Performance of the AquaCrop model in the climate risk analysis and yield prediction of cowpea (Vigna Unguiculatta L. Walp)

Abstract

The present work evaluated the Aquacrop model as a tool for climate risk analysis and yield prediction of cowpea, cultivated in a dystrophic yellow oxisol. The model was previously calibrated and validated for two harvests, in order to simulate the biomass and yield of cowpea, considering four applied water blades over its reproductive period. The good achieved results prove the model’s efficiency for this kind of simulation. After validation, the yield simulation of cowpea based on the meteorological data (2003 to 2014), soil and crop management of 12 harvests was performed. Two scenarios were given: the potential yield without water restrictions; and the actual yield, considering to pluvial availability conditions of the inserted series. The results suggested that the optimum sowing dates are between April 1st and 20th, in which there was a low yield loss (< 10 %) considering the potential yield, high probability (> 90 %) of achieving high yields (above 1300 kg ha-1) and a low risk of getting crop harvesting in the rainy period. After all, the model proved to be a feasible tool for predicting cowpea yield in the region and also over regions with similar characteristics.

Cowpea Ecophysiological Responses to Accumulated Water Deficiency during the Reproductive Phase in Northeastern Pará, Brazil

“…Bastos et al [21] observed a reduction of 60% in the productivity levels (grain yields) studying cowpea genotypes under water deficiency. Similar results were found by Hayatu and Mukhtar [5] and Nunes et al [10] that found reductions of 21.38%, 36.12% and 49.50% in treatments under water restriction. Souza et al [4] found significant reductions in the productivity of this cultivar when it was submitted to rainfed conditions, corresponding to a reduction of 41% under water deficiency of 26 mm, and 72% under a deficiency equal to 76 mm.…”

“…All sensors were connected to a CR10× datalogger (Campbell Scientific, Inc., Logan, UT, USA), configured for reading every ten seconds, recording total and average values every ten minutes. To quantify the deficiencies caused by treatments subjected to water deficit, the sequential water balance was carried out according to Carvalho et al; for more details, see in Nunes et al [10]. Accumulated soil water deficiency was obtained as a cumulative difference between daily ETc and daily actual evapotranspiration.…”