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United States Department of Agriculture

Agricultural Research Service

Research Project: Enhancing Water Conservation and Crop Productivity in Irrigated Agriculture

Location: Water Management and Conservation Research

Title: Lesquerella seed and oil yield response to split-applied N fertilizer

Author
item Jiangang, Lui
item Bronson, Kevin
item Thorp, Kelly
item Mon, Jarai
item Mohammad, Badaruddin
item Mccloskey, William
item Ray, Dennis
item Qingquan, Chu
item Guangyao, Wang

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2014
Publication Date: 7/1/2014
Citation: Jiangang, L., Bronson, K.F., Thorp, K.R., Mon, J., Mohammad, B., Mccloskey, W., Ray, D.T., Qingquan, C., Guangyao, W. 2014. Lesquerella seed and oil yield response to split-applied N fertilizer. Industrial Crops and Products. 60:273-279.

Interpretive Summary: Agronomic management guidelines and recommendations are sorely lacking for new oilseed and biofuel crops such as lesquerella. We conducted a two-year field trial to study the response and of Nitrogen (N) fertilizer rates under well-watered and water-stressed conditions in Arizona. Despite low initial soil nitrate, pre-plant N fertilizer did not affect early lesquerella growth. With higher N fertilizer rates, seed and straw N concentration increased in both well-watered and water-stressed plots. Seed and oil yields showed a quadratic (i.e. diminishing curve) response to N fertilizer rate. Optimum N fertilizer rate for oil yield was lower than the N fertilizer rate for the optimum seed yield. Well-watered lesquerella had a greater optimal N fertilizer rate for oil yield 240 kg N ha-1) than did water-stressed lesquerella in the second season (180 kg N ha-1). The results of this study provide practical guidelines for N fertilizer management for lesquerella in the southwestern US.

Technical Abstract: Agronomic management information is critical for successfully commercial production of new crops such as lesquerella [lesquerella ferndleri Gray (Wats.)]. Response of lesquerella to six nitrogen (N) fertilizer rates under well-watered and water-stressed treatments were studied in irrigated desert conditions in southwestern of United States to establish guidelines for lesquerella N management. Seed and oil yield, seed and straw N concentrations, N harvest index, and total N uptake were recorded at harvest and plant samples were also taken during growing season for plant N status. Although soil NO3-N was low due to a cover crop to remove excessive N in the soil, pre-plant N fertilizer did not affect lesquerella growth at early growth stage. For the treatments with high N fertilizer rates (224 and 336 kg ha-1), lesquerella plant N concentrations were relatively stable before the first bloom, decreased drastically until mid-bloom (one month after the first bloom), and then continued to decrease at a lower rate until harvest. As N fertilizer rates increased, seed and straw N concentration increased linearly under both well-watered and water-stressed conditions. Lesquerella seed and oil yield had a quadratic relationship with N fertilizer rate. Because seed oil concentration decreased as N fertilizer increased, N fertilizer rate for the optimum oil yield was lower than the N fertilizer rate for the optimum seed yield. According to seed and oil yield as well as plant N status under different N fertilizer rates, we provided a guideline for N fertilizer management for lesquerella crop.

Last Modified: 06/23/2017
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