Deep fertilization with controlled‐release fertilizer for higher cereal yield and N utilization in paddies: The optimal fertilization depth

Abstract

Belowground fertilization is a prevalent strategy for considerable grain yield and N utilization. However, the optimal fertilization depth remains uncertain in paddies, especially for slow/controlled release fertilizers. This study aimed to clarify the effect of deep "controlled-release blended fertilizer" (CRBF) fertilization on rice (Oryza sativa L.) yield and N utilization. Two N-fertilizer types were selected (a) urea and (b) CRBF, both combined at three fertilization depths (a) 0 cm, (b) 5 cm, and (c) 10 cm. The results showed that the grain yield was significantly affected by fertilizer type and fertilization depth. The yield achieved from CRBF was 7.8% higher than that from the urea application. Deep fertilization could also increase the rice yield with the optimum achieved from the 5-cm depth fertilization (yield increased by 15.1% compared to that from the manual surface fertilization). Overall, the 5-cm depth CRBF fertilization achieved the highest yield among all treatments with 12.21 and 11.84 t ha -1 for 2018 and 2019, respectively. The larger sink was the main reason for this performance. Additionally, the higher photosynthetic efficient population after earing was another principal driver to the higher yield from CRBF. Due to the higher N uptake, CRBF application increased both N partial factor productivity (PFP) and recovery efficiency (RE) (P < .05); fertilization depth also had a striking effect on PFP and RE (P < .05 or .01). The 5-cm depth fertilization of CRBF achieved the highest N utilization for both years. The results suggest that 5-cm depth fertilization combined with controlled-release fertilizer is a suitable strategy for higher rice yield and N utilization.

Combing mechanical side-deep fertilization and controlled-release nitrogen fertilizer to increase nitrogen use efficiency by reducing ammonia volatilization in a double rice cropping system

“…Li et al (2021) reported that mechanical deep placement with single basal fertilization of compound fertilizer could increase the grain yield and the nutrients uptake of early rice compared to broadcasting of fertilizer. Hou et al (2021) found that deep placement of CRF was a more efficient strategy for higher grain yield and NUE of rice than deep placement of urea. Considering farmers' interest, rice yield, environmental impact and economic benefit, MRSF with a one-time application of CRF is a promising fertilizer management method for double-cropping rice production in southeast China.…”

“…Compared to the CFD treatment, the combined side-deep placement and CRF further reduced the cumulative NH 3 volatilization loss in 2019 (Table 2). This is because the N released from compound fertilizers is faster than that from CRF, which may result in higher NH 4 + -N in surface water (Hou et al, 2021). The CRFD2 treatment had a higher NH 3 volatilization loss than the N0 treatment, indicating that a small quantity of NH 4 + -N may diffuse upward to the soil surface and flooded water (Huda et al, 2016;Yao et al, 2018b); which, in turn, increases the NH 3 emissions in the CRFD2 treatment.…”

“…In 2021, the rice grain yields in MRSF with CRF were higher than in the MRSF with compound fertilizer in both seasons (Figure 5C). Deep placement of CRF can increase rice yield and N utilization compared to urea deep placement due to continuous supply high level of NH 4 + -N to rice plant under MRSF with CRF during rice growing season (Hou et al, 2021;Ke et al, 2018).…”

Green Manure Amendment in Paddies Improves Soil Carbon Sequestration but Cannot Substitute the Critical Role of N Fertilizer in Rice Production

“…The specific fertilizer applications are shown in Table 1. The "pre-flooding, mid-aeration and post-drying (preharvest)" mode was used as the irrigation strategy; further details are provided by Hou et al (2021) [20]. The experiment was carried out with two-factor randomized complete block design.…”

“…The seasonal precipitation between trial years is expected to be responsible for the difference of grain yield [38]. It has been proved that the ability of photosynthesis to synthesize carbohydrates after anthesis is a crucial factor affecting rice yield [20,39]. In this context, high-frequency precipitation after anthesis in 2020 (Figure 1) could reduce rice yield by affecting photosynthesis.…”