Clay and Phosphorus Losses by Erosion in Oxisol With Sugarcane Residues

Abstract

Considering the importance of nutrients in the soil for the plants development and the soil quality conservation and the quantification relevance of them for proper soil management, the aims of this research were: (i) to quantify the clay loss, adsorbed and soluble P from interrill erosion influenced by the presence of sugarcane residues on the ground surface; (ii) to determine the minimum percentage of residues to be maintained on the soil surface to not enrich the eroded sediment by clay and soluble P (Psed) and adsorbed (Pads). The experimental area is located in Guariba -SP, with soil classified as Red Dystrophic Oxisol. The experiment was designed based on results of previous experiments with residue analysis of variance for 40 plots. These experiments were conducted by our research group, which provided field representation and the establishment of a minimum number of degrees of freedom necessary to ensure normal distribution of results and variance homoscedasticity. The experimental design was completely randomized in a factorial design, 5 treatments with straw sugarcane and 3 repetitions, totaling 15 plots. In the treatments, the straw was manually distributed across the surface of the soil in amounts of 0; 0.16; 0.35; 0.52 to 0.7 Kg by plot, giving 0% coverage (SC0), 25% (SC25), 50% (SC50), 75% (SC75) and 100% (SC100), respectively. The experimental plots were subjected to simulated rain with average intensity of 60 mm h -1 for 65 minutes. To avoid enrichment ratio (ER) of the sediment eroded by Psed, Pads and clay, a minimum soil surface coverage (SC) of 42% is necessary.

Improving phosphorus sustainability of sugarcane production in Brazil

“…For example, Sparovek and Schung () estimated soil losses in sugarcane production in São Paulo state of up to 30 Mg ha −1 year −1 , while they did not exceed 2 Mg ha −1 year −1 from forests and pastures. In addition to the loss of crop production potential, soil losses lead to P losses and reduced overall P use efficiency (Izidorio, Martins Filho, Marques Júnior, Souza, & Pereira, ; Paula, Martins Filho, Farias, & Siqueira, ; Politano & Pissarra, ). Critical periods for increased erosion risk are during the initial conversion of pasture to sugarcane when the grass is desiccated, the period between crop harvesting and regrowth, and at replanting when soils can remain bare for several months (Martinelli & Filoso, ).…”

Chemical Changes of Soil and Water in Hillside Areas Under Intensive Horticulture

“…However, successive phosphate fertilization to meet the needs of horticultural plants justify high P contents (above 100 mg dm −3 ) . The highest P contents found at a depth of 0-10 cm are from drip fertigation, which concentrates P in the upper soil layer where a higher vegetable root density can be found (up to 20 cm), as well as its low mobility in the soil profile (Paula et al, 2016;Fink et al, 2016). Because these areas are located in the hillside, high P contents are agronomically and environmentally worrisome since this nutrient may be easily carried into water sources, with a potential risk of eutrophication (Reay et al, 2012;Bai et al 2013).…”

“…An increase in precipitation reduced P concentration both in water reservoirs and in R6, but the inverse was observed for NO3 − concentration. Considering that P is slightly mobile in the soil (Paula et al, 2016) and that organic matter mineralization does not cause water eutrophication in these environments even in areas with high contents of this component (Freire et al, 2013;Vidal & Neto, 2014), the high concentration of P in reservoir waters is related to soil hillside erosion.…”

Temporal and Spatial Uncertainty of Erosion Soil Loss from an Argisol Under Sugarcane Management Scenarios

“…The soil protection provided by crop residues contributes to preserve the state of soil aggregation, due to the lower surface impact of raindrops, minimizing aggregate destruction in this layer and a consequent soil surface sealing (Laufer et al, 2016;Paula et al, 2016). In addition, plant residues left on the topsoil act as barriers that reduce runoff velocity, increasing the time of water infiltration into the soil profile (Garbiate et al, 2011).…”