Effects of supplemental irrigation on winter wheat starch structure and properties under ridge-furrow tillage and flat tillage

Optimization of the morphological, structural, and physicochemical properties of maize starch using straw returning and nitrogen fertilization in Northeast China

The combination of straw returning and nitrogen (N) fertilization is a popular tillage mode and essential strategy for achieving stable yield and high quality. However, the optimal combination strategy and the influence of tillage mode on the morphological, crystalline, and molecular structures of maize starch remain unclear. We conducted a long-term field experiment over 7 years in Northeast China using two tillage modes, rotary tillage with straw returning (RTS) and plow tillage with straw returning (PTS), and four N application rates. The relative crystallinity, 1045/1022 cm-1 value, and B2 and B3 chains of maize starch were higher under RTS than under PTS, resulting in increased stability of starch and improvements in gelatinization enthalpy and temperature. The surface of the starch granules induced by N fertilizer was smoother than that under the N0 (0 kg N ha-1) treatment. The proportion of amylose content, solubility, swelling power, and light transmittance increased under N2 (262 kg N ha-1) treatment, along with improvement in starch pasting properties. These results suggest that RTS combined with N2 treatment can regulate the morphological, structural, and physicochemical characteristics of maize starch, providing an essential reference for improving the quality of maize starch from an agronomic point of view.

Strategies for starch customization: Agricultural modification

Raw starch is commonly modified to enhance its functionality for industrial applications. There is increasing demand for 'green' modified starches from both end-consumers and producers. It is well known that environmental conditions are key factors that determine plant growth and yield. An increasing number of studies suggest growth conditions can expand affect starch structure and functionality. In this review, we summarized how water, heat, high nitrogen, salinity, shading, CO2 stress affect starch biosynthesis and physicochemical properties. We define these treatments as a fifth type of starch modification method - agricultural modification - in addition to chemical, physical, enzymatic and genetic methods. In general, water stress decreases peak viscosity and gelatinization enthalpy of starch, and high temperature stress increases starch gelatinization enthalpy and temperature. High nitrogen increases total starch content and regulates starch viscosity. Salinity stress mainly regulates starch and amylose content, both of which are genotype-dependent. Shading stress and CO2 stress can both increase starch granule size, but these have different effects on amylose content and amylopectin structure. Compared with other modification methods, agricultural modification has the advantage of operating at a large scale and a low cost and can help meet the ever-rising market of clean-label foods and ingredients.

Comparison of the fine structure and physicochemical properties of proso millet (Panicum miliaceum L.) starch from different ecological regions

Field experiments were conducted to evaluate the morphology, granule size, fine structure, thermal properties, and pasting properties of starch from a waxy (139) and a non-waxy (297) varieties of proso millet grown in Yulin (YY) and Yangling (YL). Compared with the starches from the two varieties grown in YY, the starches from the two varieties grown in YL exhibited higher relative crystallinities, 1045/1022 cm-1 ratio, and amounts of amylopectin long branch chains (APL) but lower 1022/995 cm -1 ratio, amounts of amylopectin short branch chains (APs), and APs/APL ratios. Starches from YL also synthesized long branch-chain amylopectin to enhance intermolecular interactions and form a stable granular structure, which resulted in increased starch gelatinization temperature, enhanced shear resistance, and reduced setback viscosity. Starch from the waxy (139) variety has good application prospects in the food industry because of its high gelatinization temperature and light transmittance and low setback value, which can be ascribed to its extremely low amylose content, polydispersity index, high molecular weight, and dispersed molecular density. It may serve as a reference for applying proso millet starches in the food industry and developing breeding programs to improve starch quality.

Ridge cropping and furrow irrigation pattern improved spring maize (Zea mays L.) yield and water productivity in Hetao irrigation area of north-western China

BACKGROUND

Improving irrigation water productivity is vital for sustaining high maize yield in Hetao irrigated area of northwest China. Whether ridge cropping and furrow irrigation systems (planting both on ridges and in furrows) fulfill water-saving and maize yield-increasing is unclear. A 2-year trial was conducted to reveal the influence of irrigation with three levels (270, 225, 180 mm, represented as I₂₇₀ , I₂₂₅ , I₁₈₀ , respectively) under two planting systems [traditional flat planting system (TFI) and ridge cropping and furrow irrigation system (RFI)] on maize growth, grain yield, water use efficiency (WUE) and irrigation water use efficiency (IUE).

RESULTS

RFI system increased soil water storage in 0-100 cm layer (P < 0.05), but did not cause excess water consumption, compared to TFI system. Logistic equation simulation showed that RFI system advanced the time of maximum dry matter growth rate (T_max , 2.6-4.9 days) and prolonged the duration of dry matter accumulation (T_d , 3.2-4.7 days), ultimately obtained a 4.2-9.5% improvement of dry matter. Compared with TFI system, RFI system increased WUE by 8.0-21.2%, IUE by 8.3-20.5% and grain yield increased by 9.4-21.4%. RFI₂₂₅ satisfied water-saving by 16.6% and yield-increasing by 3.6-14.7%.

CONCLUSION

Ridge cropping and furrow irrigation systems brought an improvement of soil water storage and dry matter accumulation and kernel per spike, and ultimately obtained an increase of grain yield and water productivity. © 2022 Society of Chemical Industry.