Productivity in the peanut under salt stress in soil with a cover of plant mulch

- Peanut cultivation in the northeast of Brazil has been badly a ff ected by salts accumulating in the irrigation water; in this respect, the use of plant mulch is one way of mitigating salt stress. The aim of this study was to evaluate the e ff ect of irrigation using brackish water under di ff erent mulching strategies on productivity and water use e ffi ciency in the peanut. The experiment was carried out under fi eld conditions in Redenção, in the state of Ceará, in a randomised block design of split-plots with fi ve replications, in which the plots corresponded to two levels of electrical conductivity of the irrigation water (0.8 and 4.0 dS m -1 ), and the subplots to six mulching strategies based on the phenology of the crop (MS1: mulch throughout the cycle; MS2: fl owering stage; MS3: appearance of the gynophore; MS4: pod formation; MS5: fi nal fl owering stage; MS6: no mulch). The following were determined at the end of the experimental cycle: commercial, non-commercial and total number of pods, number of grains per pod, pod length and diameter, productivity and water use e ffi ciency. Irrigation with lower-salinity water, together with mulching during the phenological stages of the peanut, a ff ords better productive performance and greater water use e ffi ciency. Salt stress reduced the length and diameter of the pods and had a negative e ff ect on productivity and water use e ffi ciency, both with and without the use of plant mulch during the phenological stages.