Forage rice varieties Fukuhibiki and Tachisuzuka emit larger CH₄than edible rice Haenuki

Abstract

To determine methane (CH 4) emission differences between edible and forage rice cultivars, we conducted a pot experiment in Yamagata, Japan to grow edible rice Haenuki, and forage rice Fukuhibiki (for feed rice) and Tachisuzuka (for whole-crop silage (WCS) rice) under similar soil and meteorological conditions. The total amounts of N, P, and K fertilizers applied for Fukuhibiki and Tachisuzuka were 1.7, 1.3, and 1.3 times, respectively, higher than those of Haenuki. CH 4 fluxes, and rice plant night respirations were measured once weekly or fortnightly. As per the results, for the whole growth period, shoot height, maximum and productive tiller numbers, and plant biomass were significantly different among the three rice varieties. The rice growth period for Haenuki and Fukuhibiki was 107 days after transplanting (DAT), while that for Tachisuzuka was 135 DAT. The highest peak of CH 4 flux occurred around the heading stage for the three varieties. Consistently significant (P < 0.05) or obvious (P < 0.1) positive correlations between CH 4 flux and night respiration among the varieties were observed from 9 weeks after rice transplanting to harvest, indicating that much of the CH 4 flux was from newly produced root exudates and plant debris through plant photosynthesis. The cumulated CH 4 emissions during the same growth period, 106 DAT, from Haenuki, Fukuhibiki, and Tachisuzuka were 55.36, 77.46, and 78.40 g C m −2 , respectively. Additionally, Tachisuzuka emitted 25.11 g C m −2 more CH 4 between 106-134 DAT. The final cumulated CH 4 emissions from Fukuhibiki and Tachisuzuka were 39.9% and 87.0% higher than that from Haenuki, respectively, throughout their growth period.

Ensuring Nutritious Food Under Elevated CO2 Conditions: A Case for Improved C4 Crops

“…In this same study, the Mn content in the brown rice decreased by 7%, while the polished rice showed a 20.5% decrease in Mn when grown under elevated CO 2 (Ujiie et al, 2019). The vast differences observed in Mn content in different tissues is a significant finding as rice is becoming an important forage crop in some regions of the world (Cheng et al, 2018). While Mn deficiency in forage animals is considered rare, such a significant decrease in micronutrients in the body of the plant suggests that forage animal nutrition will also suffer as a result of rising CO 2 .…”

Variable-timing, fixed-rate application of cattle biogas effluent to rice using a leaf color chart: microcosm experiments in Vietnam

“…Livestock production has dominated agricultural land use over the last 50 years, accounting for 65% of the land-use change (Alexander et al 2015). Such change of land use to livestock production (Cheng et al 2018) causes not only increased greenhouse gas emissions (e.g., Gerssen-Gondelach et al 2017;Caro et al 2018), but also local environmental problems, such as eutrophication and water pollution (e.g., Abe et al 2016;Wang et al 2018).…”

Continuous Sub-Irrigation with Treated Municipal Wastewater for Protein-Rich Rice Production with Reduced Emissions of CH4 and N2O

“…High grain yields of protein-rich forage rice have been produced using those novel systems, in which higher yield and rice protein content were achieved using the continuous sub-irrigation system compared with the surface irrigation system 4 . As a result, our cultivation systems are expected to promote the low-cost production of protein-rich forage rice and improve the efficiency of farmland, which inevitably secures domestic livestock production and stops the increase in abandoned farmland that has been observed in Japan since the 1970s 13 .…”

“…However, forage rice varieties have been recently reported to emit more CH 4 than common staple rice probably owing to the increased biomass production when cultivated under similar growth conditions, which indicates a possible increase in CH 4 emissions from the agricultural sector in Japan owing to the increasing production of forage rice 13 . In addition, an earlier study on wastewater irrigation in rice paddy fields claimed that the increased emissions of CH 4 and N 2 O from wastewater-irrigated fields resulted from the high availability of elements in the wastewater, such as organic C and N 14 .…”