Abstract
Rice is a staple food for about 50 percent of the world’s population. Potassium (K) is absorbed in large amounts by rice plants and adequate amounts of this element are fundamental to improve productivity and maintain sustainability of the cropping systems. A greenhouse experiment was conducted to determine the adequate rate of K for lowland rice grown on a Brazilian Inceptisol. The K rates used were 0, 50, 100, 200, 400, and 600 mg K kg−1 soil. Most of the growth, yield, and yield components were significantly and quadratically increased with increasing K levels. Based on a quadratic equation, maximum grain yield was obtained with the addition of 371 mg K kg−1 soil. Maximum plant height and shoot dry weight were obtained at 414 and 398 mg K kg−1 soil, respectively. Root growth (maximum length and dry weight) was also significantly increased in a quadratic fashion with the increasing K rate in the growth medium. Maximum root length was achieved at 58 mg K kg−1 whereas maximum root dry weight was obtained with the addition of 394 mg K kg−1 soil. Plant height, shoot dry weight, 1000-grain weight, root length, and root dry weight were significantly associated with grain yield. Hence, manipulation of these growth and yield components with the addition of K fertilizer can improve yield of lowland rice in varzea soils of central part of Brazil. Potassium uptake increased significantly in a quadratic fashion with increasing K rate. However, K-use efficiency (mg grain per mg K applied) decreased significantly with increasing K rate in a quadratic fashion. Maximum grain yield was obtained with 117 mg kg−1 Mehlich 1–extractable K, base saturation of 53 percent, Mg saturation of 9 percent, K saturation of 2 percent, and Ca/Mg ratio of 4.
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Claims 15
Claim · model-written summary
Increasing K levels significantly and quadratically increased growth, yield and yield components of lowland rice in a greenhouse.
- Taxon
- Lowland Ricet0
- Treatment
- increasing K levelse1
- Outcome
- growth, yield, and yield componentse1
- Direction
- increasede1
- Setting
- greenhousee0
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e0“A greenhouse experiment was conducted to determine the adequate rate of K for lowland rice grown on a Brazilian Inceptisol”
e1“Most of the growth, yield, and yield components were significantly and quadratically increased with increasing K levels”
Claim · model-written summary
Maximum grain yield of lowland rice was obtained with addition of 371 mg K kg−1 soil.
- Taxon
- Lowland Ricet0
- Treatment
- addition of 371 mg K kg−1 soile2
- Outcome
- grain yielde2
- Direction
- maximume2
- Value
- 371 mg K kg−1 soile2
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e2“Based on a quadratic equation, maximum grain yield was obtained with the addition of 371 mg K kg−1 soil”
Claim · model-written summary
Maximum plant height of lowland rice was obtained at 414 mg K kg−1 soil.
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e3“Maximum plant height and shoot dry weight were obtained at 414 and 398 mg K kg−1 soil, respectively”
Claim · model-written summary
Maximum shoot dry weight of lowland rice was obtained at 398 mg K kg−1 soil.
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e3“Maximum plant height and shoot dry weight were obtained at 414 and 398 mg K kg−1 soil, respectively”
Claim · model-written summary
Maximum root length of lowland rice was achieved at 58 mg K kg−1.
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e4“Maximum root length was achieved at 58 mg K kg−1 whereas maximum root dry weight was obtained with the addition of 394 mg K kg−1 soil”
Claim · model-written summary
Maximum root dry weight of lowland rice was obtained with addition of 394 mg K kg−1 soil.
- Taxon
- Lowland Ricet0
- Treatment
- addition of 394 mg K kg−1 soile4
- Outcome
- root dry weighte4
- Direction
- maximume4
- Value
- 394 mg K kg−1 soile4
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e4“Maximum root length was achieved at 58 mg K kg−1 whereas maximum root dry weight was obtained with the addition of 394 mg K kg−1 soil”
Claim · model-written summary
Root growth of lowland rice increased significantly in a quadratic fashion with increasing K rate.
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e5“Root growth (maximum length and dry weight) was also significantly increased in a quadratic fashion with the increasing K rate in the growth medium”
Claim · model-written summary
Plant height, shoot dry weight, 1000-grain weight, root length and root dry weight were significantly associated with grain yield of lowland rice.
Verbatim
t0“Potassium Requirements of Lowland Rice”
e6“Plant height, shoot dry weight, 1000-grain weight, root length, and root dry weight were significantly associated with grain yield”
Claim · model-written summary
Potassium uptake of lowland rice increased significantly in a quadratic fashion with increasing K rate.
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e7“Potassium uptake increased significantly in a quadratic fashion with increasing K rate”
Claim · model-written summary
K-use efficiency of lowland rice decreased significantly with increasing K rate.
Not reportedComparator
Verbatim
t0“Potassium Requirements of Lowland Rice”
e1“K-use efficiency (mg grain per mg K applied) decreased significantly with increasing K rate in a quadratic fashion”
Claim · model-written summary
Maximum grain yield of lowland rice was obtained with 117 mg kg−1 Mehlich 1–extractable K in soil.
Verbatim
t0“Potassium Requirements of Lowland Rice”
e2“Maximum grain yield was obtained with 117 mg kg−1 Mehlich 1–extractable K, base saturation of 53 percent, Mg saturation of 9 percent, K saturation of 2 percent, and Ca/Mg ratio of 4”
Claim · model-written summary
Maximum grain yield of lowland rice was obtained at 53 percent base saturation.
Verbatim
t0“Potassium Requirements of Lowland Rice”
e2“Maximum grain yield was obtained with 117 mg kg−1 Mehlich 1–extractable K, base saturation of 53 percent, Mg saturation of 9 percent, K saturation of 2 percent, and Ca/Mg ratio of 4”
Claim · model-written summary
Maximum grain yield of lowland rice was obtained at 9 percent Mg saturation.
Verbatim
t0“Potassium Requirements of Lowland Rice”
e2“Maximum grain yield was obtained with 117 mg kg−1 Mehlich 1–extractable K, base saturation of 53 percent, Mg saturation of 9 percent, K saturation of 2 percent, and Ca/Mg ratio of 4”
Claim · model-written summary
Maximum grain yield of lowland rice was obtained at 2 percent K saturation.
Verbatim
t0“Potassium Requirements of Lowland Rice”
e2“Maximum grain yield was obtained with 117 mg kg−1 Mehlich 1–extractable K, base saturation of 53 percent, Mg saturation of 9 percent, K saturation of 2 percent, and Ca/Mg ratio of 4”
Claim · model-written summary
Maximum grain yield of lowland rice was obtained at a Ca/Mg ratio of 4.
Verbatim
t0“Potassium Requirements of Lowland Rice”
e2“Maximum grain yield was obtained with 117 mg kg−1 Mehlich 1–extractable K, base saturation of 53 percent, Mg saturation of 9 percent, K saturation of 2 percent, and Ca/Mg ratio of 4”
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