Dry Direct-seeded Rice Research Articles

Ecology and Management of Sedges in Direct-seeded Rice: A Review

Sedges, resilient weeds from the Cyperaceae family, pose a significant threat to direct-seeded rice cultivation due to their perennial nature and robust propagules, which endure harsh conditions. Their emergence, growth and seed production during fallow periods contribute significantly to seed banks, making their management challenging compared to other weed types. Water levels in paddy fields dictate weed composition, favouring sedges and grasses under saturated conditions but shifting to grass weeds during cropping seasons, influenced by factors like soil conditions and rainfall. Managing sedges requires a multifaceted approach due to their perennial hydrophilic and pro-alkaline nature with extensive propagules. Sedges possessing strong root system with morphological similarities necessitate continuous weed control throughout the cropping season during the critical period ranging from 15 to 60 days after sowing for wet and dry direct-seeded rice. Effective weed management practices proved crucial for minimizing yield losses caused by infestation of Cyperus difformis, Fimbristylis miliacea and Schoenoplectus juncoides by many researchers. Various methods, including cultural practices like stale seedbeds, physical methods like summer tillage, biological approaches such as integrating poultry and chemical interventions like herbicide application, are utilized for sedge management in rice fields. Higher efficacy of ethoxysulfuron for management of majority of sedge weeds in rice has been reported by many workers. However, relying on a single strategy is insufficient to keep sedge populations below the threshold, necessitating a comprehensive and adaptable approach to weed control in rice cultivation.

A comparative assessment of polymer-coated and non-coated urea in direct-seeded rice: agronomic, economic, and environmental performance and sensitivity analysis

The application of polymer-coated urea (PCU) to crops is likely restricted because the product’s capsules cause plastic pollution. Although conventional fertilizer use reduces plastic pollution, it may increase nitrogen (N) pollution owing to its lower N recovery than that of PCU. Therefore, we need to develop optimal N application methods to reduce both plastic and N pollution. Here, we aimed to (1) compare the agronomic, economic, and environmental outcomes of PCU application with those of conventional urea application and (2) provide quantitative targets for developing alternatives to PCU application in dry direct-seeded rice production. We developed a model incorporating yield, brown-rice protein content, farmer profit, and environmental damage cost due to N and polymer loss according to N fertilizer application. Data were collected from field experiments at a farm in Iwate, Japan, from 2020 to 2022. The average apparent N recovery was 0.43 for PCU and 0.37 for conventional urea. Despite the plastic damage cost, the estimated total environmental cost of PCU was lower than that of normal urea owing to the former’s higher N recovery. However, our ability to simulate plastic pollution is limited, as few of the environmental effects of microplastics are understood. If new N application methods with N recovery above 0.5 are developed, an N fertilization cost within $5 × 10–3 g N–1 can maintain the same benefit as that obtained here. This model can be used to evaluate the quantitative relationships among N recovery, benefits, and implementation costs of each candidate N application method.

Effect of Zero Tillage and Different Weed Management Practices in Direct Seeded Rice (Oryza sativa L.) in Indo Gangetic Plains: A Review

Millions of rural and urban residents depend on the rice-wheat cropping system of the Indo-Gangetic plains (IGP) for their food security and means of subsistence. About 18 million hectares (m ha) of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are rotated across Asia, of which 13.5 m ha are in the Indo-Gangetic Plains (IGP) of India. This agricultural system’s viability is currently in jeopardy due to static yields of both wheat and rice and a decline in total factor productivity. The North West IGP's high input crop culture has allowed weeds to dominate the weed flora, including P. minor in wheat and Echinochloa crus-galli L. in rice. Farmers in North West India have largely used zero tillage for growing wheat, and recently, farmers in the eastern IGP have done the same. Perennial weeds in the Eastern Indo-Gangetic Plain, such Cynodon dactylon L. and Cyperus rotundus L. can occasionally be a nuisance under zero tillage. As an alternative to puddled transplanted rice, the focus is currently on dry direct-seeded rice and machine transplanting of non-puddled rice. As a result of changes in tillage, crop establishment techniques, water use, and weed control brought on by the switch from transplanted rice to direct seeded rice, weed composition and diversity frequently vary. In nations where DSR is frequently used, weedy rice has become a significant concern. Using the Zero Tillage DSR system, certified seed, cultivars that are weed-competitive, stale seedbed procedures, living mulches, and chemical and biological weed control might change weed-crop competition in the crop's favour. However, more research on emergence characteristics and mulching effects of different crop residues on key weeds under zero tillage, cover cropping, and breeding crops for weed suppression will strengthen nonchemical weed management programs. In this review, we examine the extent of weed infestation, weed flora shift and the non-chemical alternative weed management in DSR.

The impact on Cd bioavailability and accumulation in rice (Oryza sativa L.) induced by dry direct-seeding cultivation method in field-scale experiments

Dry direct-seeded rice cultivation has gained popularity and expanded its cultivated area due to reduced labor requirements and water consumption. However, the impact of this cultivation method on cadmium (Cd) bioavailability in soil and the accumulation levels in grains remains uncertain. Field experiments were conducted in acidic soils at two locations in southern China to compare rice varieties and evaluate the dry direct-seeding method alongside the wet direct-seeding and traditional transplanting methods. Dry direct-seeded rice reached significantly higher Cd concentrations in its tissues starting from the heading stage than transplanted rice. Cd accumulation levels by the maturation stage in the brown rice of dry direct-seeded rice were 18.33 %–150.69 % higher than those of wet direct-seeded and transplanted rice, with a considerable ability to translocate Cd into brown rice. Furthermore, dry direct seeding decreased iron plaque formation, particularly in the amorphous Fe form; it resulted in high soil temperature and low moisture content during tillering, elevating Cd availability in the soil. Additionally, the proportion of ions and more labile forms of Cd in the soil solution was high. Moreover, the soil under dry direct seeding had high urease and acid phosphatase enzyme activities. However, low richness and diversity in the bacterial community were characterized by a significant increase in the relative abundance of Actinobacteria and Gammaproteobacteria at the class level, while exhibiting decreased relative abundances of Alphaproteobacteria, Bacilli, and KD4-96, along with fewer biomarkers. Nonetheless, these differences are gradually reduced during the maturation stage. Overall, although dry direct seeding offers several advantages, it is crucial to implement additional measures to mitigate the increased health risks linked to rice cultivation through this approach in Cd-contaminated areas.

Agronomic Performance of Rice Genotypes under Direct Seeded Rice (Oryza sativa L.)

The twenty rice genotypes were evaluated for their performance under Dry Direct Seeded Rice (DDSR) system of cultivation. All the growth, yield and yield attributes except for days to 50% flowering showed significant variation among the genotypes indicating variability among the genotypes under study. The genotype WGL 915 recorded maximum plant height, panicle length, 1000 seed weight, seed yield per plant, seed yield per plot and seed yield per ha, while WGL 44 recorded maximum productive tillers per m2. WGL 915, JGL 24423, WGL 1246, JGL 1798 and KNM 733 genotypes recorded higher yields under DDSR system of cultivation among the genotypes under study.

Dry direct-seeded rice-wheat rotation system: Lower water and carbon footprint and higher carbon production efficiency and net ecosystem economic benefits

ContextSecuring food and energy supplies presents a significant challenge to human survival and progress. The rice-wheat rotation is one of the main food crop systems in China. However, no comprehensive assessment of the water footprint (WF), carbon footprint (CF), carbon production efficiency (CPE), and net ecosystem economic benefits (NEEB) of different rice-wheat rotation systems has been reported. ObjectiveThis study was conducted to assess the productivity, WF, CF, CPE, and NEEB of dry direct-seeded, wet direct-seeded, and transplanted rice-wheat (TR-W) rotation systems. The objective was to provide theoretical guidance for the development of clean and sustainable rice-wheat rotation production technology systems. MethodsWe used a split-plot design, with the main plots being the dry direct-seeded, wet direct-seeded, and transplanted rice planting methods, and the subplots consisting of two rice genotypes. Dry direct-seeded rice was mainly rainfed, ensuring that the soil remained relatively dry so that the soil is kept aerobic during the whole reproductive period of rice. Wet direct-seeded rice continues to keep the soil moist after sowing; the plots were maintained under a water layer of 3–10 cm following the emergence of 4.5 leaves, a condition that persisted until two weeks prior to the rice harvest. Transplanted rice was maintained under a water layer of 3–10 cm following transplanting until 2 weeks prior to the rice harvest. Subsequent to the rice harvest, the above-ground rice stubble was removed, and the ground was tilled with a rotary tiller in preparation for the subsequent wheat planting. ResultsResults demonstrated that the annual yield from the dry direct-seeded rice-wheat (DR-W) rotation system was comparable to the wet direct-seeded rice-wheat (WR-W) rotation system, while significantly lower than that of the TR-W rotation system. However, the WF of DR-W rotation system was 45.96% and 33.94% lower than that of WR-W and TR-W rotation systems, respectively, and the CF was 35.57% and 25.87% lower than that of WR-W and TR-W rotation systems, respectively. Therefore, its water and carbon production efficiencies were higher than those of WR-W and TR-W rotation systems. In addition, NEEB in DR-W and TR-W was comparable and significantly higher than that in WR-W. ConclusionsThe DR-W rotation was a promising rotation system according to the comparable annual yield, lower water and carbon footprints, higher CPE, and comparable or higher NEEB in comparison with other rice-wheat rotation systems. SignificanceWe suggest that the DR-W rotation should be promoted as the primary production mode for the rice-wheat rotation.

Dry Direct-Seeded Rice Yield and Water Use Efficiency as Affected by Biodegradable Film Mulching in the Northeastern Region of China

In the realm of agriculture, biodegradable films are emerging as a promising substitute for traditional polyethylene (PE) films. Despite their potential, there has been a notable lack of extensive research on their effectiveness in the context of dry direct-seeded rice cultivation. Addressing this gap, a comprehensive biennial study was conducted in the northeastern regions of China, focusing on the ‘Baonong 5’ rice variety. This study meticulously compared three distinct cultivation methods: (1) employing biodegradable film mulching, (2) using conventional plastic film mulching, and (3) cultivating without any mulch. The findings revealed that biodegradable film mulching significantly enhanced soil moisture control, increased leaf area, and improved rice yield and water utilization efficiency (p < 0.05) compared to the plots without mulch. Notably, there was no marked difference in outcomes between the plastic film mulching and the unmulched plots. This research underscores the profound benefits of biodegradable film in rice cultivation, particularly from an environmental sustainability perspective. This innovative method not only boosts agricultural productivity but also addresses critical environmental challenges like climate change and water conservation. The application of biodegradable mulch has proven to be remarkably effective in improving irrigation efficiency and crop water conservation, leading to enhanced rice development and higher yields. The study recorded a substantial increase in water productivity—30% in 2021 and between 52.85% and 60% in 2022—compared to traditional cultivation practices. Furthermore, the use of biodegradable mulch resulted in significantly higher rice yields than the non-mulched plots, thus contributing to increased profitability. Such methods not only yield higher crop outputs but also mitigate environmental issues like water pollution and help alleviate prevalent water shortages in rice farming.

Comparison of UAV and knapsack herbicide application methods on weed spectrum, crop growth and yield in dry direct-seeded rice

Comparison of UAV and knapsack herbicide application methods on weed spectrum, crop growth and yield in dry direct-seeded rice

Yield and quality of dry direct-seeded rice (Oryza sativa) as influenced by nitrogen and weed management practices in Eastern India

Combined use of FYM and LCC based N management gave the highest grain yield, hulling, milling, head rice recovery, crude protein, protein yield (kg/ha) as well as highest nitrogen, phosphorus and potassium in grain and straw. In case of weed management practices, the sequential application of pendimethalin (1.5 kg/ha) as pre-emergence fb brown manuring with Sesbania aculeata (knocking down Sesbania by bispyribac-Na 25 g/ha at 25 DAS) resulted in better control of diverse weeds. It also proved to be the best treatment in terms of yield, physical and chemical grain quality parameters.

Variability to flooding tolerance in barnyardgrass and early flooding benefits on weed management and rice grain yield

Barnyardgrass (Echinochloa crus-galli (L.) Beauv.) is one of the most problematic weed species in paddy fields. The recent large-scale evolution of herbicide resistance in this species requires the adoption of integrated methods of weed control. The present study aimed to determine the interaction of water depth, flooding irrigation onset, and pre-emergent herbicides on the control of barnyardgrass populations and to identify the variability and the putative genes involved in the regulation of flooding tolerance in this species. We identified tolerant, moderately tolerant, and flood-sensitive barnyardgrass populations through water depth-response experiments in a greenhouse. The relative expression of genes related to flooding tolerance were evaluated to confirm the flooding tolerance variability. A field experiment was conducted during the summer seasons of 2020/21 and 2021/22 to assess the interaction of the flooding onset, water depth, and pre-emergent herbicides on populations with different flood tolerances and herbicide resistance mechanisms. Water depths of 7.5 cm and 12.5 cm and plant height were selected for the diagnosis of flood tolerance. After 28 days under flooding, the 7.5 cm depth reduced plant height by an average of 26.82%. Of the 45 populations evaluated, 43 overcame the water depth of 7.5 cm, and four surpassed 12.5 cm. The relative expression of alcohol dehydrogenase 1 (ADH1), alcohol dehydrogenase 2 (ADH2), pyruvate decarboxylase (PDC1), aldehyde dehydrogenase (ALDH), and sucrose synthase 3 (SUS3) was between eight and sixteen times higher for the flood-tolerant population than for the sensitive one. In the field study, the anticipation of flooding to the two-leaves (V2) stage of rice resulted in an increase of up to 55.6% in the control of all populations evaluated compared with conventional irrigation at the four-leaves (V4) stage, including those resistant to herbicides. The grain yield was increased by approximately 11.4% with flooding onset in the V2 stage compared to the V4 stage. Barnyardgrass control and rice grain yield were not affected by water depths of 5 cm or 15 cm. The early flooding, in the V2 stage, increased rice grain yield and favored barnyardgrass control. However, variability in flood tolerance was identified in barnyardgrass populations, which may jeopardize the effect of early flooding for weed control in rice crops. The results we obtained add information on the basic knowledge of flooding tolerance in barnyardgrass and to the integrated weed management for dry direct-seeded rice.

Effect of row spacing and weed management practices on dry direct-seeded spring rice

Weeds are the major burden for rice-growing farmers in the case of direct-seeded rice due to the preemptive competition of weed in the species early seedling stage. A field experiment was carried out during the spring season in 2021 to evaluate the effect of different weed management practices and row spacing on dry directed-seeded spring rice under the Prime Minister Agriculture Modernization Project (PMAMP) at Rice Super Zone, Kanchanpur, Nepal. The experiment was laid out in a two-factorial randomized complete block design (RCBD) with twelve treatments and three replications. The highest number of effective tillers per m2 was obtained in weed-free plots (531.67), which is statistically similar to Pretilachlor fb 1HW (505.42). Row spacing of 10 cm showed a significantly higher number of effective tillers per square meter (521.94). A higher grain yield was observed in weed-free plots (6397.87 kg.ha-1), which is followed by Pretilachlor fb 1HW, which is statistically similar to other management practices except for weed check. All the management practices were found effective in reducing weed parameters such as weed density, weed dry weight, and weed index as compared to weed checks. A positive relation was recorded between plant height at 90 DAS and grain yield, thousand-grain weight, and grain yield, and a negative relation was recorded between weed density, weed dry biomass, and grain yield. It is recommended to apply Pretilachlor fb 1HW with 10 cm row spacing for effective weed control and to increase the yield of dry direct-seeded rice.

Effects of biochar application on rice physiological growth and water use efficiency under dry direct‐seeded mode

AbstractTo investigate the effects of various biochar application levels on the growth physiology and water use efficiency of dry direct‐seeded rice (DDSR) in the black soil region of north‐east China, five biochar application treatments consisting of 2% (BC1), 4% (BC2), 6% (BC3), 8% (BC4) and 10% (BC5) were set, and no biochar application was used as the control treatment (CK). The differences in photosynthetic properties, dry matter accumulation characteristics, water consumption pattern, yield and water use efficiency of DDSR under different biochar application levels were compared and analysed, and the effect of the water use efficiency of leaves (WUEL) at each growth stage on the water use efficiency of yield (WUEy) was also investigated. The results showed that the photosynthetic properties, dry matter accumulation and water consumption of rice increased and then decreased with increasing biochar application level. Compared with CK, the rice yield increased by 1.6%–52% with biochar application, and the 4% biochar application level showed the most significant increase in rice yield (P < 0.05). The WUEy in the BC2, BC3, BC4, BC1, CK and BC5 treatments gradually decreased in that order. Among the WUEy values, significant increases of 27%, 13% and 8% in the BC2, BC3 and BC4 treatments, respectively, compared with the CK were observed (P < 0.05). The effect of WUEL at the prophase tiller, late tiller and milk ripening stages on WUEy enhancement was significant.

Effect of different rice planting methods on the water, energy and carbon footprints of subsequent wheat

The rice-wheat rotation system is an important planting system in the middle and lower reaches of the Yangtze River. Studies on the effects of different rice planting methods on the water, energy, and carbon footprints of subsequent wheat have rarely been reported. In this study, the effects of different rice cultivation practices on the water, energy, and carbon footprints of subsequent wheat were investigated among different rice-wheat rotation systems including dry direct-seeded rice (DSR)-wheat rotation, wet direct-seeded rice (WSR)-wheat rotation and transplanted rice(TPR)-wheat rotation. Results showed that the yield of wheat after DSR was 8,552 kg ha−1, which was 14.61 and 4.72% higher than the yields after WSR and TPR, respectively. In addition, the water and carbon footprints of wheat after DSR were lower than those after WSR and TPR, while its energy and carbon production efficiencies and net ecosystem economic benefits were higher than those after WSR and TPR. Notably, the use of fertilizers and fuel are the two major contributors to the high energy inputs and greenhouse gas emissions in wheat production. In summary, wheat after DSR has higher ecological and economic benefits, and we recommend that it be promoted as the preferred wheat planting model in rice-wheat rotation areas.

Genome-wide association analysis for emergence of deeply sown rice (Oryza sativa) reveals novel aus-specific phytohormone candidate genes for adaptation to dry-direct seeding in the field.

Dry direct-seeded rice (dry-DSR) is typically sown deeply to circumvent the need for irrigation, and thus seedling emergence is a crucial trait affecting plant stand and yield. To breed elite cultivars that use less water and are climate-resilient, an understanding of the genomic regions and underlying genes that confer emergence in deeply sown dry-DSR would be highly advantageous. A combined diversity panel of 470 rice accessions (RDP1 plus aus subset of 3K RGP) was evaluated with 2.9 million single nucleotide polymorphisms (SNPs) to identify associations with dry-DSR traits in the field and component traits in a controlled-environment experiment. Using genome-wide association study (GWAS) analyses, we identified 18 unique QTLs on chromosomes 1, 2, 4, 5, 6, 7, 9, 10, and 11, explaining phenotypic variance ranging from 2.6% to 17.8%. Three QTLs, namely, qSOE-1.1, qEMERG-AUS-1.2, and qEMERG-AUS-7.1, were co-located with previously reported QTLs for mesocotyl length. Among the identified QTLs, half were associated with the emergence of aus, and six were unique to the aus genetic group. Based on functional annotation, we identified eleven compelling candidate genes that primarily regulate phytohormone pathways such as cytokinin, auxin, gibberellic acid, and jasmonic acid. Prior studies indicated that these phytohormones play a critical role in mesocotyl length under deep sowing. This study provides new insight into the importance of aus and indica as desirable genetic resources to mine favorable alleles for deep-sowing tolerance in rice. The candidate genes and marker-tagged desirable alleles identified in this study should benefit rice breeding programs directly.

Dry direct-seeded rice has higher energy and carbon production efficiencies.

Water and energy shortages and food security challenges associated with global warming are essential issues affecting human survival and development. Rice is one of the world's top three staple food crops. In this study, the energy footprint (EF), carbon footprint (CF), energy production efficiency (EPE), carbon production efficiency (CPE), and economic benefit (EB) of dry direct-seeded rice (DSR), wet direct-seeded rice (WSR), and transplanted rice (TPR) were integrated and assessed. The yield of WSR and TPR was 9.64% and 13.76% higher than that of DSR, respectively. However, DSR has less irrigation and less intensive field tillage, therefore its energy input, and CF were 37.47%, 44.29% and 29.35%, 34.77% lower than those of WSR and TPR, respectively, and the EPE and CPE were obviously improved, and the EB was not lower than that of WSR and TPR. Current rice production relies heavily on non-renewable energy inputs such as nitrogen fertilizer, diesel, and machinery. Therefore, the key to improving EPE, CPE, and EB in rice production while reducing CF was to improve water use efficiency and decrease the intensity of paddy tillage. The DSR has higher social, economic, and ecological benefits and can be the preferred rice planting method for rice production areas. This article is protected by copyright. All rights reserved.

Relationship between characteristics of basal internodes and lodging and its physiological mechanism in direct‐seeded rice

AbstractLodging is an important factor that limits rice yield and the large‐scale promotion of direct‐seeded rice (DSR). The objective of this study was to clarify the relationship between the characteristics of basal internodes and lodging and the physiological mechanism underlying this process in DSR. A field study was conducted in Changchun, Jilin Province, China, using a japonica rice variety Jiyujing with two direct seeding cultivation methods, including dry DSR (DDSR), wet DSR (WDSR) and conventional‐transplanted rice (CTSR) as a control in 2019 and 2020. Lodging‐related physical parameters, morphological characteristics and carbohydrate components of basal internodes were investigated at heading stage (HS) and 30 days after heading stage (HS30). The results showed that WDSR increased lodging index (LI) and lodging rate compared with CTSR and DDSR. LI increased rapidly from HS to HS30, primarily because of the significant reduction in the breaking strength (M). Correlation analysis revealed that the M of N4 internode was significantly positively correlated with culm plumpness and structural carbohydrate proportions at HS30. Culm plumpness decreased significantly, due to a decrease in nonstructural carbohydrate (NSC) content then primarily the decrease in starch proportions and content. Compared with CTSR and DDSR, WDSR decreased culm wall thickness, dry weight per centimetre of the culm and leaf sheaths, and the proportions and contents of cellulose, lignin and starch of internode, resulting in the decrease in internode breaking strength. Thus, it was concluded that the DSR reduced internode strength by reducing internode plumpness and carbohydrate content, thus decreasing lodging resistance.

Analysis of yield constraints and seasonal solar radiation and temperature limits for stable cultivation of dry direct-seeded rice in northeastern Japan

Analysis of yield constraints and seasonal solar radiation and temperature limits for stable cultivation of dry direct-seeded rice in northeastern Japan

Deep sowing of dry direct-seeded rice: cultivar differences in seedling establishment and grain yield

ABSTRACT Dry direct seeding of rice (DDSR) is being increasingly used in water-scarce areas across Asia. When drought occurs, deep sowing may enable germinating seeds to utilize the residual moisture below the surface. Our objective was to examine the effects of different sowing depths on DDSR crop growth. Two yield experiments, one in the Philippines and the other in Japan, were established in rainfed lowlands, but drought did not occur. Across the experiments, sowing at a depth of 6 to 7 cm reduced the percentage of emergence compared with sowing at a depth of 1 to 2 cm (25% vs. 73%), which resulted in lower yield (3.5 vs. 4.4 t ha−1). The relative yield (deep-sowing/shallow-sowing) was positively correlated with the percentage emergence under deep sowing. Cultivars with no significant yield reduction under deep sowing maintained high emergence (>30%) under deep sowing. Seedling’s ability to emerge after deep sowing greatly differed among cultivars: the percentage emergence ranging from 0% to 18% from a depth of 8 to 10 cm, and from 11% to 44% from a depth of 6 to 7 cm. An ancillary field experiment was conducted under drought during the dry season in the Philippines: deep sowing increased the percentage emergence compared with shallow sowing (41% vs. 5%), when the soil surface was severely dry. Our results suggest that choosing cultivars that can tolerate deep sowing is a prerequisite for using deep sowing in DDSR, and that future breeding of DDSR should focus on this tolerance.

Nitrogen Management Strategies to Improve Crop Performance, Recovery Efficiency and Their Relationship with Physiological Indices in Dry Direct-Seeded Rice

Nitrogen Management Strategies to Improve Crop Performance, Recovery Efficiency and Their Relationship with Physiological Indices in Dry Direct-Seeded Rice

Influence of nitrogen and weed-management practices on crop-growth indices and productivity of dry direct-seeded rice (Oryza sativa)

A field study was carried out during the rainy (kharif) season of 2019–20 at ICAR-Indian Agricultural Research Institute, New Delhi, to study the effect of nitrogen and weed management practices in dry direct-seeded rice (Oryza sativa L.) for obtaining higher productivity and crop growth. The experiment was laid out in a split-plot design, taking 3 nitrogen treatments, i.e. No N (P and K only), recommended dose of fertilizer (RDF–N : P : K = 80 : 17 : 33 kg/ha) (3 splits of nitrogen application–50% basal + 25% at tillering + 25% at panicle-initiation stage), 50% N from FYM + 50% N as real-time nitrogen management (top-dressing) as per leaf colour chart (LCC) up to panicle-initiation stage in main plots. Four weed-management treatments, viz. unweeded control, weed-free control, Pendimethalin @ 1.5 kg a.i./ha as pre-emergence followed by (fb) brown manuring with Sesbania bispinosa (Jacq.) W. Wight; Syn. S. aculeata [(Willd.) Pers.] (knocking down Sesbania by Bispyribac- Na 25 g a.i./ha at 25 days after sowing (DAS), Pendimethalin @ 1.5 kg a.i./ha as pre-emergence fb Bispyribac -Na @ 25 g a.i./ha at 25 DAS in subplots with 3 replications. Result revealed that, Pendimethalin @ 1.5 kg a.i./ha as pre-emergence fb brown manuring with Sesbania bispinosa significantly increased grain yield (2.78 t/ha) as well as growth indices like leaf-area index (1.8 and 4.4 at 40 DAS and 70 DAS, respectively), crop-growth rate (1.9 g/m2 /day, 8.8 g/m2 /day at 40 DAS and 70 DAS, respectively), relative growth rate (145.3 mg/g/day and 54.5 mg/g/day 40 DAS and 70 DAS, respectively), net assimilation rate (0.40 g/m2 /day 3.49 g/m2/day at 40 DAS and 70 DAS, respectively) and dry-matter accumulation (185.6 g/m2 , 591.6 g/m2 and 1,144 g/m2 at 40 DAS, 70 DAS and harvesting, respectively) to the other treatments. In case of N-management practices, combined use of FYM and LCC-based N management gave the highest grain yield (3.25 t/ha), growth indices like leaf-area index (1.69 and 4.0 at 40 DAS and 70 DAS respectively) crop-growth rate (1.8 g/m2/day, 8.2 g/m2/day at 40 DAS and 70 DAS, respectively), relative growth rate (145.1 mg/g/day and 55.1 mg/g/day at 40 DAS and 70 DAS, respectively) and dry-matter accumulation (168.5 g/m2 , 523.2 g/m2 and 958 g/m2 at 40 DAS, 70 DAS and harvesting, respectively) comparable with RDF application and significantly higher than the plot without N.