Oilseed rape straw returning changes soil reducibility and affects the root and yield of rice in the rape‐rice rotation field at Sichuan Basin area of China

Abstract

To elucidate the influence of rape straw returning on soil reducibility and to understand its effects on rice growth and yield in rape-rice rotation system, 3 years field experiment with 8 treatments of straw incorporation carried out at Mianyang Sichuan Province of China. Results showed that the lowest RC Eh value founded at 14-18 d after rice planting; With the increasing of rape straw incorporation, the amount of root (number, weight and length) and root bleeding intensity both increased significantly during 27-32 d after rice planting; 0-20 d are the fast decomposing period of rape straw in rice field. At 10-22 d after rice planting, there is negative correlation between rice root growth and soil reducibility and a negative correlation between rice root and straw incorporation. Oil seed rape straw returning into soil, either by mulching or by ploughing, make the soil more reducible with lower Eh and higher content of reducing material, Fe 2+ and hinder the growth of rice root with lower amount (length, weight and number) and bleeding density during this period. Comparing with other straw returning methods, straw returning by ploughing method with the rape straw of 3.0 t/hm 2 is more suitable in rice-rape rotation farms where is convenient for mechanical operation. 1 INTRODUCTION Straw is a comparatively abundant resources in China, producing 0.79 billion tons of straw annually (Zou et al., 2016). Considering from effective use of straw resources, more Abbreviation: RC Eh , Daily changes of soil redox potential; RC Fe , Daily changes of Fe2+ in soil; RC RBI , Daily changes of root bleeding intensity of rice; RC RLT , Daily changes of the total length of rice root; RC RLW , Daily changes of the length of white rice root; RC RNT , Daily changes of the total number of rice root; RC RNW , Daily changes of the number of white rice root; RC RQT , Daily changes of the total weight of rice root; RC RRM , Daily changes of total reduction substances in soil.

Increasing basal nitrogen fertilizer rate improves grain yield, quality and 2-acetyl-1-pyrroline in rice under wheat straw returning

“…Straw returning is an effective way to improve soil properties and fertility. Many studies have shown that straw returning can improve the soil nutrient content and promote the uptake of soil nitrogen by roots, thus increasing the rice yield, and the yield increases with the increase of straw returning years ( Wang et al., 2020 ; Cui et al., 2022 ). However, some studies held that straw returning has no significant effect on rice yield and even has a tendency to reduce it, which is related to soil texture and tillage methods ( Zhu et al., 2011 ; Zhang et al., 2016 ).…”

Fallow weed application alters rice yield by changing nitrogen uptake

“…, 1999); (2) reducing soil oxygen content and consequently inhibiting the growth and development of rice roots (Wang et al ., 2019); and (3) producing reducing substances that have toxic effects on rice roots (Wang et al. , 2020). These possible contributing factors highlight the need for a fundamental understanding of the effects of fallow weed decomposition on soil biological and chemical properties in rice paddies.…”

“…The present study showed that the application of fallow weeds reduced aboveground N uptake and biomass production during the early growth period (from transplanting to MT) in rice. This could be attributable to decomposition of fallow weeds (1) stimulating immobilization of N by soil microorganisms, resulting in N competition between soil microorganisms and rice roots (Cheshire et al, 1999); (2) reducing soil oxygen content and consequently inhibiting the growth and development of rice roots (Wang et al, 2019); and (3) producing reducing substances that have toxic effects on rice roots (Wang et al, 2020). These possible contributing factors highlight the need for a fundamental understanding of the effects of fallow weed decomposition on soil biological and chemical properties in rice paddies.…”

Optimizing Planting Density and Impact of Panicle Types on Grain Yield and Microclimatic Response Index of Hybrid Rice (Oryza sativa L.)

“…Mianyang (104.73°E, 31.47°N), located at the middle and upper reaches of the Fujiang River (Wang et al, 2020), has a typical subtropical monsoon climate, with an average annual temperature of 14.7-17.3 ℃ and average annual precipitation of 826-1417 mm. Its soil is typical clay-loam soil, with a bulk density of 1.29 g/cm 3 and organic matter content of 28.6 g/kg; its total nitrogen content is 1.68 g/kg, the total phosphorus is 0.37 g/kg, and the total potassium is 1.86 g/ kg, in 0-50 cm soil.…”