Effects of Pelleted and Unpelleted Composted Organic Materials on the Growth and Yield of Three Varieties of Cucumber (Cucumis Sativus L.)

ABSTRACT The main objective of this study is to determine the effects of the pelleted and unpelleted composted organic materials on the growth and yield of three varieties of cucumber (Cucumis sativus L.). The specific objectives were to: determine the physical and chemical properties of pelleted and unpelleted composted organic materials, determine the effects of pelleted and unpelleted composted organic materials on the growth and yield of three varieties of cucumber (Cucumis sativus L.) and evaluate the effects of unpelleted composted rice husks + poultry manure (75%:25%, v/v) rates on the growth and yield of three varieties of cucumber (Cucumis sativus L.). Three experiments were undertaken at the Teaching and Research Farm of the Department of Crop Science, University of Nigeria, Nsukka. Experiment one was a laboratory analysis to determine the physical and chemical properties of pelleted and unpelleted composted organic materials. Experiment two was done in the greenhouse as a 3 × 13 factorial trial in a completely randomized design (CRD) with three replications. The treatments were three varieties of cucumber (Poinsett, Marketer and Supermarketer) and unpelleted composted rice husks (100%), unpelleted composted moringa pod husks (100%), unpelleted composted maize cobs (100%), unpelleted composted rice husks + poultry manure (75%:25%, volume to volume; v/v), unpelleted composted moringa pod husks + poultry manure (75%:25%, v/v), unpelleted composted maize cobs + poultry manure (75%:25%, v/v), pelleted composted rice husks (100%), pelleted composted moringa pod husks (100%), pelleted composted maize cobs (100%), pelleted composted rice husks + poultry manure (75%:25%, v/v), pelleted composted moringa pod husks + poultry manure (75%:25%, v/v), pelleted composted maize cobs + poultry manure (75%:25%, v/v), top soil (control). Experiment three was done in the field as a 3 × 4 factorial laid out in a randomized complete block design (RCBD) with three replications. Twelve treatment combinations consisting of three cucumber varieties (Poinsett, Marketer and Supermarketer) and four rates (0 t ha -1, 5 t ha -1, 10 t ha -1 and 15 t ha-1) of unpelleted composted rice husks + poultry manure (75%:25%, volume to volume; v/v) were used. The physical properties of pelleted and unpelleted composted organic materials revealed that the top soil significantly (p < 0.05) gave a higher bulk density value of 1.21 g cm-3 compared with pelleted and unpelleted composted organic materials. Total porosity and available water holding capacity were significantly (p < 0.05) higher in the unpelleted composted rice husks (100%). The chemical properties showed that the organic matter content of unpelleted composted maize cobs (100%) was significantly (p < 0.05) higher with a value of 26.48% compared with pelleted composted maize cobs (100%). Total nitrogen and carbon nitrogen ratio were significantly (p < 0.05) higher in unpelleted composted rice husks + poultry manure (75%:25%, v/v). The morphological growth traits (plant height, leaf area per plant, number of internodes per plant, number of leaves per plant, internode length per plant and stem girth per plant) and yield performances (root, stem, leaf dry weight, fruit length, fruit width, fruit girth, number of fruits per plant and total fresh fruit weight) of the three varieties of cucumber grown in soil amended with unpelleted composted rice husks + poultry (75%:25%, v/v) had significantly (p < 0.05) the highest values compared with the other treatments. The highest application rate of 15 t ha-1 gave significantly (p < 0.05) the highest values of total nitrogen (1.36%), available phosphorus (80.36 ppm), organic carbon (4.10%), organic matter content (7.07%), exchangeable potassium (0.38 meq/100 g), exchangeable calcium (5.80 meq/100 g) and exchangeable magnesium (4.30 meq/100 g) compared with the other rates. The correlation coefficient (r = 0.995**) between soil organic carbon and exchangeable calcium was the highest and the least was the association (r = 0.473) between exchangeable potassium and exchangeable magnesium.