ABSTRACT The mechanized harvesting process of sugarcane seedlings affects the mechanized planting operation in the sense that straw adhered to the billet can reduce the quantity of non-viable gems obtained as a result of mechanical damage sustained during the mechanized operation. This study proposes a method to improve the quality of the implantation of sugarcane crop by prevention of damages caused mainly during October/November, when adverse climatic conditions of higher water stresses and high temperatures exist. The objective of this study is to evaluate the quality of the sugarcane planting operation using seedlings with and without straw, distributed by planters and distributors of chopped sugarcane, and comparing their performance to that of semi-mechanized planting. The study was conducted at Fazenda Santa Clara, located in Pradópolis - São Paulo, Brazil and considered five processes: mechanized planting of seedlings without straw, mechanized planting of seedlings with straw, mechanized distribution of seedlings without straw, mechanized distribution of seedlings with straw, and semi-mechanized planting. Fifty sample points were used to collect data for each process, as per the principles of Statistical Process Control. The number of unfeasible gems and faults in the stand reduced with the presence of straw in the grinding wheel, in addition to less variability being presented. The presence of straw in the billet enabled the best overall quality of sugarcane plantation.

RESUMO Entre os fatores que podem influenciar a produtividade do milho estão o sentido da operação de semeadura e a população de plantas, pois esses alteram o índice de sombreamento entre as linhas da cultura, e consequentemente a eficiência da interceptação da radiação fotossinteticamente ativa pelas folhas das plantas. Teve-se por objetivo nesse estudo avaliar a influência do sentido de semeadura e populações de plantas sobre a produtividade do híbrido de milho P2830VYH. O experimento foi conduzido em área da FCAV–UNESP, à latitude de 21º 14’ S e longitude 48º 16’ W no município de Jaboticabal (SP). Os tratamentos estudados foram compostos por três direções de semeadura (Norte-Sul; Nordeste-Sudoeste; e Leste-Oeste) e três densidades populacionais (40.000; 60.000; e 80.000 plantas ha-1). A lavoura com 80.000 plantas ha-1 apresentou o menor custo por saca de milho, e lucratividade 21% maior que o tratamento de 60.000 plantas ha-1, e 45% maior que o tratamento de 40.000 plantas ha-1. O sentido da semeadura não exerceu influência sobre a produtividade de grãos quando as condições ambientais foram favoráveis ao desenvolvimento da lavoura. Menores densidades de plantas apresentam maiores resultados individuais em relação ao número de espigas, comprimento de espigas e número de grãos por fileira.

ABSTRACT Among the factors that may influence corn yield are sowing operation direction and plant population, since they alter the shade index between crop rows, and consequently the efficiency of interception of the photosynthetically active radiation by the leaves of plants. The aim of this study was to evaluate the influence of sowing direction and plant populations on P2830VYH hybrid corn yield. The experiment was conducted at the facilities of FCAV-UNESP, latitude 21º 14’ S and longitude 48º 16’ W in Jaboticabal (SP). The treatments were composed of three sowing directions (North-South, Northeast-Southwest, and East-West) and three population densities (40,000, 60,000 and 80,000 plants ha-1). The treatment with 80,000 plants ha-1 had the lowest cost per sack of corn and profitability 21% higher than that of the treatment with 60,000 plants ha-1, and 45% higher than that of the treatment with 40,000 plants ha-1. Sowing direction had no influence on grain yield when environmental conditions were favorable to the development of the crop. Lower plant densities lead to higher individual results in relation to the number of cobs, length of cobs and number of grains per row.