Date of Graduation

12-2021

Document Type

Thesis

Degree Name

Master of Science in Agricultural Economics (MS)

Degree Level

Graduate

Department

Agricultural Economics and Agribusiness

Advisor

Qiuqiong Huang

Committee Member

Song Feng

Second Committee Member

Stijn Speelman

Keywords

climate variation, conventional, drought, excessive rainfall, organic, yield gap

Abstract

This thesis compares the responses of organic yields and conventional yields towards climate variations. To achieve this objective, weather variables such as growing season weather conditions (average temperature, precipitation, cloud cover, relative humidity, drought index), weather anomalies, the occurrence of severe or extreme droughts and excessive rainfalls, are combined with 23 data sets gathered from previous studies that compare organic and conventional yields from the same location and time periods. To narrow the scope, the thesis focuses on soybean, maize, and wheat production in Europe and North America. Study-level fixed-effects models are used to control for any time-invariant factors such as soil characteristics management practices and operator knowledge. For all three crops studied (maize, soybean, wheat), the estimated coefficients of most weather variables from the organic yield model and the conventional yield model have the same signs. This indicates organic and conventional yields respond to variations in most climatic factors in the same way. The results also reveal some differences in the yield responses between organic and conventional crops. For example, excessive rainfall events seem to have less negative effects on organic yields. The differences may vary across crop. For example, although the growing seasons of maize and soybean largely overlap, organic and conventional soybeans differ in their yield responses to more weather factors than maize. The differences may vary between different months. For example, excessive rainfalls in June decreased organic soybean yields but boosted both organic and conventional soybean yields in August. For most cases when the yield responses are different, the magnitudes of coefficients are larger for organic yields than for conventional yields. This indicates that organic yield responds more to climate variations. Therefore, empirical evidence from this thesis would not support the argument that organic agriculture can be more resilient to climate variations. This is an important consideration to take into account when policy makers promote organic agriculture.

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