Grain Yield Of Direct-seeded Rice Research Articles

Effect of nitrogen levels and weed management on weed flora and yield of direct-seeded rice (Oryza sativa) in southern part of Punjab

An experiment was conducted at Krishi Vigyan Kendra, Ferozepur, Punjab during rainy (kharif) seasons of 2018 and 2019 to study the effects of nitrogen levels and weed management in direct-seeded rice (Oryza sativa L.) (DSR). The results indicated that pendimethalin + bispyribac (W1) (5.25 and 2.95 m2) and oxadiargyl + bispyribac (W2) (6.05 and 3.95 m2) application reduced the density of narrow-leaved weeds (NLW) and broad-leaf weeds (BLW) followed by oxadiargyl + fenoxaprop (W3) (7.0 and 4.55 m2) during both the years. Application of W1 decreased the total weed biomass by 84–98.2%, respectively compared to weedy check (W5) (80.1 and 94.8 g/m2) in both years. Treatment W1 and W2 recorded at par values of grain and straw yield followed by W3. An increase (48.6–72.0%) in grain yield was registered with weed practices compared to weedy check in DSR. W1 and W2 significantly recorded higher N uptake in grain (61.45 and 60.85 kg/ha) and total (100.8 and 99.45 kg/ha) followed by W3 (53.85 and 90.35 kg/ha, respectively). The high infestation of BLW with W3 resulted in the lowest weed control efficiency (WCE) (46.2–53.9%) among the weed control practices. N at 120 and 150 kg/ha recorded the low density and biomass of NLW and BLW. Application of 120 and 150 kg N/ha enhanced the grain yield (4.89 and 5.25 t/ha) and net returns (55.1 and 60.5 × 103 ₹/ha) in both years. No N application recorded lowest N uptake in grain (87.71 kg/ha) and total (80.26 kg/ha) compared to 150 kg N/ha in both years. N levels at 120 and 150 kg/ha recorded higher values of water control efficiency (WCE). Based on the findings, it may be concluded that pendimethalin + bispyribac and oxadiargyl + bispyribac with N 120 kg/ha application can reduce weed flora diversity with higher grain yield of direct-seeded rice in Punjab.

Estimation of the economic threshold of Leptochloa chinensis (Chinese sprangletop) in direct-seeded fine grain rice (Oryza sativa)

: Leptochloa chinensis (L.) Nees (Chinese sprangletop) is a weed that is becoming a serious threat in upland and lowland rice. A field study was conducted at the Agronomic Research Farm, University of Sargodha, Punjab, Pakistan, during the summer seasons of 2018 and 2019 to evaluate the effect of L. chinensis density on the yield of direct-seeded fine rice. Treatments comprised of L. chinensis densities of 0, 5, 10, 15, 20 and 25 plants m-2, and the experiment was laid out in a randomized complete block design with four replications of each treatment. The results suggest that the presence of L. chinensis significantly hampered the grain yield of direct-seeded rice. Weed infestation caused 63% and 69% yield losses where 25 L. chinensis plants m-2 were sustained in 2018 and 2019, respectively. Yield reduction was due to the reduction in 1000-grain weight (22.9 and 29.1%), number of tillers m-2 (65.8 and 60.0%), and number of grains panicle-1 (53.3 and 60%) in 2018 and 2019, respectively. The highest weed infestation (25 plants m-2) produced the highest weed dry biomass (687 and 669 g m-2), N uptake (19.3 and 19.3 kg ha-1), P uptake (1.92 and 2.32 kg ha-1), and K uptake (20.53 and 20.27 kg ha-1) in 2018 and 2019, respectively. The lowest weed infestation (5 plants m-2) produced minimum weed dry biomass (47 and 85 g m-2), N uptake (1.6 and 2.9), P uptake (0.3 and 0.5), and K uptake (1.7 and 30 kg ha-1) in 2018 and 2019, respectively. The economic threshold of L. chinensis as estimated to cause 6.73% and 6.08% yield loss by the prediction model was 1.70 and 1.73 plants m-2 during 2018 and 2019, respectively. It can be concluded that L. chinensis is a serious weed in direct-seeded rice and it should be controlled when its density reaches 1.70-1.73 plants m-2 to avoid significant yield losses.

Effects of Controlled Release Urea Formula and Conventional Urea Ratio on Grain Yield and Nitrogen Use Efficiency of Direct-Seeded Rice

A one-off application of bulk blend urea (BBU), which includes a controlled release urea formula and conventional urea, has been recommended to simplify fertilisation management for direct-seeded rice. However, the effects of different basal application ratios of controlled-release urea formula and conventional urea on yield and nitrogen (N) use efficiency remain unknown in direct-seeded rice. This study set up three BBU treatments in which the controlled-release urea formula provided 50% (BBU1), 60% (BBU2), and 70% (BBU3) of the total N. This study measured their effects on grain yield and N use efficiency of direct-seeded rice. Split fertilisation with conventional urea was used as the control (CK). The study concluded four key points: (i) the grain yield of direct-seeded rice decreased as the proportion of controlled-release urea formula increased, (ii) BBU1 increased grain yields by 8.1–8.6% and 10.2–10.6% compared to BBU2 and BBU3, respectively, as well as a greater number of panicles and spikelets per m2, and post-anthesis dry matter accumulation, (iii) the N recovery efficiency and N agronomic efficiency of BBU1 were significantly higher than those of BBU2 and BBU3 treatments, and the nitrogen accumulation was also found to be more, and (iv) compared with the CK, BBU1 achieved considerable grain yield and nitrogen use efficiency while reducing the amount of fertilisation. In conclusion, the appropriate reduction of the basal application ratio of the controlled-release urea formula for direct-seeded rice increased grain yield and nitrogen use efficiency.

Seeding rate, fertiliser and herbicide effects on canopy growth and productivity of direct-seeded rice (DSR) under different management practices

A low seeding rate with seed drill is a good management practice to promote good canopy growth and increase yield of direct seeding rice (DSR) in lowland rice fields. Many studies did not evaluate seeding rates in an integrated way under different management practices in smallholder farmers’ fields. Estimating canopy cover from Canopeo and normalised vegetation difference index (NDVI) may offer a non-destructive, rapid way to assess crop growth and productivity under different field conditions. On-farm field experiments were conducted comparing the yield and canopy growth in response to seed drilled seeding rates of 20, 40, 60 and 80 kg ha −1 and hand-broadcast seeding rates of 180 kg ha −1 (farmers’ practice) grown under different management conditions in Cambodia. In the first experiment, different seeding rates were compared in two villages, Kork Ton Loab (KTL) and Svay Cheat (SVC), in the 2018 growing season. In the second experiment, seeding rates and fertiliser application rates were compared at Kork Ton Loab location in the 2019 cropping season. The third experiment compared seeding rates and pre-emergence herbicide options at Oroung village in the 2018 and 2020 cropping seasons. In experiment 1, sowing at 20 and 40 kg ha −1 consistently decreased mean canopy cover with Canopeo index at Kork Ton Loab and Svay Cheat locations. In experiment 2, sowing at 80 kg ha −1 significantly increased the mean canopy cover compared with 20 and 40 kg ha −1 seeding rates with Canopeo index at 60 and 75 DAS at the Kork Ton Loab location. The low seeding rates of 60, 80 and 180 kg ha −1 increased in canopy cover at 60 DAS with NDVI compared with the lower seeding rates at Kork Ton Loab and Svay Cheat locations. Seeding rates had significant effects on grain yield and gross margin only for experiment 1 and experiment 3 in the 2020 cropping season. For experiment 1, the seed drill rates of 60 and 80 kg ha −1 did not significantly differ in grain yield or gross margin compared with broadcast of 180 kg ha −1 in both locations. Sowing at 20, 40, 60 and 80 kg ha −1 produced similar yield and gross margin at Kork Ton Loab except for the 20 kg ha −1 seeding rate that significantly reduced yield and gross margin at Svay Cheat. For experiment 3, the seed drill of 80 kg ha −1 and 180 kg ha −1 by broadcast (Farmer’s Practice) significantly increased yield up to 3.5 t ha −1 compared with 40 and 60 seeding rates in the 2020 cropping season. Increasing fertiliser rates (high fertiliser; N-100, P-80, and K-50 kg ha −1 ) by two times increased grain yield by 12.8% compared with the low fertiliser rate of N-50, P-40, and K-30 kg ha −1 . Pre-emergence herbicide application significantly increased mean grain yield by 16% and 15% in the 2018 and 2020 cropping seasons, respectively. Therefore, the seed drill of 80 kg ha −1 , high fertiliser rate and pre-emergence herbicide interventions improved uniformity in canopy growth and increased grain yield of DSR. This information can be incorporated into integrated crop and weed management programs for the productivity of direct-seeded rice in the lowland ecosystem. • Low seeding rates (60–80 kg ha -1 ) with seed drill provide similar yield and gross margin as hand-broadcast of 180 kg ha -1 . • The use of vegetation-derived information from reflectance sensors estimates canopy growth in dynamic field conditions. • Sowing at 60 and 80 kg ha -1 with seed drill reduced undesirable agronomic traits compared with hand-broadcast of 180 kg ha -1 .

Crop Establishment Methods, Varieties and Levels of Zinc on Growth and Yield of Rice in Chitwan, Nepal

With the aim of identifying the appropriate doses of Zinc in rice for different varieties under various establishment methods, an experiment was carried out in a strip-split plot design with three replications at Agriculture and Forestry University, Rampur, Chitwan during 2015-16. The treatment consists of two crop establishment methods (Transplanted rice (TPR) and Direct Seeded Rice (DSR)) in the vertical strip and two varieties (Hybrid Gorakhnath-509 and Sabitri) in the horizontal strip and four levels of ZnSO4 (0, 15, 30 and 45 kg ha-1) in sub-sub plot. The observations were recorded on growth, yield attributes, grain yield and economics. The research results revealed that the application of ZnSO4 @ 15 Kg ha-1 significantly increased the grain yield of DSR as compared to the non-application of ZnSO4. The higher grain yield of rice was because of increased yield attributes like effective tillers, thousand-grain weight and the number of filled grains per panicle. Crop establishment methods and varieties did not have a significant influence on the grain yield of rice. DSR had a lower cost of cultivation, higher net return and higher benefit-cost ratio as compared to TPR. The variety Sabitri had lower cost of cultivation, higher net return and higher benefit-cost ratio as compared to Gorakhnath-509. Similarly, the application of ZnSO4 @ of 15 Kg ha-1 produced the highest net return and the highest benefit-cost ratio. Therefore, ZnSO4 @ 15 kg ha-1 could be an option for increased yield and net return for DSR in Chitwan.

Grain yield and lodging-related traits of ultrashort-duration varieties for direct-seeded and double-season rice in Central China

Lodging is the most common constraint on grain yield of direct-seeded rice. There is limited information about lodging resistance and its related plant traits in direct-seeded and double-season rice (DDR) in Central China. This study aims to identify the plant traits that achieve high lodging resistance in ultrashort-duration varieties (about 95 days) of DDR. Field experiments were conducted in 2017 and 2018 in Wuxue County, Hubei Province, China, with four ultrashort-duration varieties grown under two nitrogen (N) rates. Lodging-related traits were measured on the 15th day after heading, and yield and yield attributes were measured at maturity. The grain yield of the four varieties ranged from 4.59 to 7.61 t ha−1 across the two N rates, with a total growth duration of 85 to 97 days. Varietal differences in lodging index were mainly explained by the bending moment, which was closely related to plant height. Breaking resistance did not affect the lodging index significantly. Shortening plant height from 95.4 to 80.5 cm decreased the lodging index by 22.4% but did not reduce grain yield. Our results suggested that reducing plant height was effective in improving the lodging resistance of ultrashort-duration varieties of DDR. Lodging resistance should be enhanced by improving breaking resistance rather than reducing plant height to increase DDR grain yield further.

Sesbania, Azolla and herbicide use for weed management and optimizing yield in direct-seeded rice

The experiment was conducted at Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj (U.P.) during Kharif seasons of 2009 and 2010 to assess the performance of direct-seeded rice as influenced by Sesbania/ Azolla with nitrogen levels and herbicide use for managing weeds and optimizing the yield of direct-seeded rice (DSR). Weed density and dry weight were consistently lower with Azolla culture than with Sesbania during initial crop growth stages, however, they were similar at 90 days after sowing (DAS). Among weed management practices, pretilachlor (with safener) at 0.3 kg /ha at 2 DAS as pre-emergence application followed by (fb) hand weeding (HW) at 45 DAS was effective in controlling weeds and increasing the grain yield of DSR, which resulted in higher net returns and benefit cost ratio than HW twice at 20 and 45 DAS. The higher yields were recorded under Sesbania and Azolla than DSR (sole) crop. Sesbania Azolla + 100% recommended dose of nitrogen with pretilachlor (with safener) 0.3 kg /ha at 2 DAS as pre-emergence application fb HW at 45 DAS recorded lower weeds density, dry weight and higher economic returns in direct-seeded rice.

Deep tillage and irrigation impacts on crop performance of direct seeded rice–wheat cropping system in north-west India

The subsurface compact layer found in medium- to coarse-textured soils of rice-grown areas hampers the root growth of crops. Moreover, the puddled transplanted rice is being faced by water and labour shortages in the region. It is thus imperative to study the effects of deep tillage and irrigation regimes on crop performance of direct seeded rice (DSR) and wheat. A 2-year field experiment was conducted during 2016–2017 and 2017–2018 in a sandy loam soil to investigate the effects of deep tillage and irrigation regimes on crop performance of DSR–wheat cropping system. There were two irrigation regimes both in DSR [irrigation to DSR at 4-day (4-d) and 8-day (8-d) interval] and in wheat crop [based on irrigation water to pan evaporation ratio of 1.0 (I1.0) and 0.5 (I0.5)] in main plots, with three tillage treatments, viz. (1) conventional tillage in DSR + conventional tillage in wheat (DSRCT-WCT), (2) deep tillage before the sowing of DSR during first season + conventional tillage in wheat (DSRDT1-WCT) and (3) deep tillage before the sowing of DSR during both the seasons + conventional tillage in wheat (DSRDT2-WCT) in subplots. The root growth was higher in plots with deep tillage in comparison with plots with conventional tillage. The increased root growth under deep tilled conditions attributed to higher grain yield of DSR (18.3 and 12.6% during 2016 and 2017, respectively), wheat (6.6 and 7.9% during 2016–2017 and 2017–2018, respectively) and cropping system a whole (12.6 and 10.9% during 2016–2017 and 2017–2018, respectively). Though the tillage treatments were imposed before the sowing of DSR, they had residual impact on the following wheat crop. Deep tillage during both the seasons (DSRDT2-WCT) had not any significant influence on the grain yield of DSR, wheat and cropping system as a whole in comparison with deep tillage only once in 2 years (DSRDT1-WCT).

English

In order to clarify whether the shift from hand-transplanting seedlings to direct seeding will bring negative effects to rice production and to find optimal nitrogen management for direct-seeded rice in Eastern China, research has been conducted in Quzhou City, in the Zhejiang Province of China in the year 2017 and 2018. One indica inbred rice variety, “Zhongjiazao-17” was planted by two different rice establishment methods (direct seeding and hand-transplantation), and five different nitrogen application rates were set as experimental treatments (0, 120 and 180 kg ha-1 in 2017 and 0, 165 and 195 kg ha-1 in 2018). The grain yield, economic profit, and rice quality were compared between direct-seeded rice and hand-transplanted rice under different nitrogen rates. Our results indicate that the direct-seeded rice showed no obvious disadvantages in grain yield compared to the hand-transplanted rice, but improved economic profit significantly. The highest grain yield and production profit were achieved at 180 kg N ha-1 in direct-seeded rice while the hand-transplanted rice achieved highest grain yield and profit at 165 kg ha-1. The direct-seeded rice showed lower physical quality but higher cooking and tasting quality than the hand-transplanted rice. Increasing the nitrogen rate improved the physical quality but decreased cooking and tasting quality in both the direct-seeded rice and hand-transplanted rice. Hence, direct-seeded rice has the potential to be promoted in Eastern China, and 180 kg ha-1 is the optimal nitrogen rate. In addition, applying sufficient nitrogen at panicle initiation is necessary to increase the grain yield of direct-seeded rice. Key words: Direct seeding, hand-transplantation, grain yield, nitrogen management, physical quality, cooking and tasting quality. &nbsp

Direct seeded rice (Oryza sativa L.) under tillage systemswith wheat straw and nitrogen levels

Field experiment was conducted at Punjab Agricultural University, Ludhiana on direct seeded rice (DSR) with tillage systems and nitrogen (N) levels. The highest grain yield of DSR was recorded in zero tillage with wheat straw (ZTWS), which was statistically at par with zero tillage without wheat straw (ZTWOS). The application of 125 kg N/ha gave the maximum grain yield, which was at par with 100 kg N/ha. The ZTWS at 100 kg N/ha registered higher grain yield, which was at par with ZTWOS at 125 kg N/ha. However, the higher grain yield was recorded with the application of 125 kg N/ha under conventional tillage with wheat straw (CTWS) and with 150 kg N/ha in conventional tillage without wheat straw (CTWOS). Therefore, rice can be grown with ZTWS and ZTWOS with the application of 100 and 125 kg N/ha, respectively for higher productivity at low cost of cultivation by skipping the tillage operation at the time of sowing under the condition of loamy sand soils of Punjab.

Phosphorus Use Efficiency and Yield of Direct Seeded Rice and Wheat Influenced by Residues Incorporation and Phosphorus Application under Saline Soil

A two years field study according to split plot design was conducted to investigate the impactof crop residue (CR) incorporation and P application (0, 40, 80, 120 kg P2O5/ha) on P use efficiency andyield of direct seeded rice (DSR) and wheat grown under saline soil (ECe = 4.59 dS/m; pHs = 8.38;SAR = 6.57 (mmolc/L)1/2; extractable P = 4.07 mg/kg; texture = sandy clay loam), during the years 2011and 2012. Planting of DSR (with and without crop residue incorporation @ 2 tonnes/ha) were placed inmain plots and P application was in sub plots. Data on tillering, plant height, panicle length, 1000 grainweight, paddy and straw yields were collected. On an average of two years, maximum tillers (18), paniclelength (33), grain/panicle (121) and paddy yield (3.26 t/ha) were produced with P application @ 80 kgP2O5/ha along with CR incorporation. Similarly in case of wheat grown after DSR, maximum tillers (17),spike length (17), grains/panicle (66) and grain yield (3.56 t/ha) were produced with P application @ 80 kgP2O5/ha along with CR incorporation. Although, the growth and yield contributing parameters with thistreatment (80 kg P2O5/ha + CR) performed statistically equal to 120 kg P2O5/ha without CR incorporationduring both the years, but on an average of two years, grain yield of DSR and wheat was significantlysuperior (22 and 24%, respectively) than that of higher P rate (120 kg/ha) without CR. Overall, continuoustwo years CR incorporation further increased (17%) paddy yields during the follow up year of crop harvest.Higher P use efficiency and concentrations of P, K+ and Ca2+ in both DSR and wheat plant tissues wasfound where 80 kg P2O5/ha was applied along with CR incorporation or 120 kg P2O5/ha alone while Na+and Mg2+ concentration decreased with CR incorporation and increasing P rate. An increasing trend inDSR paddy and wheat grain yields was observed with increasing the rate of P application without CRincorporation, however, it was not as much as that of 80 kg P2O5/ha application with CR incorporationand found to be superior than rest of the treatments during both study years.

Effect of crop establishment methods and weed management practices on weeds, growth and yield of direct-seeded rice

Field trials were conducted at Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during kharif seasons of 2011 and 2012 to study the effect of crop establishment methods and weed management practices on weeds, growth and yield of direct-seeded rice. Results indicated that bed planting of dry-seeded rice suppressed dry matter accumulation of weeds–grasses, sedges and broad leaf weeds most effectively among crop establishment methods, and as a consequence this crop establishment method had markedly higher growth rates, higher growth and yield attributes. Among different weed management practices, integrated weed management practices, namely, pre-emergence spray of pendimethalin 1 kg/ha followed by brown manuring of dhaincha by 2,4-D 0.50 kg/ha at 25 days after sowing (DAS) and combination of pre-emergence spray of pendimethalin 1 kg/ha followed by early post-emergence spray of bispyribac 0.025 kg/ha followed by brown manuring of dhaincha by 2,4-D 0.50 kg/ha at 25 DAS significantly lowered dry matter of all weeds than other weed management practices, thus improved growth and its rate and yield attributes of direct-seeded rice. Though crop establishment methods did not significantly influence grain yield of direct-seeded rice, protein content in grain and its yield were markedly improved by bed and no-till methods than conventional method. Integration of pendithalin application with brown manuring of dhaincha and pendimethalin followed by bispyribac followed by brown manuring of dhaincha registered significantly higher grain yield, protein content in grain and its yield than remaining weed management practices.

【Short Report】Grain Yield and Leaf Area Growth of Direct-Seeded Rice on Flooded and Aerobic Soils in Japan

Direct-seeding has been proposed as a water- and labor-saving method to grow irrigated rice. Our objective was to compare the effects of flooded and aerobic conditions on the yield stability of direct-seeded rice. We set up four trials in the field: aerobic, near-saturated and flooded soils with direct seeding, and flooded soil with transplanting. Grain yield of direct-seeded rice was comparable to that of transplanted under flooded conditions. However, the yield of direct-seeded rice under aerobic conditions was up to 21% lower than that under flooded conditions. This poor performance was associated with reduced leaf growth during the vegetative stage. Our results indicate that the yield stability of direct-seeded rice could be lowered by the water-saving irrigation, compared with the conventional flooded culture. In order to save irrigation water, physiological research on direct-seeded rice should target the vulnerability of rice to aerobic soils or to soil moisture fluctuations.