World Potassium Use Efficiency in Cereal Crops

Abstract

Core Ideas Potassium use efficiency in cereals is unknown. World demand for potassium in agriculture is increasing. Potassium is a non‐renewable resource. Worldwide potassium (K) fertilizer use has grown, while the expected fertilizer use efficiency has decreased. The objective of this paper was to estimate potassium use efficiency (KUE) for cereal crops and report on methods that will most likely lead to improved KUE. World KUE was calculated using the total area under cereal production, total cereal grain production, percent K content in cereal grains and K fertilizer consumed from 1961 to 2015. All data was obtained from FAOSTAT except percent K grain content, which was acquired from the USDA. The reported KUE estimate included assumptions established in prior literature. The percent K coming from the soil was estimated at 71%, while previous year K fertilizer‐residual‐effects were offset by knowing that similar amounts of fertilizer K will be applied in following years. At current consumption rates, existing K reserves as K20 are estimated to last 100 yr meaning that mining operations will need to expand to meet expected market demands. Results showed that cereal production increased by a factor of 3.2 from 1961 to 2015 and that was accompanied by a threefold increase in fertilizer K consumed. Estimated KUE from 1961 to 2015 for world cereal crops using the difference method was 19%. Combined with findings from this paper, estimates of N, P, and K use efficiency for cereal production in the world stand at 33, 16, and 19%, respectively.

World Sulfur Use Efficiency for Cereal Crops

“…Procedures and assumptions made in work done by Raun and Johnson (1999), Dhillon et al (2017), and Dhillon et al (2019a) to compute NUE, PUE, and KUE, respectively, were used to determine SUE for major world cereal crops. It is important to note that this study did not investigate agronomic efficiency and partial productivity factor.…”

“…This low SUE together with 33% nitrogen use efficiency (NUE) (Raun and Johnson, 1999), 16% phosphorus use efficiency (PUE) (Dhillon et al, 2017), and 19% potassium use efficiency (KUE) (Dhillon et al, 2019a) for a range of cereals, represents an inefficient use of these macronutrients. With S linked to improved efficiency of N recovery in the grain (NUE), its use in crop production will only continue to grow (Klikocka et al, 2017).…”

Pre-Anthesis Nutritional Status of Spelt Wheat as a Tool for Predicting the Attainable Grain Yield

“…The impact of other basic nutrients on the productivity of this crop, including potassium (K) and magnesium (Mg) is, in fact, a black box. As recently published by Dhillon et al [12], K use efficiency in cereals is low, amounting to 19%. The physiological functions of K as related to water management by crop plants are well recognized.…”

Unpredictable Nature of Environment on Nitrogen Supply and Demand

“…Phosphorus use efficiency in cereal crops was found to be 16% on average over a 53‐yr period (range, 12–21%) (Dhillon et al, 2017). Similarly, over a 55‐yr period, potassium use efficiency averaged 19% (range, 15–26%) (Dhillon et al, 2019). Likewise, sulfur use efficiency averaged 18% (range, 14–22%) (Aula et al, 2019).…”

“…Global estimates of phosphorus (P) (Dhillon et al, 2017), potassium (K) (Dhillon et al, 2019), and sulfur (S) (Aula et al, 2019) use efficiencies in cereal crops have been found to be highly variable from one year to the next. Phosphorus use efficiency in cereal crops was found to be 16% on average over a 53‐yr period (range, 12–21%) (Dhillon et al, 2017).…”