The nutritional limitations of an organic soil supporting a lowland rice crop, cv. Inca, were identified in a greenhouse experiment in Lavras, State of Minas Gerais, from December, 1994, to June, 1995. Soil samples were collected in Northern Fluminense region. Treatments consisted of control (natural soil), complete (N, P, K, limestone, S, B, Co, Cu, Mo, and Zn) and complete lacking one of these nutrients at a time. At the grain maturation time, the treatments lacking N and K showed […]

The effectiveness of fluid (phosphoric acid and 10-30-00 colloidal suspension) and solid (monoammonium phosphate and triple superphosphate) fertilizers was evaluated in a greenhouse experiment at the Center for Nuclear Energy in Agriculture (CENA), University of São Paulo, Piracicaba, State of São Paulo, Brazil, from June to October, 1992. Corn plants were grown in pots (8 plants per pot; 3 replicates) containing 1 kg of two red-yellow latosols with different phosphorus retention capacities, for three successive cycles (30 days each). The […]

The objective of this study was to assess the relative efficiency of single superphosphate (SS), partially acidulated rock phosphate (PARP) and fused magnesium thermal phosphate (MTP) as sources of P and other nutrients for eucalypt plantations in two soils of the cerrado region: an alic quartz-sand (50 g kg-1 of clay) and an alic dark-red latosol (230 g kg-1 of clay). Experiments were carried out under greenhouse conditions at the University of São Paulo, Piracicaba, State of São Paulo, Brazil, […]

Two field experiments were carried out with corn, using no-tillage system (NTS) over oat residues, in a clay dark-red latosol at the Centro de Pesquisa Novartis – Seeds, in Uberlândia, State of Minas Gerais, Brazil, and conventional tillage system over soybean residues (CTS), in a sandy red-yellow latosol at the Santa Terezinha farm, Uberlândia. The objective of this study was to evaluate the NH3-N volatilized from nitrogen sources, side-dressed applications, of approximately 100 kg ha-1, applied in the middle of […]

A field experiment was carried out on a dark-red latosol (Oxisol) of the Centro de Pesquisas Novartis-Seeds, in Uberlândia, State of Minas Gerais, Brazil. The objective of this study was to evaluate the effects of irrigation, side-dressed application of urea, and urea partially substituted by ammonium sulphate on losses of NH3-N by volatilization in corn crop. The fertilizers were applied at 25 and 36 days after planting. The treatments, arranged in randomized complete block design, were: (i) control, (ii) urea, […]

The aim of this study was to identify corn production systems using green manure crops showing characteristics of sustainability. The experiments were carried out on a Yellow-Red Podzolic soil, 5.5% slope, at Federal University of Santa Maria, State of Rio Grande do Sul, Brazil, from 1991 to 1993. Plot dimensions were 3.5 m by 22.0 m, as defined by the methodology of natural rainfall erosion plots. The treatments consisted of: (i) bare soil, (ii) black oat (Avena strigosa) + common […]

Although the criteria for defining erosion tolerance are well established, the limits generally used are not consistent with natural, economical and technological conditions. Rates greater than soil formation can be accepted only until a minimum of soil depth is reached, provided that they are not associated with environmental hazard or productivity losses. A sequence of equations is presented to calculate erosion tolerance rates through time. The selection of equation parameters permits the definition of erosion tolerance rates in agreement with […]

The soil erodibility (K-factor) determination by indirect methods has not been adequate for application in Brazilian soils. This paper aimed the development of K-factor evaluation methods depending on easily-assessed chemical, physical and morphological soil properties. Samples from A and B horizons of 22 Brazilian soils bearing argillic horizon were submitted to several chemical and physical analyses and the morphological description of the soil profile was considered. A stepwise multiple linear regression analysis was run, relating the results of those analyses […]

The assessment of the soil erodibility (K-factor) is essential for using the universal soil loss equation. The objective of this paper was to verify the adequacy of different indirect methods to estimate the K-factors of soils with argillic horizon from diverse geographic regions of Brazil. Superficial samples of 22 soils bearing argillic horizon were collected. The K-factors measured directly in the field of all these soils are already known. Several chemical and physical analyses were performed in order to calculate […]

Litholic soils are characterized by moderate to high erodibility and low depth. Due to these attributes, litholic soils require effective conservation practices protecting their thin top soil layer from the high erosion rates in the semiarid regions of the State of Ceará, Brazil. While the consequences of erosion on these soils are well known, the long term effects of this conservation practice on the rate of soil losses and improvement of their properties have been scarcely studied. Mass of retained […]