Effect of Different Long-Term Potassium Dosages on Crop Yield and Potassium Use Efficiency in the Maize–Wheat Rotation System

Abstract

Potassium (K) is the second most important plant nutritional element and is used for numerous physiological processes. We established an eight-year experiment comparing the effects of five K fertilization treatments (0, 48, 84, 120 and 156 kg K ha−1) on crop yield, K use efficiency and soil apparent K balance under the maize–wheat rotation system in the North China Plain. The highest maize and wheat yields were achieved in the K120 treatment, increasing by up to 16.7% and 25.1%, respectively. The increase in grain yield and K agronomic efficiency (AEK) with K application was greater in wheat than in maize. The K recovery efficiency (REK) and K accumulative recovery efficiency (ARE) significantly decreased with the increase in K fertilization in the maize and wheat seasons. However, the soil apparent K balance and soil available K content increased; the former was deficiency (−24.3 kg ha−1 yr−1) in the K0 treatment, but the latter did not decrease significantly compared with that in the initial year of the experiment. The soil available K content increased by 10.9 mg kg−1 per 100 kg ha−1. In conclusion, the yield response to K fertilization was greater in wheat than in maize and alleviated soil K depletion, but the K fertilizer efficiency was lower. We believed that K fertilizer can be increased moderately in the wheat season and decreased in the maize season.

The Influence of Mineral NPK Fertiliser Rates on Potassium Dynamics in Soil: Data from a Long-Term Agricultural Plant Fertilisation Experiment

“…Studies in three long-term fertilisation experiments on agricultural crops in Rothamsted, Bad Lauchstädt, and Skierniewice also showed that the effectiveness of potassium fertilisers decreased when plants experienced deficiencies in nitrogen, phosphorus, and magnesium [42]. Studies in China showed that the most effective rate of potassium fertiliser applied to agricultural crops was 120 kg ha −1 , which increased maize and winter wheat yields by 16.7 and 25.1%, respectively [32]. It is also noted that potassium, like phosphorus, is very important for nitrogen uptake by agricultural plants.…”

“…Similar patterns were found in a long-term (8-year) fertilisation experiment in China, where annual application of 48 kg ha −1 of potassium resulted in 39.5% uptake by plants. However, when the rate of potassium fertiliser application was increased to 156 kg ha −1 , the uptake of potassium decreased to 16.4% [32]. The efficiency of potassium fertiliser use can be improved by taking into account the plant-available K 2 O content in the soil when fertilising, as studies in the USA have shown that it is not economically viable to fertilise agricultural crops with potassium fertilisers if the plant available K 2 O content in the soil is above the average, as they already have sufficient soil reserves of this plant nutrient [48].…”

“…The effects of fertilisation on crop yields and soil nutrient balance are more objectively assessed using the results of long-term fertilisation experiments on agricultural crops, because it reduces the influence of weather conditions on the results of research [17,31,32].…”

Potassium Increases Nitrogen and Potassium Utilization Efficiency and Yield in Foxtail Millet

“…Nutrient absorption efficiency is an important index for characterizing plant nutrient-absorption ability, and rational fertilization can significantly improve grain nutrient-utilization efficiency [47]. However, once the amount of K applied exceeds the crop requirement, K use efficiency will decline [48]. Crop K absorption efficiency gradually decreases with an increase in K application rate [49], while the appropriate K fertilizer improves root characteristics [50], promotes N absorption and metabolism, increases leaf N concentration [2] and N transfer to ears, and increases N and P absorption efficiency [23].…”

Polyphasic Characterization of Indigenous Potassium-Solubilizing Bacteria and Its Efficacy Studies on Maize

“…Owing to inadequate fertilizer use, significant increase in crop yield (depleting soil solution K), and depletion of K in the soil system, large quantities of K in the soil occur in a fixed form (non-available to plants indirectly) [6,7]. The rapid K depletion of the soil by high-yielding cultivars in intensive crop cultivation systems, coupled with the lack of effective K replacement protocols has induced an escalating K deficiency in soils due to the imbalanced application of fertilizers [8,9].…”