Degree Type

Thesis

Date of Award

2015

Degree Name

Master of Science

Department

Agronomy

First Advisor

Andrew Lenssen

Abstract

Part 1

Declining soil fertility due to inadequate nitrogen in most soils limits farmers’ goals of increasing yield. There is environmental and agricultural benefit of reducing dependence on nitrogen fertilizer by emphasizing adaptation of favorable farming practices that minimize nitrogen fertilizer. Cowpea [Vigna unguiculata (L.) Walp.] and lablab (Lablab purpureus (L.)] are pulses with potential for grain, forage, and cover crops in the Midwest of United States, but little is known about their growth, development, and productivity potential in Iowa. We conducted a two-year field study to determine the influence of rhizobia inoculation and fungicide seed treatment of selected pulses. The objectives of this study were to i) determine the influence of fungicide seed treatment and inoculation on nodulation and nitrogen fixation of four pulses; soybean ‘92Y82’, cowpeas (‘CA46’ and ‘Top Crop’) and lablab ‘Rongai’ and ii) determine the effect of fungicide seed treatment and Bradyrhizobium spp. inoculation on grain yield and above-ground biomass of the crops. The experimental design was a randomized complete block in a factorial of four pulse crops with and without rhizobium inoculation and a fungicide seed treatment. Although several research studies indicated that fungicide seed treatment and inoculation with Bradyrhizobium affected nodulation, nitrogen fixation and yield components, we found no significant effects of fungicide seed treatment and Bradyrhizobium inoculation on pulse grain yield.

Part 2

The role of legumes worldwide includes food, nutrition and income generation among others. Malnutrition especially in children is common in many developing countries, leading to severe stunting and death in addition to high macro and micro nutrient deficiencies which legumes can

provide. Legumes such as cowpea can thrive in adverse environments like drought, making them a climate smart technology for hunger mitigation. Total protein intake per capita from pulses exceeds 10% in several countries, including Uganda (20%) and Ethiopia (15%), yet potential legume leaf utilization for protein and other nutrients has not been widely considered. This may be a rare source of nutritional and harvest versatility compared to common leafy vegetables. However, leaf removal effects on pulses and their grain yield are unclear. Additionally, little information is available on pulse leaf nutritional composition. We conducted a two-year experiment in central Iowa to determine 1) the effects of leaf removal rate on nutritive value of removed leaf tissue, and 2) the effects of leaf removal rate on subsequent grain yield. We found that mean concentration of nutrients in dry leaves was 229, 17832, 4461, 21991, 3702, 113, 205, 13, 86, 2806 mg kg-1 for crude protein, calcium, Mg, K, P, Mn, Fe, Cu, Zn and S. Unlike 2013, leaf removal percentage had significant impact on 2014 yield and the control had 20, 32, and 35% more yield than plots at 33, 66 and 99% leaf removal. Pulse leaves have excellent potential to supplement high-carbohydrate diets that are deficient in protein and micronutrients.

Copyright Owner

Rosemary Bulyaba

Language

en

File Format

application/pdf

File Size

122 pages

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