CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / HÃ vÃrias formas de se cultivar o solo e a escolha de um determinado modelo vai depender dos fatores ambientais e dos objetivos da exploraÃÃo. Para se avaliar a influÃncia dos sistemas de exploraÃÃo agrÃcola (SE) â orgÃnico (SO) e convencional (SC) â em cana-de-aÃÃcar, foi conduzida, na Unidade Agroindustrial da YpiÃca, localizada no municÃpio de Pindoretama-CE, uma pesquisa de campo utilizando-se as variedades (V) CB38-22 (CB), RB72454 (RB) e SP71-6949 (SP). Os tratamentos constaram da combinaÃÃo de trÃs V com trÃs SE: orgÃnica acrescida do coquetel de sementes (OCS); orgÃnica acrescida do plantio de feijÃo-de-corda (cv. Epace 10) entre as linhas (OE10) e plantio convencional (SC). O delineamento experimental foi o inteiramente casualizado com quatro repetiÃÃes. As avaliaÃÃes agronÃmica e industrial foram feitas em marÃo de 2005, na primeira soca. Foram determinados os valores da Ãrea foliar (AF), do Ãndice de Ãrea foliar (IAF) e do diÃmetro (DC), nÃmero (NC), comprimento (CC) e produtividade de colmos (RC). Para a anÃlise de Brix, POL e Pureza, foram colhidos dez colmos de cada parcela e extraÃdo o caldo para anÃlise em laboratÃrio. Os SE diferiram estatisticamente entre si para as variÃveis: AF, IAF e NC. Os maiores valores de AF e IAF foram obtidos nos SO (OCS e OE10). JÃ o maior NC foi obtido no tratamento OCS. Com relaÃÃo Ãs V, apenas as variÃveis AF e IAF nÃo diferiram estatisticamente. NÃo se observaram diferenÃas estatÃsticas para as interaÃÃes entre V e SE nas diversas variÃveis estudadas. Os melhores rendimentos de colmos foram obtidos nas V RB (41,1 t/ha) e SP (38,2 t/ha), contra 29,0 t/ha na CB. A variÃvel DC foi a que mais contribuiu para o RC das V. Constatou-se, tambÃm, uma relaÃÃo positiva entre CC e DC. Com relaÃÃo Ãs variÃveis industriais, observaram-se diferenÃas estatÃsticas para POL e Pureza entre os SE e POL entre V. JÃ o Brix nÃo sofreu quaisquer influÃncias de V e SE. Assim como para as variÃveis agronÃmicas, tambÃm nÃo se verificaram interaÃÃes estatisticamente significativas entre SE e V para as industriais. O SC apresentou o maior POL (14,21%) e, entre V, o maior valor de POL foi obtido na RB. Os maiores valores de Pureza, 71, 52 e 69,14%, foram obtidos nos sistemas SC e OCS, respectivamente. / There are some forms of cultivating the soil and the choice of a determined form depends on the environment conditions and on the aim of the exploration. To evaluate the influence of the agricultural exploration systems (EA) â ornanic systems (OS) e conventional systems (CS) â in sugar cane crop, it was lead, in the YpiÃca Agro-industry, in the city of Pindoretama - CE, a field research by using varieties (V) CB38-22 (CB), RB72454 (RB) and SP71-6949 (SP). The treatments consisted of the combination of three V with three EA: organic increased of seed cocktail (OSC); organic increased of the cowpea plantation (cv. Epace 10) between the lines (OE10) and conventional plantation (CS). The experimental delineation was completely randomized with four repetitions. Agronomic and industrial evaluations were made in March of 2005, in the first beat. Foliar area values (FA), foliar area index (FAI) and diameter (DC), number (NC), length (CC), and productivity of stalks (RC) were determined. For Brix, POL, and Purity analysis, ten stalks of each parcel were harvested and the broth extracted to be examined in laboratory. EA differed statistically one from another for the variables: AF, IAF and NC. The biggest FA and FAI values were gotten from OS (OSC e OE10). The biggest NC was gotten in the treatment OSC. Relating to V, only variables FA and FAI did not differ statistically. Statistical differences were not observed for interaction between V and EA. The best stalk profits were gotten from V RB (41, t/ha) and SP (38,2 t/ha), against 29,0 t/ha in the CB. The variable DC was the one that most contributed to the RC of the V. It was also evidenced a positive relation between CC and DC. Concerning the industrial variable, statistical differences for POL and purity between EA and POL between V were observed. On the other hand, the Brix did not suffer any influences from V and EA. For the agronomic variables it were not verified any statistically significant interactions between EA and V, as well as for the industrial variables. The CS presented the biggest POL (14,21%) and, between V, the highest value of POL was gotten in the RB. The highest values of Purity, 71, 52 and 69, 14%, were gotten in systems CS and SCO, respectively.