Environmental potential for crop production and tenure regime influence fertilizer application and soil nutrient mining in soybean and maize crops

LEGUIZAMÓN, YAMILA; GOLDENBERG, MATÍAS G.; JOBBÁGY, ESTEBAN; SEPPELT, RALF; GARIBALDI, LUCAS A.

AGRICULTURAL SYSTEMS

ELSEVIER SCI LTD

Año: 2023 vol. 210

0308-521X

CONTEXT: Differences in land tenure regimes are one challenge to implementing soil conservation practices inagricultural systems. It is frequently assumed that tenants are less likely to adopt soil conservation strategies thanowners, given a shorter-term engagement with the field. Also, the field’s environmental potential (i.e., potentialfor agricultural production) may influence farmers’ investment decisions, since high-potential fields increase thechances of achieving a return on the investment.OBJECTIVE: Understand the effect of land tenure regimes and environmental potential on fertilization rates andbalance of nitrogen, phosphorus, and sulfur in soybean and maize crops in Argentina.METHODS: We applied mixed-effects models on a database of 52,588 fields of soybean and maize farms, coveringa total area of 3.8 M ha in Argentina during the period of 2017–2022. RESULTS AND CONCLUSIONS: Overall, the balance of nitrogen, phosphorus, and sulfur was (mean ± SE) − 29.11± 0.15, − 2.58 ± 0.38, and 8.26 ± 0.044 kg ha− 1 yr− 1, respectively. Despite 8.04 and 0.63 kg ha− 1 yr− 1 morenitrogen and phosphorus were applied in high-potential compared to low-potential maize fields, nutrient outputswere still higher. Therefore, net nutrient exports of the most productive fields increased by 9.99 and 2.06 kgha− 1 yr− 1 for nitrogen and phosphorus, respectively. In soybean fields, environmental potential had no effect onnutrient application, but the net export of nitrogen and phosphorus was 9.85 and 2.14 kg ha− 1 yr− 1 higher inhigh-potential fields compared to low-potential fields. Tenure regime had a weak effect, mainly on phosphorus.On average, owners applied 0.37 kg ha− 1 yr− 1 more and exported 0.28 kg ha− 1 yr− 1 less phosphorus than tenantsin both crops. Sulfur application and balance were weakly affected by the studied variables, and the positivebalance suggests overfertilization under the assumptions of this paper. We conclude that the Argentine farmingsystem depletes some of the main nutrients, regardless of the field’s environmental potential or the land tenuresystem. The effect of the tenure regime is overwhelmed by the impact of environmental potential on farmers’fertilization management, with high-potential fields degrading due to soil mining at a faster pace than lowpotential fields, putting future yields at risk.SIGNIFICANCE: By exploring a farming system based on nutrient depletion, our results contribute to the generalunderstanding of tenure regime consequences on soil degradation. Argentinean farmers should considerincreasing N and P application and contemplate environmental heterogeneity to avoid nutrient mining anddegradation of one of the most productive areas of the world.