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1.
Row spacing and weed control timing affect yield of aerobic rice   总被引：2，自引：0，他引：2  
Field experiments were conducted during the wet season of 2009 and dry season of 2010 to determine the effects of row spacing and timing of weed control on weed growth and yield of aerobic rice. Ten weed management treatments were used to identify critical periods of weed competition with aerobic rice grown in three different row spacings (15-cm, 30-cm, and as paired rows 10-20-10-cm). Dominant weed species during both growing seasons were Rottboellia cochinchinensis, Digitaria ciliaris, Echinochloa colona, and Eleusine indica. Rice grown in 30-cm rows had greater weed biomass and less grain yield than in 15-cm and 10-20-10-cm rows; weed growth and grain yields were similar between 15-cm and 10-20-10-cm rows. Rice yields in the wet season ranged from 170 kg ha−1 where weeds were not controlled throughout the crop duration to 2940 kg ha−1 in weed-free treatment, indicating a 94% yield loss with uncontrolled weed growth. Similarly in the dry season, plots with no weed control (140 kg ha−1) compared to weed-free plots (3640 kg ha−1) indicate a 96% yield loss with no weed control. Gompertz and logistic equations were fitted to yield data resulting from increasing durations of weed control and weed interference, respectively. Critical periods for weed control in the wet season, to obtain 95% of a weed-free yield, were estimated as between 18 and 52 days after sowing (DAS) for crops in rows at 15-cm, 20-51 DAS at 10-20-10-cm, and 15-58 DAS at 30-cm. These intervals in the dry season were 17-56 DAS for crops in rows at 15-cm and 17-60 DAS at 10-20-10-cm and 15-64 DAS at 30-cm. Durations of the critical periods in the wet season were 31 days at 10-20-10-cm, 34 days at 15-cm and 43 days at 30-cm, while in the dry season, these were 43 days at 10-20-10-cm, 39 days at 15-cm and 49 days at 30-cm. In both seasons, crops in the wider spacing (30-cm) were vulnerable to weed competition for the longest period. The information gained from this study suggests that the aerobic rice yields better in 15-cm rows and 10-20-10-cm arrangements than in 30-cm rows and there is very little benefit of weed control beyond 8 weeks after sowing.  相似文献   

2.
In India, dry-seeded rice (DSR) production systems are rapidly replacing conventional rice production systems due to various advantages. DSR systems can be managed under zero-till (ZT) conditions or after a preparatory tillage, often referred to as conventional tillage systems (CONT). Although previous reports indicate the contribution of tillage to weed suppression, the effect of one-time preparatory tillage in a DSR system could vary depending on the dominant weeds in the system, vertical seed distribution and the weed seed dynamics. A study was conducted to test the efficacy of ZT and CONT and their interaction with herbicide treatments on the weed population dynamics and rice grain yield in 2010 and 2011. Tillage systems did not affect weed emergence, weed biomass, tiller production and crop yield. However, herbicide treatments varied in their efficacy on individual weeds. Hand-weeding treatments and pendimethalin combined with hand weeding did not effectively control Cyperus rotundus L. and Panicum maximum Jacq. (a perennial grass weed with underground parts). The herbicide combination of metsulfuron and chlorimuron was effective in controlling C. rotundus but not grass weeds. This indicates the need for sequential applications of herbicides for grass weed control or integration of hand weeding to achieve broad-spectrum weed control. Apart from hand weeding (three times), treatment with penoxsulam–cyhalofop and pendimethalin followed by (fb) hand weeding resulted in low weed density, high tiller production and grain yield. The study clearly indicates that tillage does not always lead to weed suppression compared with ZT, and herbicides must be chosen based on the dominant weeds in a system. The results of this study are pertinent as herbicide-resistant weeds are rapidly evolving under continuous herbicide selection pressure, which warrants studies on enhancing productivity through low-input, environmentally friendly and sustainable production technology.  相似文献   

3.
《Plant Production Science》2013,16(2):228-231
Abstract

In recent years, water and labor shortage in Southeast Asia is driving the farmers towards dry-seeded rice systems. Weed infestation is a serious threat for adoption of these systems. A study was conducted in the wet and dry seasons to evaluate the performance of 10 elite “Green Super Rice” (a recently named group of rice genotypes bred for unfavorable marginal environments) genotypes at two different weed infestation levels (partial and moderate weed control) under dry-seeded conditions. Average yield loss due to weed competition in the partial weed control treatment ranged from 12 – 57% in the wet season and 2 – 23% in the dry season. In the partial weed control plots, the drought pyramiding genotype IR83140-B-11-B performed well, resulting in 2850 and 4610 kg ha–1 of yield in the wet and dry seasons, respectively. The yield loss of this genotype in the partial weed control plots relative to the moderate weed control plots was only 21% in the wet season and 10% in the dry season. Results clearly showed that grain yield in different genotypes were positively correlated with leaf area at an early stage of the crop. The study also found negative and linear correlation between grain yield and weed biomass at harvest, demonstrating the importance of weeds in dry-seeded rice systems. The study suggested that genotypes with a larger leaf area could be integrated with other weed management strategies to achieve sustainable weed control in dry-seeded rice systems.  相似文献   

4.
Large within-field variation in rice growth often causes production loss in broadcast-seeded (BC) rainfed lowland rice. The spatial variability of direct-seeded rainfed lowland rice was evaluated in 2004, 2005, and 2007 in on-station experiments at Ubon Ratchathani, northeast Thailand, in relation to soil water content and weed infestation, by adopting semivariogram and block kriging, including comparisons among BC with harrowing (BCH; no weeding), BC with no harrowing (BCNH; no weeding), and row-seeded (RS; interrow weeding once) fields. BCH and BCNH were also compared in 11 farmers’ fields in 2006 and 2007, to assess the effect of harrowing on rice growth and weed infestation. During most of the rice growing periods, flooded and non-flooded portions existed simultaneously in the fields, with different proportions among years and among seeding methods in the on-station experiment. BCH and BCNH rice had large within-field variation in seedling density, heading date, shoot dry matter, grain yield, harvest index, panicle density, and filled spikelet per panicle, as well as in weed infestation, measured by a quick visual estimation. Many of the measured variables (except mean soil water content in RS in 2007, seedling density in BCH in 2005 and 2007, shoot dry matter in BCH and BCNH in 2007, and panicle density in BCH in 2007) were spatially dependent (i.e., data from nearby locations were most similar) by geostatistical analysis. Analysis of correlations using the 420 data sets of BCH plots in 2005 and BCH, BCNH, and RS plots in 2007 revealed a positive correlation between soil water content and grain yield and negative correlations between weed infestation and soil water content and grain yield. Compared with BCH, in 2007 BCNH had much lower grain yield because of lower soil water content after establishment and more weed infestation. BCH had higher grain yield than BCNH in weedy fields in the farmers’ fields experiment. RS with interrow weeding resulted in a smaller coefficient of variation, smaller sill value, and higher grain yield than BCH, due to less weed infestation and a higher proportion of flooded water. These results indicated that reducing the spatial variability in rice growth requires careful field preparation, such as harrowing to level the soil surface and to reduce the uneven distribution of standing water and the variability in soil water content, combined with effective crop and weed management (i.e., harrowing and row-seeding). This is the first study that examined spatial variability in the growth of direct-seeded rice as a function of soil water content and weed infestation in a rainfed lowland environment.  相似文献   

5.
不同耕作和种植方式对稻田杂草及水稻产量的影响   总被引：1，自引：0，他引：1  
采用田间试验,研究了7种不同水稻耕作和种植方式[水田翻耕移栽(puddling transplanting,PT)、免耕移栽(no tillage transplanting,NTT)、水田翻耕滚筒湿播(puddling drum wet seeding,PDWS)、免耕滚筒湿播(no tillage drum wet seeding,NTDWS)、传统耕作旱穴播(conventional tillage dry drilling,CTDD)、沟垄灌溉旱穴播(furrow irrigated raised beds system dry drilling,FIRBSDD)和免耕旱穴播(no-tillage dry-drilling,NTDD)对稻田杂草和水稻产量的影响。结果表明,PT处理下水稻产量最高,杂草干物质量最低;与移栽相比,直播(direct seeded rice,DSR),包括旱直播和湿直播,杂草生长能力最强,且不管有无杂草均降低了水稻产量;直播处理因杂草使水稻减产91.4%~99.0%,而PT和NTT处理分别减产16.0%和42.0%;香附子、龙爪茅、长穗苋、珠子草和假海马齿等杂草种类在DSR处理中大量出现,但在PT处理中未出现。大田示范试验结果表明,普通水稻品种(HKR-47和IR-64)在DSR处理较PT处理减产达15.8%,但优质水稻品种(Sharbati和PB-1)在两处理间无明显差异。当前劳动力紧缺,人工插秧需要大量劳力,因此亟需开发好氧栽培(如免耕直播和机插)模式下的适宜水稻品种及其相关配套农业机械及技术。  相似文献   

6.
Weeds are a major constraint to rice (Oryza spp.) production in West Africa. Superior weed competitive rice genotypes may reduce weed pressure and improve rice productivity. Two upland and two lowland experiments were conducted in southern Benin to examine genotypic variations in weed-suppressive ability and grain yield under weedy conditions, and to identify plant characteristics that could be used as selection criteria for improved weed competitiveness. A total of 19 genotypes, including Oryza sativa and Oryza glaberrima genotypes and interspecific hybrids developed from crossing O. sativa and O. glaberrima, were grown under weed-free and weedy conditions in an upland with supplemental irrigation and in a flooded lowland. In weedy plots, hand weeding was done once or not at all. Mean relative yield loss across all genotypes due to weed competition ranged from almost 0% to 61%. Large genotypic variations in weed biomass and grain yield under weedy conditions were found. Visual growth vigor at 42 and 63 days after sowing (DAS) under weed-free conditions significantly correlated with weed biomass at maturity in both upland and lowland experiments (R2 = 0.26–0.48). Where weed pressure was low to moderate, with mean relative yield loss less than 23%, the multiple regression models using grain yield and plant height at maturity or only grain yield measured under weed-free conditions as independent variables could explain 66–88% of the genotypic variation in grain yield under weedy conditions. At higher weed pressure (mean relative yield loss: 61%), as observed in one of the upland experiments, biomass accumulation of rice at 42 days after sowing was associated with higher grain yield under weedy conditions. Biomass accumulation also significantly correlated with visual growth vigor at the same sampling dates. Therefore, we conclude that grain yield, plant height at maturity and visual growth vigor at 42–63 DAS under weed-free conditions appear to be useful selection criteria for developing superior weed competitive rice genotypes.  相似文献   

7.
《Plant Production Science》2013,16(4):377-390
Abstract

The farmers’ management practices and grain yield were examined in the consecutive 4 cropping seasons from wet season rice (WSR) in 2008 to dry season rice (DSR) in 2010 across upstream, midstream and downstream fields, along two secondary drainage canals (located either upstream or downstream side along the main canal) in the Kamping Puoy Irrigation Rehabilitation area (KPIR). In WSR, standing water depth was much deeper in downstream fields where medium and late maturing varieties were planted from May than in upstream fields where early and early medium maturing varieties were planted later (mostly in July and August). In DSR there was less difference in water conditions between upstream and downstream fields and variation in planting and harvesting time was small. As the area percentage of fields where DSR was introduced increased from 2008 (54%) to 2010 (100%), planting time in WSR was later (e.g., from May to July) with declining proportion of dry seeding method and mid-season tillage. Grain yield was low in DSR, particularly in 2010 (287 and 247 g m-2 in 2009 and 2010 on average, respectively), due to insufficient weed control and small amount of fertilizer, and the yield was lowest in fields which practiced DSR for the first time. Grain yield in WSR (286 and 291 g m-2 in 2008 and 2009 respectively) increased by transplanting, use of high yielding Raing Chey variety, and application of a larger amount of N chemical fertilizer. These findings indicated that the agriculture extension support to farmers, particularly in DSR, is a key important factor for rice yield improvement in KPIR.  相似文献   

8.
Field and pot studies were conducted to evaluate the effects of seven rice establishment techniques {puddling transplanting (PT), no tillage transplanting (NTT), puddling drum wet seeding (PDWS), no tillage drum wet seeding (NTDWS), conventional tillage dry drilling (CTDD), furrow irrigated raised beds system dry drilling (FIRBSDD), and no-tillage dry-drilling (NTDD)} and water submergence stress on weeds and rice yield. The highest yield and least weed abundance were in the PT treatment. The direct seeded rice (DSR), both dry and wet exhibited severe weed infestation, and compared to transplanting showed reduced yield both in the presence and absence of weeds. The yield losses due to weeds in the DSR treatments ranged from 91.4 to 99.0%, compared to 16.0 and 42.0% in the transplanting treatments (PT and NTT). Weeds, including Cyperus rotundus L., Dactyloctenium aegyptium (L.) Willd., Digera arvensis Forsk., Phyllanthus niruri L., and Trianthema portulacastrum L. which were found in the un-puddled DSR treatments were absent in the puddled plots, particularly the PT treatments. In pot studies, continuous water-submergence (2.5 cm) for 20 days reduced the emergence of C. rotundus, D. aegyptium, T. portulacastrum, and Echinochloa crus-galli (L.) Beauv. by 99.4, 100, 100, and 24.4%, respectively, compared to alternate wetting–drying. In farmer's field studies, when compared to the PT treatments, the DSR treatments exhibited lower yields (15.8%) with coarse varieties (HKR-47 & IR-64), but fine cultivars (Sharbati & PB-1) exhibited similar yields under both systems. In view of the shortage of labour for manual transplanting, there is a need to develop suitable cultivars for aerobic system conditions (unpuddled DSR and NT machine-transplanting).  相似文献   

9.
《Plant Production Science》2013,16(4):488-496
Environmental resources for rainfed rice production show large variability even within a small area in Northeast Thailand, and it is said that farmer’s management is well adapted to the variability. This study evaluated transplanting date and nitrogen (N) fertilizer rate in the management to improve rice productivity. The effect of transplanting date and N fertilizer rate on rice productivity was analyzed by investigating rice growth, and also by dividing rainfed rice fields located in a mini-watershed into 4 subecosystems: (1) medium deep water, waterlogged (MDW), (2) shallow water, favorable (SWf), (3) shallow water, drought- and submergence-prone (SWds), and (4) shallow water, drought-prone (SWd). Rice grew at almost a constant rate until maturity and the growth rate was higher at a lower field. The difference in productivity was derived from not only a water condition but also soil fertility, and was associated with the rate of N uptake. Small leaf area index was found to be one of the causes for low productivity in rice. Statistic analysis showed that earlier transplanting increased biomass production in all subecosystems. The biomass-increase resulted in a higher yield in SWds and SWd fields while it resulted in a reduced harvest index (HI) and did not increase yield in MDW and SWf fields. The effect of N fertilizer was apparent in the field where rice biomass was small due to later transplanting or unfertile soil, but the effect was generally small. Earlier transplanting in upper fields and later transplanting in lower fields in mini-watersheds were suggested to improve rice production, and proper distribution of N fertilizer use is considered necessary.  相似文献   

10.
Aerobic rice systems can substitute the conventional rice cultivation system in the wake of water shortage and energy crises. The major constraint in the success of aerobic rice is high weed infestation. Hence, we have discussed the weed flora, yield losses, herbicide-resistant weeds, need for integrated weed management, and approaches to manage weeds in aerobic rice systems. A review of several studies indicated that 90 weed species were competing with rice under aerobic systems, causing 23–100% reductions in grain yield. Weed control in aerobic rice gets difficult due to shifts in weed flora and herbicide resistance development in weeds. A wide increase in grain yield (15–307%) by implementing different weed control practices elaborates the scope of weed management in aerobic rice. Practices, such as soil solarization, sowing of competitive crop cultivars, stale seedbed preparation, mulch application, correct fertilization, and intercropping, were found to have particular significance for managing weeds in aerobic rice systems. Moreover, hand weeding and mechanical control were more effective when combined with other weed control methods. Herbicides, such as pendimethalin, 2,4-D, penoxsulam, ethoxysulfuron, bispyribac-sodium, triclopyr, imazosulfuron, bensulfuron, pretilachlor, and metsulfuron, were found most effective in aerobic rice systems. Keeping in view the severity of weed infestation in these systems and the evolution of herbicide resistance, reliance on a single control method is out of question. Hence, the approach of integrated weed management is the most appropriate for proper weed management and the subsequent success of rice cultivation using aerobic systems.  相似文献   

11.
A large proportion of the rice in West Africa is produced in rainfed lowland ecosystems, mainly in inland valleys. The hydrological conditions (duration and intensity of flooding) vary with the toposequence position between the fringe and the centre of the valley. Production methods tend to evolve from the currently predominant unbunded plots without external input use, to input-intensive production in bunded plots. Agronomic management interventions co-evolve and may include varietal choice, herbicide use, and mineral N fertilizer application. The response of rice and the associated weeds to such interventions is likely to vary with the prevailing hydrological regime. A 2-year field experiment was conducted in northern Ivory Coast to determine the impact of water regime (plot position in the valley, presence of bunds) and input use (mineral N fertilizer and herbicide) on the productivity (yield and N use efficiency) of traditional and modern rainfed lowland rice cultivars and the biomass and composition of the associated weeds. Installing field bunds reduced seasonal variations in ponded water depth and resulted in a mean increase in rice grain yield of 30–40% (p < 0.005). This increase was associated with a 25% lower cumulative weed biomass and a several-fold increase in the agronomic use efficiency of applied mineral N in bunded than unbunded plots. Under low input management, traditional varieties tended to out-yield modern varieties in unbunded plots. Improved crop management such as herbicide and fertilizer application, and the construction of field bunds was more effective to increase the yield and N use efficiency in the flooded valley centre than in the drought-prone valley fringes. There is a need for site-specific targeting of modern cultivars, land development and improved production methods in the inland valleys of the West African savanna zone.  相似文献   

12.
Dry-seeded rice has been introduced as an alternative to puddled hand-transplanted rice in the north Indian states of Punjab and Haryana. In dry-seeded rice, weed flora tends to be more diverse and weeds emerge in several flushes during the crop growth cycle and substantial yield reductions due to weed competition are quite common. The efficacy and compatibility of tank mixtures of different herbicides for the control of diverse weed flora in dry-seeded rice was evaluated in field experiments during the summer seasons of 2012 and 2013. The tank mixture of fenoxaprop with ethoxysulfuron improved the control of Echinochloa crus-galli and Echinochloa colona by 43–69% as compared to fenoxaprop alone while the tank-mix of azimsulfuron with fenoxaprop was antagonistic and reduced the control of Leptochloa chinensis by 86% as compared to fenoxaprop alone. Addition of azimsulfuron or ethoxysulfuron to bispyribac did not improve the control of grass weeds as compared to bispyribac alone. Weed control with the mixture of bispyribac and fenoxaprop varied over the two years. In 2012, bispyribac and fenoxaprop mixture was antagonistic for the control of Dactyloctenum aegyptium, Acrachne racemose, and L. chinensis but in 2013, there was no apparent antagonism and the addition of bispyribac to fenoxaprop reduced grass weed biomass as compared to fenoxaprop alone. In 2013, there was a strong negative correlation (r = −0.95, P < 0.001) between weed dry matter at 45 days after sowing and rice grain yield. According to the linear regression, rice crop is likely to produce no grain yield when weed dry matter exceeds 400 g m−2. Over the two seasons, fenoxaprop-ethoxysulfuron tank-mix produced similar grain yields (5.6–6.2 t ha−1) to the weed-free check (5.6–7.1 t ha−1). At the farmer fields, rice grain yield in the plots treated with pendimethalin followed by post-emergence bispyribac or a tank-mix of fenoxaprop + ethoxysulfuron ranged from 6.2 to 7.7 t ha−1 as compared to 5.3–5.6 t ha−1 in the plots treated with pendimethalin alone. The tank mixture of fenoxaprop with bispyribac needs further evaluation as this mixture has the potential to effectively control aerobic and aquatic grasses in dry-seeded rice. Single hand weeding prevented crop yield loss from weeds that escaped herbicide treatments only when it was performed within six weeks of sowing.  相似文献   

13.
Rice (Oryza sativa L.) is the most important staple food crop in the southern region of Asia, and Indian subcontinent being one of the major producers. Production of conventional transplanted rice requires a large amount of irrigation water, labor, and energy. The scarcity of irrigation water has encouraged farmers to adopt an alternative rice production system, i.e. the direct-seeded rice (DSR), which is proposed to be farmers’ friendly with a potential to save water. Our study reports the performance of DSR with respect to yield and water expense efficiency based on different irrigation regimes and dates of sowing. A field experiment was conducted in the semi-arid region of northern India during the rainy season of 2011 with two treatment combinations (dates of sowing: 15th May and 5th June and three irrigation regimes: irrigation scheduled at irrigation water-to-cumulative potential evapotranspiration; IW/CPE ratio of 1.0, 1.5 and 2.0) in a completely randomized design. We found statistically higher water expense efficiency of DSR sown on 5th June as compared to DSR sown on 15th May without any significant differences in growth and yield. A significant yield difference between DSR grown with irrigation regimes of IW/CPE 1.0 and 1.5 and DSR grown with irrigation regimes of IW/CPE ratio 2.0 were observed. The DSR grown with irrigation regimes of IW/CPE ratio of 1.5 resulted in significantly higher water expense efficiency than the one with IW/CPE ratio of 2.0. Obtaining a higher yield of DSR under scarce irrigation water might be a trade-off between optimum water use and maximum yield avoiding excess ground water exploitation in sub-tropical semi-arid regions of India. Our study suggests that sowing time and irrigation regimes are two important aspects of “rice production” to attain “win–win” solution. Thus, strategic and judicial use of irrigation water with management of sowing time could potentially escalate the rice production in water scarce regions of India.  相似文献   

14.
A field study on assessment of crop establishment methods on yield, economics and water productivity of rice cultivars under upland and lowland production ecologies was conducted during wet seasons (June–November) of 2012 and 2013 in Eastern Indo-Gangetic Plains of India. The experiment was laid-out in a split-plot design (SPD) and replicated four times. The main-plot treatments included three crop establishment methods, viz. dry direct-seeded rice (DSR), system of rice intensification (SRI) and puddled transplanted rice (PTR). In sub-plots, five rice cultivars of different groups like aromatic (Improved Pusa Basmati 1 and Pusa Sugandh 5), inbreds (PNR 381 and Pusa 834) and hybrid (Arize 6444) were taken for their evaluations. These two sets of treatments were laid-out simultaneously in two production ecologies, upland and lowland during both years. In general, lowland ecology was found favourable for rice growth and yield and resulted in 13.2% higher grain yield as compared to upland ecology. Rice grown with SRI method produced 19.4 and 7.0% higher grain yield in 2012 and 20.6 and 7.1% higher in 2013, over DSR and PTR. However, PTR yielded 13.1 and 14.5% higher grain over DSR during 2012 and 2013, respectively. On an average, Arize 6444 produced 26.4, 26.9, 28.9 and 54.7% higher grain yield as compared to PS 5, P 834, PNR 381 and IPB1, respectively. Further, the interaction of production ecologies × crop establishment methods revealed that, in upland ecology, SRI recorded significantly higher grain yield as compared to PTR and DSR, but in lowland, grain yield resulting from SRI was similar to the yield obtained with PTR and significantly higher than DSR. The latter two methods (PTR and DSR) yielded alike in lowland ecology in both study years. The production ecologies × crop establishment methods × cultivars interaction on grain yield showed that the growing of Arize 6444 cultivar using SRI method in upland ecology resulted in the higher grain yield (8.87 t/ha). But the cost of production was also highest in SRI followed by PTR and DSR across production ecologies and cultivars. Cultivation of hybrid (Arize 6444) involved higher cost of production than all other cultivars. Irrespective of crop establishment methods and cultivars, gross returns, net returns and B:C ratio were significantly higher in lowland compared to upland ecology. Owing to higher grain yield, SRI method fetched significantly higher gross returns and net returns over PTR and DSR. Average increase in net return with Arize 6444 was 68.8, 41.0, 37.7 and 33.1% over IPB 1, PNR 381, P 834 and PS 5, respectively. There was a saving of 30.7% water in SRI and 19.9% in DSR over PTR under upland ecology. Similarly in lowland ecology, water saving of 30.2% was observed in SRI and 21.2% in DSR over PTR. Due to higher yield and saving on water, SRI returned significantly higher total water productivity (TWP) (5.9 kg/ha-mm) as compared to DSR (3.5 kg/ha-mm) and PTR (3.6 kg/ha-mm) under upland ecology. In lowland ecology, also SRI (6.2 kg/ha-mm) resulted in higher TWP as compared to other two methods. However, DSR gave significantly higher TWP as compared to PTR. Among cultivars, hybrid Arize 6444 recorded the highest TWP in both upland and lowland production ecologies across crop establishment methods. Hence, growing of hybrid Arize 6444 with SRI method can enhance rice productivity and water-use efficiency in lowland and upland production ecologies of Eastern Indo-Gangetic Plains and in other similar regions.  相似文献   

15.
以紫米稻品种粮田紫1号为材料,在长沙地区比较研究了5个播期条件下紫米稻的产量与稻米品质。结果表明,粮田紫1号全生育期随播期推迟而明显缩短;有效穗数、每穗粒数、结实率与产量均随播栽期推迟而显著提高,5月31日播种处理产量达4 693.0 kg/hm~2;播期对粮田紫1号稻米品质有显著影响,碾米品质以5月11日播种处理最好,5月21日播种处理次之,稻米直链淀粉含量、粗蛋白含量与Se含量以5月21日播种处理最高,稻米Zn含量以5月31日播种处理最高。综合来看,粮田紫1号在长沙地区高产优质栽培的最佳播期为5月21-31日。  相似文献   

16.
《Plant Production Science》2013,16(3):381-389
Abstract

Scarcity of water and N fertilizer are major constraints to rice production, particularly in developing countries where rainfed upland condition dominates. Improvement of genetic adaptability to inadequate water and N fertilizer is one option to maintain productivity in these regions. NERICAs are expected to yield higher under low input conditions, but growth and yield responses of the cultivars to different ecosystems and N levels remain unknown. The objectives of this study were to characterize the growth and yield performance of NERICAs, in comparison with selected Japanese rice cultivars. The two NERICAs (NERICA 1 and NERICA 5), two Japanese upland cultivars (Toyohatamochi and Yumenohatamochi), and a Japanese lowland cultivar Hitomebore were grown under two ecosystems (irrigated lowland (IL) and rainfed upland (RU)) with two N levels (high (H) and low (L)) for two years. The cultivar difference in the aboveground dry weight and grain yield was the largest in the in RU × L plot, where the values of NERICAs were similar to those in the other plots, but the values of other cultivars were substantially reduced. Regardless of cultivar, N contents of the plants at maturity correlated significantly with the aboveground dry weight at maturity, spikelet number and grain yield per area. These results indicate that NERICAs, compared with the selected Japanese upland cultivars that were bred for drought tolerance, have a higher ability to absorb N under upland conditions, which may contribute to higher biomass production and sink formation, resulting in increased gain yield.  相似文献   

17.
【目的】研究不同机插株距下缓释氮肥与常规氮肥减量配施在水稻关键生育时期的运筹方式,为水稻机插秧配套技术的应用提供理论和实践依据。【方法】以中迟熟杂交籼稻川谷优7329为试验材料,采用两因素裂区设计,在机插行距均为30 cm下,设株距16 cm、18 cm、20 cm;并设4种缓释氮肥与常规氮肥运筹模式:1)基肥为96 kg/hm^2缓释氮肥和24 kg/hm^2常规氮肥,不施追肥;2)基肥施96 kg/hm^2缓释氮肥,追肥施24 kg/hm^2常规氮肥;3)基肥施96 kg/hm^2缓释氮肥和54 kg/hm^2常规氮肥,不施追肥;4)基肥为96 kg/hm^2缓释氮肥和24 kg/hm^2常规氮肥,追肥为30kg/hm^2常规氮肥;以不施氮肥为对照。【结果】缓释氮肥与常规氮肥减量配施运筹和株距对机插杂交籼稻叶面积指数(LAI)、拔节-齐穗期光合势及产量的影响均达显著或极显著水平,且缓释氮肥与常规氮肥减量配施运筹的效应明显高于机插株距。3种株距下,随缓释氮肥与常规氮肥配施量及常规氮肥后移量的增加,机插杂交籼稻的LAI、拔节-齐穗期光合势、干物质积累量、净光合速率及产量均呈增加的趋势。株距为16 cm时,群体茎蘖数显著增大,形成的有效穗多,对养分的竞争性增强,光合特性减弱,未能形成大穗,虽然结实率高但每穗粒数较少,产量较低;株距为20cm,由于密度降低,群体茎蘖数显著减少,形成的有效穗少,后期对养分的吸收充足,光合特性增强,形成了足够的大穗,每穗实粒数显著增加,但结实率和千粒重较小,因此未能高产;而株距为18 cm时,在足够群体茎蘖数的基础上形成的有效穗较多,后期能有效吸收养分,光合特性增强,结实率和千粒重显著增大。相关分析表明,缓释氮肥与常规氮肥减量配施运筹和株距下,尤以齐穗-成熟期群体生长率、拔节-齐穗期光合势和齐穗期有效叶面积指数与产量相关性较高。【结论】株距为18 cm,96 kg/hm^2缓释氮肥和24 kg/hm^2常规氮肥作为基肥施用,30 kg/hm^2常规氮肥作为追肥在倒4叶期施用,能充分发挥本区域机插杂交籼稻的高产优势,提高光合物质生产,产量最高可达11 681.56 kg/hm^2。  相似文献   

18.
The objectives of this research were to investigate the effect of rice straw management and application of different types of organic fertilizer on growth and yield of dry direct-seeded rice grown under rainfed conditions. The experiment was conducted in a farmer’s field at Muang Yai village, Khon Kaen province in 2005. A split-plot design was used, with the main plot under rice straw management (incorporating into the soil and burning), and sub-plots by type of organic fertilizer (green manure, cattle manure and powder organic fertilizer) and one plot under no-fertilizer application. It was found that rice straw incorporated into the soil had no significant effect on grain yield when compared with the effect of burning. Organic fertilizer of cattle manure and powder organic fertilizer significantly increased grain yield over that of green manure and no-fertilizer application. This paper is listed as a series of articles of the special issue “Water and Food” 6(1), March 2008.  相似文献   

19.
The implications of adopting alternative seeding methods for rice and wheat establishment were examined at three geographically separate sites in the rice-wheat system of the Indo-Gangetic plains, across northern India. Rice yields in cultivated plots, established by either wet or dry seeding methods, were evaluated in comparison to yields from zero-tillage plots and under conventional transplanting methods. In the same trials, the effects of crop establishment methods in wheat were assessed both on wheat yields and rice yields. Rice crop establishment methods markedly influenced the emerging weed flora and attainable yields were measured in relation to intensity of weed management. Over four years, average rice grain yields in the absence of weed competition were greatest (6.56 t ha−1) under wet seeding (sowing pre-germinated rice seed on puddled soil), and similar to those from transplanted rice (6.17 t ha−1) into puddled soil, and dry seeded rice after dry soil tillage (6.15 t ha−1). Lowest yields were observed from dry seeded rice sown without tillage (5.44 t ha−1). Rice yield losses due to uncontrolled weed growth were least in transplanted rice (12%) but otherwise large (c. 85%) where rice had been sown to dry cultivated fields or to puddled soil, rising to 98% in dry seeded rice sown without soil tillage. Weed competition reduced multiple rice yield components, and weed biomass in wet seeded rice was six-fold greater that in rice transplanted into puddled soil and twice as much again in dry seeded rice sown either after dry tillage or without tillage. Wheat grain yields were significantly higher from crops sown into tilled soil (3.89 t ha−1) than those sown without tillage (3.51 t ha−1), and also were elevated (5% on average) where the soil had been dry cultivated in preparation for the previous rice crops rather than puddled. The method of wheat cultivation did not influence rice yield. Soil infiltration rates in the wheat season were least where the land had been puddled for rice (1.52 mm h−1), and greater where the soil had been dry-tilled (2.63 mm h−1) and greatest after zero-tillage (3.54 mm h−1).These studies demonstrated at research managed sites across a wide geographic area, and on farmers’ fields, that yields of dry seeded rice sown after dry cultivation of soil were broadly comparable with those of transplanted rice, providing weed competition was absent. These results support the proposition that direct seeding of rice could provide an alternative to the conventional practice of transplanting, and help address rising costs and threats to sustainability in the rice-wheat rotation. Further, analysis of patterns of long-term rainfall data indicated that farmers reliant on monsoon rainfall could prepare fields for dry direct seeded rice some 30 days before they could prepare fields for either transplanting or seeding with pre-germinated seed. Dry, direct seeding of rice contributes a valuable component of an adaptive strategy to address monsoonal variability that also may advance the time of wheat establishment and yield. Whilst the results illustrate the robustness, feasibility and significant potential of direct seeded rice, they also highlight the critical nature of effective weed control in successful implementation of direct seeding systems for rice.  相似文献   

20.
【目的】研究不同机插株距下缓释氮肥与常规氮肥减量配施在水稻关键生育时期的运筹方式，为水稻机插秧配套技术的应用提供理论和实践依据。【方法】以中迟熟杂交籼稻川谷优7329为试验材料，采用两因素裂区设计，在机插行距均为30 cm下，设株距16 cm、18 cm、20 cm；并设4种缓释氮肥与常规氮肥运筹模式：1)基肥为96 kg/hm2缓释氮肥和24 kg/hm2常规氮肥，不施追肥；2)基肥施96 kg/hm2缓释氮肥，追肥施24 kg/hm2常规氮肥；3)基肥施96 kg/hm2缓释氮肥和54 kg/hm2常规氮肥，不施追肥；4)基肥为96 kg/hm2缓释氮肥和24 kg/hm2常规氮肥，追肥为30 kg/hm2常规氮肥；以不施氮肥为对照。【结果】缓释氮肥与常规氮肥减量配施运筹和株距对机插杂交籼稻叶面积指数(LAI)、拔节-齐穗期光合势及产量的影响均达显著或极显著水平，且缓释氮肥与常规氮肥减量配施运筹的效应明显高于机插株距。3种株距下，随缓释氮肥与常规氮肥配施量及常规氮肥后移量的增加，机插杂交籼稻的LAI、拔节-齐穗期光合势、干物质积累量、净光合速率及产量均呈增加的趋势。株距为16 cm时，群体茎蘖数显著增大，形成的有效穗多，对养分的竞争性增强，光合特性减弱，未能形成大穗，虽然结实率高但每穗粒数较少，产量较低；株距为20 cm，由于密度降低，群体茎蘖数显著减少，形成的有效穗少，后期对养分的吸收充足，光合特性增强，形成了足够的大穗，每穗实粒数显著增加，但结实率和千粒重较小，因此未能高产；而株距为18 cm时，在足够群体茎蘖数的基础上形成的有效穗较多，后期能有效吸收养分，光合特性增强，结实率和千粒重显著增大。相关分析表明，缓释氮肥与常规氮肥减量配施运筹和株距下，尤以齐穗-成熟期群体生长率、拔节-齐穗期光合势和齐穗期有效叶面积指数与产量相关性较高。【结论】株距为18 cm，96 kg/hm2缓释氮肥和24 kg/hm2常规氮肥作为基肥施用，30 kg/hm2常规氮肥作为追肥在倒4叶期施用，能充分发挥本区域机插杂交籼稻的高产优势，提高光合物质生产，产量最高可达11 681.56 kg/hm2。  相似文献   

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