Black walnut alley cropping is economically competitive with row crops in the MidwestUSA

Abstract

The maize–soybean rotation (MSR) dominates the Midwest United States and degrades many ecological functions. Black walnut (Juglans nigra L.) plantation forestry (PF) and alley cropping (AC) are two alternative land‐uses that can enhance productivity and restore ecosystem services. Given the lack of robust market mechanisms to monetize ecosystems services, we tested whether the profitability of PF and AC could drive adoption in the Midwest. Publically available data on black walnut soil suitability, timber prices, crop productivity, and cash rents were combined in a high‐resolution spatial analysis to identify regions where these alternatives can outcompete MSR. To avoid selecting an arbitrary discount rate at which to make comparisons, we determined the threshold discount rate necessary to make PF or AC economically competitive with MSR. We show that, with a 5% discount rate, PF and AC could be more profitable on 17.0% and 23.4% of MSR land, respectively. Contrary to the common assumption that woody agricultural alternatives should first be adopted in marginal row crop areas, the economic competitiveness of PF and AC was not correlated with MSR productivity. Instead, black walnut growth rate was the central driver of PF and AC competitiveness, underscoring a necessary shift away from the current MSR‐centric perspective in defining target regions for land‐use alternatives. Results reveal major opportunities for landowners and investors to increase profitability by investing in PF and AC on both “marginal” and productive MSR land.

Ecosystem services for intensification of agriculture, with emphasis on increased nitrogen ecological use efficiency

“…According to Wolz and DeLucia (2019), alley cropping has shown great potential as a scalable agricultural alternative that can enhance production while simultaneously improving sustainability in the Midwest United States. Our results from alley cropping in the humid tropics of Amazonian periphery also showed that the biomass of Gliricidia had a positive effect on soil improvement and nitrogen uptake, thereby contributing to agricultural intensification by increasing maize grain yield by 3.5 tons/ha.…”

Germplasm Development of Underutilized Temperate U.S. Tree Crops

“…Spatial mapping and economic analysis have demonstrated improvement of farm-level profitability through targeted subfield cultivation of perennial grasses, switchgrass (Panicum virgatum), and miscanthus (Miscanthus giganteus), in place of low-yielding maize and soybean [4,5]. A recent study by Wolz and DeLucia [6] utilized similar spatial mapping of timber-based black walnut (Juglans nigra) plantations and alley cropping systems to demonstrate increased profitability through targeted system placement. Across four states in the Midwest U.S., this study showed that black walnut alley cropping systems could increase profitability for landowners on 23.4% of cultivated land, assuming a 5% discount rate in future yields [6].…”

“…A recent study by Wolz and DeLucia [6] utilized similar spatial mapping of timber-based black walnut (Juglans nigra) plantations and alley cropping systems to demonstrate increased profitability through targeted system placement. Across four states in the Midwest U.S., this study showed that black walnut alley cropping systems could increase profitability for landowners on 23.4% of cultivated land, assuming a 5% discount rate in future yields [6]. In effect, the studies by Brandes et al [4,5] and Wolz and DeLucia [6] provide evidence for considering the targeted integration of other low-input perennials, which extends to a growing number of tree crop species.…”

“…(C) The specific adaptability traits required to expand tree crop cultivation to the defined targeted environments can be discretely specified and used to guide a breeding program. High-resolution geospatial techniques, such as this, clarify the spatial distribution of each target environment and create the potential to add additional variables (e.g., photoperiod and climate) for recurrent assessment of variation within target environments to test for sub-environments [5,6,135].…”

“…The benefits of agroforestry's regulatory services are well characterized for the Midwest U.S., where annual cropping systems such as the corn-soybean rotation dominate the landscape [1][2][3]. Under the appropriate conditions, select agroforestry systems have even demonstrated superior production capacity and profitability compared to their respective annual grain counterparts [4][5][6], which brings pragmatism to the strategic diversification within Midwest U.S. Nevertheless, adoption of agroforestry continues to be relatively limited throughout this region.…”