NUTRITIONAL STATUS AND ROOT SYSTEM OF ANNA APPLE UNDER ALCALINE SOIL IN A WARM DRY CLIMATE OF MEXICO.

Trees were 5 yr-old on MM106 and Seedling rootstock, spaced 5×2 m and 5×5 m respectively, and flood irrigated on a deep sandy loam soil. Levels of foliar N, P, K, Zn and Cu were progressively lower as the season advanced, although no depletion occurred by december when trees were chemically defoliated. Mg, Ca, Mn, Fe and Cl, increased their levels as the season went by, but declined unexpectedly from mid-summer onwards, except Na, possibly as an effect of high soil temperature and water shortage. Comparing rootstocks, only Mg and Mn were found higher in Anna/MM106 than on Seedlings, while between cultivars Anna had more P and Mg than Dorsett Golden.

Root distribution was evaluated on observational trenches, dug every 40 cm from the trunk in a triangle pattern over the row, and at every 20 cm horizons down to 1.2 m depth. Considering total number of roots, more than twice (1117 vs 524) were found on Seedlings than on MM106 rootstock. About 50% of total MM106 roots were on 0–40 cm depth, while on Seedling 40% were between 40–80 cm. Horizontally there were more roots away from trunk, being highest at 1.2–1.6 m.

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