An assessment of irrigated rice cultivation with different crop establishment practices in Vietnam

Overuse of seed and chemical inputs is a major constraint for sustainable rice production in Vietnam. In this study, two seasons of field trials were conducted to compare different crop establishment practices for rice production in the Mekong River Delta using environmental and economic sustainability performance indicators. The indicators including energy efficiency, agronomic use efficiency, net income, and greenhouse gas emissions (GHGEs) were quantified based on four treatments including manual broadcast-seeding, blower seeding, drum seeding, and mechanized transplanting. Across the four treatments, yields ranged from 7.3–7.5 Mg ha−1 and 6.2–6.8 Mg ha−1 in the Winter-Spring (WS) and Summer-Autumn (SA) seasons, respectively. In comparison with direct seeding methods, mechanized transplanting decreased the seed rate by 40%. It also led to a 30–40% reduction in pesticide use during the main crop season (WS). Mechanized transplanting required higher inputs, including machine depreciation and fuel consumption, but its net energy balance, net income and GHGE were at a similar level as the other non-mechanized planting practices. Mechanized transplanting is a technology package that should be promoted to improve the economic and environmental sustainability of lowland rice cultivation in the Mekong River Delta of Vietnam.

Avaliação da interação de níveis de fertilizantes e misturas de herbicidas na cultura do arroz (Oryza sativa L.) / Evaluation of the interaction of levels of fertilizers and herbicide mixtures in rice cultivation (Oryza sativa L.)

A presente investigação foi realizada com o objetivo de determinar a interação entre os diferentes níveis de fertilização e misturas de herbicidas no cultivo de arroz (Oryza sativa) na área de Babahoyo. Foi utilizada a variedade de arroz INIAP 15. Foi aplicado o delineamento de Parcelas Divididas, cujos tratamentos consistiram em níveis de fertilização, subtratamentos por mistura de herbicidas e três repetições. Para a comparação das médias, foi utilizado o teste de Tukey com significância de 5%. Para estimar os efeitos dos tratamentos e subtratamentos, os dados do índice de toxicidade foram avaliados aos 7 e 14 dias após a aplicação dos herbicidas, controle de plantas daninhas aos 15 e 30 dias após a aplicação dos herbicidas, altura da planta na colheita, número de perfilhos / m2, número de panículas, dias para o florescimento, maturidade fisiológica, comprimento da panícula, grãos por espiga, peso de 1000 grãos, rendimento de grãos e análise econômica. Os resultados mostram que a interação dos níveis de fertilizantes e misturas de herbicidas obteve efeitos positivos na produção da cultura do arroz (Oryza sativa L.), na área de Babahoyo; Aos 7 dias, a toxicidade na cultura era sem danos e aos 14 dias poucos danos foram mostrados; o melhor controle de plantas daninhas foi apresentado com as misturas de Piribenzoxim + 2,4 D amina (1,0 L + 0,7 L) aos 15 e 30 dias após a aplicação dos produtos; Características agronômicas como altura da planta, perfilhos e panículas / m2, comprimento das panículas e grãos por espiga foram influenciadas em suas médias com a aplicação de Nitrogênio (160 kg / ha) + Fósforo P2O5 (40 kg / ha) + Potássio K2O (60 kg / ha); Nos dias para a floração e maturidade fisiológica, todos os tratamentos e subtratamentos responderam da mesma forma porque foi utilizada a variedade Iniap 15; o maior peso de 1000 grãos e produtividade foi apresentado na aplicação de Nitrogênio (160 kg / ha) + Fósforo P2O5 (40 kg / ha) + Potássio K2O (60 kg / ha) e nas misturas de herbicidas aplicadas nos três subtratamentos e. o maior benefício líquido foi alcançado aplicando como fertilizantes Nitrogênio (160 kg / ha) + Fósforo P2O5 (40 kg / ha) + Potássio K2O (60 kg / ha) complementar às misturas herbicidas baseadas em Clomazone + Pyrazosulfuron Etil (1,0 L + 0,35 kg) com $ 662,02 / ha.

Profitability and productivity of drought tolerant Aus rice variety Binadhan-19 in some areas of Bangladesh

The present study was conducted in five districts namely Mymensingh, Ranpur, Pabna, Rajshahi and Chapainwabganj in Bangladesh. The objectives of the study were i) to identify the socio-economic characteristics of Aus rice growers; ii) to estimate profitability and productivity of Binadhan-19 in the study areas; and iii) to find out the major preferences and constraints for the variety cultivation. A total of 200 farmers were randomly selected (40 from each location) to collect the data with a pre-designed questionnaire. The distribution of the farmers by age showed that the mean age for Binadhan-19 cultivated farmers was 43 years. In the study areas among the farmer 86% was educated. Farmers average experience was 20 year and income were Tk. 235066 (USD 2611.84) per year. Per hectare average yield of rice was 1.37 ton. It was estimated that, to produce one kilogram of rice, total cost incurred was Tk. 14 where per kg average selling price of rice was Tk. 17. The average gross return and gross margin of rice cultivation were found Tk. 90679 (USD 1007.54)/ha and Tk. 51290 (USD 559.88)/ha, respectively. Per hectare average net return was Tk. 2459 (USD 27.32) which was found to be highest in Chapainwabganj Tk. 29739 (USD 330.43) and lowest in Rangpur Tk. 12692 (USD 141.02) district. BCR on total cost basis was found 1.37. The highest preference was for neat rice 98% and the highest constrain said by the farmer was crop destroy by animal and bird of paddy for early ripening in Binadhan-19 cultivation.

Economic analysis of rice (Oryza sativa L.) cultivation in Gorkha district of Nepal

A study was conducted to analyze the production economics and factors contributing to the gross return of rice production in the Gorkha district of Nepal in 2020, where a rice block was established under the Prime Minister Agriculture Modernization Project (PM-AMP). Altogether, 76 rice-growing farmers were selected as a sample by using a simple random sampling technique. Primary data were collected by using a pre-tested interview schedule, while secondary data were collected by reviewing related literature. The data was analyzed using descriptive statistics, chi-square, independent sample t-tests, and Cobb-Douglas production function. The results showed that the average landholding was 0.74 ha and the average area under rice cultivation was 0.52 ha, with a productivity of 3 mt ha-1. The findings revealed that the cost of rice production for small farmers was significantly higher (NRs. 171466 ha-1) than that for large farmers (NRs. 132088 ha-1). The study reveals that investment in rice cultivation was economically viable in the study area because the overall B: C ratio was greater than one (1.17). The production function analysis reveals that a 10% increase in expenditure on seeds, total labor, and nutrients, keeping all other variables constant, could increase the gross return of rice by 2.97%, 2.19%, and 0.62%, respectively. The sum of coefficients was 0.56, reflecting a decreasing return to scale. Thus, a 100% increase in expenditure on variables presented in the model caused a 56% increase in the gross return of rice production. The findings suggest that human and bullock labor needs to be replaced by the use of farm machinery. Hence, the cost of cultivation would be reduced with the improvement in production and the gross returns of rice cultivation.

Soil Organic Carbon Dynamics in Two Rice Cultivation Systems Compared to an Agroforestry Cultivation System

After changes in tillage on croplands, it is necessary to assess the effects on soil organic carbon (SOC) dynamics in order to identify if soil is a sink or emitter of carbon to the atmosphere. This study was conducted in two plots of rice cultivation, where tillage and water management changes occurred. A third plot of native forest with Cacao trees was used as reference soil (agroforestry). For SOC balance estimation, measurement of organic carbon (OC) inputs was determined from necromass, roots, microbial biomass, and urea applications. CO2 and CH4 emissions were also measured. Results showed that the change in the use of irrigation and tillage in rice cultivation did not cause significant differences in OC inputs to soil or in outputs due to carbon emissions. Further-more, it was found that both irrigation and tillage management systems in rice cultivation com-pared with agroforestry were management systems with a negative difference between OC inputs and outputs due to CO2 emissions associated with intense stimulation of crop root respiration and microbial activity. The comparison of SOC dynamics between the agroforestry system and rice cultivation systems showed that an agroforestry system is a carbon sink with a positive OC dynamic.