1) The study assessed the effect of mechanical shaking time on clay-dispersible water levels in a Red Dystroferric Latosol under different crop rotations. 2) Soil samples from six crop rotations were shaken for either 2 hours or 16 hours, and clay-dispersible water and flocculation levels were measured. 3) Crop rotations of maize-maize and maize-oats had lower negative charge and higher zero point of charge, resulting in higher clay flocculation and aggregation even at normal soil pH levels.

1. Clay-dispersible water of a Latosol in Direct Drilling System affected by time of mechanical
shaking and crop rotation
Henrique Hiroki Yamada¹, Cezar F. Araujo-Junior², Vinicius C. Sambatti³,
João H. Vieira de Almeida Junior⁴, Paulo César Cardoso⁵
¹Scientific Initiation at IAPAR, PIBIC/CNPq /, E-mail: henriquehiroki@gmail.com; ²Researcher at IAPAR, Soils Area, Professor and Adviser in the Graduate Programme in
Conservation Agriculture. email address: cezar_araujo@iapar.br; ³Agronomic Institute of the State of Paraná – IAPAR, Post Graduate Programme in Conservation Agriculture.
This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. Email: viniciussambatti@hotmail.com;
⁴Scientific Initiation at IAPAR, PIBIC/CNPq / Agronomy student at State University of Londrina – UEL, E-mail address: junioribipa151@gmail.com; ⁵Former researcher at
IAPAR, Crop Science Area. E-mail: cardosopc1621@gmail.com
5th Brazilian Soil Physics Meeting
May 26 – 29, 2019 – Lavras, MG
Sponsors
Achievement Suport
Introduction
Clay-dispersible water - CDW is a physical property related to
electrochemical properties and required to modeling water erosion.
The time of shaking soil samples might affect the results and
misleading interpretation. In this context, the aim of this study was to
assess the time effect of shaking of soil samples on clay-dispersible
water of a Red Dystroferric Latosol.
Methods
The study was carried out at Experimental Station of
Agricultural Research Institute of the State of Paraná – IAPAR (23 °
22 '11' 'S south latitude and 51 ° 10' 84 '' longitude west), at an altitude
of 574 m above sea level, at Londrina County, State of Paraná, and
Southern Brazil. The experiment was installed in October of the year
2012 in a randomized block design, with eighteen treatments (3
summer and 6 winter crops) and three replications. However, for this
study six crop rotation were selected to assess the time effect of
mechanical shaking behavior.
Table 1 - Treatments and their respective crop rotations.
In September 2018, soil samples were collected in layers 0–10
cm and 10–20 cm depth for the physical characterization (total
dispersion, clay-dispersible water with 2 h and 16 h of mechanical
shaking) and soil electrochemistry (pH in potassium chloride, pH in
water, delta pH, Zero Load Point (PCZ).
Results and Discussion
Conclusion
Among the treatments it was observed that T11 - Maize / Maize
and T12 - Maize / oats provided lower amounts of net negative charge
and higher PCZ, values of 4.3 and 4.4, respectively, which may provide
higher flocculation of the clay fraction in the pH values of cultivated
soils and favor the process of aggregation of the soil.
Aknowledgments
Thanks for Conselho Nacional de Desenvolvimento Científico e
Tecnológico (CNPq) and Agronomic Institute of Paraná (IAPAR).
Treatments Summer crops Winter crops
1 Soybean Black Oat
3 Soybean Maize
6 Soybean Safflower
7 Maize Safflower
11 Maize Maize
12 Maize Black Oat
GRANULOMETRIC COMPOSITION
CLAY
CONTENT
AND
CLAY
DISPERSIBLE
WATER,
dag
kg
-1
0
20
40
60
80
100
DEGREE
OF
FLOCCULATION,
%
0
20
40
60
80
100
AT ADA 2h GF 2h ADA 16h GF 16h
27 dag/kg
45 dag/kg
67 %
44 %
81 dag/kg
Iapar Londrina | Projeto Agroenergia | Sampling: September 2018 | LVdf: 0–10 cm
Iapar Londrina | Projeto Agroenergia | Sampling: September 2018 | LVdf: 10–20 cm
GRANULOMETRIC COMPOSITION
CLAY
CONTENT
AND
CLAY
DISPERSIBLE
WATER,
dag
kg
-1
0
20
40
60
80
100
DEGREE
OF
FLOCCULATION,
%
0
20
40
60
80
100
AT ADA 2h GF 2h ADA 16h GF 16h
30 dag/kg
49 dag/kg
63 %
39 %
81 dag/kg