Sustainability indicators in irrigated rice farming

A projection of population growth to 10 billion people in 2050 and the consequent increase in food demand, combined with concerns regarding conservation of the environment and biodiversity, highlight the importance of increase production vertically in a sustainable manner. Productivity irrigated rice potential in southern Brazil is 14.8 t/ha (figure 1), or that is, productivity defined exclusively by the concentration of CO2 in the atmosphere, temperature, radiation and genetics. However, productivity economically sustainable achievable is around 80% of the potential productive. In this scenario, the current average productivity is 8.2 t ha-1, thus, there is a productivity gap of 3.6 t ha-1, which being closed through sustainable intensification, would result in the production of over 3.5 million tons of rice produced in the same arable area, or, 411 thousand hectares would be avoided from expansion.

In that sense, in order to increase the profitability and sustainability of the system and the rice productivity, soybeans emerge as a rotation alternative, increasing rice productivity by 26%, reducing the use of inputs such as nitrogen fertilizer by 4%, and labor by 27%. Thus resulting in a 30% reduction in production system costs. In view of this, it is It is important to determine the sustainability that this system presents in in relation to the absence of rotation, such as the reduction in the use of herbicides, soil disturbance, among other agricultural practices, thus reducing impacts the environment, and also the costs.

Rice Money Maker Sustainability Championship

Front the need to classify the level of sustainability of rice crops irrigated in different production systems, for example with rotation or not, the Rice Money Maker Championship appears, which aims to evaluate the sustainability of rice crops in areas where there is a great expansion of soybeans in areas cultivated with irrigated rice, such as southern Brazil, Argentina and Uruguay. It arises not only to identify the most sustainable systems and management, but also to carry out producer-to-producer technology transfer, since There are producers from different rice-growing countries in Latin America. The participation of producers occurs through a diagnosis based on a database of management and agricultural practices of more than 600 crops monitored since 2015, where producers who are moving towards production are invited sustainable. In the first edition held in the 2021/22 harvest, 15 participated producers in Argentina, Brazil and Uruguay (figure 2).

To the crops are monitored from sowing to harvesting together with its audit. Through questionnaires applied to the producer, collected data on the property, producer, management, inputs and practices agricultural areas in the area, used to calculate sustainability indicators. At the end of the championship, results are delivered to producers, as well as such as the visit to the champion crop.

Crop sustainability indicators

A methodology used throughout the championship, aims to use indicators of sustainability to classify the level of sustainability of crops. To the Over the years, indicators have come to be considered the most important for the assessment of sustainability in the economic, social and environmental.

 Through sustainability indicators of the production system, it is possible to develop management strategies based on management practices that present greater efficiency in the use of resources, lower impact on the environment and greater economic profitability in the irrigated rice production. The best metric for sustainability is quantifying the efficiency of use of input inputs to the crop, such as productivity per unit input of energy, nutrients and per impacts on a wide range of ecosystem services. In this sense, the figure 3 presents some indicators used in the construction of the index of sustainability.

The economic sphere addresses profitability and production efficiency depending on the potential of productivity. Productive potential is conceptualized as maximum productivity end of a given culture in a certain region, and is defined by the intercepted radiation, CO2, water, temperature and genetics under a context free from biotic and abiotic stresses. The potential is estimated through of direct methods (field experiment under potential conditions) or indirect methods (mathematical models). In the championship crops, the SimulArroz model was used which is a mathematical model based on processes and developed to simulate the rice growth, development and productivity.

Profitability is determined by the costing method variable. To apply the method, it is necessary to collect, interpret and analysis of data only related to the variable costs of farming. You fixed costs are related to the structure of the organization and not to production; already variable costs are those arising from agricultural production. Therefore, to determine profitability, production costs and net economic return (i.e. gross income minus production costs). For each crop, revenue and costs are calculated based on data reported by the producer on productivity, inputs and prices.   

The environmental sphere considers efficiency in the use of nutrients, the environmental impact quotient and the efficiency in CO2 emissions. Nutrient efficiency allows us to diagnose crops rice crops, in relation to nutrition, since each nutrient has an ideal range of efficiency. Efficiencies below or above this range indicate application in excess fertilization, or occurrence of soil mining, respectively. A CO2 emission efficiency considers the amount of CO2 emitted to produce one kilo of paddy rice grains, considering diesel, seeds, fertilizers and agricultural pesticides, and is estimated through factors conversion rate for each type of input. The environmental impact ratio of agricultural pesticides, based on the concentration of the product and dose used, considers the impact of active ingredients in three spheres: applicator (farmworker), consumer and ecological.

A social sphere considers some criteria related to the profile of each producer and their families, such as family succession and the form of acquire knowledge, as well as how these factors interfere in the management of their crops.

Assigning given weight on each indicator, there is the sustainability index that will classify how sustainable crops are, based on social levels, environmental and economic (figure 4). In this context, the main objective of sustainability index is to boost the development of a Seal of Sustainability that adds value to rice from areas that have reached a sustainable level of production.

Camille Flores Soares, UFSM; Michel Rocha da Silva, Crops Team Consulting; Giovana Ribas, GDM Seeds; Enzo Pilecco Sonego, UFSM; Raul Moraes dos Santos, UFSM; Kátia Mileni Manzke, UFSM; Lorenzo Dalcin Meus, UFSM; Anderson Haas Poersch, UFSM; Alexandre Ferigolo Alves, UFSM; Bruna San Martin Rolim Ribeiro, UFSM; Enrico Fleck Tura, UFSM; Alencar Junior Zanon, UFSM