Yield of Williams Hybrid Banana in Relation to Fertility, Plants Size and Climate

Bananas (Musa asuminata cv. 'Williams Hybrid') were grown continuously for over seven years from an original planting under 48 levels of nitrogen and potassium fertilization (6N x 8K) in a continuous function design with eight replicated blocks. Total production of untrimmed bunches ranged from 33 mt/ha/yr (zero N, moderate K) to 101 mt/ha/yr (high N, high K) over all years. Response to N was observed each year, primarily due to increased numbers of pseudostems in high N treatments. Average bunch weight differences due to K were clear only after 4 years. Average bunch weight decreased over time in all treatments but increased numbers of bunches were harvested each year. Depressions in total yield which occurred in most treatments were due to production of smaller bunches resulting most likely from increased density, soil compaction and diseases. Bunch weight and components of yield were related to climate up to 8 months prior to harvest. Bunch weight was not closely correlated with concentration of N or K in the plant at harvest, but total uptake of N and K were related to the size of pseudostems. Bunch weight was closely related to the size of the pseudostem, as measured by height and girth at bunch emergence and to the size of the leaves sampled at harvest. Equations relating bunch weight to pseudostem measurements were modified by N and K fertilization status, climate and crop age. Reductions in bunch weight occurring relative to pseudostem size were determined to be due to reduced leaf area caused by poor nutrition, high density and diseases. A survey of commercial banana plantings showed that variations in pseudostem size of 3 cultivars was not closely related to levels of plant and soil nutrients, probably because of widely varying irrigation, disease levels and other management practices