Search Results (27)

Mitigation of greenhouse gases (GHGs), improving nutrient-use efficiency (NUE), and maximizing yield in rainfed lowland rice cultivation poses significant challenges. To address this, a two-year field experiment (2020 and 2021) was conducted in Assam, India, to examine the impact of different fertilizer-management practices on grain yield, NUE, and GHGs in wet direct-seeded rice (Wet-DSR) during the kharif season. The experiment included eight treatments: control; farmer’s practice (30-18.4-36 kg N-P₂O₅-K₂O ha⁻¹); state recommended dose of fertilizer (RDF) @ 60-20-40 kg N-P₂O₅-K₂O ha⁻¹ with N applied in three splits @ 30-15-15 kg ha⁻¹ as basal, at active tillering (AT), and panicle initiation (PI); best fertilizer management practices (BMPs): 60-20-40 kg N-P₂O₅-K₂O ha⁻¹ with N applied in three equal splits as basal, at AT, and PI; and fertilizer deep placement (FDP) of 120%, 100%, 80%, and 60% N combined with 100% PK of RDF. The experiment was arranged out in a randomized complete block design with three replications for each treatment. The highest grain yield (4933 kg ha⁻¹) and straw yield (6520 kg ha⁻¹) were achieved with the deep placement of 120% N + 100% PK of RDF. FDP with 80% N + 100% PK reduced 38% N₂O emissions compared to AAU’s RDF and BMPs, where fertilizer was broadcasted. This is mainly due to the lower dose of nitrogen fertilizer and the application of fertilizer in a reduced zone of soil. When considering both productivity and environmental impact, applying 80% N with 100% PK through FDP was identified as the most effective practice. Full article

Mechanical transplanting has become an important part of modern Chinese rice production, and an inadequate sowing rate severely inhibits rice seedling growth and development. Precision drill sowing is an effective method for obtaining higher quality seedlings during machine transplanting. There is a lack of systematic research on the precision drilling of rice. Therefore, we carried out research on the quality of machine-transplanted seedlings and precision drill sowing transplantation. A greenhouse experiment (Liaoning Rice Research Institute) and field experiment (Sujiatun District, Shenyang City, Liaoning Province, China) were conducted between 2020 and 2021 to analyze the influence of precision drill sowing on rice growth and yield. Precision drill sowing was conducted at four sowing rates (3400, 3600, 3800, and 4000 seeds/tray), and traditional broadcasting was also conducted at a sowing rate of 4000 seeds/tray. We evaluated the seedling rice quality, physiological and biochemical characteristics and transplanting quantity. The results indicated that precision drill sowing at a sowing rate of 3400 seeds/tray resulted in the highest plumpness value (0.18) and seedling strength index (0.42) of individual plants. However, the empty hill rate was as high as 3.05%, which did not satisfy the field seedling number requirement. Precision drill sowing at a sowing rate of 4000 seeds/tray resulted in the lowest physiological (the average levels of SOD, POD and soluble protein were 311.78 µg/g, 8.25 µg/g and 1.28 µg/g) and biochemical indices of individual plants. The damaged seedling rate increased by 2.07%, and the dead seedling rate increased by 0.25%, resulting in poor seedling and transplanting quality. In this study, 3800 seeds/tray was the best option and had the highest yields of 10,776.60 kg/ha and 10,730.85 kg/ha over the two years. This sowing approach performs well in terms of field transplanting, provides a balance point between seedling number and quality and is conducive to rice yield production. The results of this study are important for improving rice seedling quality, enhancing field transplanting quantity and increasing rice yield and food security. Full article

High temperature frequently occurs during rice’s early grain-filling period in the south of China, negatively affecting rice yield and quality and posing a major threat to local rice production. This experiment researched the influence of 3.5 °C warming during the first 20 grain-filling days on rice yield and quality and emphatically investigated the effects of the low-broadcast nitrogen fertilizer application level (LBN), high-broadcast nitrogen fertilizer application level (HBN) and foliar nitrogen fertilizer application (FN) at heading on the rice organ temperature, leaf photosynthesis, chlorophyll fluorescence, yield and grain quality, pasting and thermal properties under high temperature in 2020 and 2022, with a widely planted japonica rice variety, “Wuyunjing31”, in order to explore the practical mitigation measures for reducing the adverse impact of high temperature on rice productivity. The results showed that high temperatures during grain filling increased the rice plant temperature, damaged the chlorophyll fluorescence system and decreased the net photosynthesis rate. This led to a decline in the seed-setting rate and grain weight, resulting in a 7.0% and 13.9% yield loss in 2020 and 2022, respectively. In addition, high temperature caused a decline in the head rice rate and an increase in chalk occurrence and pasting temperature, thereby deteriorating rice grain quality. Under high temperatures, HBN enhanced the rice yield by 3.6% and 13.0% in 2020 and 2022, respectively, while FN enhanced the rice yield by 11.5% in 2022. The increase in yield was linked to the increased seed-setting rate and 1000-grain weight. LBN did not significantly affect the rice yield under high temperatures. The positive effects of nitrogen fertilizer measures on rice yield were associated with their role in lowering plant temperature and protection against the damage to the chlorophyll fluorescence system. All three nitrogen application measures generally improved rice milling quality and appearance quality under high temperature, with HBN generally showing the greatest impact. Under high temperature, LBN and FN tended to make the texture of cooked rice softer due to the decreased consistency, retrogradation enthalpy and retrogradation percentage, and this was closely associated with the decline in amylose content. In summary, nitrogen supplementation at the heading could efficiently mitigate the adverse impact of high temperature during the early grain-filling period on rice yield and quality. Full article

The tillage method determines several soil physical parameters that affect the emergence of post-rice chickpea (Cicer arietinum L.) in the Indo-Gangetic Plain of South Asia. Mechanised row-sowing with minimum soil disturbance and crop residue retention in medium-to-heavy-textured soils will alter the seedbed when compared to that prepared after traditional full tillage and broadcast sowing. Whilst minimum soil disturbance and timely sowing may alleviate the soil water constraint to crop establishment, other soil physical properties such as soil strength, bulk density, and aggregate size may still inhibit seedling emergence and root elongation. This study’s objective was to determine the limitations to chickpea crop establishment with increasing bulk density and soil strength, and different aggregate sizes below and above the seed. In two growth cabinet studies, chickpea seed was sown in clay soil with (i) a bulk density range of 1.3–1.9 Mg m⁻³ (Experiment 1) and (ii) the combination of bulk densities (1.3 and 1.8 Mg m⁻³) and aggregate sizes (<2 mm and >4 mm) above and below the seed (Experiment 2). Root length was significantly reduced with increasing bulk density (>1.4 Mg m⁻³), and soil strength impeded early root growth at >1 MPa. Where main root growth was impeded due to high bulk density and soil strength, a greater proportion of total root growth was associated with the elongation of lateral roots. The present study suggests that the soil above the seed needs to be loosely compacted (<1.3 Mg m⁻³) for seedling emergence to occur. Further research is needed to determine the size of the soil aggregates, which optimise germination and emergence. We conclude that soil strength values typical of field conditions in the Indo-Gangetic Plain at sowing will impede the root growth of chickpea seedlings. This effect can be minimised by changing tillage operations to produce seedbed conditions that are within the limiting thresholds of bulk density and soil strength. Full article

Phosphorus (P) deficiency resulting from P fixation is a major constraint limiting sustainable rice cultivation in sub-Saharan Africa. Soil texture also affects P availability and use efficiency. In a factorial experiment, we evaluated the combined effect of soil texture (sand, clay loam, and clay) and P treatments P-dipping (Pdip) and two other broadcasted P fertilizer levels (Brod1 and Brod2) on the growth of NERICA 4 rice in the initial growth stages. Across all soil textures and P treatments, total plant biomass ranged from 1.06 to 4.63 g pot⁻¹. The Pdip treatment significantly increased shoot and root biomass relative to control from 1.27 to 1.98 and 0.23 to 0.38 g pot⁻¹, respectively. Mean photosynthetic rate values under Pdip (20.1 μmol m⁻² s⁻¹), Brod2 (19.5 μmol m⁻² s⁻¹), and Brod1 (19.3 μmol m⁻² s⁻¹) treatments showed significant 42%, 37%, and 36% increases over control, regardless of soil texture. In a striking contrast, P-dipping significantly promoted growth of root length under clay soil, but without a commensurate increase in shoot P uptake. Contrary to our hypothesis, the interactive effect of soil texture and P-dipping influenced NERICA 4 shoot and root physiological and morphological characteristics under clay loam soil texture as opposed to clay. Full article

Despite growing interest in controlled-release N fertilizers (CRNFs) because of their potential for enhancing nitrogen use efficiency (NUE) and economic returns, their comprehensive impact on machine-transplanted rice remains to be understudied. To address this gap, here, we present a two-year field experiment that assessed the impact of CRNF using mechanical deep placement fertilization (DPF) on rice cultivation. The study involved three CRNF types (bulk blending fertilizer (BBF), polymer-coated urea (PCU), and sulfur-coated urea (SCU)) and two fertilization methods (DPF and broadcast application), with a high-yield split fertilization of urea as a control (CK). The results showed that DPF, especially with SCU, greatly enhanced soil NH₄⁺-N concentrations, NUE, rice yield, and economic benefits compared to broadcast application. BBF consistently exhibited superior NUE and notable economic benefits, regardless of the application method used. Conversely, single-time application of PCU was less favorable for rice growth. In conclusion, for optimal economic benefits and NUE, DPF combined with single-time application of SCU is recommended. However, if deep application is not feasible and only broadcasting is possible in rice cultivation, BBF emerges as the ideal choice for both high NUE and significant economic returns. This research offers insights for improved nitrogen management in machine-transplanted rice, effectively optimizing yield, NUE, and profitability. Full article

This study aimed to assess the feasibility of a novel weeding and fertilization scheme, namely, mechanical weeding plus a one-time deep application of a reduced amount of slow-release fertilizer for rice cultivation. The effects of the weeding and fertilization method on rice yield and quality were investigated using a split plot test as the research method. Two weeding methods, namely, chemical weeding (CW) and mechanical weeding (MW), and four fertilization methods were tested, including the conventional fertilization method (quantitative split broadcast application of fast-release N fertilizer (CK)), the quantitative split broadcast application of 80% fast-release N fertilizer (LCK), the one-time base application of slow-release fertilizer (SR), and the one-time deep application of 80% slow-release fertilizer (LSR). The results showed that the rice yield under MW with LSR treatment can maintain a high level—higher than 9.2 t ha⁻¹ per year. This was attributed to the slow-release fertilizer and deep fertilization, which increased the number of stems and tillers in the pre-fertility and spike rate, respectively, resulting in a high panicle number with a 20% reduction of N fertilizer. Furthermore, mechanical weeding improved the seed-setting rate, resulting in a higher number of grains per panicle, a higher panicle number, and an increased thousand-grain weight, thereby maintaining a high yield. At the same time, the quality of rice under MW with LSR treatment improved, specifically reflected in the significant improvement of the processing and appearance quality of rice, a slight increase in protein content, and a reduction in the amylose content, thereby improving its nutritional quality while maintaining good cooking quality. Full article

Rice–wheat cropping system (RWCS) is a dominant agricultural practice in the Indo-Gangetic plains, particularly in the North–Western states of India. The prevalent practice of open burning of rice residue, driven by the need for timely land preparation, poses severe environmental and health consequences, including nutrient loss, greenhouse gas emissions, high concentrations of particulate matter (PM), and disruption of the ecological cycle. This study focuses on implementing effective management practices in the RWCS through tillage-based crop establishment, residue retention, and incorporation methods. The objective is to improve crop yield and its attributes by enhancing soil health properties. A split-plot experimental design was practiced with four different treatments, zero-tillage with manual harvesting (ZT), Happy Seeder with combine harvester (HS), Happy Seeder with Mulcher and combine harvesting, and conventional tillage (CT). By evaluating soil nutrient content, including organic carbon (OC), N, P, and K, at a 0–10 cm depth, the study demonstrates the superiority of the mulcher with Happy Seeder (MHS), which significantly increased soil nutrient levels by 105, 59, 102, and 97%, respectively, compared to conventional tilled broadcasted wheat (CT). Furthermore, the MHS treatment exhibited the highest yield of 56.8 q ha⁻¹, outperforming the yield of 43.6 q ha⁻¹ recorded under conventional tilled broadcasted wheat. These findings underscore the critical role of surface residue retention with MHS in ensuring crop productivity and overall production sustainability of the RWCS in Haryana, India. Moreover, effective rice residue management holds long-term implications for agricultural resilience, farm economics, environmental conservation, and human health. It emphasizes the importance of adopting sustainable practices, prioritizing research efforts, and advocating for policies that ensure the prolonged sustainability and productivity of the RWCS while safeguarding environmental well-being. Full article

A growing population, changing climate, scarcity of resources, and the urgent need to achieve sustainable development goals makes it imperative to reimagine agriculture in a way that makes it economically profitable, climate-resilient, resource-efficient. Traditional rice production technology involving puddling and transplanting has often been criticized for its inefficient resource utilization, high cost of production, and emission of greenhouse gases such as methane. Direct-seeded rice (DSR), promoted for its climate-resilient nature, is often utilized by farmers in three different ways: broadcasting, line sowing, and zero tillage. However, these establishment methods have certain advantages and limitations, as perceived by farmers. The present study attempts to closely study the crop performance of rice under the abovementioned crop establishment methods. The study was conducted in farmers’ fields in a way where both the farmers’ freedom and research conditions were equally taken care of. The study aims to analyze crop performance while emphasizing farmers’ field-based knowledge to ensure a lab-land-lab loop for understanding the scope of refinement in agronomic as well extension strategies. The results of this study reveal the superiority of zero tillage over broadcasting and line sowing in terms of crop performance and economic performance in the northwest alluvial plain zone of Bihar. The study has also identified the constraints associated with adoption of line sowing and zero tillage. Full article

Management of nitrogen (N) fertilizer and irrigation can play a critical role to increase nitrogen use efficiency (NUE). However, the impacts of N application at the root zone via urea briquette deep placement (UDP) and water-saving irrigation alternate wetting and drying (AWD) on N₂O emissions are not well-understood. A greenhouse study was conducted to investigate the impacts of UDP on N₂O emissions, NUE, and grain yields of rice and wheat compared with broadcast prilled urea (PU). For rice, the effect of UDP was evaluated under continuous flooding (CF) and AWD, while the control (no N) and PU were tested only under CF. In rice, UDP under CF irrigation produced similar emissions to PU-CF, but UDP under AWD irrigation increased emissions by 4.5-fold compared with UDP under CF. UDP under CF irrigation increased (p < 0.05) rice grain yields and N recovery efficiency (RE) by 26% and 124% compared with PU-CF, respectively. In wheat, UDP had no effects (p > 0.05) on emissions compared with PU. However, it produced higher wheat grain yields (9%) and RE (35%) over PU. In conclusion, UDP under CF irrigation increases the RE and grain yields of rice without increasing N₂O emissions, but the yield may reduce and N₂O emissions may increase under AWD. Full article

(1) Background: the broadcast is an outdated fertilization method with a low fertilizer-utilization rate and environmental problems, which seriously restricts the development of agriculture. (2) Methods: Under a machine-transplanted rice with side-deep fertilization (MRSF) mode, five treatments were applied: 0 cm (D0), 5 cm (D5), 7.5 cm (D7.5), and 10 cm (D10), comprising four different depths of fertilization, and no fertilization (CK). The yield, the accumulation of N and P in the straw and in grains of rice, concentrations of N and P in the surface water, ammonia (NH₃) volatilization, and soil nutrients were measured in rice fields. (3) Results: In rice yields, compared with the D0 treatment, only the D7.5 treatment significantly increased by 7.84% in late rice, while the other treatments showed no significant difference between early and late rice. The N- and P-use efficiency of D10 increased by 5.30–24.73% and 0.84–17.75%, respectively, compared with the D0-D7.5 treatments. In surface water, compared with the D0 treatment, D5, D7.5, and D10, the total N (TN), total P (TP) concentration, and NH₃ volatilization decreased by 10.24–60.76%, 16.30–31.01%, and 34.78–86.08%, respectively; the D10 treatment had the best inhibition effect on the TN, TP concentration, and NH₃ volatilization, which were 58.48–60.76%, 22.04–31.01%, and 77.21–86.08%, respectively. (4) Conclusions: The optimized depth for side-deep fertilization was 10 cm. We would like to emphasize the impact of the paddy on various deep fertilizations and provide an important reference for developing precise fertilization in rice fields in this area. Full article

As a widely implemented irrigation regime for paddy fields, water-saving irrigation (WSI) is capable of ensuring water resource security and improving nitrogen use efficiency (NUE). Higher gaseous nitrogen losses (GNL) lead to a low recovery rate of basal nitrogen, and this is the primary reason that restricts further improvements in the NUE under WSI. The deep placement of nitrogen fertilizer (DPN) is considered an efficient agricultural management measure to reduce GNL. However, the effects of WSI combined with the deep placement of basal nitrogen fertilizer on NUE, GNL, and rice yield in paddy fields remain largely unknown. In this study, a 2-year field experiment was conducted to measure GNL (N₂O emissions and NH₃ volatilization), NUE, and rice yield. Four treatments were utilized: (i) conventional flooding irrigation + broadcast of nitrogen fertilizer (110 kg N hm⁻², CFN); (ii) water-saving irrigation + deep placement of basal nitrogen fertilizer (110 kg N hm⁻², WSN); (iii) water-saving irrigation + deep placement of basal nitrogen fertilizer (99 kg N hm⁻², WSN1); (iv) water-saving irrigation + deep placement of basal nitrogen fertilizer (88 kg N hm⁻², WSN2). The results showed that the GNL in paddy fields under treatment ranged from 5.29 to 10.67 kg hm⁻². Deep placement of basal nitrogen fertilizer mitigated the GNL of the paddy fields under WSI. The GNL of CFN was significantly higher than those of WSN1 and WSN2 by 26.9% and 54.0% in 2021 and 14.4% and 23.3% in 2022, respectively (p < 0.05). Under WSI, the deep placement of basal nitrogen fertilizer reduced the GNL primarily via the reduction of NH₃ volatilization. NH₃-N of CFN was higher than those treatments under WSI. The rice yield of CFN was significantly lower than those of WSN and WSN1 by 22.4% and 21.6% in 2021 and 4.6% and 1.5% in 2022, respectively. (p < 0.05). Moreover, the NUE of each treatment under WSI was higher than that of CFN. These changes exhibited similar trends in 2021 and 2022. These results demonstrated that deep placement of basal nitrogen fertilizer is an effective practice to ensure food and environmental security under WSI. Full article

Although urea placed deep reduces nitrogen (N) loss and increases rice yield, its use is not expanding due to the lack of effective application methods. A study was carried out to determine how different urea application techniques affected the yield and nitrogen use efficiency (NUE) of transplanted Aman rice (cv. BRRI dhan46). The experiment was set up in a RCBD design with seven treatments: T₁ (deep placement of urea briquettes (DPUB) by hand), T₂ (DPUB by battery-powered applicator), T₃ (deep placement of prilled urea (PU) briquettes by BRRI applicator), T₄ (DPUB by injector applicator), T₅ (DPUB by push-type applicator), T₆ (broadcast application of PU), T₇ (zero-N), and three replications. Findings showed that the NH₄⁺-N concentration in field water peaked on day 3 and then rapidly fell as time passed, while the NO₃⁻-N concentration in the water and soil was minimal. T₁ reported the highest grain yield, total N content and uptake, whereas T₇ had the lowest values. On T₁, the apparent N recovery reached its highest level (73.5%). The NUE varied from 13.26% in T₃ to 29.38% in T₁. Based on this finding, deep placement of urea briquette by hand is recommended for increasing the yield and NUE of T. Aman rice. Full article

To characterize the adaptability of strip tillage for wheat production in a rice–wheat rotation system in China, a two-year experiment was conducted. Three methods of tillage and sowing were designed, including broadcast and drill sowing following full tillage (TS1 and TS2) as well as drill sowing following strip tillage (TS3), under two planting densities. Compared to TS2, TS1 only increased seedling tiller number (by 17%–54%) at the beginning of the over-wintering stage, while TS3 improved tiller number, leaf area, and shoot weight (by 17%–39%, 14%–15%, and 19%–27%, respectively), achieving individual seedlings with improved growth vigor. An increased planting density (300 vs. 225 plants m⁻²) significantly promoted culms, leaf area, and shoot weight per m² seedlings (by 8%–14%, 7%–23%, and 11%–19%, respectively) under TS3, improving seedling growth quality. The present results indicate that vigorous seedling growth promoted the potential and synergy of the source and sink (maximum leaf area, grains per m², and sink–source ratio), thereby increasing grain yield. Furthermore, TS3 promoted nitrogen (N) uptake (by 7%–9%) compared with TS1 and TS2. The present study highlights the good adaptability and applicability of strip tillage for the environmentally conscious and efficient production of wheat in rice–wheat rotation systems. Full article

Efficient management of fertilizers and irrigation could mitigate greenhouse gas (GHG) emissions and increase crop yields. Field experiments were conducted to determine the effects of an integrated plant nutrient system (IPNS) and water regime—alternate wetting and drying (AWD) and continuous flooding (CF)—on GHG emissions and rice yield. Fertilizer treatments included control (no N), prilled urea (PU), urea deep placement (UDP), and IPNS (50% N from poultry litter and 50% N from PU). Gas sampling and analysis were performed using a closed-chamber technique and gas chromatography. IPNS produced significantly (p < 0.05) higher seasonal total methane (CH₄) emissions (9–15%) compared to the UDP treatment, but the emissions with IPNS were similar to those of PU. IPNS had an interaction effect with the water regime on nitrogen oxide (N₂O) emissions. IPNS produced more emissions than PU under AWD, but their emissions were similar under CF irrigation. IPNS produced a significantly higher total global warming potential (GWP) than UDP but a GWP similar to the PU treatment in both Aus (pre-monsoon) and Aman (wet) seasons. AWD irrigation reduced the total GWP by 8% over CF without yield reductions. IPNS significantly increased rice yields compared to broadcast PU but yields were similar to those of UDP. These findings suggest that both IPNS and UDP could be effective in increasing crop yields without increasing GHG emissions. Full article