Midseason application of organic fertilizer improves yield and nitrogen uptake in rice

Abstract

Organic rice (Oryza sativa L.) systems in California utilize a 30‐d drain approximately one month into the growing season to control weeds. This drain may result in N losses and reduce yields. Two field trials were initiated to evaluate whether top‐dressing fertilizer N following the drain period could mitigate this problem by increasing N uptake and yields. Treatments evaluated rates and sources of commercially available organic fertilizers varying in N content and C to N ratio. The six treatments were a control with no top‐dress fertilizer, and top‐dress applications of 12–3–0 (applied at 22, 45, and 67 kg N ha−1) and 6–3–2 and 4–1–4 applied at 45 kg N ha−1. Total plant N uptake at harvest increased linearly with increasing N rate at both locations. At both sites, grain yields increased linearly (by 15 to 22 kg ha−1 for every kg N ha−1 applied) up to 45 kg N ha−1 above which yields plateaued at one site but continued to increase linearly at the other site. Application of 12–3–0 increased yields relative to the control at both locations but yields were not significantly different between the three fertilizer sources at the 45 kg N ha−1 rate at either location. Total plant N uptake and N recovery were higher in the 12–3–0 treatment compared to the other fertilizer sources at only one location. An economic analysis indicates that at the yield responses reported here, top‐dress N fertilizer applications were economical.

One-time fertilization of controlled-release urea with compound fertilizer and rapeseed cake maintains rice grain yield and improves nitrogen use efficiency under reduced nitrogen conditions

“…In contrast, our results showed that the RNF and CRF treatments exhibited no significant differences in NUE under the same N level, which may be attributable Hu et al 10.3389/fpls.2023.1281309 to the different release times of CRU or the CRU-CU mixing ratio. In previous studies, under reduced N conditions, increasing plant density or organic fertilizer increased N uptake and NUE (Murray and Linquist, 2020;Luo et al, 2022). In this study, the CRF+ID treatment improved N uptake and NUE (NRE, NAE, and FPN) compared with RNF and CRF treatments.…”

Greenhouse gas emissions and grain arsenic and cadmium concentrations as affected by a weed control drainage in organic rice systems

“…Fields are then reflooded and remain so for duration of the season. Fertility management in these systems often involves the application of manures before planting and just before reflooding, following the weed control DD (Murray et al., 2020; Wild et al., 2011).…”