Effects of Soil Types and Irrigation Modes on Rice Root Morphophysiological Traits and Grain Quality

Abstract

Soil moisture plays an important role in rice (Oryza sativa L.) root development and grain quality. However, little is known about the effects of soil type on rice root morphophysiological traits (RMTs) and grain quality under different irrigation modes. A soil-grown experiment was conducted during the 2016–2017 rice growing seasons in Yangzhou city with three soil types, namely, clay soil, loamy soil, and sandy soil, and three irrigation regimes, namely, conventional irrigation (CI, 0 kPa), alternate wetting and moderate drying (AWMD, −15 kPa), and alternate wetting and severe drying (AWSD, −25 kPa). The AWMD regime improved the RMT by 3.05–48.95% when compared with the CI and AWSD regimes, and the RMTs in loamy were 7.38–93.67% higher than those in clay and sandy soil under AWMD across 2016 and 2017. The AWMD regime improved the rice milling quality and appearance quality both in clay and loamy soil by 2.88–10.08% and 15.43–45.77%, respectively. The CI regime improved the processing quality and nutritional quality of rice in sandy soil. Both loamy and clay soils improved the rice RMTs and grain quality under an AWMD regime. The RMTs were very significantly correlated with water use efficiency, rice milling, and cooking quality and were negatively correlated with rice appearance quality. The AWMD regime can affect the rice RMT and can improve the rice grain quality in loamy soil. Our results provide a theoretical basis for the design of water-saving rice irrigation regimes and for an improvement in rice grain quality in the process of rice cultivation.

Yield, Grain Quality, and Starch Physicochemical Properties of 2 Elite Thai Rice Cultivars Grown under Varying Production Systems and Soil Characteristics

“…The results of amylopectin fine structure of starches isolated from the two rice cultivars revealed differences in CLD of amylopectin branches between the net-house pot and open-field production systems (Table 5). Generally, amylopectin branch chains are compartmentalized into four different chain types including A chains (DP 612), B1 chains (DP 13-24), B2 chains (DP [25][26][27][28][29][30][31][32][33][34][35][36], and B3+ chains (DP ≥ 37) [9,48]. Here, the sensitivity of the HPAEC-PAD system allowed the resolve of glucans with DP ≤ 56.…”

“…Nonetheless, these elite rice cultivars grown in distinct cultivation locations display significant variations in grain qualities such as grain appearance (e.g., grain length or grain size and grain length-towidth ratio or grain shape), grain storage product composition, and starch physicochemical properties [22,23]. These grain quality parameters could be directly affected by the soil's physical and chemical characteristics, which vary based on production systems and climatic conditions within each cultivation location [22,[24][25][26]. In several agricultural areas, various types of crop production system are crucial agricultural practices that influence soil physical characteristics and play important roles in maintaining good soil condition [23,26,27].…”

“…These grain quality parameters could be directly affected by the soil's physical and chemical characteristics, which vary based on production systems and climatic conditions within each cultivation location [22,[24][25][26]. In several agricultural areas, various types of crop production system are crucial agricultural practices that influence soil physical characteristics and play important roles in maintaining good soil condition [23,26,27]. Good soil condition includes the availability and movement of water and air in the soil as well as the existences of organic matter (OM), lime requirement (LR), and three major elements (i.e., nitrogen (N), phosphorous (P), and potassium (K)) throughout the plant growth stages [26,[28][29][30].…”

“…In several agricultural areas, various types of crop production system are crucial agricultural practices that influence soil physical characteristics and play important roles in maintaining good soil condition [23,26,27]. Good soil condition includes the availability and movement of water and air in the soil as well as the existences of organic matter (OM), lime requirement (LR), and three major elements (i.e., nitrogen (N), phosphorous (P), and potassium (K)) throughout the plant growth stages [26,[28][29][30]. These are greatly necessary for growth and development of the rice plant, and eventually improve its yield and grain eating and cooking quality [23,26,28,31].…”

“…Good soil condition includes the availability and movement of water and air in the soil as well as the existences of organic matter (OM), lime requirement (LR), and three major elements (i.e., nitrogen (N), phosphorous (P), and potassium (K)) throughout the plant growth stages [26,[28][29][30]. These are greatly necessary for growth and development of the rice plant, and eventually improve its yield and grain eating and cooking quality [23,26,28,31]. Not only the nutrient deficiency condition but also the nutrient toxicity condition owing to excessive supplies of nutrients can enhance the invasion of pathogen and insects [32,33].…”