No abstract

No abstract

Furrow-irrigated rice (Oryza sativa L.) is a relatively new production system that has been shown to have increased water-use efficiency and reduced operational costs.However, due to spatial variations in soil moisture, field studies are necessary to evaluate potential resulting variations in rice growth and yield in the furrow-irrigated production system. This study was conducted to evaluate the effects of tillage practice (conventional tillage, CT; no-tillage, NT) and site position (up-, mid-, and downslope) on aboveground biomass, yield, and plant nutrient uptake from rice grown in a silt-loam soil in a direct-seeded, furrow-irrigated production system in eastern Arkansas. Field research was conducted from May to September during the 2018 and 2019 rice growing seasons. Total aboveground dry matter, vegetative dry matter, and yield were unaffected (P > .05) by tillage treatment or site position in either growing season. Vegetative tissue nutrient concentrations and uptake were generally at least 10% greater (P < .05) under CT than NT but did not substantially differ by site position during the drier growing season (2018). During the wetter growing season (2019), vegetative tissue nutrient concentrations and uptake were generally at least 20% greater (P < .05) at the up-than at the mid-or down-slope positions.Results suggest that different approaches, in terms of soil and nutrient management per site position, in combination with tillage practices, may need to be considered for implementation to maximize nutrient uptake and reduce losses, thus improving the agronomic suitability of the furrow-irrigated rice production system. INTRODUCTIONRice (Oryza sativa L.) is a staple food for a large human population and is grown in many areas around the globe.

No abstract

In recent years, electrochemical precipitation has gained interest as an alternative method for the synthesis of various minerals, including struvite, from waste streams that can serve as an alternative fertilizer. Studies in lowland cultivations, specifically rice (Oryza sativa) under flood-irrigated conditions, evaluating struvite as a possible alternative phosphorus (P) fertilizer source have been limited. The objective of this study was to evaluate rice response to electrochemically precipitated struvite (ECST) compared to triple superphosphate (TSP), diammonium phosphate (DAP), a chemically precipitated struvite (CPST), and an unamended control (UC), grown under flooded-soil conditions in the greenhouse. Aboveground vegetative dry matter (DM) P concentration was greatest from the UC (0.18%) and was lowest from DAP (0.08%). Root DM Mg concentration was greatest from ECST (0.13%) and was lowest from TSP (0.10%). Grain yield was greatest from DAP (11.2 Mg•ha −1 ) and was lowest from the UC (4.0 Mg•ha −1 ). Grain N, P, K, and Mg uptake were consistently greatest from DAP and consistently lowest from the UC. Grain N concentration was 1.1 times greater from CPST than from ECST, while all other measured rice properties did not differ between the struvite-P sources. The many similar rice responses between struvite materials (ECST and CPST) and TSP and DAP demonstrate that struvite, particularly ECST, is a valid alternative fertilizer-P source for rice-production systems. Further studies should evaluate potential environmental implications (i.e., runoff water quality and greenhouse gas emissions) from struvite use that could affect agricultural sustainability.