https://digitalcommons.calpoly.edu/nres_rpt/18
Date of Award
8-2021
Degree Name
MS in Environmental Sciences and Management
Department
Natural Resources Management
College
College of Agriculture, Food, and Environmental Sciences
Advisor
Nicholas Babin
Advisor Department
Natural Resources Management
Advisor College
College of Agriculture, Food, and Environmental Sciences
Abstract
Conventional agriculture that uses machinery management, synthetic fertilizers, and pesticides, is a contributor to greenhouse gas emissions, reduction of biodiversity and soil health. Agroecological methods, such as intercropping, have the potential to make farming more sustainable, financially feasible and to be implemented on a large scale. Gaps in agricultural research have led to limited information as to how intercropped arrangements can be adapted to be as productive as conventional systems. This research evaluates the ecological and economic performance of a lettuce and chard agroecosystem, specifically investigating the impact that density and intercropping has on plant productivity and profitability. Both species were grown in monocrop and intercrop arrangements at recommended density of 6”. The results from these plots were compared with the outcome of an intercropped arrangement at an increased density of 4”. To determine the ecological dynamics of the crop systems, percent herbivory, soil temperature and moisture, leaf area index, plant growth, rooting length, width and mass and harvested biomass were measured. Stomatal conductance and chlorophyll inflorescence levels were measured throughout the growing cycle to monitor the level of plant stress and photosynthetic capability. The economic performance of the crops was calculated from the total harvested biomass of each crop, using the standard market price. Both intercrops overyielded when compared to the monocrops. The land equivalency ratio of the recommended density intercrop was 1.19 and the increased density intercrop was 1.26, indicating that the intercrop was able to produce the same yield on less land and therefore benefit land conservation in agriculture. Economically, the intercrops also outperformed the monocrops. Overyielding in the intercrops was driven by heightened photosynthetic ability and greater resource sharing. These results serve as evidence that intercropping lettuce and chard can improve land-use efficiency and provide a higher gross revenue to farmers, and due to reduced competition, crops can be grown in a higher density arrangement.