Water availability to soybean crop as a function of the least limiting water range and evapotranspiration1

Abstract

Irrigation management aimed at optimal production has been based only on the water factor. However, in addition to the water potential of the soil, factors such as soil penetration resistance and soil O2 diffusion rate also affect plant growth and interfere with water absorption, even if moisture is within the available water range. This study aimed at quantifying the least limiting water range and demonstrating its potential in soil and water management in irrigated agriculture. In order to determine the least limiting water range, soil water retention curves and soil resistance to penetration were determined from undisturbed soil samples. The sequential water balance and the reference, crop and real evapotranspiration were determined for a soybean crop season. Soil aeration was the least limiting water range upper limit for soils with bulk density greater than 1.33 Mg m-3, whereas soil resistance to penetration was the lower limit for bulk density higher than 1.43 Mg m-3. The bulk density of the soil studied was 1.35 Mg m-3, indicating 0.37 m3 m-3 of water availability, based on the least limiting water range, which is sufficient to supply the crop evapotranspiration. Irrigation management based on the least limiting water range is more efficient and complete than that based only on available water.

Determinação da Velocidade de Infiltração Básica da água no Neossolo por meio de anéis de concêntricos na área experimental da UFS

“…Cada época recebeu em média um total de 750 mm de água durante o ciclo, somando as chuvas e irrigações. Para Rodrigues et al (2017), a lâmina ideal para o ciclo da soja está entre 450 a 850 mm. Dallacort et al (2011), observaram que em setembro ocorre o início das chuvas e como característica principal elas ocorrem com grande variabilidade, justificando o déficit na fase inicial da cultura da soja, sendo recomendado o uso da irrigação para o desenvolvimento da cultura, para a segunda época a semeadura foi realizada em condições ideais de umidade do solo, mas a ocorrência de um veranico no decêndio 29 proporcionou um déficit.…”

An Innovative Land Suitability Method to Assess the Potential for the Introduction of a New Crop at a Regional Level

“…By using the regional soil database, the Soil Typological Units (STUs) of the area were distributed into three suitability classes for soybean production, according to the agronomic constraints for soybean. Three agronomic constraints were considered based on the literature and local expert knowledge (Table 1): iron deficiency chlorosis [41], harvest quality loss and hydric stress [42]. For summer crops under Oise climatic conditions these constraints were correlated to a high carbonate content (>15%), a high stone/gravel abundance (>15%) and a low soil-available water capacity (<100 mm).…”

Concordance Modeling With a Gold Standard for Variables From the Three-Parameter Gamma Distribution

“…In soybean culture, water availability is important, especially, during two development stages: germination-emergence and flowering-grain filling. (Rodrigues et al, 2017).…”