Articles
SOIL AMELIORATION FOR APPLE PRODUCTION IN SOUTHERN BRAZIL
Article number
232_26
Pages
193 – 203
Language
Abstract
Soils in the apple growing region of Brazil are acid to strongly acid with high organic matter content, low phosphorus but fairly high potassium availability.
Phosphorus and potassium application, according to soil analysis, and liming of a soil layer of 40 cm to pH 6 are recommended before planting.
The most severe problem in apple nutrition in Brazil is the low calcium uptake into leaves and fruits.
In two experiments the effects of the incorporation of high rates of dolomitic lime into the soil before planting, and of annual applications of dolomitic lime and gypsum in small rates on the soil surface, on soil chemical characteristics, on nutrient uptake by the plants, and on the occurrence of bitter pit and fruit rots were investigated.
Soil pH. effective CEC, and exchangeable Ca and Mg increased and Al decreased with liming while the exchangeable K content remained unaltered.
Gypsum increased Ca but decreased K, Mg, and Al contents of the soil.
The Ca uptake by the plants increased with soil Ca levels, but significantly more with increasing soil Ca/Mg ratio.
The Mg uptake was mainly dependent on the soil Mg level.
Leaf K was decreased by lime and gypsum and leaf Mn decreased by lime and slightly increased by gypsum.
Only gypsum reduced the incidence of bitter pit significantly due to increase of Ca and decrease of K and Mg contents in the fruit flesh and decreased the incidence of fruit rots.
At present the application of lime with a Ca/Mg ratio ≥ 3 is recommended for apple orchards.
The results of these experiments lead to the suggestion to increase the Ca/Mg ratio in the soil at least to 5, with a minimum Ca + Mg level.
In established orchards with a satisfactory pH gypsum may be used to increase this ratio.
Phosphorus and potassium application, according to soil analysis, and liming of a soil layer of 40 cm to pH 6 are recommended before planting.
The most severe problem in apple nutrition in Brazil is the low calcium uptake into leaves and fruits.
In two experiments the effects of the incorporation of high rates of dolomitic lime into the soil before planting, and of annual applications of dolomitic lime and gypsum in small rates on the soil surface, on soil chemical characteristics, on nutrient uptake by the plants, and on the occurrence of bitter pit and fruit rots were investigated.
Soil pH. effective CEC, and exchangeable Ca and Mg increased and Al decreased with liming while the exchangeable K content remained unaltered.
Gypsum increased Ca but decreased K, Mg, and Al contents of the soil.
The Ca uptake by the plants increased with soil Ca levels, but significantly more with increasing soil Ca/Mg ratio.
The Mg uptake was mainly dependent on the soil Mg level.
Leaf K was decreased by lime and gypsum and leaf Mn decreased by lime and slightly increased by gypsum.
Only gypsum reduced the incidence of bitter pit significantly due to increase of Ca and decrease of K and Mg contents in the fruit flesh and decreased the incidence of fruit rots.
At present the application of lime with a Ca/Mg ratio ≥ 3 is recommended for apple orchards.
The results of these experiments lead to the suggestion to increase the Ca/Mg ratio in the soil at least to 5, with a minimum Ca + Mg level.
In established orchards with a satisfactory pH gypsum may be used to increase this ratio.
Authors
F.W.W. Wilms, C. Basso
Keywords
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