Lowland Rice Production Research Articles

Effects of Bacillus spp. inoculation on suggested shoot tolerance mechanisms in lowland rice (Oryza sativa L.) grown under iron toxicity

AbstractBackgroundIn areas of lowland rice production, high iron concentrations in the soil often lead to yield reductions. Local adapted varieties possess different adaptation mechanisms, which, however, are not fully understood. Previous studies have shown that endophytic bacteria can influence plant tolerance to abiotic stresses, including iron toxicity.AimThis study aims at analyzing the effects of different Bacillus isolates on distinct shoot tolerance mechanism in different rice cultivars grown under iron toxicity.MethodsThree lowland rice cultivars, varying in their tolerance against iron toxicity (IR31785‐58‐1‐2‐3‐3, Sahel 108, Suakoko 8), were inoculated with three Bacillus strains (two of B. pumilus and one of B. megaterium). One week after Bacillus inoculation plants were subjected to high iron levels (1000 ppm) for 7 days. Leaf symptom scoring was used to assess tolerance levels. Activities of ascorbate peroxidase (APX), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (PRX) were measured by spectrophotometric assays. Transcription of genes related to iron toxicity (OsFER, OsFRO1, OsNRAMP6) was determined by RT‐qPCR. Bacterial production of NO was evaluated by measuring nitrite levels in the culture supernatants.ResultsIn general, iron toxicity affected the activities of APX, GR, CAT, and PRX but not SOD activity. Only PRX activity in response to iron differed between cultivars with a significantly stronger increase in IR31785‐58‐1‐2‐3‐3. Inoculation with B. pumilus Ni9MO12 led to higher activity of CAT in the leaf sheaths of all cultivars and an increase in GR activity in the sheaths that was significantly higher in Suakoko 8. In the young leaf blades of IR31785‐58‐1‐2‐3‐3, transcription of OsFRO1 and OsNRAMP6 was not significantly affected by Bacillus inoculation, whereas accumulation of OsFER mRNA was significantly higher in iron‐stressed, B. pumilus Ni9MO12 inoculated plants compared to non‐inoculated, non‐iron‐stressed plants. Nitrite concentration as an indicator for NO production was increased in B. pumilus Ni9MO12 culture supernatants.ConclusionOur results show that in the sensitive cultivar IR31785‐58‐1‐2‐3‐3 tolerance to iron toxicity increases when inoculated with B. pumilus Ni9MO12, coinciding with higher levels of ferritin transcription. NO production by the Bacillus isolate might confer the promotion of OsFER gene transcription in the inoculated plants.

Optimizing transplanting densities for lowland rice production under low-yielding environments in the Madagascar highlands

ContextRice yield is low at 2.1 t ha−1 in sub-Saharan Africa. Increased yield is a critical challenge to food security and environmental conservation in this region. However, smallholder farmers have limited access to irrigation, mineral fertilizers, and improved crop varieties. One approach that even resource-limited farmers can easily manipulate is to optimize planting densities. However, there is limited empirical evidence to provide technical recommendations under such low-yielding conditions. ObjectiveThis study aimed to identify the effect of dense transplanting on lowland rice yields under low-yielding conditions, with a target range below 5 t ha−1. MethodsMulti-field trials were implemented with transplanting densities of a regular rate at 25–26.7 hills m−2, a doubled rate at 50–53.3 hills m−2, and a tripled rate at 88.9 hills m−2 in the central highlands of Madagascar, where rice yields are limited by nutrient deficiency and low temperature. Canopy coverage and cumulative intercepted radiation (CIR) were monitored from transplantation to maturity using digital imagery analysis. Field observations (n=306) and four-year household surveys (n=356) were combined to calculate the costs and benefits of changing transplanting densities. ResultsDoubling densities from 25.0–26.7 hills m−2 to 50.0–53.3 hills m−2 had a consistent yield advantage by approximately 0.4 t ha−1 across a yield range of 1.8 t ha−1–4.4 t ha−1. The yield was further increased by tripling the transplanting densities to 88.9 hills m−2 when the yield range was 1.9–2.3 t ha−1. The yield advantage of higher transplanting densities was attributed to a greater CIR at the initial growth stages and a significantly greater panicle number. Household surveys and field observations indicated that the benefit of yield gain was more than three times greater than the additional cost of doubling the seed amounts. No significant yield differences were observed by changing the transplanting densities when the yield level was higher than 5 t ha−1 or lower than 1.3 t ha−1 where substantial reductions in grain fertility occurred owing to low-temperature stress. ConclusionsA relatively high transplanting density of 50–53.3 hills m−2 or even higher is recommended to ensure initial canopy development and panicle number in low-yielding conditions where individual plant growth is stagnant, except in fields with high risks of grain set failure. ImplicationsThis study provides an easy-to-use opportunity for smallholder farmers to increase their rice yield. Further studies are required to determine whether these findings apply to warmer climatic conditions.

Technical Efficiency Of Rice Farming Around The Nickel Mining In Konawe Selatan District

South Konawe Regency has vast potential agricultural land, It can support the regional economy by supplying the food needs of the community and being a major player in trade across districts. In addition to providing food, the agricultural sector also serves as a market for goods produced by the industrial sector in rural communities and urban areas, a source of labor for industry, a source of capital for modern economic growth, particularly in its early stages, and a source of foreign exchange. Policy support is needed from the government in developing the agricultural sector considering the importance of synergy between the agricultural and mining sectors to minimize negative impacts in order to achieve economic balance so that it becomes the basis for local governments in taking appropriate policies to support the agricultural sector amidst mining activities. The purpose of this study is to examine lowland rice farming's technical effectiveness and production characteristics in the vicinity of South Konawe Regency's nickel mine. The data collected used primary and secondary data, with a total of 20 farmers as respondents. Stochastic Frontier Analysis (SFA) was utilized to analyze the data. The findings of the study indicate that lowland rice farming is technically efficient when it is conducted near nickel mining and that the production elements that actually affect lowland rice farming include land area, labour force, urea and NPK fertilisers, and insecticides.

Effects of Soil Type, Irrigation Method, and Biomass Application on Grain Yield and Its Determinants in Irrigated Lowland Rice of Agusan

Information about the influence of soil type, irrigation method, and biomass use on rice productivity in Agusan is insufficient, despite their importance in developing or improving irrigated lowland rice production. Hence, this study determined the influence of these factors on grain yield and yield-contributing crop traits. It also explained grain yield based on yield determinants and recommended water management for improving grain yield. The greenhouse experiment was laid out in a three-factor randomized complete block design with 10 replications. The treatments were [a] Butuan sandy loam soil (SLS) and Butuan loam soil (LS); [b] continuously flooded (CF) and controlled irrigation (CI); and [c] applied and unapplied biomass. Data on grain yield and yield determinants were gathered weekly, during harvesting, and after harvesting. Relative to LS, SLS had a statistically greater grain output owing to its higher root and water permeability and better balance among soil nutrients, leading to closer-to-the-optimum soil nutrient uptakes and better yield-contributing crop traits. Compared with CI, CF had a statistically superior grain output as it induced the crop to produce more robust tillers, leading to significantly better yield-contributing crop characteristics. Biomass application modified the soil type x irrigation method interaction since the degree at which CF was exhibiting higher grain yield than CI was significantly greater in SLS than LS for experimental units or pots applied with biomass. Moreover, the level at which CF was attaining greater grain yield than CI was statistically similar in SLS and LS for pots unapplied with biomass. It is therefore recommended that rice be grown in Butuan sandy loam instead of Butuan loam, and that CF instead of CI be used in soil with a mild zinc deficiency or sufficient zinc status.

Effects of Methods of Planting and Time of Herbicide Application on the Economic of Lowland Rice in Badeggi, Nigeria

The experiment was conducted in 2021 and 2022 wet season at National Cereals Research Institute headquarters, Badeggi, Niger state (latitude 9o041 02.05’’N, longitude 0.6o011 3.31’’E) in the Southern Guinea Savannah Agro-Ecological Zone of Nigeria. To evaluate the cost-effectiveness of different planting methods and herbicide application timings on lowland rice production for farmers in the region. The experiment was laid out in a factorial experiment. The treatment consists of five sowing methods (broadcasting dry, broadcasting wet, dibbling wet, dibbling dry and transplanting) with two different timing of herbicide application. The 10 treatment combinations were laid out in a factorial experiment with a split-plot design with timing of herbicide application allocated to the main plot while sowing methods were designated to the sub-plot. Data were collected on Plant height, number of tillers, day to 50% flowering, day to maturity, number of seeds per panicle, seed yield per panicle, 1000-grain weight and grain yield per hectare. The result indicated that overall, the transplanting method of planting resulted in the significantly highest for all parameters, followed by the dibbling wet and dibbling dry methods. The broadcast method resulted in the poorest outcomes. Applying herbicide at 2 WAS resulted in better outcomes compared to 3 WAS. The transplanting method with herbicide application at 2 WAS resulted in the significantly highest grain yield, gross returns, and gross margin, making it the most profitable option.

The role of ascorbate redox turnover in iron toxicity tolerance

Iron (Fe) toxicity is a major abiotic stress in lowland rice production. Breeding tolerant varieties has proven challenging due to the complex genetic architecture of Fe toxicity tolerance and the strong genotype-by-environment interactions. Additionally, conventional methods for phenotyping visible stress symptoms are often inaccurate, inconsistent, and lack reproducibility.In our previous work, we identified that ascorbate redox regulation, mediated by the activities of dehydroascorbate reductase (DHAR) and ascorbate oxidase (AO), contributed to high tolerance in an indica rice genotype across various environments. To explore whether this mechanism is common among other rice genotypes, we selected ten genotypes with contrasting stress symptoms under Fe-toxic conditions to examine the roles of DHAR and AO in regulating Fe toxicity tolerance. Additionally, we aimed to develop objective and accurate image-based phenotyping methods to replace the traditional leaf bronzing scoring method.Among the ten genotypes we tested, we found significant positive correlations between DHAR activity and stress symptoms in plants grown under both Fe toxicity and control conditions, suggesting a general link between ascorbate redox regulation and Fe toxicity tolerance. Using RGB signals from leaf images of plants exposed to 1000 mg/L Fe2+, we evaluated 36 different color indices to quantify stress symptoms. We identified the normalized green‒red difference index as most significant in quantifying stress symptoms under Fe toxicity conditions.Our findings suggest that DHAR activity could be potentially employed as a biomarker in the screening of rice germplasms and breeding tolerant cultivars to Fe toxicity.

Cultivo de soja em área de arroz irrigado para reduzir a infestação de plantas daninhas

ABSTRACT Lowland rice in Santa Catarina (SC), Brazil, is grown as a sole crop, which has aggravated problems with weeds. In this context, the objective of this study was to evaluate the efficacy of weed management systems in soybean crops to decrease weed infestation in lowland rice production areas, using pre- and post-emergence herbicides. The experiment was conducted in Turvo, SC, from August 2021 to April 2022. A randomized block design with four replications was used, in a 6 × 5 factorial arrangement. The factors consisted of six pre-emergence herbicides treatments (S-metolachlor, diclosulam, sulfentrazone, sulfentrazone + diuron, pyroxasulfone + flumioxazin, and a control without herbicide), and five post-emergence herbicide treatments: control without herbicide, glyphosate at two rates (930 and 1,550 g a.e. ha-1), applied alone or in combination with clethodim. The herbicide sulfentrazone caused persistent phytotoxicity and resulted in the lowest soybean grain yield. The herbicide S-metolachlor was ineffective in controlling weed species, except barnyard grass, even when combined with post-emergence application. The poor control of these weed species does not result in significant interference, causing no significant decreases in grain yield of soybean crops grown in floodplain soils. The use of S-metolachlor, diclosulam, and pyroxasulfone + flumioxazin, combined with post-emergence application of glyphosate (930 g a.e. ha-1), resulted in highly effective control of barnyard grass, inhibiting weed seed production. Only the combination of glyphosate (1,550 g a.e. ha-1) with clethodim can suppress barnyard grass seed production without using pre-emergence herbicides.

Nutrient Assessment of Rain-Fed Lowland and Upland Rice Production Systems in Okigwe, South-Eastern Nigeria

Nutrient Assessment of Rain-Fed Lowland and Upland Rice Production Systems in Okigwe, South-Eastern Nigeria

Analysis of Farmers' Perceptions Towards Rice Farming for Rice Fields from Gold Mining Without a License (PETI) in Pangkalan Jambu Subdistrict, Merangin District, Jambi Province

Rice is a strategic commodity and is the main priority of the Indonesian people in supporting national food security. Merangin Regency was ranked 5th with a percentage of harvested area of 8.29% while production was 8.47%, and lowland rice productivity in Merangin Regency was 10.21%. Pangkalan Jambu Subdistrict is not the main supplier of lowland rice in Merangin Regency, but research shows that farmers assess the use of ex-PETI rice farming both economically, technically, socially and norms or legally as positive, ex-PETI land is still promising, economically ex-PETI land is profitable and economically Technically, farmers can carry out activities well on former PETI land, and there are no obstacles from social aspects, applicable norms and regulations. The Farmers' Perception score reached 87.33% for economic aspects, 82.49 percent for technical aspects, 79.41 percent for social aspects and 80 percent for aspects of applicable norms and regulations. The productivity of lowland rice farming on former PETI land reaches 3 to 4 tons per hectare. Keywords: Perception, lowland rice, PETI

Dinamika Perkembangan Luas Panen, Produksi Dan Produktivitas Padi Sawah Sebelum Dan Sesudah Program Humasa Sebbel Khumaha Heba Di Kabupaten Simeulue

Meeting food needs is a right and is protected by law in Indonesia. The harvested area for lowland rice in Indonesia and the Province of Aceh has fluctuated every year. Simeulue Regency in 2020 has implemented the Humasa Sebbel Khumaha Heba Public Relations Program (Together down to the fields) with the aim of food self-sufficiency in Simeulue Regency. The purpose of this study was to determine the development of harvested area, production, and productivity of lowland rice in Simeulue Regency before and after the Humasa Sebbel Khumaha Heba program. The analytical method used is descriptive comparative based on secondary data obtained from the Agriculture and Food Crops Office of Simeulue Regency and the Statistics Indonesia-BPS in the form of time series from 2018 to 2021. The results of this study are the Humasa Sebbel Khumaha Heba program can increase harvested area and lowland rice production in Simeulue Regency but its productivity continues to decline.

KOMPARASI SISTEM TANAM JAJAR LEGOWO DAN KONVENSIONAL PADA PRODUKSI DAN PENDAPATAN USAHA TANI PADI SAWAH DI DESA KUIMASI KECAMATAN FATULEU KABUPATEN KUPANG

The Jajar Legowo planting system is a new innovation which in its application aims to increase production and income in lowland rice farming businesses when compared with Conventional planting systems, so this study aims to determine production and income and the magnitude of the difference in productivity and income from lowland rice farming using the Jajar Legowo and Conventional planting systems in Kuimasi Village, Fatuleu District, Kupang Regency. To find out the production and income of rice farming, it is necessary to calculate the farmer's income level using farming income analysis calculations. The results of this study (1) The total production cost of lowland rice farming in Kuimasi Village, Fatuleu District, Kupang Regency using the Jajar Legowo planting system is IDR. 8,420,754.3/Ha, total revenue of Rp. 41,250,000/Ha with an average income of Rp. 32,829,245.7/Ha and the total cost of lowland rice production using a conventional planting system is Rp. 7,258,456.3/Ha, total revenue of Rp. 52,500,000/Ha with an average income of Rp. 45,241,543.7/Ha. (2) The total production costs of lowland rice farming using the Jajar Legowo planting system and the conventional planting system have a difference of Rp. 1,162,289/Ha. The total revenue from rice farming using the Jajar Legowo planting system and the conventional planting system has a difference of Rp. 11,250,000/Ha. The average income using the Jajar Legowo planting system and the conventional planting system has a difference in income of Rp. 12,412,298/Ha in one planting season. Based on these calculations, it can be concluded that the total production costs using the Jajar Legowo planting system are greater than the total production costs using the Conventional planting system, but the total revenue and income using the Conventional planting system is greater than the total revenue and income using the Jajar Legowo planting system.

ANALISIS FAKTOR-FAKTOR YANG MEMPENGARUHI PRODUKTIVITAS PADI SAWAH DI KECAMATAN AESESA KABUPATEN NAGEKEO PADA TAHUN 2013-2017

The purpose of this study was to determine the effect of rice harvest area, human resources and rainfall on lowland rice productivity and determine the factors that most influence lowland rice productivity. The data used are quantitative and qualitative data sourced from lowland rice productivity data, harvested area data, human resource data and rainfall data taken from BPS Kabupaten Ende and other relevant agencies, within the last five years. The results of his research were three factors, namely harvested area, human resources and rainfall, all of which did not significantly influence the productivity of lowland rice. Of the three independent variables, namely the rice field harvest area variable, the Human Resources variable and the rainfall variable, it can be seen from the coefficient numbers which are more influential on the productivity of lowland rice, namely the harvest area variable and the Human Resources variable which are positive, namely the coefficient of harvested area is 70.451 and the coefficient of Human Resources is 1.671, while the rainfall variable is negative, namely -160.985. From the results of this study, the local government wants to increase the participation of extension workers to the farming community so that their business spirit and creativity are continuously fostered. It is hoped that lowland rice farmers try as often as possible to get direction or socialization from the local government to improve Human Resources or knowledge.

System shift in rice: Processes and pathways of change in rice-based production systems of Southeast Asia

CONTEXTPredicting future production trends and associated land use and management practices requires an understanding of past changes in productivity and of pathways of evolving system configurations. We argue that rice systems' evolution reflects a process of adaptation to changing availabilities of production resources and the adoption of technological innovations and that differs by marginality/favorability of sites. Understanding past change trends and their determinants can help avoiding undesirable future developments and guide policy decisions for a sustained supply of rice. OBJECTIVEWe aimed to assess agronomic system change and practices, to quantify pathways of change and to identify likely drivers of but also possible risks or opportunities associated with observed patterns of agronomic system transformation in six representative lowland rice production environments in Asia. METHODSWe implemented a diachronic analysis (years 2000 vs. 2018) of rice production practices and yield attributes in 1024 households. We documented changes between 2000 and 2018 in lowland rice-based systems in six rice-growing environments in the Philippines, Myanmar and Cambodia, differentiating marginal and favorable sites in irrigated and in rainfed environments. RESULTS AND CONCLUSIONFarmers' household attributes, resource endowment, rice yields, and key constraints differed among sites. We observed relatively low annual yield in marginal (2.2–3.0 t/ ha) than favorable (3.3–8.9 t/ ha) sites depending on countries and seasons. The farmers adopted intensification related agronomic practices has increased significantly between 2000 and 2018, especially in dry season (i.e., improved seeds by 28%, mechanical tillage by 52%, direct seeding by 21%, combined harvester by 62%). The marginality of climatic and edaphic conditions, the systems' evolutionary state in 2000, and differential pressures (policy environment), opportunities (technological change) and household attributes (resource endowment) determined the observed transition pathways across study sites. SIGNIFICANCEThe trends towards maximizing land use intensity (double or multiple cropping), converging in the emergence of high-input and highly mechanized (laborsaving) in irrigated, and diversified rotations in rainfed rice production systems may help to elucidate agricultural research needs and potentially predict the requirements for future sustainable intensification of rice-based systems. Additionally, we argue for a continued need for further mechanization of rice establishment, especially shifting from transplanting to direct seeding during dry and wet seasons, and of the rice harvest, especially during wet season under fully irrigated environments.

Investigation of yield-limiting nutrients for rain-fed lowland rice production in the Fogera floodplain of the Amhara Region in Northwest Ethiopia

The productivity of rice (Oryza sativa L.) in Ethiopia is below the potential due to spatial and temporal soil fertility variability and sub-optimal fertilization. This on-farm study was conducted in 2019 and 2020 to determine yield-limiting nutrients, quantify yield gaps, and determine indigenous soil nutrient supply (ISNS) for lowland rice in Fogera floodplain of Northwest Ethiopia. The study comprised the following treatments; NPKSZnB, -N (PKSZnB), -P (NKSZnB), -K (NPSZnB), -S (NPKZnB), -Zn (NPKSB), -B (NPKSZn), and Zero fertilizer (F0). The treatments were arranged in a randomized complete block design considering farmers’ fields as replications. The results revealed that the growth and yield of rice were significantly affected by the -N and F0 treatments. However, the other nutrient omissions did not significantly influence the mentioned parameters. The highest (2299.5 kg ha−1) yield response was recorded from the -N treatment. However, very low and insignificant yield responses were recorded from the other nutrient omissions. The average agronomic N use efficiency was 16.7 kg kg−1, which indicated a high probability of yield response to the application of N fertilizer. The lowest (42.4%) ISNS was found for N, while the highest ISNS (>90%) were recorded for P, K, S, Zn, and B. The yield gaps due to the omission of N was 57.6%, while the yield gaps due to the omission of P, K, S, Zn, and B were very low. Therefore, N was found to be the most yield-limiting and most deficient nutrient for the lowland rice production in the study area.

Cost and returns analysis of upland and lowland rice production among farmers in North Central Nigeria

Sustainability of the rice production and farmers’ income in Nigeria raises a serious concern due to the rising costs of production inputs and other factors beyond farmers’ control. As a result, the study compared the cost and returns of rice production in North central, Nigeria. A multistage sampling technique was used to select 387 rice farmers in the study area. Descriptive statistics, gross margin analysis and seeming unrelated regression were used to analyze the dataset collected. The findings revealed that most of the rice farmers were male, averagely young and have at least 9 family members in their respectively households. Results from Kwara State showed that total cost is higher among the upland rice farmers compared to their lowland counterparts, but reverse was the case in term of net profit, as this favoured the lowland rice farmers. For Niger State and pooled data, the lowland rice farmers had higher net profit than the upland rice farmers. Seemingly unrelated regression estimates indicated that costs associated with fertilizer, herbicide, seed, pesticide and labour used were significant and influencing factors affecting the revenue of rice farmers in the study area. While inaccessibility to cheap farm inputs was the major constraint affecting the rice farmers, other challenges include lack of storage, inadequate rainfall and inadequate credit facilities. The study recommended seamless access to improved rice varieties by the farmers as this can scale up adoption of improved technologies, boost production and ultimately the net revenue of rice farmers. Farmers are also advised to join and/or form a registered occupational groups through which credit facilities can easily be accessed, to expand the farming operations because of the positive and complementary role of social group and access to credit.

Farmer’s Income and Allocative Efficiency Analysis in Rice Production in Koto Tangah Subdistrict Padang City

The low productivity of lowland rice (Oryza sativa L.) in Koto Tangah District is affecting farmers’ income. The objectives of this research were to analyze : (i) income from lowland rice cultivation, (ii) factors that influence rice production, and (iii) the efficiency of utilization of lowland rice production factors in Koto Tangah District. The method used in this research was quantitative, using probability sampling techniques with proportional random sampling method and 44 respondents were involved. The data analysis techniques used were income analysis, Cobb-Douglas production function, T-test (partial), F-test (simultaneous), coefficient of determination, and efficiency analysis. Based on the survey results, it was known that the total income from lowland rice cultivation in Koto Tangah District was IDR2,607,860.36/average land area/ MT, and lowland rice cultivation was possible with an R/C value of 1.21. The factors that influenced lowland rice production in Koto Tangah District were land area, seeds, and chemical fertilizers, which significantly affected production levels. In contrast, pesticides, labor within the family, and labor outside the family do not significantly affected lowland rice production in Koto Tangah District. Although production factors such as land area, seeds, fertilizers, pesticides, and family labor (TKDK) were still inefficient, non-family labor (TKLK) had almost reached an efficient level.

Factors Influencing the Production of Padi Rice (Oryza sativa L) in Talang Kering Village, Air Napal District, Bengkulu Utara District

This study aims to determine what factors influence the production of lowland rice in Talang Kering Village, Air Napal District, North Bengkulu Regency. In this study, the samples taken were 27 respondents from a total of 80 populations. The data used are secondary data and primary data, the analysis used in this study is Cobb-Douglass and uses SPSS analysis. Cobb-Douglass is a function or equation that involves two or more dependent variables that are explained (Y), and the others are called independent variables that are explained (X). The results of the regression coefficients show that production is influenced by seed (0.50), land area (0.389), fertilizer (0.209), and use of pesticides (0.181) which greatly affect production while labor (-0.043) does not affect rice production.

Optimization of Rice (Oryza sativa) Crop in Simalungun District using Quadratic Programming Wolfe Model and Exterior Penalty Function Method

Optimization is a way of optimizing the objective function while still paying attention to existing constraints. The aim of this research is to form a mathematical model to optimize the average production of lowland and field rice in Simalungun Regency and to complete the model using Wolfe model quadratic programming and the exterior penalty function method. The mathematical model in this research is a nonlinear model created using the least squares method. Quadratic programming solves nonlinear problems by turning them into linear problems using the Kuhn Tucker condition and linear problems are solved using the Wolfe model. Meanwhile, the exterior penalty function method solves limited (constrained) nonlinear problems into unlimited (unconstrained) nonlinear problems. Based on the calculations of the two methods, optimal results were obtained for both the Wolfe quadratic programming model and the exterior penalty function method, where the average production of wetland and field rice in Simalungun Regency was 203.1925 tonnes with a wetland rice harvest area of 90.077 hectares and a field rice harvest area of 13.092. hectare. Optimization testing using this algorithm can be used as a basis for related parties such as the community and government in developing productivity. The implication of this research is an increase in harvested area and average rice production, in this case maintaining productivity stability.

Azolla pinnata ammendment and P-solubilizing bacteria inoculation for improving Inceptisols fertility and rice (Oryza sativa L.) yield production

Continuous and long-term use of chemical fertilizers in lowland rice fields can have negative impacts on the environment, causing harm to aquatic life and a decrease in soil health. Applying Azolla pinnata and inoculating phosphate solubilizing bacteria (PSB) in organic farming is an appropriate strategy to increase soil nutrients and lowland rice production. Azolla pinnata plays a role in increasing N nutrients, while phosphate solubilizing bacteria (PSB) increase available phosphate in the soil. This study aims to assess the effectiveness of varying doses of Azolla pinnata and PSB inoculant in increasing soil available P, plant-P concentration, plant hegh, productive tiller, and rice yield. The experimental design used a Factorial Randomized Block Design of two factors in three replications. The first factor was Azolla pinnata application (0 ton ha-1; 10 ton ha-1; 20 ton ha-1; 30 ton ha-1), and the second factor was PSB inoculation (0 kg ha-1; 12.5 kg ha -1; 25 kg ha-1). The experimental results showed that the Azolla pinnata application at a dose of 10 t ha-1 with inoculation of 12.5 kg ha-1 PSB significantly increased the highest soil available P by 48.3 ppm. The application of Azolla pinnata 30 t ha-1 significantly increased the P content of plants—0.26 mg g-1. Azolla pinnata 30 t ha-1 application and PSB inoculation produced significantly the highest productive tillers of rice plants, 38 plants pot-1. Azolla pinnata 10 tons ha-1 application with BPF inoculant 12.5 kg ha-1 significantly increased the highest grain yield, namely 81.47 g pot.-1

Farmers Perceptions of the Price of Certified Rice Seeds in Padang City, West Sumatra Province, Indonesia

In the Strategic Plan Document (RENSTRA) of the Agriculture Service in Padang City for 2019–2024, it is determined that rice is a strategic commodity. One effort to increase rice production is a policy of increasing the use of certified rice seeds at the farmer level. Lowland rice production in Padang City shows a downward trend in the period 2018 to 2020. Total rice production in 2018 was 104,561 tons and rice production in 2020 was 80,092 tons, this condition shows a decline in rice production from 2018 to 2020 of 23.45%. The decline in rice production in Padang City is thought to be caused by farmers not responding well to the use of certified rice seeds. The price of certified rice seeds in Padang City is Rp. 11,000 – Rp. 15,000 per kg and the price of uncertified rice seeds in Padang City is Rp. 5,500 – Rp. 7,500 per Kg. The aim of this research is to describe farmers perceptions of the price of certified rice seeds in Padang City. Data collection was carried out using interviews and questionnaires. The sampling technique used was purposive sampling. The total research sample was 96 farmers taken from 6 sub-districts in Padang City. The selected subdistrict is an area designated by the Padang City Agricultural Service as a food area. Based on research results, farmers perceptions of the price of certified rice seeds in Padang City are 42.7% of farmers perceptions of the price of certified rice seeds at affordable prices, Farmers perception of the suitability of the price of certified rice seeds in accordance with the benefits obtained is 77.1%, Farmers perception of the suitability of the price of certified rice seeds according to the quality obtained is 90.6%, The perception of farmers regarding the price of certified rice seeds compared to the price of non-certified rice seeds is that all respondent farmers said that the price of certified seeds has a high price.