse relationships were observed between clay content and bulk density values (Bd) under different structural conditions. Bd values corresponding to critical soil macroporosity (BdcMAC) were more restrictive to a sustainable use of the studied Latosols than the critical Bd corresponding to LLWR (BdcLLWR). The high tolerable compression potential of these oxidic Latosols was related to the high aeration porosity associated to the granular structure.

In the south-central region of Brazil, there is a trend toward reducing the sugarcane inter-harvest period and increasing traffic of heavy harvesting machinery on soil with high water content, which may intensify the compaction process. In this study, we assessed the structural changes of a distroferric Red Latosol (Oxisol) by monitoring soil water content as a function of the Least Limiting Water Range (LLWR) and quantified its effects on the crop yield and industrial quality of the first ratoon crop of sugarcane cultivars with different maturation cycles. Three cultivars (RB 83-5054, RB 84-5210 and RB 86-7515) were subjected to four levels of soil compaction brought about by a differing number of passes of a farm tractor (T0 = soil not trafficked, T2 = 2 passes, T10 = 10 passes, and T20 = 20 passes of the tractor in the same place) in a 3 × 4 factorial arrangement with three replications. The deleterious effects on the soil structure from the farm machinery traffic were limited to the surface layer (0-10 cm) of the inter-row area of the ratoon crop. The LLWR dropped to nearly zero after 20 tractor passes between the cane rows. We detected differences among the cultivars studied; cultivar RB 86-7515 stood out for its industrial processing quality, regardless of the level of soil compaction. Monitoring of soil moisture in the crop showed exposure to water stress conditions, although soil compaction did not affect the production variables of the sugarcane cultivars. We thus conclude that the absence of traffic on the plant row maintained suitable soil conditions for plant development and may have offset the harmful effects of soil compaction shown by the high values for bulk density between the rows of the sugarcane cultivars.

Anacardium othonianum Rizz. is a medicinal plant species that is native to the Brazilian savannah. Adult plants are different from other genus members in this ecosystem due to their size, and efforts to locate the plants may lead to their extraction from the savannah and, frequently, plant death. Micropropagation has played a significant role in the propagation and preservation of specimens of several plant species; therefore, this study evaluated the effect of various salt concentrations and culture medium volumes on the in vitro cultivation of A. othonianum Rizz. Trial (I) evaluated two culture media (MS and WPM) and three salt concentrations (100, 50 and 25%) in a completely randomized design. Trial (II) evaluated two culture media and salt concentrations, MS (50%) and WPM (100%), and five medium volumes (10, 15, 20, 25 and 30 mL per test tube) as a 2 x 5 factorial in a completely randomized design. After 30 and 60 days of growth, the percentage of plantlet survival, average plantlet and leaf lengths and the average number of leaves and buds per explant were evaluated. The MS (50 and 25%) media and WPM (100 and 50%) media were the most effective for plantlet regeneration. The best responses were observed in 15- and 25-mL volumes of the MS (50%) medium. Therefore, the use of a 15-mL volume is suggested for greater medium economy.

Objetivou-se, com este trabalho, avaliar o efeito do espaçamento e da complementação hídrica no crescimento e produtividade do pinhão-manso. O experimento foi conduzido na área experimental do Instituto Federal Goiano, campus Rio Verde,GO, no período de 12/09/2009 a 30/04/2011, no delineamento de blocos casualizados com três repetições, os fatores foram sete espaçamentos e duas condições hídricas, cada parcela constituída de 16 plantas, sendo as quatro plantas centrais a área útil. Aos 60 dias após o transplantio das mudas foram feitas, bimensalmente, as avaliações dos parâmetros altura de planta, número de ramificações, área foliar e produtividade. O fator espaçamento não apresentou diferença significativa para os parâmetros altura, ramificação e produtividade e a complementação hídrica teve efeito significativo para altura aos 240 dias após transplantio. A produção de sementes em sequeiro foi maior no espaçamento 3 x 3 e com complementação hídrica no espaçamento 4 x 4.