麦茬旱稻不同播量对产量形成的影响

2001年在沂水、费县以早稻65为材料进行了6个播种量处理的试验。结果表明．随着播量的增加。群体逐渐增大．穗数明显提高。合理的播量。形成了适宜的群体结构．光能利用率提高，光合产物增加．最终产量较高。试验认为以播量75～90kg／hm。较适宜。     

Farmers' perspectives of rodent damage and management from the highlands of Tigray,Northern Ethiopian

A farmers' knowledge, attitude and practice (KAP) survey was conducted in the highlands of Tigray, northern Ethiopia, to better understand rodent damage and rodent management from the farmers' perspective. Farmers (n = 191) from Dogu'a Temben district, were interviewed using a semi-structured questionnaire. The large majority of the farmers stated that rodents are the main pests in crop fields (92.1%) and storage (88.5%). The farmers (64.2%) reported they experienced 100–500 kg ha⁻¹ damage in crop fields, which is equivalent to 8.9–44.7% loss in annual production. There was some overlap between the most common crops grown in the highlands and the most common crops susceptible to rodent attack. Farmers identified barley as the crop most susceptible to rodent attack (76.4%) and the booting stage as the crop developmental stage with the highest rodent abundance and damage. Rodenticide application was the most commonly practiced management strategy in crop fields (51.8%); in storage, farmers mainly keep domestic cats around granaries (80.6%). We recommend a reduction in reliance on chemical rodenticide in crop fields and a shift to a more sustainable rodent management approach to reduce rodent numbers and damage.     

Pesticide diversity in rice growing areas of Northern Vietnam

Pesticide use in developing countries increases rapidly. In many regions, we miss knowledge of how frequently pesticides are applied and which active ingredients are used. We present a new cost-efficient and rapid assessment method of recording pesticides diversity in rice-dominated landscapes and present some evidence of the misuse of active ingredients in our study regions. We investigated 17 rice fields in two regions of Northern Vietnam in 2014 and 2015. At each region, we explore the abundance of pesticides used with three methods including (1) the novel approach of collecting pesticide packages close to our target rice fields, (2) observations of farmers spraying pesticides in the surrounding and (3) interviewing local farmers. By collecting pesticide packages, we found 811 packages containing 74 different active ingredients. On average, 19 active ingredients (ranging from four to 40 active ingredients) were applied with an average content of 275.3 g of active ingredients per site. Insecticide packages (39%) were most abundant followed by those of fungicides (31%), herbicides (16%) and other active ingredients (14%). On all sites, active ingredients banned in the European Union were applied by the farmers. Collecting pesticide packages proved to be an efficient and rapidly implemented method to obtain some baseline information about pesticide application (for Northern Vietnam). We suspect that improved agricultural extension services could contribute to good agricultural practices in pest management. Generally, better information and education for local farmers for appropriate use of pesticides seem a necessity.     

多效唑对麦茬旱稻农艺性状影响及生理作用的研究

以早稻277为材料．在l叶l心期进行了不同浓度多效唑喷施试验。麦茬早稻苗期喷洒多效唑对植株高度有明显的降低作用．可提高秧苗素质和抗倒力。同对照相比．叶面喷施多效唑可使麦茬早稻产量增加10％左右。增产的生理作用主要表现在光合速率提高，气孔导度和蒸腾速率提高。叶面喷施多效唑可增加麦茬早稻的穗粒数。     

老挝北部山区主要土壤类型的养分状况

以老挝北部4种主要土壤类型为研究对象,分析不同土壤类型的养分含量和养分的垂直分布特点,为老挝农业生产过程中化肥的合理使用和老挝土地资源的可持续开发利用提供依据。结果表明：土壤pH值为5.46,呈微酸性;有机质含量为2.1%,处于中等水平;碱解氮、有效磷和速效钾的含量分别是109.4、3.26、93.4 mg/kg,含量比较低;交换性钙和镁的含量分别为1 735.9、328.9 mg/kg。不同土壤类型的养分含量随着土壤深度的增加呈现不同的变化规律和分布特征,在土地利用方式和肥料投入方面存在较大差异。因此,在农业生产中,要依据土壤养分状况合理调整施肥量。     

The large-effect drought-resistance QTL qtl12.1 increases water uptake in upland rice

Drought stress is the most important abiotic factor limiting upland rice yields. Identification of quantitative trait loci (QTL) conferring improved drought resistance may facilitate breeding progress. We previously mapped a QTL with a large effect on grain yield under severe drought stress (qtl12.1) in the Vandana/Way Rarem population. In the current paper, we present results from a series of experiments investigating the physiological mechanism(s) by which qtl12.1 affects grain yield under drought conditions. We performed detailed plant water status measurements on a subset of lines having similar crop growth duration but contrasting genotypes at qtl12.1 under field (24 genotypes) and greenhouse (14 genotypes) conditions. The Way Rarem-derived allele of qtl12.1 was confirmed to improve grain yield under drought mainly through a slight improvement (7%) in plant water uptake under water-limited conditions. Such an apparently small increase in water uptake associated with this allele could explain the large effect on yield observed under field conditions. Our results suggest that this improvement of plant water uptake is likely associated with improved root architecture.     

Weed management in aerobic rice systems

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.     

Field evaluation of upland rice lines selected for QTLs controlling root traits

A marker-assisted back-cross (MABC) programme was used to introgress four root quantitative trait loci (QTLs) from the tropical japonica rice variety Azucena into the Indian upland rice variety, Kalinga III. Previously we tested the products for root traits and reported that the introgressed QTL9 (on chromosome 9) significantly increased root length in the new genetic background. Here we describe field testing for agronomic traits in near-isogenic lines (NILs) that differ for introgressed QTLs. Four NILs were selected and characterised in replicated field experiments in eastern and western India over 3 years. They were tested by upland farmers in a target population of environments (TPE) in three states of eastern India, over 2 years. NILs out-performed Kalinga III for grain and straw yield and there was interaction between the genotypes and the environment (G × E). No effect was found for the root QTL9 on grain or straw yield, however, the presence of several introgressions significantly improved both traits. Some of this effect was due to introgression of Azucena alleles at non-target regions. Overall, the Azucena introgressions increased straw yield more than grain yield. While it has yet to be demonstrated whether this effect is due to improved root systems, this finding fits with the assumption that introgressed genes are involved in partitioning of biomass to the roots and stems, rather than to the grain. The NILs could replace Kalinga III for cultivation in medium upland environments in eastern India.     

Performance of diverse upland rice cultivars in low and high soil fertility conditions in West Africa

Traditional tropical japonica (Oryza sativa) and Oryza glaberrima cultivars are typically grown in low-input, subsistence production systems in the uplands of West Africa by resource-poor farmers. In these systems, low soil fertility (LF), which is generally associated with lower organic carbon content, and N and P availability, is one of the major constraints to rice productivity. Thus, cultivars adapted to LF are needed for the food security of farmers, who would otherwise be solely reliant on nutrient inputs to increase productivity. This study evaluated the performance of six diverse cultivars grown in LF and high soil fertility (HF) conditions with supplemental irrigation over two seasons. Average grain yield across all cultivars in LF was 54% of that in HF (156 vs. 340 g m⁻²). Three improved indica rice cultivars and CG 14 (O. glaberrima) out-yielded Morobérékan (traditional tropical japonica) and WAB450-IBP-38-HB (progeny from interspecific hybridization of tropical japonica and O. glaberrima) in LF (181 vs. 105 g m⁻² on average). The high grain yield in LF was the result of large spikelet number m⁻² due to superior tillering ability and high harvest index rather than biomass production. The high-yielding cultivars in LF consistently had lower leaf chlorophyll content and higher specific leaf area during the period from the early vegetative stage through the reproductive stage. Among them, two indica cultivars (B6144F-MR-6-0-0 and IR 55423-01) were also high yielding in HF. The use of improved indica cultivars adapted to LF, but also with input-responsiveness, appears to offer an attractive and economical approach to improving upland rice productivity and widening genetic diversity in this region.     

Changes in farmers' knowledge,attitudes and practices after implementation of ecologically-based rodent management in the uplands of Lao PDR

Rodents are a severe and chronic pest for farmers in the upland farming system of Lao PDR where upland rice is the predominant subsistence crop. Farmers participated in developing and implementing a series of ecologically-based rodent management (EBRM) strategies designed to reduce the impact of rodents in their upland farming system. These were tested in replicated Treatment and Reference sites in two provinces of northern Laos. A survey was conducted with farmers to determine their knowledge, attitudes and practices prior to and after the implementation of EBRM. This paper reports on the results of the post-implementation survey and compares results with the pre-implementation survey. The survey revealed that rodents remained the most important pest for these farmers. The mean estimated yield loss of upland rice was 12%. There was a significant reduction in the yield loss from pre- to post-treatment, but the time by treatment interaction was not significant. Trapping rodents in the fields remained the most important control strategy for these farmers and also was considered the most effective method. There was an increase in effort expended by farmers in controlling rodents post-treatment on Treatment sites in Luang Namtha, but no difference for other sites. The money spent on controlling rodents was lower on all sites post-treatment except for Treatment sites in Luang Namtha. Farmers on the Treatment sites in Luang Namtha had the lowest effort during the pre-treatment period and thought they needed to increase their rodent management efforts because of their involvement in this project. As a result of the project, farmers were more aware of the problems of rodents and were interested in adopting EBRM strategies.     

Yield potential and water use efficiency of aerobic rice (Oryza sativa L.) in Japan

Intensive rice farming in aerobic soil, referred to herein as aerobic rice, can greatly reduce the water input compared to that of flooded rice cultivation. The objective of this study was to compare the potential productivity of aerobic rice and flooded rice using high-yielding varieties at two locations in Japan in two successive years. In aerobic fields, the total amount of water supplied (irrigation plus rainfall) was 800–1300 mm. The soil water potential at 20-cm depth averaged between −15 and −30 kPa each growing season, but frequently reached −60 kPa. The average yield under aerobic conditions was similar to or even higher than that achieved with flooded conditions (7.9 t ha⁻¹ in 2007 and 9.4 t ha⁻¹ in 2008 for aerobic versus 8.2 t ha⁻¹ for flooded). The average water productivity under aerobic conditions was 0.8–1.0 kg grain m⁻³ water, slightly higher than common values in the literature. The super-high-yielding cultivar Takanari achieved yields greater than 10 t ha⁻¹ with no yield penalty under aerobic conditions in 3 out of 4 experiments. The favorable agronomic characteristic of Takanari was its ample sink capacity (grain number × grain weight). In conclusion, high-productivity rice cultivation in aerobic soil is a promising technology for water conservation. With continued breeding, future aerobic rice varieties will possess large numbers of spikelets and sufficient adaptation to aerobic conditions such that they will consistently achieve yields comparable to the potential yield of flooded rice.     

海南山栏稻种质资源的保护与利用

山栏稻是黎族人民二千多年原始的刀耕火种农耕文化延续下来的稻种,是宝贵的遗传资源,但这一资源面临濒危,亟需保护。本文综述山栏稻种质资源保护和利用研究进展,分析了目前存在的问题,并提出保护和利用的建议。     

Knowledge, attitudes and practices of farmers on rodent pests and their management in the lowlands of the Sierra Madre Biodiversity Corridor, Philippines

A survey of the knowledge, attitudes and practices (KAP) of 100 rice farmers and 50 coconut farmers was conducted in the coastal lowland agro-ecosystems of the Sierra Madre Biodiversity Corridor, Luzon, Philippines to identify current rodent management practices and to understand the extent of rat damage and the attitudes of farmers to community actions for rodent management. Pests were most commonly listed as one of the three most important rice and coconut production constraints. Other major crop production constraints were typhoons and insufficient water. Farmers consider rats to be the major pest of coconut and of rice during the wet season rice crop, with average yield losses of 3.0% and 13.2%, respectively. Rice and coconut farmers practised a wide range of rodent management techniques. These included scrub clearance, hunting and trapping. Of the 42 rice farmers and 3 coconut farmers that applied rodenticides to control rodents, all used the acute rodenticide, zinc phosphide. However, only ten rice farmers (23.8%) applied rodenticides prior to the booting stage and only seven farmers (15.6%) conducted pre-baiting before applying zinc phosphide. The majority of farmers belonged to farmer organisations and believed that rat control can only be done by farmers working together. However, during the last cropping season, less than a third of rice farmers (31.2%) applied rodent management as a group. In order to reduce the impact of rodents on the farmers of the coastal lowlands of the Sierra Madre Biodiversity Corridor, integrated management strategies need to be developed that specifically target the pest rodents in a sustainable manner, and community actions for rodent management should be promoted.     

Implications of genotype × input interactions in breeding superior genotypes for favorable and unfavorable rainfed upland environments

Resource-poor farmers in India cultivate upland rice as a subsistence crop in poor soil with minimum inputs, often applying little or no fertilizer and controlling weeds by hand. Consequently, upland rice yields are very low. In our study, the response to management intensification of fertilizer application at rates of 40 N ha⁻¹, 13 P ha⁻¹, and 16.7 K ha⁻¹ and two weed control treatments as compared with no fertilizer, and one hand weeding practice commonly followed by farmers in rainfed upland areas was examined with a large set of advanced breeding lines and adapted upland varieties tested over 3 years in multi-location trials. Highly significant genotype × environment interaction was observed in combined analyses across environments, leading to sub-grouping of sites into the high-yielding or favorable and low-yielding or unfavorable upland environment groups. A significant effect of management regime was observed. Averaged over 15 environments, the moderate-input treatment out-yielded the low-input treatment by nearly 65% or 0.8 t ha⁻¹ under favorable environments and by nearly 48% (0.3 t ha⁻¹) in unfavorable environments. A significant genotype effect and genotype × input management interaction for yield at favorable sites was observed. However, the same was not significant at unfavorable sites. Varietal differences were relatively small at unfavorable sites across input levels. The heritability estimates for grain yield were moderately high in both moderate- and low-input conditions in favorable environments. The genetic correlation between yields in moderate- and low-input conditions was high in both favorable and unfavorable environments. The study indicated that improved varieties performed well relative to landraces under low-input management. Improved varieties along with modestly intensified management offer an attractive option to increase the productivity of rainfed upland environments. For both favorable and unfavorable environments, indirect selection under moderate-input conditions was less efficient than direct selection for grain yield in low-input conditions, indicating upland breeding programs to adopt selection for grain yield under both moderate- and low-input conditions.     

Protein and lysine digestibility and protein quality of cooked Filipino rice diets and milled rice in growing rats

The protein quality of typical rice-based menu of Filipino preschool child and adult and cooked milled rice was assessed for true digestibility (TD), biological value (BV) and net protein utilization (NPU) in growing rats. Lysine and energy digestibilities were also determined. For the preschool child diet, TD was 88.8%, BV 90.0%, and NPU 79.9%. For the adult diet, TD was 87.3%, BV 86.6%, and NPU 75.5%, whereas cooked rice had 90.0% TD, 82.5% BV and 74.3% NPU. Lysine digestibility was 95.4% for preschool child diet, 95.7% for adult diet, and 100.0% for rice. Digestible energy was 91.3% for preschool child diet, 93.0% for adult diet, and 95.3% in rice. Amino acid scores were 100.0% for preschooler diet, 92.1% for adult diet, and 62.2% for rice. Protein quality based on amino acid score corrected for TD was 88.8% for preschool child diet. 80.4% for adult diet, and 56.0% for rice. If based on lysine digestibility instead of TD, protein quality would be 7.1% higher.     

Integrated nutrient management for environmental-friendly rice production in salt-affected rice paddy fields of Saemangeum reclaimed land of South Korea

This study was conducted in an attempt to determine the proper nitrogen and phosphorus application levels, nitrogen split application ratio, and application method for environmental-friendly rice production in a salt-affected rice paddy field, which was located in the Saemangeum reclaimed tidal belt on the western coast of South Korea, between April 1, 2003 and October 10, 2004. All treatments were replicated three times in a randomized block design (5 m × 4 m plot) with 11 treatments (total 33 plots). We designed three treatments for the evaluation of reasonable application levels of nitrogen and phosphorus fertilizers (A1–A3); five treatments to evaluate the nitrogen split application system (T1–T5); and three treatments to determine the proper application for chemical fertilizer (M1–M3). There was no significant difference of amylose and protein content among the application levels, application methods, and nitrogen split application ratios (P < 0.05). No significant differences in grain yield and yield components of rice were observed among the different application levels, application methods, and nitrogen split application ratios (P < 0.05). In order to save labor in agricultural households, preserve or enhance the grain quality of rice, and reduce nutrient losses, we determined that the optimum application level of nitrogen fertilizer was 140 kg ha⁻¹; the application split ratio of nitrogen fertilizer at four different periods was 40% for basal fertilization, 20% for maximum tilling stage, 30% for the panicle formation stage, and 10% for the booting stage; and the best application methods were deep layer application and whole layer application.     

Growth and yield responses of upland NERICAs to variable water management under field conditions

This study aimed to investigate the possible causes for inconsistent performances of upland New Rice for Africa (NERICA) varieties in uplands and lowlands, while identifying important determinants in grain yield under deficient soil moisture. We compared the growth and yield of NERICA 1 and NERICA 5 to those of Yumenohatamochi, a Japanese upland variety, and Hinohikari, a Japanese lowland variety, subjected to different water management regimes (continually flooded, supplementary irrigation, and non-irrigation). Under conditions of deficient soil moisture, panicle number per square meter, spikelet number per panicle, and 1000-grain weight of NERICAs decreased, whereas the panicle number of the Japanese varieties experienced little change. In contrast, the grain filling ratio was unaffected by water management, irrespective of variety. The primary source of yield reduction under low soil water conditions was a decrease in spikelet number per panicle, and water stress intensity was the primary factor for the degree of this reduction. Variation in the abortion of secondary rachis-branches caused differences between NERICAs in their spikelet number response to soil moisture deficiency. The inconsistency in NERICA performance across uplands vs. lowlands can be partially attributed to variation in yield response to low soil water conditions. Moreover, water stress intensity and the presence of a water gradient along the vertical soil profile may combine to affect the fluctuation in NERICA performance under upland conditions.     

黔北杂交水稻高产栽培体系探讨

从自然条件、水稻种植水平、病虫草鼠害等方面分析了黔北水稻产量限制因素,系统地开展了高效集成技术的研究与应用,探索适宜黔北水稻实现高效的途径和技术模式。     

Effect of irrigation method and N-fertilizer management on rice yield, water productivity and nutrient-use efficiencies in typical lowland rice conditions in China

Alternate wetting and drying irrigation (AWD) has been reported to save water compared with continuous flooding (CF) in rice cultivation. However, the reported effects on yield varied greatly and detailed agro-hydrological characterization is often lacking so that generalizations are difficult to make. Furthermore, it is not known how AWD modifies nutrient use efficiencies and if it requires different N-fertilizer management compared with CF. This study quantified the agro-hydrological conditions of the commonly practiced AWD and compared the impact of AWD and CF irrigations at different N-fertilizer management regimes on rice growth and yield, water productivity, and fertilizer-use efficiencies in five crop seasons in 1999 and 2000 at two typical lowland rice sites in China (Jinhua, Zheijang Province and Tuanlin, Hubei Province), with shallow groundwater tables.Grain yields varied from 3.2 to 4.5 t ha^–1 with 0 kg N ha^–1 to 5.3–8.9 t ha^–1 with farmers N-rates (150 kg N ha^–1 in Jinhua and 180 in Tuanlin). In both sites, no significant water by nitrogen interaction on grain yields, biomass, water productivity, nutrient uptakes and N-use efficiency were observed. Yield and biomass did not significantly differ (P >0.05) between AWD and CF and among N timings. The productivity of irrigation water in AWD was about 5–35% higher than in CF, but differences were significant (P <0.05) only when the rainfall was low and evaporation was high. Increasing the number of splits to 4–6 times increase the total N uptake, but not total P-uptake, and total K-uptake compared with farmers practices of two splits. Apparent Nitrogen recovery (ANR) increased as the number of splits increased, but there was no significant difference in ANR between AWD and CF. During the drying cycles of AWD irrigation, the perched water table depths seldom went deeper than – 20 cm and the soil in the root zone remained moist most of the time. The results suggest that in typical irrigated lowlands in China, AWD can reduce water input without affecting rice yields and does not require N-fertilizer management differently from continuous flooding. The results can be applied to many other irrigated lowland rice areas in Asia which have a shallow groundwater table.     

Management of complex weed flora in dry-seeded rice

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.