Response of Corn and Cotton to Starter Phosphorus on Soils Testing Very High in Phosphorus

Abstract

A gronomy J our n al • Volume 10 0 , I s sue 3 • 2 0 0 8 537 ABSTRACT Phosphorus from agricultural lands poses a problem in water resources. In 2003, more than 48% of soil samples submitted to the North Carolina Department of Agriculture and Consumer Services (NCDA&CS) soil testing laboratory tested very high in soil P (>120 mg dm -3 P). As soil test P increases, off -site P loss increases, through erosion, soluble P runoff , or leaching. On soils testing above high soil test P (60-120 mg dm -3 P), studies from the northeast and midwest United States demonstrate that no corn (Zea mays L.) or cotton (Gossypium spp.) yield response from additional fertilizer is expected. However, there have been limited studies on the eff ects of starter-P fertilizer on soils with very high P status in North Carolina and the southeast. Th erefore, we undertook a study in the three physiographic regions (coastal plain, piedmont, and mountains) of North Carolina to determine if the use of starter-P fertilizer would aff ect the growth of corn and cotton on soils having very high soil test P. Treatments were starter N and P, and starter N only. Treatment diff erences were not observed for corn, while the N-only treatment had greater tissue N than the N-and P-starter treatment in Piedmont cotton. Additionally, the use of only starter-N is typically more cost eff ective than using both N and P starter fertilizer. For production, environmental, and economic reasons, starter-P fertilizer is not warranted on North Carolina fi elds with very high soil test P values.

Reducing carbon: phosphorus ratio can enhance microbial phytin mineralization and lessen competition with maize for phosphorus

“…applying a small amount of uniformly mixed fertilizer and placed fertilizer which also contains inorganic P, is widely used in crop production to ensure good seedling establishment and, ultimately, crop yield (Costigan 1984;Cahill et al 2008). These P fertilizers are able to not only increase soil available P but also subsequently decrease the ratio of C:P in the rhizosphere.…”

“…Starter P fertilizer technology, applying a small amount of inorganic P fertilizer near the seed, is widely used in crop production to ensure good seedling establishment and, ultimately, crop yield (Costigan 1984;Cahill et al 2008). The applied P fertilizers increase soil available P for plants (Attar et al 2012;Djodjic & Mattsson 2013) and subsequently decrease the C:P ratio in the rhizosphere.…”

“…In addition, increasing soil available P can also directly (DeForest et al 2012) or indirectly affect the C:P ratio by reducing the amount of carbohydrates released per unit of plant root (Schilling et al 1998), which influences the activity of MBP and soil P turnover in the rhizosphere. However, previous studies have mainly focused on the direct function of inorganic P in improving plant P nutrition (Bittman et al 2006;Cahill et al 2008), neglecting its effects on inducing organic P mineralization and utilization by plants roots mediated through soil bacteria. The aim of this study was to investigate the effect of reducing the C:P ratio in the rhizosphere by adding a small amount of inorganic P on plant P uptake from phytin, which is the main form in the soil organic P pool.…”

Fertilizer Use in Regulated River Basins: Is it What We Think?

“…The mean and weighted mean for soil test P for the Tar‐Pamlico River Basin (Figure ) were always above the critical soil test levels of 60 mg dm −3 ; at this level crops do not need additional P (Cahill et al ; Hardy et al ). In the Jordan Lake Watershed 85 percent of all fields needed additional P fertilizer.…”

Evaluation of an Organic Copolymer Fertilizer Additive on Phosphorus Starter Fertilizer Response by Corn

“…Plénet and Lemaire (14) reported N concentrations in corn shoots of 0.75 to ~3.75% as a function of aerial dry matter accumulation of corn from emergence to silking across six N treatments in France. Cahill et al (2) reported corn grain tissue N values of approximately 3.0 to 5.0% and P values of 0.25 to 0.40%. These percentages are similar to, or less than, the values seen in our study, indicating that plants were not N or P deficient.…”