A carregar...
Publicação
Estado da fertilidade do solo e da nutrição das principais culturas em Ribeira dos Picos (Cabo Verde)
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 3.01 MB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
A agricultura é um setor de primordial importância no desenvolvimento de Cabo Verde. Estratégias de fertilização que conduzam a um bom estado nutricional das culturas e promovam a sua produtividade são fundamentais para o crescimento do setor agrícola. Neste estudo, realizou-se um levantamento da fertilidade do solo e do estado nutricional de diversas culturas importantes para a economia do país, num trabalho de campo realizado em Ribeira dos Picos, na ilha de Santiago. As culturas incluídas no estudo foram pimentão (Capsicum annuum L.), tomateiro (Solanum lycopersicum L.), bananeira (Musa paradisíaca L.), cana-de-açúcar (Saccharum officinarum L.), papaeira (Carica papaya L.), mandioqueira (Manihot esculenta Crantz) e mangueira (Mangifera indica L.). O número de parcelas amostradas variou conforme a espécie. Tomateiro, mangueira, mandioqueira e cana-de-açúcar foram amostrados apenas numa parcela, enquanto a bananeira foi amostrada em dezasseis. No processo de amostragem, colheram-se folhas das culturas e solos na zona de influência das suas copas, permitindo estabelecer a relação entre a nutrição das plantas e as propriedades do solo. Em termos gerais, os solos apresentaram tendência para teores baixos de matéria orgânica, pH alcalino, teores elevados de fósforo (P) e potássio (K), bem como níveis elevados de sódio (Na) no complexo de troca. Todas estas características são típicas de solos de origem vulcânica em regiões áridas e semiáridas. O estado nutricional azotado das culturas variou entre adequado e deficiente, refletindo situações com e sem aplicação de fertilizantes. Os teores de P nas folhas seguiram tendência semelhante ao azoto (N). A bananeira, por exemplo, apresentou teores baixos de N e P nas folhas. Ainda que os solos apresentassem teores elevados de K, algumas espécies não exibiram níveis elevados nas folhas, possivelmente devido a antagonismo iónico com o Na ou à extrema secura do solo, dificultando a absorção. Cálcio (Ca) e magnésio (Mg), embora tenham surgido em níveis baixos no complexo de troca, mostraram níveis tendencialmente adequados nas folhas, parecendo não representar um problema relevante na nutrição das espécies analisadas. O boro (B) apresentou-se em níveis elevados ou mesmo excessivos. Entre os micronutrientes catiónicos, o zinco (Zn) mostrou tendência à deficiência, revelando-se como um possível problema nutricional das culturas. Embora este estudo tenha incluído um número reduzido de parcelas, a diversidade de resultados obtidos sugere que a definição de estratégias de fertilização para este território é complexa e que se beneficiaria significativamente de estudos complementares, incluindo ensaios de resposta das plantas a diferentes estratégias de fertilização.
Agriculture is a sector of paramount importance for the development of Cabo Verde. Fertilization strategies that ensure adequate plant nutrition and promote crop productivity are fundamental for the growth of the agricultural sector. In this study, the fertility of the soil and the nutritional status of several crops important to the national economy were assessed in a field survey conducted in Ribeira dos Picos, on the island of Santiago. The crops included in the study were bell pepper (Capsicum annuum L.), tomato (Solanum lycopersicum L.), banana (Musa × paradisíaca L.), sugarcane (Saccharum officinarum L.), papaya (Carica papaya L.), cassava (Manihot esculenta Crantz), and mango (Mangifera indica L.). The number of sampled plots varied by species: tomato, mango, cassava, and sugarcane were sampled in only one plot, whereas banana was sampled in sixteen plots. During sampling, leaves from the crops and soils within the influence zone of their canopies were collected to allow the establishment of relationships between plant nutrition and soil properties. In general terms, the soils tended to exhibit low organic matter content, alkaline pH, high phosphorus (P) and potassium (K) levels, as well as elevated sodium (Na) in the cation exchange complex. These characteristics are typical of volcanic soils in arid and semi-arid regions. The nitrogen (N) nutritional status of the crops ranged from adequate to deficient, reflecting situations with and without fertilizer application. Leaf P levels followed a similar trend to N. For instance, banana showed low levels of both N and P in its leaves. Although soils exhibited high K levels, some species did not show elevated leaf K concentration, possibly due to ionic antagonism with Na or extreme soil dryness, which limited nutrient uptake. Calcium (Ca) and magnesium (Mg), although low in the cation exchange complex, were generally adequate in the leaves, appearing not to constitute a significant limitation to the nutrition of the studied species. Boron (B) was generally present at high or even excessive levels. Among cationic micronutrients, zinc (Zn) tended to be deficient, suggesting it may represent a potential nutritional constraint for the crops. Although this study included a limited number of plots, the diversity of results obtained suggests that defining fertilization strategies for this territory is complex and would greatly benefit from complementary studies, including trials assessing plant responses to different fertilization strategies.
Agriculture is a sector of paramount importance for the development of Cabo Verde. Fertilization strategies that ensure adequate plant nutrition and promote crop productivity are fundamental for the growth of the agricultural sector. In this study, the fertility of the soil and the nutritional status of several crops important to the national economy were assessed in a field survey conducted in Ribeira dos Picos, on the island of Santiago. The crops included in the study were bell pepper (Capsicum annuum L.), tomato (Solanum lycopersicum L.), banana (Musa × paradisíaca L.), sugarcane (Saccharum officinarum L.), papaya (Carica papaya L.), cassava (Manihot esculenta Crantz), and mango (Mangifera indica L.). The number of sampled plots varied by species: tomato, mango, cassava, and sugarcane were sampled in only one plot, whereas banana was sampled in sixteen plots. During sampling, leaves from the crops and soils within the influence zone of their canopies were collected to allow the establishment of relationships between plant nutrition and soil properties. In general terms, the soils tended to exhibit low organic matter content, alkaline pH, high phosphorus (P) and potassium (K) levels, as well as elevated sodium (Na) in the cation exchange complex. These characteristics are typical of volcanic soils in arid and semi-arid regions. The nitrogen (N) nutritional status of the crops ranged from adequate to deficient, reflecting situations with and without fertilizer application. Leaf P levels followed a similar trend to N. For instance, banana showed low levels of both N and P in its leaves. Although soils exhibited high K levels, some species did not show elevated leaf K concentration, possibly due to ionic antagonism with Na or extreme soil dryness, which limited nutrient uptake. Calcium (Ca) and magnesium (Mg), although low in the cation exchange complex, were generally adequate in the leaves, appearing not to constitute a significant limitation to the nutrition of the studied species. Boron (B) was generally present at high or even excessive levels. Among cationic micronutrients, zinc (Zn) tended to be deficient, suggesting it may represent a potential nutritional constraint for the crops. Although this study included a limited number of plots, the diversity of results obtained suggests that defining fertilization strategies for this territory is complex and would greatly benefit from complementary studies, including trials assessing plant responses to different fertilization strategies.
Descrição
Palavras-chave
Fertilidade do solo Estado nutricional das culturas Solos vulcânicos alcalinos Sodicidade Antagonismo iónico Cabo Verde