Francisca Gislene Albano

Planting spacing and NK fertilizing on physiological indexes and fruit production of papaya under semiarid climate

The nutritional requirements of papaya (Carica papaya L.) increase continuously throughout the crop cycle, especially for potassium and nitrogen, which are the most required nutrients and act on plant vital functions such as photosynthetic activity, respiration, transpiration and stomatal regulation. An experiment was conducted from November 2010 to December 2012 to evaluate physiological indexes and fruit production of papaya cv. Caliman-01 as a function of planting spacing and NK fertilizing. The experimental design consisted of randomized blocks, with treatments distributed in a factorial arrangement (2 × 4 × 4), using 2 planting spacing [simple rows (3.8 × 2.0 m) and double rows (3.8 × 2.0 × 1.8 m)], 4 nitrogen doses (320, 400, 480 and 560 g of N per plant-1) and 4 potassium doses (380, 475, 570 and 665 g of K2O per plant-1) with 4 replications of 3 plants each. The following variables were evaluated: leaf area index (LAI), leaf chlorophyll index (a, b and total index), intercepted photosynthetically active radiation (Int.PAR, in µmol∙m-2∙s-1), efficiency use of photosynthetically active radiation (Ef.PAR) and fruit yield. The fruit production and physiological characteristics of papaya cv. Caliman-01 depend on planting spacing. Under the soil, climate and plant conditions of this study, 665 g of K2O and 320 g of N per plant under double spacing could be recommended for the production of papaya cv. Caliman-01.

Substrato alternativo para produção de mudas de mamoeiro formosa (cv. Caliman)

For the successful cultivation of papaya, fruits of high quality are essential and this starts with seedlings of high genetic potential and quality. The objective of this project was to evaluate the decomposed trunk of buriti (CDB) (Mauritia vinifera Mart.) plants for the formation of seedlings of ‘Caliman’ cv. of papaya of the formosa type. The experimental units were distributed in the greenhouse (a screen covering which allowed 50% luminosity) according to a completely random design. The treatments consisted of six formulations of the substrata : S1 : soil and sand 1:1 (80%) + CDB (20%), S2 : soil and sand 1:1 (60%) + CDB (40%), S3 : soil and sand 1 : 1 (40%) + CDB (60%), S4 : soil and sand 1:1 (20%) + CDB (80%), and S5 : CDB (100%). Each replication of each treatment was formed by five seedlings. The evaluated variables were the following : seedling emergence, speed of emergence index, seedling height, stem diameter, chlorophyll concentration, leaf area, radicular area, mean root length, mean radicular diameter, root density, and mean aerial part and root dry mass. The results showed that CDB can be used at the proportion of 20% to compose substrata for the development of papaya seedlings. This formulation favors plant height, stem diameter, leaf area, leaf chlorophyll, radicular diameter, aerial part and root dry mass. Additional keywords: Carica papaya L; regional substrates; seedling quality.

CRESCIMENTO, FISIOLOGIA E PRODUTIVIDADE DO MAMOEIRO FORMOSA CULTIVADO SOB DIFERENTES DOSES DE UREIA PROTEGIDA E CONVENCIONAL

Mineral fertilizer management is one of the most important agronomic techniques applied in papaya cultivation, which generally extracts large amounts of nutrients from soil, especially nitrogen. This study aimed to assess the phytotechnical and physiological attributes and yield of „Formosa‟ papaya hybrid Caliman 01 as a function of different doses of coated and conventional urea in the region of Bom Jesus PI, Brazil. The treatments were arranged in a factorial scheme (2 × 4) and distributed in a randomized block design with four replications, corresponding to 2 nitrogen sources (coated urea, 43% of N; and conventional urea, 45% of N) and 4 doses nitrogen (350, 440, 530 and 620 g per plant). The N doses used corresponded to 80, 100, 120 and 140% of the nitrogen fertilization. It was used six plants per plot with two row borders, totaling 192 plants cultivated in the field. It was assessed the intercepted photosynthetically active radiation (int.PAR), radiation interception efficiency (PAREff.), leaf area index (LAI), plant height, stem diameter and yield. The coated urea promotes a higher growth and yield of „Formosa‟ papaya compared to the conventional urea. The application of 1.0 g of coated N promotes the production of 2.87 g of fruit per hectare while the application of 1.0 g of conventional N produces only 1.89 g of fruit per hectare, showing that the source of polymerized N increases the use efficiency of N applied to soil.