Atributos químicos, acúmulo de carbono e nitrogênio e nutrição da cana-de-açúcar orgânica em Latossolo de Cerrado

• Autor(a) principal: Borges, Lurdineide de Araújo Barbosa
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/0013000006c21
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/4198
• topic: Agroecologia; Agricultura orgânica; Macronutrientes; Adubação; Micronutrientes; Agroechology; Organic agriculture; Macronutrients; Fertilizing; Micronutrients; AGRONOMIA::CIENCIA DO SOLO

There were studied attributes related to sugarcane production in the organic cultivation system aiming to evaluate the efficiency of this system. There were evaluated the soil fertility, the nutrition and productivity of sugarcane and the impacts of the production system on the stocks of carbon and nitrogen on soil. There were analyzed the following attributes of soil fertility: organic matter (OM), soil chemical reaction (pH), potential acidity (H+Al), aluminum (Al3+), sulfur (S), cation exchange capacity (CEC), base saturation (V), aluminum saturation (m), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg). In order to establish the crop nutritional status and its productivity: total number and total production of stalks, carbon (C), nitrogen (N) e and C/N ratio of the plants, straw production, production of dry matter and the extraction of P, Ca, Mg, K, Fe, Zn, Cu and Mn. The impact of sugarcane cultivation on the soil was evaluated through the soil density (Sd), content and stocks of carbon and nitrogen on soil. Regarding the fertility and nutritional status of sugarcane it was studied the following chronosequence of cultivated areas in the organic system: Org.0 – area cultivated under conventional system, representing the beginning of the organic system cultivation; Org.2 – area cultivated for 2 years in the organic system; Org.6 – area cultivated for 6 years in the organic system; Org.10 – area cultivated for 10 years in the organic system. There were evaluated also two different situations that may occur in any production system: one area where it occurred an accidental burn, Org.2Q – area cultivated for two years in the organic system with an accidental burn and other area where the sugarcane plantation was grown for twelve years and since then it was not reformed and replanted, being cultivated for ten years in the organic system - Org.10SR. In the study of impact of sugarcane cultivation on soil it was excluded the area Org.6 because the clay content in this area was inferior to the others. One area of native cerrado (CN) was used as reference for the calculated stocks of carbon and nitrogen. The soil (Oxisol), and plant samples, were collected in plantations belonging to Usina Jalles Machado, Goianésia – GO. The design was entirely randomized with five repetitions. The soil was collected in the following depths: 0-5, 5-10, 10-20-, 20-30, 30-40, 40-60, 60-80 and 80-100 cm, December 2010. The vegetal tissue was collected in February 2011. The organic cultivation was found more efficient than the conventional one of sugarcane. There was a rise up on the levels of fertility of the soil and of productivity. The extraction of nutrients of the soil was higher in the organic areas, which require special management of fertilizing to avoid weakening of the soil. Regarding the tillering and productivity, it was verified that in the beginning of the conversion to the organic system, after two years, there was reduction of tillering, however with no compromising of the final productivity of the plantation. The plants cultivated in the organic system absorbed more nutrients than in the conventional system. The soil density reduced highly in the superficial layers. In the organic system the carbon stocks raised considerably in relation to the conventional cultivation.