Abstract
The proper use of potassium fertilizer can stimulate a significant yield increase. However, the application of excessively high rates of potassium can reduce the availability of soil calcium for apple trees. The potassium fertigation rate must meet the apple tree's requirements so that the applied fertilizers can be absorbed by the roots as much as possible. Crop load in apple orchards sometimes varies significantly in different years. The potassium content in apple fruits is relatively high, and the maximum requirement for this nutrient occurs when fruits grow and ripen. Different crop loads at that time mean the various demands of trees and need for changing application rates for this nutrient. The investigation was carried out in the experimental orchard of I.V. Michurin Federal Scientific Centre (Michurinsk, Russia) in 2016 and 2017 (52.885131, 40.465613). We studied seasonal changes of potassium and calcium contents in soil, fruits, and leaves and their relationship with yield during the research. We paid much attention to the potassium rate shift on its content in leaves and fruits and cultivars "Lobo" and "Zhigulevskoye" yield. If the potassium application rate changes according to the actual crop load, it stimulates the yield growth or (if the crop load was relatively low) the reduction of the rate did not lower the productivity. Moreover, we studied the relationship between potassium and calcium nutrition. The decrease in potassium fertigation rate increased the availability of soil calcium. It was the reason for fruit calcium concentration enlargement and mitigation of the K/Ca ratio. We also specified some parameters for soil-leaf diagnosis for potassium nutrition during the growing season.
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Claims 6
Claim · model-written summary
Adjusting potassium application to crop load stimulated apple yield growth.
- Taxon
- Apple Tree
Malus domesticat0 - Treatment
- potassium application rate changes according to the actual crop loade0
- Outcome
- yield growthe0
- Direction
- growthe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“If the potassium application rate changes according to the actual crop load, it stimulates the yield growth”
t0“Apple Tree (Malus domestica Borkh.)”
Claim · model-written summary
Reducing the potassium rate at low crop load did not lower productivity.
- Taxon
- Apple TreeMalus domesticat0
- Treatment
- reduction of the ratee0
- Outcome
- productivitye0
- Direction
- did not lowere0
- Qualifier
- crop load was relatively lowe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“if the crop load was relatively low) the reduction of the rate did not lower the productivity”
t0“Apple Tree (Malus domestica Borkh.)”
Claim · model-written summary
Decreased potassium fertigation increased soil calcium availability.
- Taxon
- Apple TreeMalus domesticat0
- Treatment
- decrease in potassium fertigation ratee0
- Outcome
- availability of soil calciume0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in potassium fertigation rate increased the availability of soil calcium”
t0“Apple Tree (Malus domestica Borkh.)”
Claim · model-written summary
Decreased potassium fertigation enlarged fruit calcium concentration.
- Taxon
- Apple TreeMalus domesticat0
- Organ / stage
- fruite0
- Treatment
- decrease in potassium fertigation ratee0
- Outcome
- fruit calcium concentratione0
- Direction
- enlargemente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in potassium fertigation rate increased the availability of soil calcium. It was the reason for fruit calcium concentration enlargement”
t0“Apple Tree (Malus domestica Borkh.)”
Claim · model-written summary
Decreased potassium fertigation mitigated the fruit K/Ca ratio.
- Taxon
- Apple TreeMalus domesticat0
- Treatment
- decrease in potassium fertigation ratee0
- Outcome
- K/Ca ratioe0
- Direction
- mitigatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decrease in potassium fertigation rate increased the availability of soil calcium. It was the reason for fruit calcium concentration enlargement and mitigation of the K/Ca ratio”
t0“Apple Tree (Malus domestica Borkh.)”
Claim · model-written summary
The study specified soil-leaf diagnostic parameters for potassium nutrition.
- Taxon
- Apple TreeMalus domesticat0
- Outcome
- soil-leaf diagnosis for potassium nutritione0
Not reportedComparatorValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We also specified some parameters for soil-leaf diagnosis for potassium nutrition during the growing season”
t0“Apple Tree (Malus domestica Borkh.)”
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