Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Fluid Journal 1999-2001
2 Fluid Journal Fall 2000 where it is not likely to become immobilized. Potassium. Additional K treatments had no significant effect on grain yield. These results agree with earlier research showing banded K increased grain yield in soils with low soil exchangeable K levels but had no Table 1. Average monthly air temperature for 1993-1995 growing seasons near Pierre, SD, Riedell, et al. Mo nth 1993 1994 1995 .............oF............ May 586355 June 657067 July 717275 August 717176 effect when soil K levels were high. The lack of significant fertilizer placement x additional K two--way interactions or fertilizer placement x additional K x year three-way interactions suggest that K treatments did not interact with N and P to affect grain yield during our experiments. hoot con e tr ion Sh c cntraton Shoot concentration Shoot concentration Shoot concentration Nitrogen. Plants grown under additional K fertilization had significantly higher shoot N concentration at the tassel development. Shoot mineral nutrient concentration is a single-point measurement that results from the integration of mineral nutrient absorption and dry matter accumulation. Because mineral nutrient absorption and dry matter accumulation are dynamic processes, increase in shoot N concentration could result if a positive factor increased N absorption, or a negative factor decreased dry weight accumulation. Our data suggest that a negative factor (a detrimental effect of the additional K on shoot dry weight accumulation) was responsible for the higher N concentration from the additional K applied. The fact that additional K had no significant effect on total N accumulated by the shoot supports this contention. Phosphorus. Additional K decreased shoot P accumulation but had no significant effect on K concentration or accumulation when measured at the tassel stage. Such a decrease in P accumulation would result if some negative factor decreased shoot dry weight accumulation or decreased shoot P concentration. Our data show that dry weight was decreased by additional K while shoot P concentrations were not significantly affected. This suggests that reduced P accumulation probably was related to decreased shoot dry weight accumulation from additional K. Root pull Root pull ot ll Ro pul Root pull Fertilizer placement significantly affected root pull resistance (force needed to pull root from ground) at the tassel stage. Placing N in a 2 x 2 band and P with the seed produced plants with greater root pull resistance than that banded or surface applied. Figure 2 shows how root systems are much smaller when N and P are surface applied, compared to P with the seed and N in a subsurface band. Earlier research has shown that surface banding P results in stratification of high levels of P within the top 1.6 inches of the soil profile, while inches of the soil profile, while subsurface banding of P results in highest soil P levels in the region of the soil directly Figure 2. Effect of N and P starter placement on root proliferation, Riedell, et al. , Brookings, SD.
Fluid Journal 1996-1998
Fluid Journal 2002-2004