Integrated Nutrient Management Significantly Improves Pomelo (Citrus grandis) Root Growth and Nutrients Uptake under Acidic Soil of Southern China

Abstract

Root system plays a crucial role in plant growth and development by uptake of soil nutrients, which is affected by intensive use of NPK fertilizer. However, it is unknown how integrated nutrient management (INM) could affect the root growth and its nutrient uptake in the red soils of southern China. For this, the impacts of different INM practices on root morphological traits and root nutrient uptake were investigated in the pomelo tree. First, we investigated the spatial root distribution of various tree ages (i.e., 8, 13, 18, and 23 years old) and found the optimum root growth at 20–80 cm around the tree trunk in topsoil (0–20 cm). Hence, the pomelo trees were fertilized at 20–80 cm around the trunk, i.e., FFP (farmer fertilization practice), optimization NPK fertilizer (O) combined with lime (L) and mushroom residue (M) known as O+L+M treatment, and O+L combined with Mg fertilizer called as O+L+Mg treatment. We found that root length (RL) significantly increased by application of O+L+M (108.5 and 219.1 cm) and O+L+Mg (73.6, 66.8 cm) in topsoil and subsoil, respectively, in 2019. Similarly, root surface area (RSA) was significantly higher under INM, i.e., O+L+Mg > O+L+M > FFP. For root diameter (RD), O+L+M (0.8 mm) and O+L+Mg (1.5 mm) showed significantly lower diameter than FFP (2.54 mm). The root tips (RT) also improved considerably under INM practices compared with FFP. Besides, root nutrient contents (N, P, K, Ca, and Mg) also significantly improved under O+L+M and O+L+Mg over FFP. Overall, these findings suggest that INM plays a significant role in root development and nutrient uptake under acidic soil, which could be useful for maximizing crop productivity.

Effects of Chemical Fertilizer Combined with Organic Fertilizer Application on Soil Properties, Citrus Growth Physiology, and Yield

“…According to Xiao et al [19], organic fertilizer combined with compound fertilizer improved soil quality, whereas the utilization of compound fertilizer worsened soil quality and made the soil acidize; this result was similar to that of Song et al [20] and Pachuau et al [23]. Qiu et al [15] reported that chemical fertilizer combined with biofertilizer application significantly promoted root growth, improved the rate of nutrient distribution in citrus, and improved the external and internal qualities of tarocco blood orange; this result was similar to those of previous study of citrus [24][25][26]. According to Pei et al [7], organic fertilizer is an alternative to chemical fertilizer with no loss in yield and fruit quality for citrus.…”

“…This has led to deterioration of soil properties and ecological environment. However, a combination of chemical and organic fertilizer is not only beneficial in improving the properties and environment of soils, but also promotes crop yield and quality [19][20][21][22][23][24][25][26][27][28][29][30]. Here, our work confirmed that CFOF was helpful in increasing citrus yield and improving soil properties.…”

Effect of Different Levels of Zinc and Compost on Yield and Yield Components of Wheat

“…Ample uptake of P in plants promotes better yield attributes through enhancement of root elongation [55]. Healthy roots facilitate the optimum uptake of water and nutrients in plants, thus causing a significant enhancement in the grain weight [56]. They also regulate physiological, phonological and morphological processes in plants, causing significant improvements in quality attributes.…”

Soil pH: a key edaphic factor regulating distribution and functions of bacterial community along vertical soil profiles in red soil of pomelo orchard

“…This region is characterized by subtropical monsoon climatic conditions with an annual precipitation 1600–2000 mm, and an average annual temperature ranges from 17.5–21.34ºC. The soil type is classified as haplic ferrasol with sand, silt and clay about 39.2%, 35.8%, and 25.1%, respectively [ 63 , 64 ]. In June 2019, we collected 57 soil samples of the red soil from three different vertical soil depths, i.e., 0–20 cm (RS1), 20–40 cm (RS2), and 40–60 cm (RS3) and each depth contained 22, 17, and 18 soil samples, respectively, with the removal of top 5 cm soil layer to evade the exogenous disturbance.…”