Surface drainage in leveled land: Implication of slope

Abstract

A B S T R A C TIn the lowlands of Rio Grande do Sul, land leveling is mostly carried out with no slope for the purpose of rice production. In this environment, soils with a low hydraulic conductivity are predominant owing to the presence of a practically impermeable B-horizon near the surface. Land leveling leads to soil accommodation resulting in the formation of depressions where water accumulates after heavy rainfalls, subsequently leading to problems with crops implanted in succession to rice, such as soybeans. The objective of this research was to quantify the areas and volumes of water accumulation in soil as a function of the slope of land leveling. Five typical leveled lowland areas were studied as a part of this research. The original areas presented slopes of 0, 0.20, 0.25, 0.28 and 0.40%, which were used to generate new digital elevation models with slopes between 0 and 0.5%. These newly generated digital models were used to map the depressions with surface water storage. In conclusion, land leveling with slopes higher than 0.1% is recommended to minimize problems with superficial water storage in rice fields.Drenagem superficial em área sistematizada: Implicação da declividade R E S U M O Nas terras baixas do Rio Grande do Sul, a sistematização é realizada, na maioria das vezes, sem declividade com o objetivo de cultivar arroz. Neste ambiente, são predominantes solos com baixa condutividade hidráulica devido à presença de um horizonte B, praticamente impermeável, perto da superfície. Depois da sistematização, por causa da acomodação do solo são formadas depressões onde se acumula água após a ocorrência de fortes chuvas, causando problemas nas culturas implantadas em sucessão ao arroz, como é o caso da soja. Objetivou-se neste trabalho quantificar áreas e volumes de acumulação de água, em função da declividade da sistematização. Foram estudadas cinco áreas sistematizadas típicas de terras baixas. As áreas originais apresentaram declividades de 0, 0,20, 0,25, 0,28 e 0,40%, sendo que a partir delas foram gerados os novos modelos digitais de elevação com declividades entre 0 e 0,5%. Através dos novos modelos gerados foram mapeadas as depressões com armazenamento superficial de água. A sistematização com declividades maiores que 0,1% são recomendadas para minimizar problemas com armazenamento superficial de água em áreas cultivadas com arroz.

Land gradient and configuration effects on yield, irrigation amount and irrigation water productivity in rice-wheat and maize-wheat cropping systems in Eastern India

“…In a simulation study using the WinSRFR and POZAL models to optimize basin irrigation design, González et al (2011) found a 20% reduction in irrigation amount for rice with a gradient of 0.04% in comparison with 0% gradient in 200 m x 50 m plots with a flow rate of 100 l s −1 . In a similar study in Brazil, Winkler et al (2018) compared 0%, 0.20%, 0.25%, 0.28% and 0.40% gradients on the flat for rice. They recommended using >0.1% gradient to improve drainage and soil drying, and thus ability to establish the next (upland) crop after rice harvest.…”

Effect of Leveling and Tillage Equipment on Soil Bulk Density and Yield of Maize

“…Leveling and amending the soil surface leads to improving the productivity and efficiency of irrigation, whether it is from traditional or modern methods, by conducting the laser leveling process, as it saves 15-30% of water, also increases water use efficiency, improves crop productivity and reduces irrigation time, (Das and Chalodia 2018;Winkler et al, 2018). On the other hand, the multiplicity of soil types, different climatic conditions, and different crops have created many types of equipment for soil preparation (Jasim and Saadoon, 2020).…”