Nutritional Diagnosis of the Mineral Elements in Tainong Mango Leaves during Flowering in Karst Areas

Abstract

The balance of the mineral nutrition in mango leaves during the flowering period affects the flowering of mango trees and fruit production. Because the soil in karst areas has a slow and unbalanced supply rate of nutrients, mango orchards in a karst area generally have a low yield. There are few studies on the fertilization of mango orchards in karst areas, especially on the diagnosis of leaf mineral nutrition. In this study, mango orchards in the typical karst areas of Guangxi province, one of the main mango-producing areas in China, were selected from the low-yielding and medium-yielding mango orchards. Surface soil samples and leaf samples from mango orchards in full bloom were collected to test for macronutrients and micronutrients. The Diagnosis and Recommendation Integrated System (DRIS) graphical method, the DRIS method, the Modified DRIS (M-DRIS), and the Deviation from Optimum Percentage (DOP) index diagnostic methods were applied to the leaves. The results showed that the DRIS graphical analysis yielded appropriate ratios of N, P, K, Mg, S, Fe, Mn, Cu with the corresponding three elements, Ca, Zn, and B , which can be used as reference diagnostic criteria. Based on the values of the DRIS diagnostic criteria for high-yielding orchards, the critical ranges of the suitable values of the mineral nutrients in the Tainong mango leaves during flowering were determined as N (14.87–17.27 g/kg), P (0.69–0.89 g/kg), K (4.45–6.90 g/kg), Ca (9.51–16.55 g/kg), Mg (1.44–2.20 g/kg), S (0.75–1.06 g/kg), Fe (0.10–0.13 g/kg), Mn (0.61–1.02 g/kg), Cu (5.41–8.89 mg/kg), Zn (7.91–18.95 mg/kg), and B (8.38–16.23 mg/kg). The results of the DRIS, M-DRIS, and DOP index methods were analyzed to determine the order of the fertilizer requirements for the low-yielding orchards: Mg > Fe > S > Zn > B > Cu > K > N > P > Mn > Ca, and for the medium-yielding orchards: Mg > Fe > B > Zn > S > Cu > N > Mn > K > P > Ca. The soil and leaf correlation analysis showed that the soil exchangeable Ca and effective Fe were significantly negatively correlated. Leaf Ca and Fe elements had a mutually antagonistic effect, leaf Mn-rich contents inhibited the uptake of the Mg and Fe elements, and low-yielding orchards had an excess of Mn and a deficiency of Mg. We found that there is lack of the Mg and Fe, a low content of the S and B, and an excess of the Ca and Mn in the mango orchards of the Baise karst area. We suggested that the DRIS graphical method is suitable for the diagnosis of three nutrient elements, and either the DRIS or M-DRIS index method can be chosen. The present research can be used for the precise fertilization of mango orchards in karst areas to improve the yield and quality of local mango orchards.

Impact of Twig-Tip Dieback on Leaf Nutrient Status and Resorption Efficiency of Mango Trees

“…The DOP index of mineral elements was determined to evaluate the deviation of the nutrient concentration from the optimum level [27,[35][36][37]. Regardless of the MTTD level, most of the analyzed nutrients (N, P, Ca, Mg, S, B, Cu, Fe, and Zn) had a negative DOP index, indicating that their concentrations were below the optimum concentration (Figure 5a), and only Mg had a higher concentration than the optimum level owing to its positive DOP index.…”

“…Therefore, it is important to elucidate the effects of MTTD on the nutrient dynamics and resorption efficiency (RE) of mangoes. Because leaves are the most dynamic and responsive plant part for metabolic activity and nutrient availability [27], leaf nutrient analysis provides the actual uptake of nutrients and indicates the existing nutrient levels when compared to the standard optimum leaf nutrient content [28]. Leaf analysis can identify imbalances and aid in formulating fertilizer recommendations to address nutritional deficiencies [16].…”

Impact of Twig-Tip Dieback on Leaf Nutrient Status and Resorption Efficiency of Mango (<em>Mangifera indica</em> L.) Trees

“…The DOP index of mineral elements was determined to evaluate the deviation of the nutrient concentration from the optimum level [29,[40][41][42]. Regardless of the MTTD level, most of the analyzed nutrients (N, P, Ca, Mg, S, B, Cu, Fe, and Zn) had a negative DOP index, indicating that their concentrations were below the optimum concentration (Figure 5a), and only Mg had a higher concentration than the optimum level owing to its positive DOP index.…”

“…Therefore, it is important to elucidate the effects of MTTD on the nutrient dynamics and RE of mangoes. Because leaves are the most dynamic and responsive plant part for metabolic activity and nutrient availability [29], leaf nutrient analysis provides the actual uptake of nutrients and indicates the existing nutrient levels when compared to the standard optimum leaf nutrient content [30]. Leaf analysis can identify imbalances and aid in formulating fertilizer recommendations to address nutritional deficiencies [15].…”

Interaction Mechanism of Fe, Mg and Mn in Karst Soil-Mango System

“…Healthy leaves in the non-karst areas were used as the background value. Therefore, the DRIS nutritional diagnosis according to Gott et al [28] and Huang et al [29] was carried out on the karst unhealthy mango leaves. The results showed that the unhealthy leaves were severely deficient in Fe and Mg, and severely in excess in Mn when compared with the healthy leaves (Figure 2b).…”