Rainfed Lowland Research Articles

Assessing rice production sustainability performance indicators and their gaps in twelve sub-Saharan African countries.

The benchmarking and monitoring of rice production performance indicators are essential for improving rice production self-sufficiency, increasing profitability, reducing labor requirements, optimizing fertilizer inputs, engaging youths in rice production, and increasing the overall sustainability of smallholder rice production systems in countries in sub-Saharan Africa (SSA). In this paper, we quantified five sustainability performance indicators (grain yield, net profit, labor productivity, and nitrogen (N) and phosphorus (P) use efficiencies) to benchmark rice production systems in SSA. Data were collected between 2013-2014 from 2907 farmers from two rice production systems (irrigated and rainfed lowlands) across five agroecological zones (arid, semiarid, humid, subhumid and highlands) in 12 countries (Benin, Cameroon, Cote d'Ivoire, Ghana, Madagascar, Mali, Niger, Nigeria, Senegal, Sierra Leone, Tanzania and Togo). The exploitable gap for each indicator (the difference between the mean of 10 % highest-yielding farms and the mean-yielding farms) was calculated across the countries, the two production systems and agroecological zones. The mean yield varied widely between 2.5 to 5.6 t ha-1 and 0.6 to 2.3 t ha-1 in irrigated and rainfed lowlands, respectively, with an average yield of 4.1 and 1.4 t ha-1, respectively. Across the country-production system combinations, there were yield gaps of 29-69 %, profit gaps of 10-89 %, and labor productivity gaps reaching 71 %. Yield, profit, and labor productivity were positively correlated. They were also positively correlated with N and P fertilizer application rate, but not with N and P use efficiencies. Only between 34-44 % of farmers had desirable ranges in N- or P-use efficiencies in the two production systems. All sites for rainfed lowlands were characterized by low-yield and large gaps in yield, profit, and labor productivity, whereas irrigated lowlands in some countries (Madagascar, Mali, and Togo) have similar characteristics as rainfed ones. We conclude that there is an urgent need to disseminate precision nutrient management practices for optimizing nutrient use efficiency and enhancing rice performance indicators especially in rainfed lowlands as well as low-yielding irrigated lowlands. Furthermore, we propose recommendations for specific categories (i.e. farmer, rice production system, agroecological zone and country) to close performance indicator gaps and to allow the production at scale to achieve rice self-sufficiency in SSA.

Determinants of Production and Income Risks of Rainfed Lowland Farming: A Case Study in Maros Regency, Indonesia

Rainfed lowland farming production is generally lower than irrigated lowland rice due to area differentiation regional features. Rainfed lowland rice farming can only produce rice during the rainy season because lowland rice cannot be planted in the dry season. The purposes of this study are (1) to analyze the risk of production and income of rice farming in rainfed lowland farming and (2) to investigate the factors influencing the risk of rice farming in rainfed lowland farming. Data were collected from 100 respondents of rice farmers in four sub-districts in Maros Regency using the multi-stage cluster random sampling technique. The analysis of production and income risks were performed using multiple linear regression with the heteroscedastic method. The results have shown that rice farming in rainfed lowland farming poses a risk to production and income. The variables that significantly influence the rainfed lowland rice farming are land area, the number of seeds, the amount of urea fertilizer and the amount of pesticide. Farmers are required to manage risk by prioritizing the effectiveness and efficiency production factors as needed. Similarly the government is expected to assist farmers in maintaining the level of rice selling prices.

Rice yield and economic response to micronutrient application in Tanzania

• Foliar fertiliser application is only effective under drought-free conditions. • Sole application of micronutrients (Zn-B-Mg-S) is not effective in any environment. • Compared to NPK alone, yield increased 0.5–1.8 t ha –1 from NPK + micronutrients. • Micronutrient application to soil or foliar is profitable with adequate soil moisture. Nutrient deficiencies limit rice production in sub-Saharan Africa. The conventional recommended remedy for this is the soil application of fertilizers composed of the macro-nutrients, N, P and K, whereas crop micronutrient requirements are neglected. This leads to nutrient mining and diminished fertiliser use efficiency. Application of micronutrients along with recommended NPK fertiliser rates can prevent nutrient mining and boost rice yields. In this study, we assessed the productivity and profitability of different soil- and foliar-applied micronutrients in 30 on-farm trials per year for two consecutive years (2015, 2016) in Tanzania, East Africa. Five locally available foliar formulations (combinations of macro- and micronutrients or micronutrients alone) and soil application of micronutrients (3−2−7.5−10 Zn-B-Mg-S kg ha –1 ) were assessed under two NPK-fertilization regimes (80−17.5−33.2 and 0−0−0 kg N-P-K ha –1 ) in three rice growing environments (RGEs): Irrigated Lowland (IL), Rainfed Lowland (RL), and Rainfed Upland (RU). The effect of foliar and soil applied micronutrients on yield was consistent in IL but was highly variable in the RL and RU conditions across years. The soil application of micronutrients in the absence of NPK was ineffective in any of the RGEs. In IL, without NPK, foliar application alone increased yield by 0.3−0.4 t ha –1 , compared to control (3.1 t ha –1 ). Only NPK application increased yield by 1 t ha –1 , while NPK and micronutrients application increased yield by 1.5 t ha –1 , compared to control. The benefit-cost (B:C) ratio for NPK with soil applied micronutrients was 4–4.5 compared to NPK application alone. In RL, application of NPK alone increased yield in 2015 from 2.7 to 5.0 t ha –1 while NPK and soil applied micronutrients application increased yield to 6.8 t ha –1 . However, a drought incidence in 2016 nullified this effect. With NPK, two foliar products (F2 and F3) increased yield significantly by 1 t ha –1 . The highest B:C ratio was obtained with soil applied micronutrients (B:C of 14), and two of the foliar products obtained a B:C ratio of 7 and 7.2, respectively. In RU, no significant yield differences were observed among treatments in any year, likely due to drought. Foliar application was effective only under drought-free conditions across the rice growing environments. This study demonstrated that soil applied micronutrients together with NPK significantly increased yields in IL and RL in the absence of drought-stress. Application of macronutrients is a likely prerequisite for maximizing the benefits of applying micronutrients to increase rice yields in Tanzania.

Application of infrared spectroscopy for estimation of concentrations of macro- and micronutrients in rice in sub-Saharan Africa

Determination of the concentration of nutrients in the plant is key information for evaluating crop nutrient removal, nutrient use efficiency, fertilizer recommendations guidelines, and in turn for improving food security and reducing environmental footprints of crop production. Diffuse infrared (IR) reflectance spectroscopy is a powerful, rapid, cheap, and less pollutant analytical tool that could be substituted for traditional laboratory methods for the determination of the concentration of nutrients in plants. However, its accuracy for predicting the concentration of nutrients in rice plants is poorly known. This study aimed i) to determine macro- and micronutrients concentration that can be accurately predicted by near-infrared (NIR, 7498–4000 cm−1), mid-infrared (MIR, 4000–600 cm−1), or their combination (NIR-MIR, 7498–600 cm−1) spectra, ii) to identify the most suitable spectral range with the best prediction potential for the simultaneous analysis of nutrients concentrations in rice plants (straw and paddy) and iii) to assess the influence of agro-ecological zone and production system on nutrients concentrations in straw and paddy (unhulled grains) samples. Second-derivative spectra were fitted against plant laboratory reference data using partial least-squares regression (PLSR) to estimate six macronutrients (N, P, K, Ca, Mg, and S) and seven micronutrients (Na, Fe, Mn, B, Cu, Mo, and Zn) concentration in paddy and rice straw samples collected at harvest from 1628 farmers’ fields in 20 sub-Saharan African (SSA) countries. The modeling prediction potential was assessed by coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), and ratio of performance to interquartile distance (RPIQ). Good prediction models (0.75 < R2 ≤ 0.95) were obtained for 7 nutrients concentrations consisting of N, P, K, Ca, Mg, Mn, and Cu. Satisfactory predictions (0.62 ≤ R2 ≤ 0.75) were obtained for S, Fe, and B. NIR, MIR, and combined NIR-MIR diffuse reflectance spectroscopy demonstrated the best prediction potential for 3, 1, and 6 of these 10 well-predicted nutrients concentrations, respectively. All nutrients concentrations both in straw and paddy were moderate to highly variable (CV = 15–111%). Agro-ecological zone and production system had a significant impact on most nutrients concentrations both in rice straw and paddy. N, P, and K concentrations in rice in irrigated lowland (IL) fields were higher than in rainfed lowland (RL) and upland (RU). From the studied fields, 2%, 16%, and 16% of straw samples were deficient in N, P, and K, respectively. K deficiency occurred in all three production systems, whereas P deficiency mainly occurred in the rainfed upland systems. Overall, the combined NIR-MIR diffuse reflectance spectroscopy has a good potential to be applied as an alternative method in the determination of macronutrient concentrations in rice plants. Further investigation on the relationships between soil attributes, rice productivity, and nutrients concentration data determined in this study is needed for providing fundamental information for site-specific soil management and fertilizer recommendations in SSA.

An improved draft genome assembly of Meloidogyne graminicola IARI strain using long-read sequencing.

The rice root-knot nematode Meloidogyne graminicola is a major biotic stress for the rice crop under upland, rain-fed lowland and irrigated cultivation conditions. Here, we present an improved draft genome assembly of M. graminicola IARI strain using the long-read sequencing approach (PacBio Sequel platform). The assembled genome size was 36.86Mb with 514 contigs and N50 value of 105kb. BUSCO estimated the genome to be 88.6% complete. Meloidogyne graminicola genome contained 17.83% repeat elements and showed 14,062 protein-coding gene models, 4,974 conserved orthologous genes, 561 putative secreted proteins, 49 RNAi pathway genes, 1,853 proteins involved in pathogen-host interactions, 1,575 carbohydrate-active enzymes, and 32,138 microsatellites. Five of the carbohydrate-active enzymes were found only in M. graminicola genome and were not present in any other analysed root-knot nematode genome. Together with the previous two genome assemblies, this improved genome assembly would facilitate comparative and functional genomics for M. graminicola.

Assessing Opportunities to Increase Yield and Profit in Rainfed Lowland Rice Systems in Indonesia

In this study, we aimed to improve rice farmers’ productivity and profitability in rainfed lowlands through appropriate crop and nutrient management by closing the rice yield gap during the dry season in the rainfed lowlands of Indonesia. The Integrated Crop Management package, involving recommended practices (RP) from the Indonesian Agency for Agricultural Research and Development (IAARD), were compared to the farmers’ current practices at ten farmer-participatory demonstration plots across ten provinces of Indonesia in 2019. The farmers’ practices (FP) usually involved using old varieties in their remaining land and following their existing fertilizer management methods. The results indicate that improved varieties and nutrient best management practices in rice production, along with water reservoir infrastructure and information access, contribute to increasing the productivity and profitability of rice farming. The mean rice yield increased significantly with RP compared with FP by 1.9 t ha−1 (ranges between 1.476 to 2.344 t ha−1), and net returns increased, after deducting the cost of fertilizers and machinery used for irrigation supplements, by USD 656 ha−1 (ranges between USD 266.1 to 867.9 ha−1) per crop cycle. This represents an exploitable yield gap of 37%. Disaggregated by the wet climate of western Indonesia and eastern Indonesia’s dry climate, the RP increased rice productivity by 1.8 and 2.0 t ha−1, with an additional net return gain per cycle of USD 600 and 712 ha−1, respectively. These results suggest that there is considerable potential to increase the rice production output from lowland rainfed rice systems by increasing cropping intensity and productivity. Here, we lay out the potential for site-specific variety and nutrient management with appropriate crop and supplemental irrigation as an ICM package, reducing the yield gap and increasing farmers’ yield and income during the dry season in Indonesia’s rainfed-prone areas.

Yield of Soybean and Corn Intercropping Farming in Rainfed Lowland in Central Lampung, Lampung Province

Soybean and corn are strategic commodities to meet community needs. As the population increases, the demand for these commodities tends to increase. A breakthrough innovation is needed to increase food production. The purpose of this study was to determine the yield of several varieties of corn and soybean growth using the intercropping system on rainfed lowland areas. The study was conducted in Central Lampung during the 3rd planting season from September to December 2019. The soybean varieties are Anjasmoro, Dena, Devon and local existing. Corn varieties are Nasa-29 and local existing. The intercropping system used corn-soybean pattern 2-7. The study involved 5 farmer cooperators. The results of the study indicated that the intercropping system provide the highest production of soybean and corn for local and existing varieties. The average corn production was 9340 kg/ha and the average soybean production was 1971 kg/ha. The intercropping system provides an increase in the cropping index from 100-150 to 200-300 on rainfed lowland

Analysis of income and expenditure of farmers’ household in the rain-fed area of Boyolali district

Farmers usually work in various activities to obtain income and fulfill household demands. The objectives of this study are to determine and investigate the structures and factors influencing farmer households’ income and expenses in the rain-fed areas. This research was conducted in Tegalgiri Village, Nogosari Sub-district, Boyolali District from January to March 2020. The study used survey technique. Data were analyzed descriptively and quantitatively using multiple linear regression analysis. The results showed that the average household income of IDR 5,262,387/month with the largest proportion (65.31%) came from on-farm activities and 34.70% came from non-agricultural activities. Factors influencing household income were rice production and farmers’ education. The average household expenditure was IDR 3,869,634/month consisted of food expenditure 30.17%, 23.94% for non-food expenditure, and 19.42% for farming cost. Factors influencing household expenditure are income and land area. To increase household income and welfare, farmers need to optimize the management of rain-fed lowland and upland fields.

SUB1 varieties increased rice (Oryza sativa) yield in flood-prone rainfed lowlands of coastal regions

Submergence of lowland rice (Oryza sativa L.) fields during the wet season in coastal regions adversely affects survival and productivity of rice. A field experiment was conducted for two consecutive wet seasons in 2016 and 2017 at ICAR-Central Soil Salinity Research Institute, Regional Research Station, Canning Town, West Bengal to evaluate the performance of six varieties carrying the SUB1 gene (BR11-Sub1, Ciherang-Sub1, CR1009-Sub1, IR64- Sub1, Samba-Sub1, and Swarna-Sub1) along with two checks (DRR Dhan39 and Sabita) under stagnant and flash flooding situations. Sabita produced the highest grain yield (3.45 t/ha) followed by CR1009-Sub1 (3.27 t/ha) under stagnant flooding. Sabita is the local check under stagnant flooding. Under flash flooding, CR1009-Sub1 produced the highest grain yield of 4.11 t/ha, followed by Swarna-Sub1 (3.11 t/ha) and BR11-Sub1 (2.78 t/ha). Participatory varietal selection (PVS) was conducted during both the years to assess the preferences of farming communities for these varieties. Under stagnant flooding, the highest preference score was recorded for Sabita (0.62) followed by BR11-Sub1 (0.32) and CR1009-Sub1 (0.31). The lowest preference score was observed for IR64-Sub1 (-0.56), Samba-Sub1(-0.31), and Ciherang-Sub1 (-0.26). Under flash flooding, the highest preference score was recorded for CR1009-Sub1 (0.63) followed by BR11-Sub1 (0.38) and Swarna-Sub1 (0.20). The lowest preference score was observed for IR64-Sub1 (-0.62), Samba-Sub1 (-0.34), Ciherang-Sub1 (-0.29), and DRR Dhan39 (-0.27). Based on the results of field experiments and farmers’ preferences, CR1009-Sub1, BR11-Sub1, and Swarna-Sub1 could be recommended for cultivation in areas affected by flash floods in coastal areas of India.

MANAGEMENT OPTIONS FOR DROUGHT PRONE RAINFED LOWLAND RICE IN ASIA: A REVIEW

The rice-based rainfed lowland system in Asia covers about 45 million hectares which is almost 30% of the total rice area worldwide. Rice (Oryza sativa L.) is the main crop in this system and grown in bunded fields that are flooded for at least part of the season. Altogether, drought stress is the most important limitation to production in rainfed lowlands and is estimated to affect frequently about 19 to 23 million hectares resulting the reduced yield and hunger problems. In addition, drought-prone environments are often simultaneously affected by other abiotic stresses like submergence, adverse soil conditions, pests and weeds. In turn two main management strategies for drought stress alleviation in rice can be distinguished. The first strategy is based on management options which allow to escape drought by either avoiding severe dry periods or by providing access to additional water resources. The second strategy is to moderate drought by reducing unproductive water losses and thereby “saving” water for productive transpiration. Within both strategies there are several management options which offer considerable scope for improvement of drought-prone rainfed lowlands, however, direct seeding and improved nutrient management are probably the most widely applicable options. “Aeroabic rice” a new system of rice cultivation still under development and is thought to have potential to adopt in specific target environments within the rainfed lowlands of Asia.

Agronomic Performance and Selection of Doubled-Haploid Rice Lines for Rainfed Lowland Paddy Field

Rainfed lowland rice cultivation is an alternative to increase national rice production. Breeding of high yielding rice varieties suitable for rainfed lowland condition can be accelerated by using doubled-haploid (DH) as genetic materials. This study aimed at obtaining information on the agronomic performance including yields in several DH rice lines and selecting DH lines suitable for rainfed lowland paddy field. The experimental design used was a Randomized Complete Block Design with 3 replications. The treatment was thirty DH lines and 4 check varieties namely RJ31 Ciherang, RJ32 Inpari 18, RJ33 Inpari 40, and RJ43 Inpari 41. The results showed that there were variability in all agronomic performances, i.e., plant height, number of tillers, days to heading and to harvest, panicle length, number of filled and empty grains, 1000-grain weight and grain yield. The DH lines, namely RJ19 DR8-43-3-1 and RJ25 DR10-14-1-1, gave the same productivity as 4 check varieties. Index selection showed that twelve DH lines with medium number of productive tillers, early maturing, and productivity of more than 4.40 tons.ha-1 were selected for further evaluation.

BRRI dhan80: High Yielding Jasmine Type Aromatic Rice Variety for Wet Season of Bangladesh

A newly released jasmine type, aromatic, high yielding, long slender grain and exportable rice variety viz., BRRI dhan80, suitable for rain-fed low land ecosystem of Bangladesh is advancement over existing premium quality rice varieties. The variety has reasonably conceded the Proposed Variety Trial (PVT) conducted at the farmer’s field. As a result National Seed Board (NSB) of Bangladesh has sanctioned this variety for its commercial cultivation in the wet season (Transplanted Aman season) in 2017. It has modern plant type with 120 cm plant height and matures by 130-135 days. The salient feature of this variety is like jasmine as having good quality grain, aroma, ten days earlier maturing than check variety. The proposed variety exposed around 1.0 t/ha higher yield than check variety namely BRRI dhan37. Isolating characters of this variety are deep blackish green leaf, erect to semi erect flag leaf, long slender aromatic grain with colored tip and presence of anthocyanin pigmentation/coloration on stem nodes. Its grain yield producing range is 4.5-5.0 t/ha grain yield. It has long and erect flag leaf with deep green color, brownish root and strong stem. Thousand grain weight of the variety is 26.2 gm and it has colored grain tip and pointed awn. This variety has 23.6% amylose content and 8.5% protein content. The jasmine type, exportable, aromatic rice variety (BRRI dhan80) is a superb variety for cultivating in the wet season and therefore, farmers can be economically more benefited if they will prefer BRRI dhan80 for its cultivation at large scale.

Growth and yield of new hybrid rice in irrigated and rain-fed lowlands

Two experiments were conducted at (i) irrigated lowland, village of Bojong, Cikembar, Sukabumi Sub-district, Indonesia, from November 2011 to February 2012, and (ii) rain-fed lowland, village of Sanca, Gantar sub-district, Indramayu, Indonesia, from April to July 2012. The objective of the experiment was to determine the yield of drought-tolerant hybrid rice genotypes. A randomized block design with three replications was used. The treatment consisted of 8 hybrid rice genotypes (BI485A/BP3, BI485A/BP5, BI485A/BP10, BI485A/BP12, BI485A/BP15, BI599A/BP5, BI599A/BP15 and BI665A/BP6) and 2 check varieties (Hipa 7 and Ciherang) for the experiment in irrigated lowland, 4 hybrid genotypes (BI485A/BP3, BI485A/BP12, BI485A/BP15 and BI599A/BP15) and 3 check varieties (Hipa 7, IR64 and Limboto) for the experiment in rain-fed lowland. On irrigated lowland, all tested-genotypes produced grain yield per hectare, which was not significantly different from the check varieties Ciherang and HIPA 7. The yield of genotype BI485A/BP12, BI485A/BP15 and BI559A/BP15 under irrigated lowland showed non-significant different with check varieties Ciherang and Hipa 7, i.e 5.63, 6.87, and 6.30 tons ha-1, respectively. Genotype BI599A/BP15 under severe drought rain-fed lowland yielded 0.90 tons of grain ha-1, whereas Hipa 7 (hybrid variety, suitable for rain-fed lowland) and Limboto (drought-tolerant check variety) reached 0.34 and 0.29 tons ha-1, respectively. Genotype BI599A/BP15 is a new hybrid genotype that potential for advanced development in rain-fed lowland and in irrigated lowland with a high yield potential and quiet early-maturity age.

Effect of Organic Amendments on the Productivity of Rainfed Lowland Rice in the Kilombero Floodplain of Tanzania

Organic amendments can reportedly sustain and increase lowland rice productivity in smallholder systems. Few studies have assessed locally-available substrates in hydrologically variable floodplain environments. We investigated the effects of green and farmyard manures on rice yields, and total soil C and N in the Kilombero floodplain, Tanzania. At both the fringe and the middle positions, five treatments were applied in 2016 and 2017, comprising (1) non-amended control, (2) farmyard manure, (3) pre-rice legumes, (4) post-rice legumes and (5) a combination of green and farmyard manures. Residual treatment effects were assessed in 2018 when rice plots were uniformly non-amended. Depending on the year and the position, organic amendments increased rice grain yields by 0.7–3.1 Mg ha–1 above the non-amended control. Sole green and farmyard manure applications had similar effects on grain yield, while a combination of green and farmyard manure led to a significant increase in grain yield above both the control and sole applications of organic amendments in both years. The contribution from biological N2 fixation by legumes ranged from 4 to 61 kg N ha–1. Despite partial N balances being mostly negative, we observed positive residual effects on the yield of the non-amended rice in the third year. Such effects reached up to 4 Mg ha−1 and were largest with post-rice legumes, sole or combined with farmyard manure. Irrespective of the position in the floodplain, manures significantly increased soil C and N contents after two years, hence enhancing soil fertility and resulting in increased rice grain yields. Comparable benefits may be obtained along the hydrological gradients of other large river floodplains of the region and beyond.

Genotype-Environment Interaction and Stability for Yield of Inbred and Hybrid Rainfed Lowland Rice (Oryza sativa L.) Varieties in Bangladesh

Genotype-Environment Interaction and Stability for Yield of Inbred and Hybrid Rainfed Lowland Rice (Oryza sativa L.) Varieties in Bangladesh

Resilience of Rainfed Lowland Farming Communities on the Threat of Food Insecurity due to Climate Change (A Case in South Lampung)

Rain-fed lowland has a risk of drought, flooding, nutrient imbalance, and increasing pest and weed disturbance. These conditions will get worse when experiencing climate change. This can cause a decrease in production, so the community needs to develop strategies to survive in facing the threat of food insecurity. The purpose of this study was to analyze the resilience of rain-fed farming communities against the threat of food insecurity due to climate change. The study was conducted in the Marga Kaya Village, Lampung Province. Data was collected using a survey method by taking 100 respondents with simple random sampling. The results showed that the rain-fed farming community has been resilient to face the threat of food insecurity due to climate change. Rain-fed farming community through a network of adaptive capacity, especially social capital and manage available resources can maintain the existence of institutional barns to face the threat of food insecurity.

Anticipate of Climate Change Impacts In Rainfed Lowland Rice Through Applying Appropriate Technology

Rainfed lowland covers about 2.1 million ha in Indonesia that are generally distributed in Java, Sumatera, Kalimantan, Sulawesi, and Nusa Tenggara. Rainfed lowland ecosystems have great potentially to be more productive agriculture to avert possible food shortage. However, productivity of rainfed lowland rice is low due to low soil fertility, lack of water resources and its infrastructure, high weeds infestation, drought stress, and susceptible to climate change. The higher rainfed lowland rice yields can be attained by implementing appropriate crop and soil management technique. Incorporating 5 ton cattle manure per ha into soil significantly increased grain yield of DSR, also improve soil tillage and supply nutrients required by rice plants. The application of composted organic matter, slow release materials, and direct seeded system could reduce greenhouse gas emissions, and water harvesting could be used as adaptation of climate change. During the TPR and the upland crops, the crops often suffer from severe drought, resulting in drastic yield reduction. One of the alternatives to solve drought stress is to collect excess water during the water surplus rainy season in on-farm reservoirs (OFR) and use the water for the dry season crops.

PENGELOLAAN TANAMAN TERPADU PADI VARIETAS UNGGUL BARU DI LAHAN SAWAH TADAH HUJAN DI KABUPEN JAYAPURA, PAPUA

The cultivation technology and the use of new superior varieties (VUB) is one of the main components in increasing rice productivity in rainfed land. The study aims to evaluate the performance of the rice VUB in rainfed lowland cultivated land with integrated crop management (PTT) approach. This activity was carried out in the village of Benyom Jaya 1, Nimbokrang District, Jayapura Regency, Papua Province, from April to September 2017 using a Randomized Group Design. each variety used is. VUB tested by Inpari, 7, Inpari 30, Inpari 32 and Inpari 33, were planted in a plot measuring 2 hectares of experimental area for each treatment was 20 x 20 m2. The parameters evaluated include plant height, number of tillers, yield components and pest and disease attacks. The results of the study showed that the Inpari 33 variety gave a significantly different growth and yield to the Inpari 30 and 7 varieties. The suitable and high yielding varieties at the study site were the high production varieties obtained from the Inpari 33 variety (5.9 t / ha) and the lowest variety is Inpari 32 (4.47 t / ha) Keywords: Rice Varieties, Rainfed Rice Fields, Performance, PTT

Site and Management Effects on Grain Yield and Yield Variability of Rainfed Lowland Rice in the Kilombero Floodplain of Tanzania

In East Africa, smallholder farmers produce rainfed lowland rice mainly in floodplains. Low nitrogen contents of the predominant Fluvisols and highly variable hydrological conditions result in low yields and large yield variations, and hence, result in high production risks for farmers. We investigated crop management strategies aimed at increasing yield and reducing yield variability. The field trials were carried out in the Kilombero floodplain near Ifakara in Tanzania, in three hydrological zones (potentially drought-prone fringe, favorable middle and submergence-prone center positions) over three years. The study compared farmers’ management practices (no field levelling and bunding, no fertilizer input), with the effect of bunding and levelling alone, or in combination with mineral N use at 0 (bunding), 60 (recommended rate) and 120 kg + 60 kg PK ha−1 (attainable yield). Rice mean grain yields (averaged over the four treatments) were higher in the fringe (6.5 t ha−1) and the middle (5.7 t ha−1) than in the center positions (4.6 t ha−1). Farmers’ practice resulted in lowest yield (3.0 t ha−1) and highest yield variability, with an adjusted coefficient of variation (aCV) of up to 91% between fields, years and positions. Simple bunding of the plots and field levelling increased yields by 40% above farmers’ practice, particularly in the fringe and middle positions, while reducing yield variation (aCV of 36–61%). Mineral N application resulted in the highest yields (7.0 t ha−1) and further reduced yield variation (aCV of 14–27%). However, only in bunded fields of the floodplain fringe rice could benefit from N application beyond 60 kg ha−1, while mineral N use efficiency was lower in middle and center positions. Improved crop management options are most beneficial in floodplain fringe positions, where they can increase yields and reduce production risks. Due to low yield, high production risks and poor responsiveness to management interventions, the center may be taken out of rice production and could be considered for future use as protection zones.

Technological interventions to enhance rice productivity and profitability in rainfed lowlands of Asom

Improved technological interventions are important to sustain production and productivity of rice. A study was conducted by Regional Rainfed Lowland Rice Research Station, ICAR–National Rice Research Institute, Gerua, Kamrup in four districts of lower brahmaputra valley and north bank plains agro-climatic zones of Asom during boro seasons from 2012–13 to 2016–17 to enhance productivity of boro rice through introduction of latest rice varieties and application of improved production technology. Performance of open-pollinated varieties, viz. Naveen, Chandrama and CR Dhan 909, and hybrids, viz. Ajay and Rajalaxmi under application of improved production technology were demonstrated. At all the locations, application of improved technologies showed superior results in terms of growth, yield attributes, productivity and profitability over local checks under farmers’ practice. Rice varieties with application of improved production technologies, increased mean grain yield by an average of 38.8% and extra earning of `18137/ha over existing farmer’s practice with only `3632/ha extra expenditure on inputs. The mean gap indices,viz.extension gap (1.56 t/ha), technology gap (0.96 t/ha), technology index (14.5%) and mean B:C (4.99) clearly indicated the superiority of technological demonstrations over farmers’ practices. The study also lays emphasis on the framing intensive technology transfer programmes like technological demonstrations on field to motivate the farmers for higher adoption rate of improved rice production technology.