Teff (Eragrostis tef) dry matter yield, nutrient uptake partitioning, and nitrogen use efficiency indices affected by nitrogen rate under balanced fertilization

Teff [Eragrostis tef (Zucc.) Trotter] has gained high demand and popularity across the world in recent years. Data on nutrient uptake and partitioning and nitrogen use efficiency (NUE) indices of teff under balanced fertilization are scarce. A greenhouse experiment was conducted to study the effect of six different nitrogen (N) rates (0,25,50,100,150,200 mg N kg−1) on the agronomic performance of teff. These treatments were arranged in a Complete Randomized Design with four replicates. Aboveground dry matter N and phosphorus (P) uptake increased with an increasing N rate, while potassium (K) uptake increased up to 50 mg N kg−1 and then started to decline. The dry matter yield followed the order straw > grain > roots. N uptake followed the order grain > straw > roots. P uptake also showed significant (p  straw > roots. Most of the K was taken up by straw, followed by grain and roots. N fertilization had a significant (p < 0.001) effect on grain protein, N partial factor productivity and NUE of teff. Differences in N harvest index, N recovery efficiency, N agronomic efficiency, and N agrophysiological efficiency were not statistically significant due to the N rate. Nitrogen rates of 100 mg kg1 gave an optimal NUE for teff. However, the application of 150 mg kg1 N rate resulted in the highest grain yield. Additionally, the results indicated a negative correlation between yield and NUE. In summary, our findings suggest that applying 150 mg kg N−1 to teff could be considered a beneficial nitrogen fertilization practice. This approach enhances yield, nutrient uptake, and various traits related to nutrient use efficiency, thereby elevating teff’s importance as both a food and feed crop

Improving rice models for more reliable prediction of responses of rice yield to CO2 and temperature elevation

Improving rice models for more reliable prediction of responses of rice yield to CO2 and temperature elevation . International Crop Modelling Symposiu

Causes of variation among rice models in yield response to CO2 examined with Free-Air CO2 Enrichment and growth chamber experiments

Abstract The CO2 fertilization effect is a major source of uncertainty in crop models for future yield forecasts, but coordinated efforts to determine the mechanisms of this uncertainty have been lacking. Here, we studied causes of uncertainty among 16 crop models in predicting rice yield in response to elevated [CO2] (E-[CO2]) by comparison to free-air CO2 enrichment (FACE) and chamber experiments. The model ensemble reproduced the experimental results well. However, yield prediction in response to E-[CO2] varied significantly among the rice models. The variation was not random: models that overestimated at one experiment simulated greater yield enhancements at the others. The variation was not associated with model structure or magnitude of photosynthetic response to E-[CO2] but was significantly associated with the predictions of leaf area. This suggests that modelled secondary effects of E-[CO2] on morphological development, primarily leaf area, are the sources of model uncertainty. Rice morphological development is conservative to carbon acquisition. Uncertainty will be reduced by incorporating this conservative nature of the morphological response to E-[CO2] into the models. Nitrogen levels, particularly under limited situations, make the prediction more uncertain. Improving models to account for [CO2] × N interactions is necessary to better evaluate management practices under climate change