Short planks in the crop nutrient barrel theory of China are changing: Evidence from 15 crops in 13 provinces

Abstract

Large quantities of fertilizers, mainly nitrogen (N), phosphorus (P), and potassium (K), are used in China's crop production; however, whether N, P, and K still limit yield under the current high input remains unknown. In addition, it is not clear whether magnesium (Mg) potentially limits crop production. To address these issues, a national survey of the soil nutrient status and farmers' fertilization practices was conducted in China to determine the soil N, P, K, and Mg status and current fertilization practices. In addition, various experiments, including optimized NPK (OPTNPK) and Mg fertilizer combined with OPTNPK (OPTNPK + Mg) in comparison with farmers' practices (FFP), were performed across China to identify the potential for reducing NPK application and the need for Mg application in crop production. The survey data from 2699 questionnaires indicated that (1) all soil samples were not deficient in NPK, but 73.0% were limited by Mg. (2) The average N, P (in P2O5), K (in K2O), and Mg (in MgO) balances were 422.6, 334.1, 326.3, and −22.6 kg ha−1, respectively. Only 15.7% of all farmers applied Mg fertilizer. (3) NPK fertilization can be reduced by an average of 28.8% without reducing the crop yield and quality. (4) For most crops, the application of Mg fertilizer increased the crop yield by 5.5–40.6% and improved the quality. However, different crops under different conditions had different responses to Mg fertilization. These results indicate that reduced NPK inputs and increased Mg inputs are equally important for the healthy development and sustainability of China's agriculture.

Photosynthetic plasticity aggravates the susceptibility of magnesium‐deficient leaf to high light in rapeseed plants: the importance of Rubisco and mesophyll conductance

“…Magnesium (Mg) deficiency is increasingly observed in intensive crop production systems and becomes an important limiting factor to plant growth after nitrogen, phosphorus, and potassium, especially in soils with low pH, high leaching potential or intensively fertilized with potassium (Cakmak & Yazi̇ci̇, 2010; Chen et al., 2022; Gransee & Führs, 2013; Wang et al., 2020). Leaf interveinal chlorosis, as one of the typical symptoms of plants affected by Mg deficiency stress, is highly dependent on light intensity (Cakmak & Marschner, 1992; Cakmak & Yazi̇ci̇, 2010; Hermans & Verbruggen, 2005; Peng et al., 2019; Tränkner et al., 2018; Verbruggen & Hermans, 2013).…”

Assessment of magnesium deficiency in greenhouse tomato crops grown on calcareous soil

“…Magnesium (Mg) is ‘the forgotten element’ in crop production (Cakmak & Yazici, 2010) and has become a nutritional obstacle in crop yield and quality (Chen et al, 2022; Wang et al, 2019). In China, a national soil and plant nutrition survey showed that the limiting factor on crop yields and quality has shifted from NPK to Mg (Chen et al, 2022).…”

“…Magnesium (Mg) is ‘the forgotten element’ in crop production (Cakmak & Yazici, 2010) and has become a nutritional obstacle in crop yield and quality (Chen et al, 2022; Wang et al, 2019). In China, a national soil and plant nutrition survey showed that the limiting factor on crop yields and quality has shifted from NPK to Mg (Chen et al, 2022). A decrease in plant dry matter (DM) because of Mg deficiency has been observed in various plants, including tomato (Li et al, 2018), citrus (Wang et al, 2022), rice (Tanoi et al, 2014) and Arabidopsis (Mao et al, 2020).…”

“…However, this overlooks potential and acute Mg deficiency in crops (Puthiyaveetil et al, 2017) and will bias the analysis of the degree and causes of Mg deficiency. Soil‐exchangeable Mg content and Mg content in leaf are also common methods to determine whether crops are Mg limited (Chen et al, 2022; Hauer‐Jákli & Tränkner, 2019). To avoid neglecting early crop Mg deficiency, critical threshold values for Mg concentrations in the plant tissue and corresponding soils are required.…”

“…It has been proposed that the antagonistic effect of K enrichment on absorption of Mg by plants is the main cause of Mg deficiency for greenhouse vegetables on calcareous soil (Farhat et al, 2016; Guo et al, 2016; Yan et al, 2020). However, the relationship between Mg deficiency and plant and soil physicochemical characteristics is not well understood (Chen et al, 2022; Lu et al, 2022).…”