Effect of Crop Residues Management on Soil Fertility and Sugar Beet Productivity in Western Morocco

Abstract

The competitiveness of sugar beet in the Doukkala irrigated perimeter makes this crop the main one compared to wheat, vegetables and forage. However, the dominance of small plots drives farmers to practice 2 to 3 years rotation of sugar beet. This work, carried out on contrasting and representative soils between 2012 and 2019, aims to study the effects of sugar beet residues incorporation on the soil organic matter, soil properties, and sugar beet root yield and sugar content under reel field conditions and actual rotation system. The results showed that the rate of soil organic matter (SOM) increased by +28.8% during eight agricultural seasons. Plots that never received crops residues experienced an average decrease in SOM rate of -19%. The maximum average increase in the SOM rate of +194% was observed at the level of the plots, where sugar beet residues were incorporated six times. This variation in SOM is more marked in coarse-textured soils. The variations of Mg, K, P, Ca, Zn, B, CaCO 3, soil pH, CEC are positively correlated with statistical significance with SOM variation. The multiple linear regression model for predicting the variation in SOM content, depending on soil texture, initial SOM content and number of residue incorporations, with (R 2 = 0.81, RMSE = 26.15) shows that this variation is significantly favored by coarse soil elements and the number of residues incorporation and that it is unfavorable in soils with a dominant fine texture and initially rich in organic matter. Yield and sugar content were improved by 31% (67,45 Mg•ha -1 in 2012 and 86,38 Mg•ha -1 in 2019) for root yield and by 4% (16.68% in 2012 and 17,37% in 2019) for sugar content in plots with six residues incorporations. Data from this study suggest that the use of sugar beet residues is benefical for improving soil properties and thus increasing soil organic status and crop performances.

Occurrence of <i>Sclerotium rolfsii</i> Inducing Sugar Beet Root Rot and its Sustainable Management by Acting on Soil Fertility in Western Morocco

“…Since of the humification of sugar beet wastes, there may be a drop in the soil Fe and Cu concentrations because these ions bind to humic compounds. Due to low level of humification of sugar beet residues, this slight drop can be explained (Rerhou et al 2022) who found an increase in SOM content of DIP between 2012 and 2019 accompanied by a slight decrease in the soil content of Fe and Cu. This finding supports laboratory research by Vizier (1978) that demonstrated the ability of humic and fulvic acids to form complexes with iron in amounts ranging 2019) demonstrated a strong correlation between total carbon losses and, to a lesser extent, iron losses, and the rate at which humified material is extracted.It appears that these losses are all the more important as the organic matter is more humified.…”