Effects of field high temperature on grain yield and quality of a subtropical type japonica rice—Pon-Lai rice

Typical japonica type rice is sensitive to high temperature. Pon-Lai rice is a special japonica type with adaptation to the subtropical climate in Taiwan. Facing climate change, rising temperatures would damage the yield and quality of rice production. This research was conducted using Pon-Lai rice in the field of a subtropical climate. We conducted 2 experiments, including a year-round experiment and collection of samples from different districts for building different temperature conditions. We analyzed the correlation between rising temperature and rice yield or quality. In our results, the critical period of temperature effect is 0–15 days after heading (H15). The threshold of high temperature damage in yield and appearance quality was 25–27 °C. Grain weight decreased about 2–6%, while the temperature of H15 was raised 1 °C above the thresholds. Perfect grain ratio and chalky grain ratio decreased and increased, respectively, while the temperature of H15 was raised above the thresholds. However, the high temperature in H15 affected the physicochemical characteristics. In addition, we found positive correlation between grain length to width ratio and perfect grain ratio. Grain length to width ratio could be an index of temperature effects for grain quality. In our study, when the temperature was below 30 °C, a rising temperature of H15 could damage rice yield and appearance quality, and change grain shape. Our results could provide reference for dealing with the warming future in other temperate rice-cultivated countries.     

Effects of interspecific competition on the growth and competitiveness of five emergent macrophytes in a constructed lentic wetland

To evaluate the performance of new rice establishment methods viz., system of rice intensification (SRI) and integrated crop management (ICM), a field study was conducted during 2008–11 in South Garo Hills, Meghalaya, foot hills of Eastern Himalayas, India. Field demonstrations were undertaken during wet seasons of 2008–11 and socio-economic information in the context of farmer’s realities were obtained during 2010–11 using a well structured questionnaire administered to 134 farmers. The results indicated that the average higher productivity of rice under SRI and ICM demonstration was 209.9 and 185.4 %, respectively, over conventional rice culture (CRC). The SRI and ICM methods of rice cultivation could save seeds (97.56 and 60.98 %), saving water (78.05 and 63.66 %), reduce cost (70.33 %), higher yield etc. compared to CRC. The main reasons for non-adoption of SRI/ICM was related to involvement of more efforts, faith towards traditional practices, ignorance and lack of knowledge on scientific water management. The net-return of $816.69, $706.63 and $51.48/ha was realized under SRI, ICM and CRC, respectively. The co-efficient of multiple determinations (R ²) of the production function was 0.695 in SRI, 0.714 in ICM and 0.734 in CRC which indicated that about 69.5, 71.4 and 73.4 % of the variation in rice productivity under SRI, ICM and CRC, respectively were explained by the independent variable and remaining 30.5, 28.6 and 26.6 %., respectively in SRI, ICM and CRC were as a result of non-inclusion of some explanatory variables as well as other factors outside the farmers control.     

Differences in rice water consumption and yield under four irrigation schedules in central Jilin Province,China

The center of Jilin Province is one of the major rice-producing areas of Northeast China; however, rice production consumes large amounts of water, which is incompatible with the increasingly limited water supply. Rice yield and water consumption are the two most important considerations in the rice production process, and they may vary under different irrigation schedules. In this study, conducted in 2011 and 2012, differences in water consumption and rice yield were observed and analyzed under four different irrigation schedules—flooding irrigation (FI), shallow-wet irrigation (SWI), intermittent irrigation (II), and controlled irrigation (CI)—in a typical rice-growing area of central Jilin. The results showed that, under the four irrigation schedules, water consumption rates were (from highest to lowest) FI (1137.9 mm), SWI (984.0 mm), II (804.3 mm), and CI (678.5 mm), and rice yield rates were (from highest to lowest) SWI (9777.5 kg/ha), FI (9006.1 kg/ha), II (8936.3 kg/ha), and CI (8843.7 kg/ha), respectively. This indicated that, in central Jilin Province, the application of an advanced irrigation schedule not only saved a large amount of water for irrigation, but also that rice yields were not greatly reduced, and even increased in SWI. Therefore, we hope that in this and other similar rice cultivation areas, a universal high-yield and water-saving irrigation schedule can effectively reduce the problem of agricultural water use.     

Climate variability and yield risk in South Asia’s rice–wheat systems: emerging evidence from Pakistan

Rice and wheat are the principal calorie sources for over a billion people in South Asia, although each crop is particularly sensitive to the climatic and agronomic management conditions under which they are grown. Season-long heat stress can reduce photosynthesis and accelerate senescence; if extreme heat stress is experienced during flowering, both rice and wheat may also experience decreased pollen viability and stigma deposition, leading to increased grain sterility. Where farmers are unable to implement within-season management adaptations, significant deviations from expected climatic conditions would affect crop growth, yield, and therefore have important implications for food security. The influence of climatic conditions on crop growth have been widely studied in growth chamber, greenhouse, and research station trials, although empirical evidence of the link between climatic variability and yield risk in farmers’ fields is comparatively scarce. Using data from 240 farm households, this paper responds to this gap and isolates the effects of agronomic management from climatic variability on rice and wheat yield risks in eight of Pakistan’s twelve agroecological zones. Using Just and Pope production functions, we tested for the effects of crop management practices and climatic conditions on yield and yield variability for each crop. Our results highlight important risks to farmers’ ability to obtain reliable yield levels for both crops. Despite variability in input use and crop management, we found evidence for the negative effect of both season-long and terminal heat stress, measured as the cumulative number of days during which crop growth occurred above critical thresholds, though wheat was considerably more sensitive than rice. Comparing variation in observed climatic parameters in the year of study to medium-term patterns, rice, and wheat yields were both negatively affected, indicative of production risk and of farmers’ limited capacity for within-season adaptation. Our findings suggest the importance of reviewing existing climate change adaptation policies that aim to increase cereal farmers’ resilience in Pakistan, and more broadly in South Asia. Potential agronomic and extension strategies are proposed for further investigation.     

Importance of basic cultivation techniques to increase irrigated rice yields in Tanzania

The productivity of irrigated rice is low in Tanzania. We hypothesized that this is caused by the absence of a packaged application of basic cultivation techniques. A baseline survey of 31 rice irrigation schemes across the country revealed that a large proportion of fields were cultivated without a technical package. Thus, a package was introduced to each of the 31 schemes through a farmer-to-farmer (FTF) extension approach. First, selected key farmers (KFs) were trained with the basic cultivation techniques at agricultural training institutes. Second, the KFs transferred their knowledge to intermediate farmers (IFs) by working together at a demo-field established in each scheme. Third, the KFs and IFs exhibited the rice performance to other farmers (OFs). The paddy yield across the 31 schemes greatly increased from the pre-training level of 2.4 t ha^?1 to 3.6 t ha^?1after the FTF extension. However, the farmer interviews in the four selected schemes suggested that the technical package was not adopted by all farmers owing to the time-consuming nature of the FTF extension. It was inferred from our study that the low productivity of irrigated rice is caused by the absence of basic cultivation techniques in Tanzania. However, the post-training yield remained relatively low compared with high-yields (4.3–8.4 t ha^?1) recorded in cultivar selection trials and high-performing schemes in the county. This “yield gap” could be partly ascribed to the insufficient technical diffusion and the technique-dependent adoption among OFs.     

Salinity intrusion and rice production in Red River Delta under changing climate conditions

This study was carried out to identify the vulnerability of rice production to salinity intrusion arising from climate change in Giao Thuy, a coastal district of Nam Dinh Province, located in Red River Delta in Vietnam. From the analysis of historical climate data at Nam Dinh city, both mean maximum and minimum temperatures increased by about 0.3 and 0.1 °C per decade, respectively, during the period of 1961–2010. Salt concentration of the river water was higher at the irrigation gate closer to river mouth (Con Nhat) than at the upstream gate (Ha Mieu), which generally increased from 2003 to 2012, with the average maximum concentration up to 2.13 % at Con Nhat gate in 2010. The salt water concentration in the riverside field outside the dyke reached 3.6 %, while among the fields within dyke the salinity was only 0.7 % at maximum in January 2013, and the values were higher in paddy fields close to the dyke than far from the dyke. Average yield among the selected 27 fields from 2011 summer to 2013 spring rice was higher in spring rice (748 g m^?2) but lower in summer rice (417 g m^?2) mainly due to unfavorable weather such as cold spell at flowering and flood at harvesting time. Rice yield was lowest in general in the most downstream commune Giao Thien, and was significantly lower in field located close to the dyke than those far from the dyke. This spatial variability of rice yield may not be directly attributable to salinity, but to the other factors such as shift of irrigation intake gate to further upstream and/or different management such as less input of N fertilizer and use of traditional local variety.     

Applicability of APSIM to capture the effectiveness of irrigation management decisions in rice-based cropping sequence in the Upper-Gangetic Plains of India

Rice–wheat (RW) production system, which covers over 13.5 million ha in the Indo-Gangetic Plains of south Asia, is vital for food and nutritional security and livelihood of millions of poor people in this part of the region. Availability of irrigation water under projected climate change scenarios is a great concern, and demonstration of the impact of different irrigation regimes on rice, wheat, and system yields is essential to adopt suitable water saving technologies to minimize risk. This study tested the ability of the agricultural production systems simulator (APSIM) model to simulate the effects of different irrigation regimes on yield, irrigation water requirement, and irrigation water productivity (WP_i) of rice, wheat, and RW system in upper-gangetic plains of India. The long-term simulated rice yield showed a steadily declining trend at an average rate of 120 kg ha^?1 yr^?1 (R ² = 0.94, p < 0.05), while long-term simulated wheat yields showed a lower declining trend at an average rate of 48 kg ha^?1 yr^?1 (R ² = 0.48, p < 0.05). The highest WP_i of 8.31 kg ha^?1 mm^?1 was observed under RW system with the rice irrigation (IR) regime of 8 days alternate wetting and drying (AWD) and five irrigations for wheat with a yield penalty of 25.5 %. The next highest WP_i was observed in the treatment with a 5-day AWD regime in rice and five irrigations for wheat, with a yield penalty of 20.1 %. Thus, we can suggest that a 5-day AWD irrigation regime for rice combined with five irrigations during wheat could be the best option under water limiting situations.     

Climate change impacts on agriculture and irrigation in the Lower Mekong Basin

According to hydrological simulations by the Mekong River Commission, average annual flow of the Mekong will not change significantly despite climate change. However, they projected increased variability in wet and dry season flows, which will tend to increase the flood and drought risks to crops. To learn the implications of climate change for rice farming in the Lower Mekong Basin (LMB), a lower part of the Basin from China-Lao PDR border to the South China Sea, climate and hydrological figures related to rice production were compared in between the baseline in 1985–2000 and the climate change scenario in 2010–2050. Special attention was given to their 10 and 90 % exceedance values, which are rough equivalence of 10 and 90 % cumulative probabilities, to see changes in the frequency and extent of extreme weather events. Major findings of this study include the followings: (1) evapo-transpirations will increase in both average and 90 % cumulative probability values, raising irrigation demand. (2) Deviation of the annual rainfall will become larger, causing water shortage in reservoirs more frequently in the future. (3) The transplanting date of rain-fed rice will be delayed more likely due to insufficient precipitation in the early wet season, which may result in decreasing rice production. (4) Longer dry spells will be observed during the wet season, raising the drought risk to rain-fed rice. (5) These changes will be generally observed across the LMB, while the extent of the changes varies among regions.

     

Increasing paddy yields and improving farm management: results from participatory experiments with good agricultural practices (GAP) in Tanzania

Rice is an increasingly important commodity in sub-Saharan Africa. In Tanzania, the rice yield gap is as high as 87%, due to a combination of production constraints and sub-optimal crop management. Reducing this yield gap may be partly achieved through the introduction and dissemination of good agricultural practices (GAP). We conducted 18 farmer-managed on-farm trials in Tanzania, to test a set of GAP components against conventional farmers’ practices (FP) for two consecutive growing seasons in 2013 and 2014. The objectives were: (1) to understand farmers’ capabilities in implementing GAP; (2) to acquire better insights into the merits, relevance and suitability of individual GAP components; and (3) to provide a case study showing that exposure to good practices combined with the farmers’ own experimentations can serve to improve and, trigger a positive change in the participating farmers’ crop management. Compared to the farmers’ own practices, average yield increases of 1 t paddy ha^?1 in 2013 and 2.7 t ha^?1 in 2014 were achieved when following GAP. These yield advantages were mainly obtained by a higher panicle number, improved harvest index and improved weed control. Farmers experienced difficulties with land levelling, planting or sowing in lines and using rotary weeders, but they were convinced that these technologies are important to boost their rice yields. The case of Tanzania shows that paddy yields can be substantially improved by GAP and that adoption of GAP by smallholder rice farmers can be triggered by stimulating experimentations with such practices on their own farms.     

Climate change impacts on agriculture and irrigation in the Lower Mekong Basin

According to hydrological simulations by the Mekong River Commission, average annual flow of the Mekong will not change significantly despite climate change. However, they projected increased variability in wet and dry season flows, which will tend to increase the flood and drought risks to crops. To learn the implications of climate change for rice farming in the Lower Mekong Basin (LMB), a lower part of the Basin from China-Lao PDR border to the South China Sea, climate and hydrological figures related to rice production were compared in between the baseline in 1985–2000 and the climate change scenario in 2010–2050. Special attention was given to their 10 and 90 % exceedance values, which are rough equivalence of 10 and 90 % cumulative probabilities, to see changes in the frequency and extent of extreme weather events. Major findings of this study include the followings: (1) evapo-transpirations will increase in both average and 90 % cumulative probability values, raising irrigation demand. (2) Deviation of the annual rainfall will become larger, causing water shortage in reservoirs more frequently in the future. (3) The transplanting date of rain-fed rice will be delayed more likely due to insufficient precipitation in the early wet season, which may result in decreasing rice production. (4) Longer dry spells will be observed during the wet season, raising the drought risk to rain-fed rice. (5) These changes will be generally observed across the LMB, while the extent of the changes varies among regions.     

Comparative Analysis of Irish Potato (<Emphasis Type="BoldItalic">Solanum tuberosum</Emphasis> L.) Production in the Farming Sectors that Emerged from Zimbabwe’s Radical Land Reform of 2000

Irish potato production in Zimbabwe can be traced back to the early 1900s. Large-scale commercial farmers dominated production until the early 2000s. Potato is the most important horticultural crop and has been declared a strategic national food security crop in 2012. In 2000, the Fast Track Land Reform Programme completely restructured commercial agriculture and potato farming. A product of the agrarian reforms, the A2 and A1 resettlement growers, started growing potato. The A1 resettlement model has individually owned cropping land and shared grazing, while A2 resettlement comprises of self-contained farm units. A survey was conducted to characterise potato growers, mainly to understand the current potato production systems and to assess the impact of the landmark reform programme on potato farming. Four production systems, large-scale commercial, communal area, A2 resettlement and A1 resettlement, were identified, and two main growing agro-ecological zones, the Highveld and Eastern Nyanga Highlands. In 1961–2013, significant positive trends for annual planted area, average yield and total production were observed. In terms of yield, Zimbabwe is fourth in southern Africa with an average yield of 17 t ha^?1 in the 2009–2013 period. Large-scale commercial and A2 resettlement systems were well-mechanised, and growers owned large land holdings ranging from an average of 165–1600 and 31–390 ha across the different areas, respectively, with average potato areas of 11 and 8 ha, respectively. A1 resettlement and communal area growers owned an average of 4 and 3 ha cropping area, respectively, with average potato areas of 0.4 and 1.1 ha, respectively. Input use was significantly different among the production systems. High synthetic fertiliser and biocide use was observed.     

Effect of added organic matter on soil fertility after stripping-off Cs-contaminated top soil at Iitate village in Fukushima Prefecture

The agricultural fields were contaminated by the radionuclides ¹³⁴Cs and ¹³⁷Cs after the nuclear power plant accident in Fukushima. Prior to the accident, local farmers had successfully established sustainable agriculture in Iitate Village using natural farming practices and recycling. Since 2011, decontamination work such as stripping-off the top soil has been ongoing on agricultural land. Although decontamination is essential, it could cause an unfortunate decrease in soil fertility. Here, we examined the use of organic matter as a means to quickly recover the fertility of the agricultural top soil. We transplanted rice crops into three paddy plots: one received rice straw that had been harvested there last year, another received composted manure, and the third (control) received no additives after decontamination. We applied 40 kg/10a of basal fertilizer and 20 kg/10a of KCl each plot. The rates of Cs concentration in unhulled rice/rice straw were around 0.001. Tendency of plant heights increase and leaf chlorophyll content decrease were similar in the three treatment plots. However, the numbers of stems on 111 days after the transplant were 21, 15, and 19, unhulled rice yield were 513, 462, and 310 g/m², in the rice straw, cattle manure compost, and control plots, respectively. Soil properties of three plots were similar. Radioactive Cs concentrations in the new rice from each treatment plots were lower than the maximum allowed level set by the Japanese government. These results revealed that treating soil with rice straw might have great potential to aid the recovery of a paddy field after stripping-off the top soil. Notably, this treatment significantly improved the yield of rice and supplied organic matter without additional labor.     

The intrinsic plasticity of farm businesses and their resilience to change. An Australian example

This paper examines the idea that plasticity in farm management introduces resilience to change and allows farm businesses to perform when operating in highly variable environments. We also argue for the need to develop and apply more integrative assessments of farm performance that combine the use of modelling tools with deliberative processes involving farmers and researchers in a co-learning process, to more effectively identify and implement more productive and resilient farm businesses.In a plastic farming system, farm management is highly contingent on environmental conditions. In plastic farming systems farm managers constantly vary crops and inputs based on the availability of limited and variable resources (e.g. land, water, finances, labour, machinery, etc.), and signals from its operating environment (e.g. climate, markets), with the objective of maximising a number of, often competing, objectives (e.g. maximise profits, minimise risks, etc.). In contrast in more rigid farming systems farm management is more calendar driven and relatively fixed sequences of crops are regularly followed over time and across the farm. Here we describe the application of a whole farm simulation model to (i) compare, in silico, the sensitivity of two farming systems designs of contrasting levels of plasticity, operating in two contrasting environments, when exposed to a stressor in the form of climate change scenarios;(ii) investigate the presence of interactions and feedbacks at the field and farm levels capable of modifying the intensity and direction of the responses to climate signals; and (iii) discuss the need for the development and application of more integrative assessments in the analysis of impacts and adaptation options to climate change.In both environments, the more plastic farm management strategy had higher median profits and was less risky for the baseline and less intensive climate change scenarios (2030). However, for the more severe climate change scenarios (2070), the benefit of plastic strategies tended to disappear. These results suggest that, to a point, farming systems having higher levels of plasticity would enable farmers to more effectively respond to climate shifts, thus ensuring the economic viability of the farm business. Though, as the intensity of the stress increases (e.g. 2070 climate change scenario) more significant changes in the farming system might be required to adapt. We also found that in the case studies analysed here, most of the impacts from the climate change scenarios on farm profit and economic risk originated from important reductions in cropping intensity and changes in crop mix rather than from changes in the yields of individual crops. Changes in cropping intensity and crop mix were explained by the combination of reductions in the number of sowing opportunities around critical times in the cropping calendar, and to operational constraints at the whole farm level i.e. limited work capacity in an environment having fewer and more concentrated sowing opportunities. This indicates that indirect impacts from shifts in climate on farm operations can be more important than direct impacts from climate on the yield of individual crops. The results suggest that due to the complexity of farm businesses, impact assessments and opportunities for adaptation to climate change might also need to be pursued at higher integration levels than the crop or the field. We conclude that plasticity can be a desirable characteristic in farming systems operating in highly variable environments, and that integrated whole farm systems analyses of impacts and adaptation to climate change are required to identify important interactions between farm management decision rules, availability of resources, and farmer's preference.     

Policy measures to promote mid-summer drainage in paddy fields for a reduction in methane gas emissions: the application of a dynamic,spatial computable general equilibrium model

Rice production is affected by climate change, while climate change is simultaneously accelerated by methane gas (CH₄) emissions from paddy fields. The rice sector must take suitable mitigation measures, such as prolonging mid-summer drainage (MSD) before the rice flowering period. To propose a mitigation policy, this study aims to demonstrate the environmental and economic effects of MSD in Japanese paddy fields by using a dynamic, spatial computable general equilibrium (CGE) model and crop model; the study also considers environmental subsidies with a carbon tax scheme to promote MSD measures. The results demonstrate that climate change under the 8.5 representative concentration pathway (RCP) scenario will reduce rice prices and rice farmers’ nominal income due to bumper harvests until the 2050s. Promoting MSD in paddy fields can prevent a decrease in farmers’ nominal income and effectively reduce CH₄ emissions if all farmers adopt this measure. However, some farmers can potentially increase their own yield by avoiding MSD under high rice prices, which would be maintained through other farmers’ participation. A strong motivation exists for some farmers to gain a “free ride,” and an environmental subsidy with a carbon tax can help motivate farmers to adopt MSD. Therefore, the policy mix of prolonging MSD and environmental subsidies can increase all farmers’ incomes by preventing “free rides” and decrease greenhouse gas emissions with a slight decrease in Japan’s GDP.

     

Sustainable intensification in the production of grass and forage crops in the Low Countries of north‐west Europe

Production of grass and fodder crops in areas under intensive production systems in the Low Countries of north‐west Europe faces a number of threats related to increased regulations, scarcity of land and restricted freedom of use of the land, and from climate change. Grassland‐based farmers are pushed to do more with less, i.e., to improve eco‐efficiency, and this requires “more knowledge per ha.” This article argues that progress in variety breeding, the application of crop rotation instead of monocultures, a proper use of catch crops, ley‐arable farming and overall good management offer realistic opportunities to cope with current threats. A large capacity for mechanization also allows improvement of net yields per ha. This article highlights that progress in plant breeding has compensated for yield declines caused by nutrient‐input restrictions in forage maize (Zea mays L.). Both forage maize and grass–clover can take advantages of ley‐arable farming, and crop rotation provides an insurance against the effects of low‐yielding years and a buffer for reduced nutrient inputs.     

Disseminating modern sweetpotato varieties using participatory variety demonstration trials on informal nodal multipliers’ fields at hub locations

It is shown for the first time how participatory variety demonstration (PVD) trials can establish modern varieties in informal seed systems in a developing country by targeting nodal multipliers occupying hub locations. A series of relatively few, small (each 36 m²) PVD trials was conducted over a period of 3 years in sweetpotato multipliers’ fields at three locations in Uganda; multipliers and farmers were encouraged to visit during crop growth and on field days; yields at final harvest and other traits considered important to multipliers and farmers were recorded. In the following dry season, the areas of the introduced varieties established in the lowland crops used by multipliers to conserve planting material were recorded. The two most popular varieties had a recorded area of about 1 ha each and were calculated to have increased sixfold annually from the trials; the next two occupied 0.5 ha each, confirming that the method is effective, cheap, and efficient.     

High-yield SRI in West Java by decomposing straw in waterlogged paddy field

System of Rice Intensification (SRI) often achieved higher yield than conventional practice. We identified the high-yielding farmers from the yield records of 1909 paddy fields belonging to an organic farmers’ association. Farmers whose yields were from 8.4 to 10.4 t ha^?1 were interviewed and their fields surveyed. Their yields had increased by an estimated average of 40% following the adoption of SRI practices. They applied 2–12 t ha^?1 of compost. Compared to the conventional practice, they shortened seedling age at transplanting from 27.4 to 17.6 days and reduced the number of seedlings per hill from 4–6 to 2–3, while hill spacing remained unchanged. Instead of intermittent irrigation which is recommended in standard SRI, they kept shallow flooding of 1–2 cm. Although they applied a lot of compost, no correlation was found between the amount of compost application and the yields. Instead, high-yielding farmers returned rice straw into waterlogged paddy after harvest, which presumably is an ideal condition for biological nitrogen fixation. This may occur around rice straw during decomposition under waterlogged condition and might supplement the negative nitrogen balance, thereby enabling the high yield as compared with conventional practices where the fresh rice straw is removed and/or burned.     

Agronomic and economic performance of seed yam production using minisetts in the middle belt of Nigeria

White yam (Dioscorea rotundata) is an important tuber crop of West Africa and the Caribbean, and one of the key limiting factors in its production is the availability of good quality planting material. The Adaptive Yam Minisett Technique (AYMT) was designed to help overcome this constraint. The paper presents an analysis of agronomic and economic data collected across four years (2013 to 2016) of AYMT plots planted in two areas within the middle-belt of Nigeria. Of the 136 plots that were established, 11% were lost to flooding and damage from Fulani cattle. Mean yield was 13.16 t/ha, 17,747 tubers/ha and the mean tuber weight was 0.73 kg. Plot yield declined with an increase in planting time, while plots owned by female farmers were on average planted later than those owned by their male counterparts; this helps explain the effect of gender noted in a previous study. Differences in yield were also noted between the two areas, which could also partly be explained by differences in planting time. The plots were profitable, with a mean cost over the four years of Naira 915,196/ha, revenue of Naira 3,197,786/ha and gross margin of Naira 2,282,591/ha (equivalent to US$4,039, US$14,319 and US$10,280 respectively). The main factor influencing costs and revenue was year, with no effect of gender. There is a need for more research on planting time in AYMT and how it interacts with factors, such as yam variety.     

A conceptual framework for eco-friendly paddy farming in Taiwan,based on experimentation with System of Rice Intensification (SRI) methodology

This paper reviews the constraints and challenges of paddy farming in Taiwan. Based on those evidences, a set of eco-friendly rice farming practices raised by SRI principles are proposed from exploratory SRI trials conducted in Taiwan. The trials show that even with less exact leveling in the SRI field than is ideally provided, the average yield for SRI was higher than for CP; with an aerobic soil situation, the combination of biocontrol agent application and SRI management was seen to give better rice blast control; and the highest paddy yield was obtained from single-seedling transplants from potted nursery trays which protect the young seedlings’ roots from shock or twisting, compared with the planting of more numerous seedlings grown on flat nursery trays by a mechanical rice transplanter. In conclusion, a conceptual framework for eco-friendly paddy farming is formulated to encourage farmers to practice SRI principles. Among the participants in this collaboration, a co-operating group of SRI farmers is organized under investor sponsorship to guarantee the quality and safety of food, integrating an inspection service and food-source traceability from field to market with the production process. It is seen that in Taiwan, SRI principles can be adopted by local farmers without need for additional premiums through eco-friendly collaboration that can raise simultaneously the productivity of land, capital, and irrigation water. In addition, this collaboration can take advantage of increasing consumer demand for safe food with fewer chemicals and for supporting a greater level of biodiversity.