Continuous applications of biochar to rice: Effects on nitrogen uptake and utilization

Abstract

Improving soil quality is critical for increasing rice yield, and biochar could be a beneficial soil amendment for high yield. This study was conducted to determine the effects of continuous (repeated seasonal) applications of biochar on nitrogen (N) uptake and utilization in rice. A fixed field experiment was done in Yongan Town, Hunan Province, China, in six continuous seasons (the early and late rice-growing seasons from 2015 to 2017). Results showed that biochar application did not significantly affect soil N uptake in the first four seasons. The effect of biochar application on fertilizer N uptake was not significant in three of the first four seasons. In the fifth and sixth seasons, biochar application resulted in 14–26% increases in soil N uptake but 19–26% decreases in fertilizer N uptake. Soil N availability did not explain the increased soil N uptake with biochar application. The decreased fertilizer N uptake with biochar application was attributed to both decreased fertilizer N availability and increased N loss through ammonia volatilization. As a consequence of a compensation between the increased soil N uptake and the decreased fertilizer N uptake, the effect of biochar application on total N uptake was not significant in the fifth and sixth seasons. However, biochar application led to 7–11% increases in internal N use efficiency in the fifth and sixth seasons and 6% increase in grain yield in the sixth season. Our study suggests that the effects of repeated seasonal applications of biochar on N uptake and utilization in rice depend on the duration of biochar application. Longer continuous applications of biochar can increase internal N use efficiency and grain yield in rice with insignificant change in total N uptake.

Soil–climate contribution to DNDC model uncertainty in simulating biomass accumulation under urban vegetable production on a Petroplinthic Cambisol in Tamale, Ghana

“…Similarly, Huang et al. () showed in a field experiment that biochar was able to increase soil N uptake in rice on a clay soil after a two‐year application.…”

Effects of Mixed Controlled Release Nitrogen Fertilizer with Rice Straw Biochar on Rice Yield and Nitrogen Balance in Northeast China

“…In addition, MBCB also had a better effect on N uptake than did MBC. Previous studies also found that biochar used as compound fertilizer and combined with chemical nutrients could significantly increase both nitrogen-use efficiency and agronomic-use efficiency by 43.1% 7,31 . This may be because the adsorption function of biochar improves soil physical and chemical properties, making them more conducive to the growth of rice roots 32 .…”

“…Previous studies noted that biochar application alone led to an increase of 7-16.5% in N-use efficiency 32,37 . Other studies also showed that the nutrient supply capacity of biochar in combination with N fertilizer was www.nature.com/scientificreports www.nature.com/scientificreports/ greater than that of biochar or N fertilizer alone 31,35 . This may have promoted the adsorption function of biochar, which improves N uptake and reduces the N loss 36 .…”

Effects of Different Feedstock Type and Carbonization Temperature of Biochar on Oat Growth and Nitrogen Uptake in Coapplication with Compost

“…For example, phosphorus availability in organic amendments and biochar application varied with soil and manure types, and the biochar's ability to phosphorus sorption was highly influenced by soil acidity (Ara et al 2018;Xu et al 2014). Further, some recent studies have reported that the impact of biochar application on soil properties and plant growth in long-term cultivation sometimes differs from the impact observed after short-term use (Huang et al 2018;Oladele 2019). These studies suggest that the proposed coapplication method may also be affected by such conditions, and further examinations would be necessary before applying the coapplication technology on site.…”