Phosphorus Fertilizer Solution Distribution in the Band as Affected by Application Variables1
- B. Eghball and
- D.H. Sander2
Phosphorus fertilizer applied with the seed or knifed into the soil as a band application has been shown to be more effective than broadcast P. Several experiments have shown that P fertilizer applied as a band becomes increasingly superior compared with broadcasting P as the P rate increases to the optimum rate. Phosphorus distribution in the band was judged to be a potential contributing factor. Therefore, an experiment was conducted to determine the distribution of P fertilizer solution in the band as affected by P rate and band spacing. A solution applicator was utilized to deliver fertilizer solution as ammonium polyphosphate (10-15-0, N-P-K) to application knives set about 3 cm above the surface of a catch paper. The fertilizer solution was placed on the paper and the distribution of the fertilizer droplets was measured. Knife spacings of 30, 45, 60, and 75 cm along with four P rates (7.5, 15, 22.5, and 30 kg ha−1), five traveling speeds (1.6, 2.6, 4.5, 7.1, and 9.8 km h−1), and three delivery tube sizes (0.9, 1.1, and 1.5 i.d.) were used. The results indicate that at lower rates the P solution is not distributed as a continuous band but rather as droplets of different sizes. At 7.5 and 15 kg P ha−1, the band consists of droplets at all banding spacings. Continuous bands of solution were formed at 22.5 and 30 kg P ha−1 at spacings >40 and 50 cm. Traveling speed affected the distance between droplets. The greater the speed the smaller the distance between the droplets. The increasing superiority of banding compared with broadcasting as the P rate increases may possibly be explained by the distribution of droplets in the band, where a continuous band may provide greater opportunity for the roots to utilize the fertilizer. When droplets are widely scattered, many droplet-root contacts are necessary to supply adequate P to the plant, but in a continuous band, only one contact may be sufficient for root uptake of adequate P if the roots continue to proliferate along the continuous P fertilizer band.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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