Soil Chemical Properties and Sunflower (Helianthus Annuus L) Productivity Responses to Sunn Hemp Intercropping and Mineral Fertilizer Application in Dodoma, Tanzania
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Date
2023
Authors
Chappa, Luciana Raphael
Journal Title
Journal ISSN
Volume Title
Publisher
kenyatta university
Abstract
Sunflower (Helianthus annuus L.) is one of Tanzania's high-potential cash crops. Nonetheless, nutrient depletion, especially nitrogen (N), is limiting its productivity. An integrated soil fertility management technique that entails intercropping sunflower with a leguminous plant like Sunn hemp (Crotalaria juncea) and the application of mineral N fertilizer can boost N availability for crop uptake hence resulting in high crop productivity. The study was conducted in the semi-arid -Dodoma region in Tanzania where it adopted a randomized complete block design (RCBD) with six treatments each replicated four times. These treatments were T1; Control (sunflower pure stand) without mineral nitrogen (N) fertilizer, T2; Sunflower-Sunn hemp intercrop under 1:1 row ratio without fertilizer, T3; Sunflower-Sunn hemp intercrop under 1:1 row ratio with fertilizer, T4; Sunflower-Sunn hemp intercrop under 2:1 row ratio without fertilizer, T5; Sunflower-Sunn hemp intercrop under 2:1 row ratio with fertilizer and T6; Sunflower pure stand with fertilizer. Data that were collected are soil chemical properties (soil pH, organic carbon, total nitrogen, available phosphorus, potassium, calcium, magnesium, and sodium), sunflower growth and yield parameters (plant height, leaf area, number of leaves per plant, sunflower head diameter, N uptake by sunflower leaves, achene yield, number of seeds per plant, weight of seed per plant, and stover yield), economic returns (gross income, net income, and benefit-cost ratio-BCR). The data from this study were tabulated in excel and then subjected to analyses of variance. The means of treatments that were significant were distinguished by using the least significant difference (LSD) at a 95% confidence interval. The results indicated that except for soil pH, the other chemical soil properties tended to increase significantly (p ≤ 0.05) under all the treatments containing integrated approaches like Sunn hemp and N fertilizer application relative to the sunflower pure stand treatment across the sites. Regardless of the site, T6 and T3 showed the best performance based on the sunflower growth and yield. For instance, at Kongwa the sunflower leaf area was highest in T3 (285 cm2) and T6 (282 cm2) with T4 having the least value of 149 cm2. A similar trend was observed for the number of Sunflower seeds per plant, the weight of sunflower seeds per plant, Sunflower achene yield, and Sunflower stover yields with the best- performing treatments being T6 and T3. T5 and T2 had the highest (US$ 278 ha-1) and the lowest (US$ 205 ha-1) cost of production. Economically, Kongwa outperformed Bahi. Specifically, based on treatments, T3 had the highest gross income both at Kongwa (US$ 3412 ha-1) and Bahi (US$ 1756 ha-1). This translated into respective net income and BCR of US$ 1639 and 698, and 7.50 and 3.20. This study's findings will help rural poor farmers achieve better economic returns, hence reducing poverty.
Description
A Research Thesis Submitted in Partial Fulfilment of the Requirements for the Award of Master of Science Degree in Integrated Soil Fertility Management (Isfm) in the School of Agriculture and Environmental Sciences, Kenyatta University
Keywords
Soil Chemical Properties, Sunflower (Helianthus Annuus L), Sunn Hemp, Intercropping, Mineral Fertilizer, Dodoma, Tanzania