Variation in foliar nutrient status in relation to leaf age, position and sample size in sapota

Abstract

There has not been much research on variation in foliar concentration of nutrients in sapota as affected by leaf age, position and sample size of leaves. Standardized leaf sampling technique forms the basis for fertilizer recommendation in fruit crops. Therefore, in the present study, the effect of leaf age, position of leaves on the shoot and leaf sample size on the nutrient status of sapota cv. Cricket ball was studied. The leaf age and position of leaves on the shoot significantly influenced the leaf mineral composition. It was found that N, P, K, Zn, Cu contents decreased, whereas Ca, Mg, Fe and Mn contents increased with increasing leaf age. The N, P, K and Cu contents decreased from apical to basal leaves while Ca, Mg, Fe and Mn contents were more in the basal and middle leaves. The effect of position of leaves on Zn content remained non significant. The different sample sizes taken in the experiment did not exert significant effect on the mineral content of leaves except for Fe and Mn which increased with the sample size, however, the difference between 40 and 60 pairs of leaves was non significant. The interaction effect of position of leaf with sample size was significant for Fe, Mn and Cu while that between leaf age and position of leaves affected Cu content only. The results provide important information that the concentration of different nutrients changed with age, position on the shoot and sample size of sapota leaves. The data may be valuable for proper assessment of nutritional status of sapota plants and in the formulation of fertilizer doses eventually.