Soil, water and nutrient losses by interrill erosion from green cane cultivation

Abstract

Interrill erosion occurs by the particle breakdown caused by raindrop impact, by particle transport in surface runoff, by dragging and suspension of particles disaggregated from the soil surface, thus removing organic matter and nutrients that are essential for agricultural production. Crop residues on the soil surface modify the characteristics of the runoff generated by rainfall and the consequent particle breakdown and sediment transport resulting from erosion. The objective of this study was to determine the minimum amount of mulch that must be maintained on the soil surface of a sugarcane plantation to reduce the soil, water and nutrient losses by decreasing interrill erosion. The study was conducted in Pradópolis, São Paulo State, in 0.5 x 1.0 m plots of an Oxisol, testing five treatments in four replications. The application rates were based on the crop residue production of the area of 1.4 kg m-2 (T1- no cane trash; T2-25 % of the cane trash; T3- 50 % trash; T4-75 % trash; T5-100 % sugarcane residues on the surface), and simulated rainfall was applied at an intensity of 65 mm h-1 for 60 min. Runoff samples were collected in plastic containers and soon after taken to the laboratory to quantify the losses of soil, water and nutrients. To minimize soil loss by interrill erosion, 75 % of the cane mulch must be maintained on the soil, to control water loss 50 % must be maintained and 25 % trash controls organic matter and nutrient losses. This information can contribute to optimize the use of this resource for soil conservation on the one hand and the production of clean energy in sugar and alcohol industries on the other.

Clay and Phosphorus Losses by Erosion in Oxisol With Sugarcane Residues

“…When 50% of straws were kept on the soil surface, the Di was reduced by 91.4% when compared to the value obtained for bare soil. These results are superior to those observed by SILVA et al (2012) to interrill erosion in Oxisol similar to this research that reported 85% of Di reduction in this condition. These differences are probably due to the erodibility of the soil and straw amount applied per plot.…”

“…Such coverage, however, does not guarantee the absence of sediment enriched with clay and/or other nutrients at levels capable of conducting an ER ≤ 1. Furthermore, they are lower than the ones determined by SILVA et al (2012) in Oxisol similar to this research, which evaluate for ER ≤ 1, in case of P has the need of a SC ≥ 25%. These differences are probably due to higher ER rates obtained by SILVA et al (2012), 2.1 for SC of 0% and 0.5% for SC of 100%, regarding the ones of this research of 1.3 for SC of 0% and 0.4 for SC of 100%.…”

“…Furthermore, they are lower than the ones determined by SILVA et al (2012) in Oxisol similar to this research, which evaluate for ER ≤ 1, in case of P has the need of a SC ≥ 25%. These differences are probably due to higher ER rates obtained by SILVA et al (2012), 2.1 for SC of 0% and 0.5% for SC of 100%, regarding the ones of this research of 1.3 for SC of 0% and 0.4 for SC of 100%. In the specific case of sediment enrichment rate by clay (ERCla), depending on the soil surface coverage by sugarcane residues (SC), the following linear relation was obtained: ERCla = 1.39021 e -0.00788 SC (R 2 = 0.95**).…”

“…In the treatments, the straw was manually distributed across the soil surface, in quantities of 0; 0.16; 0.35; 0.52 and 0.70 kg per plot according to SILVA et al (2012), providing coverage of 0% (SC0), 25% (SC25), 50% (SC50), 75% (SC75) and 100% (SC100), respectively.…”

“…A certain speed is considered the maximum flow velocity. The average flow velocity was established according to SILVA et al (2012), which is given by the product of the maximum speed by an adjustment factor, α = 2/3.…”