Nitrogen fertilization impact on hemp (Cannabis sativa L.) crop production: A review

Abstract

Regained interest in hemp cultivation has created opportunities and challenges, especially regarding crop management, for example, fertilizer application rate. Most of the literature on nitrogen (N) management in hemp production is from Asia and Europe, with more established cropping systems than in North America. Through our review, we found evidence that N fertilizer has a noticeable positive impact on basic crop morphology and physiology parameters, or at least the crop responds to such infield fertilizer applications. Some physiological parameters that show positive response include photosynthetic pigments, N and nitrate concentration, and water use efficiency. N fertilizer has been demonstrated to increase stem and fiber yield but reduce fiber quality. Increasing N also appears to increase seed yield and protein content. Both excess and low rates of N fertilizer are detrimental to floral hemp. There is little evidence that Δ9‐tetrahydrocannabinol concentration is more affected by N fertilization than genetics. The impact of fertilizer source and timing remains a critical area for research. There is still a need for research on developing a sustainable nutrient management program for hemp.

Nitrogen application and cultivar effects on industrial hemp yield dynamics

“…Moreover, different grain, flower, or fiber hemp production systems may require differing N recommendations based on the final production goal and environmental conditions (Fike, 2016;Kaur et al, 2023). Literature has shown that the N requirement for grain and flower production is higher than fiber production (high N reduces fiber quality) (Fike, 2016;Kaur et al, 2023;Mylavarapu et al, 2020). Therefore, optimizing N fertilization for different economic products obtained from hemp is essential.…”

Intercropping Industrial Hemp and Cowpea Enhances the Yield of Squash—A Pollinator-Dependent Crop

“…According to [19], the acreage harvested for grain and fiber in the United States was estimated at over 24,000 acres, an indication that growers are turning towards scaling up the cultivation of fiber and grain varieties. Despite the resource efficiency of intercropping, there has been limited research on the impact of intercropping hemp, a crop that has resurfaced in the United States as the "new crop on the farm", requiring about 60 and 273 kg ha −1 N fertilizer, contingent on available soil N and weather conditions [20]. This requirement of hemp for nitrogen can be supplemented by cowpea, (Vigna unguiculata L. Walp), a legume crop grown worldwide and capable of fixing about 116 kg N ha −1 N 2 [16,21].…”