System Of Rice Intensification Management Research Articles

Utilizing the Genetic Potentials of Traditional Rice Varieties and Conserving Rice Biodiversity with System of Rice Intensification Management

The genetic potentials of rice cultivars will need to be expressed to their fullest if global rice production is to be expanded enough by 2050 to meet the increased demand of the expanding population while the availability of land and water per capita dwindles. New and ‘improved’ rice varieties have contributed greatly to increased production over the past 50 years, but the rate of rice yield increase based on genetic changes has declined in recent decades compared with the early years of the Green Revolution. In fact, many rice consumers continue to prefer to consume ‘traditional’ rice varieties (referred to also as local, native, unimproved, or indigenous varieties) because of their taste, aroma, texture, and other qualities. Furthermore, many farmers prefer to cultivate these varieties because of their better adaptation to local climatic and soil conditions and their evolved resistance to endemic stresses. The practices that comprise the System of Rice Intensification (SRI), including transplanting rice seedlings at a young age, wide spacing between plants, keeping the soil well aerated rather than inundated, and enhancing soil organic matter, provide traditional rice varieties with micro-environments that are more favorable for the expression of their genetic and agronomic potentials. Interactions among rice plants, soil characteristics, water, energy, and other inputs improve the phenotypic and physiological performance of rice plants. This paper considers how the cultivation of traditional rice varieties with SRI methods can raise yields, reduce farmers’ costs of production, and generate higher incomes while contributing to the conservation of rice biodiversity.

Evaluating the underlying physiological and molecular mechanisms in the system of rice intensification performance with Trichoderma-rice plant symbiosis as a model system.

The system of rice intensification (SRI) is an extensively-researched and increasingly widely-utilized methodology for alleviating current constraints on rice production. Many studies have shown physiological and morphological improvements in rice plants induced by SRI management practices to be very similar to those that are associated with the presence of beneficial microbial endophytes in or around rice plants, especially their roots. With SRI methods, grain yields are increased by 25-100% compared to conventional methods, and the resulting plant phenotypes are better able to cope with biotic and abiotic stresses. SRI management practices have been shown to be associated with significant increases in the populations of certain microorganisms known to enhance soil health and plant growth, e.g., Azospirillum, Trichoderma, Glomus, and Pseudomonas. This article evaluates the effects of applying Trichoderma as a model microbe for assessing microbial growth-promotion, biological control activity, and modulation of gene expression under the conditions created by SRI practices. Information about the molecular changes and interactions associated with certain effects of SRI management suggests that these practices are enhancing rice plants' expression of their genetic potentials. More systematic studies that assess the effects of SRI methods respectively and collectively, compared with standard rice production methods, are needed to develop a more encompassing understanding of how SRI modifications of crops' growing environment elicit and contribute to more robust and more productive phenotypes of rice.

Insect Pest Incidence with the System of Rice Intensification: Results of a Multi-Location Study and a Meta-Analysis

The System of Rice Intensification (SRI) developed in Madagascar has spread to many parts of the world, including India. This study assessing insect pest prevalence on rice grown with SRI vs. conventional methods at multiple locations in India was prompted by reports that SRI-managed rice plants are healthier and more resistant to pest and disease damage. Field experiments were conducted under the All-India Coordinated Rice Improvement Project over a 5-year period. The split-plot design assessed both cultivation methods and different cultivars, hybrids and improved varieties. Across the eight locations, SRI methods of cultivation showed a lower incidence of stem borer, planthoppers, and gall midge compared to conventional methods. Whorl maggots and thrips, on the other hand, were observed to be higher. Grain yield was significantly higher with SRI management across all locations. Higher ash, cellulose, hemicellulose, as well as silica content in rice plants under SRI management could explain at least in part the SRI plants’ resistance to pest damage. Analysis of guild composition revealed that in SRI plots, there were more natural enemies (insect predators and parasitoids) present and fewer crop pests (phytophages). A meta-analysis that considered other published research on this subject revealed a lower incidence of dead hearts, white ear-heads, and leaf folders, along with higher grain yield, in SRI plots.

Rice Plants’ Resistance to Sheath Blight Infection Is Increased by the Synergistic Effects of Trichoderma Inoculation with SRI Management

The capability of endophytic Trichoderma spp. to reduce sheath blight disease in rice caused by Rhizoctonia solani was assessed under the growth conditions established by practices of the System of Rice Intensification (SRI), compared to those of standard irrigated rice cultivation. Rice seeds inoculated with a local isolate of the fungus Trichoderma asperellum SL2 were grown under respective SRI and conventional conditions with the inoculated or uninoculated plants and then infected with the pathogen R. solani. It was seen that inoculation with this strain of Trichoderma protected rice plants against R. solani infection while enhancing plant growth, photosynthetic rate, and stomatal conductance. The biocontrol effectiveness of inoculation with a particular strain of Trichoderma was significantly greater under SRI management compared to conventional cultivation. This is the first report on how a crop management system, in this case, SRI, can influence the biocontrol effectiveness of Trichoderma spp.

Impact of Rice Cultivation Methods on Insect Pest Incidence and Their Management

Under the influence of fluctuating global climate scenario and limited resources of water availability, different methods of rice cultivation like System of rice intensification (SRI), Direct seeded rice (DSR), Alternate wetting and drying (AWD) and Aerobic rice have become popular as alternatives to conventional transplanting method. Due to these shifting cultivation situations, insect pest profiles have also undergone changes with associated influence on beneficial insects and other natural enemies. Multi-location studies carried out under All India Coordinated Rice Improvement Project (AICRIP) have revealed significantly less incidence of major pests like stem borers, planthoppers in SRI compared to normal rice transplanting method. Overall, the SRI method leads to more robust plant health with enhanced capacity to resist pest attacks. In case of DSR, AICRIP studies have consistently revealed higher incidence of all the insect pests in the normal transplanted method compared to DSR. However, few reports have indicated association of insect pest outbreaks with higher seed rate and plant densities. Limited studies have shown that AWD also has the potential to minimize the incidence of insect pests and diseases compared to irrigated rice. However, soil borne pests, particularly root-knot nematode can be more damaging under aerobic conditions. Field cum laboratory studies carried out at ICAR IIRR on impact of cultivation systems on the rich insect biodiversity in rice have revealed association of higher total abundance and greater richness of beneficial insect species with SRI management.

Intercropping in Rice Farming under the System of Rice Intensification—An Agroecological Strategy for Weed Control, Better Yield, Increased Returns, and Social–Ecological Sustainability

Rice is the staple food for more than half of the world’s population. In South Asia, rice farming systems provide food to the majority of the population, and agriculture is a primary source of livelihood. With the demand for nutritious food increasing, introducing innovative strategies in farming systems is imperative. In this regard, intensification of rice farming is intricately linked with the challenges of water scarcity, soil degradation, and the vagaries of climate change. Agroecological farming systems like the System of Rice Intensification (SRI) have been proposed as water-saving and sustainable ways of food production. This study examines the effect of intercropping beans with rice under SRI management on the growth of weeds and on the different plant growth parameters. Intercropping led to a 65% decrease in weed infestation on average, which is important given that weed infestation is stated as a criticism of SRI in some circles and is a major factor in limiting yield in rice-producing regions. In addition to the water savings of about 40% due to the SRI methodology, the innovation led to an increase in rice yield by 33% and an increase in the net income of farmers by 57% compared to the conventional rice farming method. The results indicate that intercropping can be a positive addition to the rice farming system, hence contributing to social–ecological sustainability.

Evaluating direct dry-seeding and seed-priming used with the system of rice intensification vs. conventional rice cultivation in Pakistan

ABSTRACT Establishing rice (Oryza sativa L.) crops by direct-seeding requires less water and less labor than transplanting. However, farmers need to know the net effects of suites of practices. So, evaluations of direct-seeding should also consider its interactions with other factors, including a practice, such as seed-priming. This paper reports on an experiment conducted in 2014 and 2015 at University of Agriculture, Faisalabad, Pakistan. Three interacting factors were assessed: crop establishment by direct dry-seeding vs. transplanting of seedlings; crop management with either the System of Rice Intensification (SRI) or conventional methods, which include continuous flooding rather than alternate wetting and drying; and seed-priming, comparing no priming with both hydropriming with water and osmopriming with CaCl2. Leaf area index, leaf area duration, crop growth rate, and net assimilation rate were significantly affected by all three factors evaluated. Best performance resulted from transplanted seedlings grown from osmoprimed seeds and raised with SRI management. Overall, direct-seeding did not perform as well as transplanting, the major finding. Lower yield with direct-seeded rice (DSR) was attributable to plants having fewer productive tillers and grains after early rapid growth. Osmopriming with CaCl2 produced highest grain yield in the trials, 3.96 t ha−1 vs. 3.39 t ha−1 with no priming; highest straw yield of 13.8 t ha−1 vs. 13.3 t ha−1 with no priming; and Harvest Index of 28.7% vs. 25.6% with no priming. Hydropriming produced intermediate values. Osmopriming significantly improved phenological and grain-quality attributes. Transplanting osmoprimed seedlings under SRI management gave the highest economic benefit ($642 ha−1).

An Economic Comparison between Alternative Rice Farming Systems in Tanzania Using a Monte Carlo Simulation Approach

Tanzania is the second-largest producer of rice (Oryza sativa) in Eastern, Central, and Southern Africa after Madagascar. Unfortunately, the sector has been performing poorly due to many constraints, including poor agricultural practices and climate variability. In addressing the challenge, the government is making substantial investments to speed the agriculture transformation into a more modernized, commercial, and highly productive and profitable sector. Our objective was to apply a Monte Carlo simulation approach to assess the economic feasibility of alternative rice farming systems operating in Tanzania while considering risk analysis for decision-makers with different risk preferences to make better management decisions. The rice farming systems in this study comprise rice farms using traditional practices and those using some or all of the recommended system of rice intensification (SRI) practices. The overall results show 2% and zero probability of net cash income (NCI) being negative for partial and full SRI adopters, respectively. Meanwhile, farmers using local and improved seeds have 66% and 60% probability of NCI being negative, correspondingly. Rice farms which applied fertilizers in addition to improved seeds have a 21% probability of negative returns. Additionally, net income for rice farms using local seeds was slightly worthwhile when the transaction made during the harvesting period compared to farms applied improved varieties due to a relatively high price for local seeds. These results help to inform policymakers and agencies promoting food security and eradication of poverty on the benefits of encouraging improved rice farming practices in the country. Despite climate variability, in Tanzania, it is still possible for rice farmers to increase food production and income through the application of improved technologies, particularly SRI management practices, which have shown a promising future.

Water balance analysis on water management of organic System of Rice Intensification (organic-SRI) in West Java, Indonesia

The System of Rice Intensification (SRI) has been known in Indonesia since 1999. However, there are some difficulties in utilizing SRI water management recommendations in the field, particularly in combination with organic nutrient management. While many demonstrations have given impressive gains in productivity, many farmers remain skeptical about applying this system. The current study was carried out to analyze water balance components in SRI paddy fields when applying intermittent irrigation. The experiment was conducted in Gabus Wetan village, Indramayu District, West Java, Indonesia from 17 Nov 2016 to 1 March 2017. We involved a local farmer who had been trained in SRI methods at an Organic SRI Center on how to conduct organic SRI management in his fields. Weather and soil sensors were set up in the fields to acquire data on daily field conditions as well as on plant growth. Data on weathers such as precipitation, air temperature, relative humidity, and wind speed were collected automatically during the season every 60 min, as well as the soil water depth. Analyzing the data collected, water balance analysis was well performed with low error (1.00%) in which the water inflows through precipitation and irrigation were 560 mm and 865 mm, respectively, while the outflows by crop evapotranspiration, percolation, and runoff were 430, 306 and 675 mm, respectively. Compared to conventional rice farming as commonly practices by applying continous flooding irrigation, water productivities of organic SRI were 30% and 27% higher with respect to total water input (WPIR) and with respect to the amount of evapotranspiration (WPET, respectively. Organic SRI produced 33% higher yield than that the average of conventional methods in the same subdistrict. The key was intermittent irrigation by maintaining shallow water depth (nearly soil surface) in the vegetative and generative stages. Therefore, it is an attractive option to farmers in irrigated areas where water resources is limited due to regional climate change effects. Keywords:Â Â Â Â Â Â Â

Impact of crop and nutrient management on crop growth and yield, nutrient uptake and content in rice

System of rice intensification (SRI) together with appropriate nutrient management holds promise in increasing rice productivity with micronutrient enriched grains. Trials were conducted to investigate the performance of SRI vis-a-vis conventional management practices (CMP), both with either integrated nutrient management (INM) or organic sources of nutrients. Grain yields were consistently higher under SRI (34.6%) than with CMP under the same nutrient management system. At the same time, yields under INM were higher than for those with organic fertilization. There were significant differences among treatment combinations also; both SRI–INM and SRI–organic out-yielded CMP–INM and CMP–organic, respectively, by 43.8 and 24.8%. Further, SRI with organic sources produced 18.6% higher grain yield than CMP with INM, which showed a way to achieve higher output of rice grain grown organically. Significant improvements were observed with SRI in root growth, xylem exudation rate, LAI, canopy light interception, SPAD chlorophyll level, photosynthesis rate, and grain-filling rate. The improvements in physiological functioning evidently contributed to better grain formation and yield under SRI management. Both the rice grains and straw obtained with SRI methods contained more N, P, K, Fe, Mn, Cu, and Zn than grains and straw produced with CMP. SRI methods not only raised rice productivity, but also enhanced nutrient uptake due to greater root growth and activity, and improved the nutritional content and quality of produced grain.

Optimizing rice paddies’ lower greenhouse gas emissions and higher yield with SRI management under varying water table levels

The System of Rice Intensification (SRI) is known as a climate-smart agricultural practice that increases rice production by changing the management of plants, soil, water, and nutrients. SRI water management relies on intermittent irrigation rather than on the continuous flooding of conventionally managed rice production. Different water table levels affect the soil conditions which contribute to different fluxes of greenhouse gas (GHG) emissions. This study estimated the impact on global warming potential (GWP) of GHG emissions from rice paddies when an SRI crop is managed with different water table levels. In this study, CO2 equivalence was assessed using a Simple Greenhouse Gas model, and an artificial neural network model for assessing CH4 and N2O. SRI paddy rice was grown in experimental pots under varying water table treatments, with the water table controlled by using Mariotte tubes set at + 2, 0, − 3, − 5, − 7, and − 12 cm from the soil surface. GHG emissions, which could be monitored more closely in pot trials than in fields, are a composite of the plants’ respiration, soil respiration (which is a result primarily of microbial activity), and the respiration that results from root exudates. With SRI practices, rice paddies can serve as a sink rather than a source for CH4 as seen from the negative values for CH4 emissions at all water table treatments. While there were N2O emissions with SRI practice, they were much less in terms of CO2 equivalence than the GWP reduction achieved by reducing CH4. Overall, under the experimental conditions the best water table level for SRI cultivation, with the most rice produced relative to GHG emissions, was − 5 cm from the soil surface. For each kg of grain produced, there were 0.80 kg CO2 eq of GHG emissions. By comparison, a normally flooded paddy field with usual crop management methods emits 1.97 kg CO2 eq per kg of grain produced, almost 150% more. This finding that a water table of − 5 cm is optimal will not necessarily apply for all field conditions, but the research addresses the desirability of seeking to optimize between GHG reductions and increased yield when growing paddy rice, and of developing appropriate methodology for achieving this composite objective.

Evaluating system of rice intensification using a modified transplanter: A smart farming solution toward sustainability of paddy fields in Malaysia

This paper presents the study reports on evaluating a new transplanting operation by taking into accounts the interactions between soil, plant, and machine in line with the System of Rice Intensification (SRI) practices. The objective was to modify planting claw (kuku-kambing) of a paddy transplanter in compliance with SRI guidelines to determine the best planting spacing (S), seed rate (G) and planting pattern that results in a maximum number of seedling, tillers per hill, and yield. Two separate experiments were carried out in two different paddy fields, one to determine the best planting spacing (S=4 levels: s1=0.16 m×0.3 m, s2= 0.18 m×0.3 m, s3=0.21 m×0.3 m, and s4=0.24 m×0.3 m) for a specific planting pattern (row mat or scattered planting pattern), and the other to determine the best combination of spacing with seed rate treatments (G=2 levels: g1=75 g/tray, and g2= 240 g/tray). Main SRI management practices such as soil characteristics of the sites, planting depth, missing hill, hill population, the number of seedling per hill, and yield components were evaluated. Results of two-way analysis of variance with three replications showed that spacing, planting pattern and seed rate affected the number of one-seedling in all experiment. It was also observed that the increase in spacing resulted in more tillers and more panicle per plant, however hill population and sterility ratio increased with the decrease in spacing. While the maximum number of panicles were resulted from scattered planting at s4=0.24 m×0.3 m spacing with the seed rate of g1=75 g/tray, the maximum number of one seedling were observed at s4=0.16 m×0.3 m. The highest and lowest yields were obtained from 75 g seeds per tray scattered and 70 g seeds per tray scattered treatment respectively. For all treatments, the result clearly indicates an increase in yield with an increase in spacing. Keywords: system of rice intensification, sustainable cultivation, smart farming, modified transplanter, paddy fields, Malaysia DOI: 10.25165/j.ijabe.20191202.2999 Citation: Shamshiri R R, Ibrahim B, Balasundram S K, Taheri S, Weltzien C. Evaluating system of rice intensification using a modified transplanter: A smart farming solution toward sustainability of paddy fields in Malaysia. Int J Agric & Biol Eng, 2019; 12(2): 54–67.

Effects of Trichoderma seedling treatment with System of Rice Intensification management and with conventional management of transplanted rice.

Many benefits of Trichoderma inoculation for improving crop production have been documented, including growth and yield enhancement and the alleviation of biotic and abiotic stresses. However, because rice is usually cultivated under continuous flooding that creates anaerobic soil conditions, this limits the benefits of these beneficial fungi. Cultivating rice with the methods of the System of Rice Intensification (SRI) provides rice plants with a more favorable environment for their colonization by beneficial microbes in the soil because the soil is more aerobic under SRI management and contains more organic matter. This study evaluated the effects of Trichoderma inoculation of rice plants under SRI management compared with transplanted and flooded rice plants, considering also the effects of different means of fertilization and different varieties in rice. Experiments were conducted in 2015 and 2016 under the tropical climate of Nepal’s western terai (plains) during both the rainy season (July to November) and the dry season (March to July). The results indicated significantly better performance (P = 0.01) associated with Trichoderma inoculation for both seasons and for both systems of crop management in terms of grain yield and other growth-contributing factors, compared to non-inoculated rice cropping. Relatively higher effects on grain yield were recorded also with organic compared to inorganic fertilization; for unimproved (heirloom) varieties compared with improved varieties; and from SRI vs. conventional flooded crop management. The yield increase with Trichoderma treatments across all trials was 31% higher than in untreated plots (4.9 vs 4.5 mt ha−1). With Trichoderma treatment, yields compared with non-treated plots were 24% higher with organic SRI (6.38 vs 5.13 mt ha−1) and 52% higher with non-organic SRI (6.38 vs 3.53 mt ha−1). With regard to varietal differences, under SRI management Trichoderma inoculation of the improved variety Sukhadhan-3 led to 26% higher yield (6.35 vs 5.04 mt ha−1), and with the heirloom variety Tilkidhan, yield was 41% higher (6.29 vs 4.45 mt ha−1). Economic analysis indicated that expanding the organic cultivation of local landraces under SRI management should be profitable for farmers where such rice has a good market price due to its premium quality and high demand and when SRI enhances yield. These varieties’ present low yields can be significantly increased by integrating Trichoderma bio-inoculation with SRI cultural methods. Other recent research has shown that such inoculation can be managed profitably by farmers themselves.

Evaluating system of rice intensification using a modified transplanter: A smart farming solution toward sustainability of paddy fields in Malaysia

This paper presents the study reports on evaluating a new transplanting operation by taking into accounts the interactions between soil, plant, and machine in line with the System of Rice Intensification (SRI) practices. The objective was to modify planting claw (kuku-kambing) of a paddy transplanter in compliance with SRI guidelines to determine the best planting spacing (S), seed rate (G) and planting pattern that results in a maximum number of seedling, tillers per hill, and yield. Two separate experiments were carried out in two different paddy fields, one to determine the best planting spacing (S=4 levels: s1=0.16 m×0.3 m, s2= 0.18 m×0.3 m, s3=0.21 m×0.3 m, and s4=0.24 m×0.3 m) for a specific planting pattern (row mat or scattered planting pattern), and the other to determine the best combination of spacing with seed rate treatments (G=2 levels: g1=75 g/tray, and g2= 240 g/tray). Main SRI management practices such as soil characteristics of the sites, planting depth, missing hill, hill population, the number of seedling per hill, and yield components were evaluated. Results of two-way analysis of variance with three replications showed that spacing, planting pattern and seed rate affected the number of one-seedling in all experiment. It was also observed that the increase in spacing resulted in more tillers and more panicle per plant, however hill population and sterility ratio increased with the decrease in spacing. While the maximum number of panicles were resulted from scattered planting at s4=0.24 m×0.3 m spacing with the seed rate of g1=75 g/tray, the maximum number of one seedling were observed at s4=0.16 m×0.3 m. The highest and lowest yields were obtained from 75 g seeds per tray scattered and 70 g seeds per tray scattered treatment respectively. For all treatments, the result clearly indicates an increase in yield with an increase in spacing. Keywords: system of rice intensification, sustainable cultivation, smart farming, modified transplanter, paddy fields, Malaysia DOI: 10.25165/j.ijabe.20191202.2999 Citation: Shamshiri R R, Ibrahim B, Balasundram S K, Taheri S, Weltzien C. Evaluating system of rice intensification using a modified transplanter: A smart farming solution toward sustainability of paddy fields in Malaysia. Int J Agric & Biol Eng, 2019; 12(2): 54–67.

Rooting System of Rice Cultivated under System of Rice Intensification (SRI) Method which Improving Rice Yield

The development of plant roots is known to play a very important role in the uptake of water and nutrients by rice plants. However, there are few studies on what changes, if any, are induced in the rooting systems of rice plants under System of Rice Intensification (SRI) management. This research evaluated changes of rice roots with SRI method compared to conventional method of irrigated rice cultivation and assessed influences that could improve rice yield. Under SRI management, plant roots were significantly longer and heavier than with conventional method. SRI method also increased the number of root hairs by 60%, and root hairs were healthier and more vigorous compared with conventional method. However, root respiration was not different in the two methods. There was less formation of aerenchyma (air pockets) in rice roots with SRI method, as both the number and size of root aerenchyma were lower with SRI than with conventional method. The SRI method was able to improve the root length, root dry weight compared to the conventional method. The SRI method was also able to increase the number of root hairs by 60% compared with the conventional method. Eh measurements in the soil with SRI method were higher than with conventional method. However, there was no significant different in root respiration. The aerenchyma formation of rice roots in SRI method was lower than conventional method.

Rice root growth, photosynthesis, yield and water productivity improvements through modifying cultivation practices and water management

Achieving higher productivity in irrigated rice production is becoming ever-more important. A modified rice-cultivation method, the System of Rice Intensification (SRI), recommends keeping rice fields moist but unflooded during the crop’s vegetative stage, usually with alternate-wetting-and-drying (AWD), then maintaining shallow flooding during the post-vegetative stage of crop growth. However, no evidence is available on how flooding paddy fields continuously vs. alternately during the post-vegetative stage under SRI might influence the crops’ physiology, root growth, grain yield, and water productivity.Field experiments were conducted to investigate the impacts of two alternative crop management systems, namely, SRI and conventional management practice (CMP) under different water management treatments during the vegetative stage [continuous flooding (CF) vs. AWD] and then during post-vegetative stage: CF vs. AWD @ 1-DAD (days after disappearance of ponded water), 3-DAD or 5-DAD.SRI practices, compared to CMP methods, significantly improved plants’ root growth and xylem exudation rate, leaf area index and light interception by the crop canopy, plus photosynthesis rate at the grain-filling stage, resulting in higher grain yield. Overall, this modified method of rice crop management produced 58% higher grain yield with 16% less water. Across all water management treatments, significantly more grain was produced per unit of water applied with SRI management (6.3 kg ha-mm−1) compared to CMP (3.3 kg grain ha-mm−1). The highest grain yield with SRI (6.2 t ha−1), and the greatest water productivity (6.7 kg ha-mm−1) were obtained with SRI and 3-DAD post-vegetative irrigation. With CMP, highest grain yield (4.1 t ha−1) and water productivity (3.5 kg ha-mm−1) were with 1-DAD irrigation.Differences measured in plants’ response to modified management practices and alternative irrigation schedules indicated how phenotypic and physiological performances can be improved for a given genotype. Combining changes in crop and water management can improve water productivity as well as grain yield.

Productivity Assessment of Drought Tolerant Rice Cultivars under Different Crop Management Practices in Central Terai of Nepal

Proper selections of resource conservation technologies and drought tolerant cultivars are being potential strategies determining productivity of rice in drought prone areas. Thus, a field experiment was accomplished in central-terai of Nepal during 2014 to assess the productivity of drought tolerant rice cultivars under different crop management practices. The experiment was carried out in strip-plot design with three replications consisting four drought tolerant rice cultivars and three crop management practices. The analyzed data revealed that SRI (System of Rice Intensification) produced significantly higher grain yield (5.28 t ha-1) than other management practices. The straw yield of SRI (5.12 t ha-1) was also significantly higher than other management practices. The cultivars had no influence on grain yield, but the straw yield was significantly influenced by cultivars, with the highest straw yield in Sukkha-3 (5.21 t ha-1). Thus, SRI management practice can be adopted as adaptation approach for obtaining higher productivity in central terai and similar agro-climatic regions of Nepal.

Agronomic fortification of rice grains with secondary and micronutrients under differing crop management and soil moisture regimes in the north Indian Plains

Although the System of Rice Intensification (SRI) has been reported to produce higher paddy (Oryza sativa L.) yields with better-quality grains, little research has addressed the latter claim. This study investigated the interactive effects of rice cultivation methods with different irrigation schedules and plant density on the uptake and concentration of sulfur (S), zinc (Zn), iron (Fe), manganese (Mn) and copper (Cu) in the grain and straw of two rice cultivars during two rainy seasons in the northern plains of India. As the two seasons differed in amounts of rainfall, there were impacts of soil moisture differences on nutrient uptake. Plots with SRI cultivation methods enhanced the grain uptake and concentrations of S, Zn, Fe, Mn and Cu by 36, 32, 28, 32 and 63%, respectively, compared to conventional transplanting (CT). Under SRI management, the highest concentrations of S, Zn and Cu in the grain and straw occurred with irrigation intervals scheduled at 3 days after disappearance of ponded water (DADPW; 3D), whereas Fe and Mn concentrations in the grain and straw were higher with irrigation at 1 DADPW (1D) compared with plots under 3D or 5 DADPW (5D). The higher nutrient uptakes were also manifested in higher grain yield in 1D and 3D plots (by 9 and 6%, respectively) compared with 5D. Wider spacing (25 × 25 cm) compared with closer spacing (20 × 20 cm) significantly increased yield and the uptake and concentrations of all the said nutrients in the grains. When comparing the performance of two cultivars, the total uptakes of Zn, Fe, Mn and Cu in both grain and straw were significantly more in Hybrid 6444 than the improved variety Pant Dhan 4. Overall, SRI crop management compared to CT practices led to more biological fortification of rice grains with respect to S and the four micronutrients studied, giving a concomitant yield advantage of about 17% on average in this region.

Factors explaining variability in rice yields in a rain-fed lowland rice ecosystem in Southern Cambodia

There is a growing body of literature documenting higher productivity of the System of Rice Intensification (SRI) than conventional practices; however, few studies have been conducted to explore the factors explaining this higher productivity. This paper investigated key factors influencing yields in a rain-fed lowland rice ecosystem in Cambodia under farmer’s SRI and conventional management practices (CMP). Rice yields from 70 plots with recorded management practices (36 plots under farmer’s SRI and 34 plots CMP) were measured. Composite soil samples (210 in total) were collected from the harvested plots and analyzed for physical and chemical properties. Stepwise multiple regression analysis was performed to identify important predictors explaining rice yield variability. Variables contributing significantly to yield variation included: number of cattle (access to farmyard manure [FYM]), farmer’s SRI practices, planting density and soil organic carbon (SOC). These four variables explained 39% of variance in rice yield. Keeping other variables constant, rice yields were increased by 14% (458kgha−1) by shifting from CMP to farmer’s SRI practices. The change of one unit in cattle (head), hill density (hillm−2) and SOC (gkg−1) results in an increase of rice yield by 5% (153kgha‐1), 2% (66kgha‐1) and 9% (289kgha‐1), respectively. The higher rice yield obtained by transplanting with narrower spacing suggests that the wider spacing recommended by SRI is not likely advisable, especially in nutrient-poor soil. Although the application of manure did not emerge as a key variable, three out of the four key variables (farmer’s SRI, access to FYM, and SOC) are directly linked to its use. Farmer’s SRI was strongly associated with the use of FYM, and the plots that received more FYM and belonged to farmers with more cattle had higher total soil N. Total soil N was positively correlated with SOC. The results highlighted the important role of livestock in crop-animal integration and the contribution of animal manure to increase agricultural productivity within smallholder farmers on infertile sandy Cambodian soils.

Effect of different fertilizer treatments on the performance of some local rice varieties under SRI (system of rice intensification) and conventional management practices at district Swat

Effect of different fertilizer treatments on the performance of some local rice varieties under SRI (system of rice intensification) and conventional management practices at district Swat