Evolution and current state of soybean production in northwestern Argentina

DEVANI, M.R.; PEREZ, D.; LEDESMA, F.; PLOPER, L.D.

Durban

Congreso; World Soybean Research Conference IX (WSRC IX); 2013

Protein Research Foundation

The region known as northwestern Argentina (NWA) is located between Latitude 22º and 29º South and Longitude 63º and 68º West, and includes the subtropical provinces of Tucumán, Salta, Jujuy, Santiago del Estero, and Catamarca. In the 2010/11 season, 5,094,549 t of soybean were produced in this region in a 2,019,353 ha area, which amounts to a 2.5 t/ha average yield. Thanks to research work, adoption of technologies by farmers, and the increasingly high prices recorded in the last decades, soybean production, planted area, and average yields in NWA, grew at average annual rates of 17%, 15% and 1.72%, respectively. The objective of this study was to analyze soybean production evolution in NWA from 1970/71 through 2011/12. Commercial soybean production in NWA dates back to the late 1960s. From then onwards, production systems have experienced substantial changes in almost all crop management aspects: tillage practices, use of different maturity groups and cultivars, nutrition, pest control, seed production etc. During the 1970s and 1980s, decreasing soil structural stability and soybean monocropping in NWA caused soil degradation. In the 1990s no-tillage reduced erosion, improved soil water content and yields, and reduced production costs. Since early 2000s, more than 99% of soybean planted area has been under no-tillage systems and transgenic glyphosate-resistant cultivars with yield potential have been planted. But monocropping has become widespread, with negative consequences. All these practices have changed the complex of pests, weeds, and diseases which affect the crop. Distribution of cultivars available in the 1980s was stable, using mainly maturity group (MG) VIII (70%) and MG IX (30%). In the late 1990s, due to disease problems, environment changes, new tillage practices, and transgenic soybean planting, soybean cultivars were replaced and MG distribution started changing. Distribution of MG in NWA for the 2011/12 season was MG VIII: 70%; MG VII: 10%; MG VI: 10%, and MG V: 10%. MG VIII cultivars have shown the highest stability and yields through the last 15 seasons. Currently, the most important pests that attack the crop are: a complex of curculionids (Sternechus pingui, Promecops carnicolis, and Rhyssomatus subtilis), cutting worms, caterpillars (Anticarsia gemmatalis, Rachiplusia nu, Pseudoplusia sp.), and a complex of stink bugs. Main pathogens in the region are Fusarium spp., Cercospora sojina, Macrophomina phaseolina, Septoria glycines, Cercospora kikuchii, Corynespora cassiicola, Phomopsis spp. and Sclerotinia sclerotiorum. The continuous use of glyphosate has changed weed population, so resistant weeds like Sorghum halepensis, Echinocloa colona, and Amaranthus sp. have appeared. Soybean production growth in NWA has been the result of intensive research work and farmers’ investment in technologies to improve yields and accelerate planting and harvesting. The complex of pests, weeds and diseases affecting soybean is changing. Therefore, constant prevention and monitoring become essential tools to control them. In NWA, techniques to increase soil water content, such as no-tillage, and rotation practices are essential.