Uber den einflub der beschattung auf die nahrstoffversorgung von kaffeekulturen in Costa Rica, aufgezeigt anhand der blattanalyse
In connection with an investigation of the effects of shade upon the nutrient requirements of coffee trees, which was carried out in 1968 and 1969 at the Inter-American Institute of Agricultral Science in Turrialba, Costa Rica, a study was made to seee the variation of the mineral composition (N,P,K,Ca, and Mg) of coffee leaves on single trees, depending on: distance of sampling from the ground, trees with or without fruits, different cardinal points, and different amounts of light received. The results are: (5.1) The mineral composition of coffee leaves is greatly affected by the distance of sampling from the ground. For all minerals under investigation the percentage is lowest in the top of the trees as compared to the point nearest to the ground. (5.2) Leaves of trees with fruits show a higher percentage of Ca and a lower percentage of N,P, and K than those without fruits. For Mg the effect is insignificant. (5.3) In the area of the experiments the cardinal points have no effect upon the mineral composition of the leaves. (5.4) The different amount of light received by leaves of individual trees, according to different self-shade, has a great influence on the percentage of P and K. With full light the percentage is lower than in the shade. The percentage of N, Ca, and Mg shows no significant difference between full light and shade. (5.5) When using leaf analysis, all these factors have to be taken into account and effort have to be made to eliminate them as far as possible by an exact determination of the sampling conditions
| Main Authors: | , , |
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| Format: | biblioteca |
| Published: |
1971
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| Subjects: | CULTIVO, SOMBRA, FISIOLOGIA, NECESIDADES DE NUTRIENTES, ANALISIS DE TEJIDOS, HOJAS, CONTENIDO MINERAL, COSTA RICA, CULTIVO BAJO SOMBRA, |
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| Summary: | In connection with an investigation of the effects of shade upon the nutrient requirements of coffee trees, which was carried out in 1968 and 1969 at the Inter-American Institute of Agricultral Science in Turrialba, Costa Rica, a study was made to seee the variation of the mineral composition (N,P,K,Ca, and Mg) of coffee leaves on single trees, depending on: distance of sampling from the ground, trees with or without fruits, different cardinal points, and different amounts of light received. The results are: (5.1) The mineral composition of coffee leaves is greatly affected by the distance of sampling from the ground. For all minerals under investigation the percentage is lowest in the top of the trees as compared to the point nearest to the ground. (5.2) Leaves of trees with fruits show a higher percentage of Ca and a lower percentage of N,P, and K than those without fruits. For Mg the effect is insignificant. (5.3) In the area of the experiments the cardinal points have no effect upon the mineral composition of the leaves. (5.4) The different amount of light received by leaves of individual trees, according to different self-shade, has a great influence on the percentage of P and K. With full light the percentage is lower than in the shade. The percentage of N, Ca, and Mg shows no significant difference between full light and shade. (5.5) When using leaf analysis, all these factors have to be taken into account and effort have to be made to eliminate them as far as possible by an exact determination of the sampling conditions |
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