Florida Histosols Research Articles

Row-spacing and cultivar effects on sugarcane growth and yields in Florida histosols

Sugarcane (Saccharum spp. hybrids) is a major row crop in Florida. The effect of row-spacing on total row length per hectare can significantly effect the cost of major farm operations, including planting, harvesting and fertilizer application. In Florida, sugarcane is commonly planted at 1.5 m row-spacing. There is little information available on the effect of relatively narrow or wide spacing on the growth and yield of sugarcane, especially in new high-biomass cultivars. To determine sugarcane growth response to different row-spacing, a field trial was conducted in organic soil (Histosols) with four different row-spacings (1.2, 1.5, 1.8 m and a double row on a 1.5 m bed) and three sugarcane cultivars (CP 96-1252, CP 00-1101 and CP 01-1372). Data showed differential row-spacing effects on plant cane versus the first ratoon. In plant cane, depending on the cultivar, double row and 1.2 m spacing produced 17–46% and 23–42% greater sugar yield per hectare (TSH) than the current 1.5 m spacing, respectively. Overall, the combined average TSH of plant cane and the first ratoon in double and 1.2 m spacing was 20% and 26% greater than 1.5 m spacing. However, the yields in 1.5 m and 1.8 m row-spacing were similar. There was no significant effect in the first ratoon. There was no row-spacing effect on sucrose concentration. A similar response of cultivars to the tested row-spacings suggests that selecting cultivars for different row-spacings may not potentially show any yield improvements. Compared to the current 1.5 m spacing, narrow-spacing (1.2 m and double row) may potentially increase yields and wide (1.8 m) spacing reduce the production cost but further research is needed to understand the economic feasibility of different row configurations.

Low levels of arsenic and cadmium in rice grown in southern Florida Histosols - Impacts of water management and soil thickness

Rice is planted as a rotation crop in the sugarcane-dominant Everglades Agricultural Area (EAA) in southern Florida. The Histosols in this area are unlike other mineral soils used to grow rice due to the high organic content and land subsidence caused by rapid oxidation of organic matter upon drainage. It remains unknown if such soils pose a risk of arsenic (As) or cadmium (Cd) mobilization and uptake into rice grain. Both As and Cd are carcinogenic trace elements of concern in rice, and it is important to understand their soil-plant transfer into rice, a staple food of global importance. Here, a mesocosm pot study was conducted using two thicknesses of local soil, deep (D, 50 cm) and shallow (S, 25 cm), under three water managements, conventional flooding (FL), low water table (LWT), and alternating wetting and drying (AWD). Rice was grown to maturity and plant levels of As and Cd were determined. Regardless of treatments, rice grown in these Florida Histolsols has very low Cd concentrations in polished grain (1.5–5.6 μg kg−1) and relatively low total As (35–150 μg kg−1) and inorganic As (35–87 μg kg−1) concentrations in polished grain, which are below regulatory limits. This may be due to the low soil As and Cd levels, high soil cation exchange capacity due to high soil organic matter content, and slightly alkaline soil pH. Grain As was significantly affected by water management (AWD < FL = LWT) and its interaction effect with soil thickness (AWD-D ≤ AWD-S ≤ FL-D = LWT-S = LWT-D ≤ FL-S), resulting in as much as 62 % difference among treatments. Grain Cd was significantly affected by water management (AWD > FL > LWT) without any soil thickness impact. In conclusion, even though water management has more of an impact on rice As and Cd than soil thickness, the low concentrations of As and Cd in rice pose little health risk for consumers.

Nitrogen management of shallow Florida histosols for sugarcane production

Sugarcane production in Florida occurs mainly in artificially drained Histosols of the Everglades Agricultural Area (EAA). Nowadays, the nitrogen (N) mineralization of these soils is the main source of N to the plants, however, depending on environmental conditions and the restricted soil depth of these organic soils, N availability might be limited for crop establishment and growth. The aims of this study were to analyze N concentration in sugarcane leaf and in the soil, while evaluating the influence of external N input application on sugarcane yields and sugar content, to determine the effectiveness of the current N recommendations for shallow organic soils of the EAA. To address the issue, a small plot trial was conducted in the 2017/2018 crop season, in two commercial sugarcane fields in south Florida Histosols. The experiment consisted of gradual increasing doses of N from control, 56, 112 and 168 kg N ha−1 year, applied as ammonium nitrate. We evaluated N levels in the soils and the leaves, chlorophyll index (SPAD) measurements, and sugar and biomass yields. Our results indicated that the N application did not affect the N leaf concentration and yield components did not have any improvement with N application. We concluded that the current recommendation of no N application is still accurate for these shallow soils, since the N mineralization is still sufficient in the supply of the nutrient.

Nitrogen Assessment of Shallow Florida Histosols

ABSTRACT The soils of the Everglades Agricultural Area (EAA) are mainly organic soils (Histosols), and their artificial drainage promoted aeration and resulted in soil subsidence. Sugarcane (Saccharum spp.) nitrogen (N) requirement has been fulfilled historically by organic matter mineralization, so very shallow soils could be limiting N availability for the crop. The objectives of this study were to measure sugarcane leaf N concentration and levels of available N across EAA organic soils with variable soil depth and then determine if there are relationships among soil depth, soil N concentration, and sugarcane leaf N concentration in Florida Histosols. A total of 60 plots were established in 30 commercial sugarcane fields in the EAA with soil depth varying from 15 to 145 cm over limestone bedrock. In each location, soil depth, soil, and leaf nutrient concentrations, and leaf chlorophyll measurements were determined during the grand growth period (June 1 – October 15) of the crop. There were no significant correlations between soil depth and either leaf N concentration or leaf chlorophyll measurements. There were positive correlations between soil water and soil NH4 +-N concentration and between soil NO3 –N concentration and leaf N concentration. Our results determined that mineralization is still providing adequate N supply for sugarcane.

Soil chemical and biological fertility, microbial community structure and dynamics in successive and fallow sugarcane planting systems

ABSTRACTSugarcane yields are declining under successive planting (monoculture) compared to other planting systems in Florida Histosols. To evaluate soil properties related to the sugarcane yield decline, an on-farm study was conducted on soil chemical, biological, and microbial indicators variation with soil samples collected from successive green cane or burnt cane harvest, flooded fallow, and rice and sweetcorn rotation planting sites. Overall, harvest residue incorporated in the soil in green cane harvest and corn rotation increased organic matter, total carbon and C:N ratios which resulted in higher microbial biomass parameters and total PLFA biomass. However, successive planting with burnt cane harvest reduced total soil carbon and hence microbial biomass. Findings suggested that these parameters should be considered for further research to determine specific causes of sugarcane yield decline in successive planting.

Effects of Nitrogen Fertilization and Seed Piece Applied Fungicides on Establishment, Tiller Dynamics, and Sucrose Yields in Successively Planted Sugarcane

Sugarcane (Saccharum spp.) successive planting causes 25–30% yield reduction in comparison to fallow or rice rotation planting in a three-year production cycle on Florida Histosols. Field experiments were established to manage the yield losses associated with successive planting through nitrogen fertilization and seed piece application of fungicides in plant and first ratoon crops each at two sites. Nitrogen fertilization treatments included 0 (N0), 50 (N50), and 100 (N100) kg ha−1 applied in furrows at the time of planting, and one split application (N50+50) with 50 kg ha−1 applied at planting and 50 kg ha−1 applied at 90 days after planting as side-dress. Fungicides treatments were mancozeb at 2.5 kg a.i. (active ingredient) ha−1, mefenoxam at 0.57 kg a.i. ha−1, and azoxystrobin at 0.30 kg a.i. ha−1 applied to seed cane pieces laid in the furrows at planting. Nitrogen fertilization showed increasing trends of the tiller and millable stalks production in plant and ratoon crops. N response varied with the time of ratooning. Overall, N50+50 produced greater tons of cane per hectare (TCH) and tons of sucrose per hectare (TSH) compared to other N treatments in plant crop and late season ratoon crop (ratooned in March). N100 treatment enhanced tillering and TCH in December ratooned crop. In 2016 plant crop, mefenoxam produced higher TCH than others, but no carryover effects were observed in ratoon crops. Both nitrogen fertilization and fungicides seem to be promising cultural practices to minimize yield losses in successive sugarcane planting in Histosols.

Minimum or No‐Tillage Improves Sugarcane Ratoon Yield on Florida Histosol

Core Ideas Tillering was better in conventional than no‐tillage in plant cane but it was opposite in second ratoon. Minimum or no‐tillage produced higher sugarcane ratoon yields than conventional tillage in Florida Histosols. Overall, in a 3‐yr crop cycle, the yields were similar in all three tillage levels. Tillage effect on yield did not vary with the varieties. ABSTRACTMinimum or no‐tillage reduces soil carbon oxidation in Histosols, however tillage effect on sugarcane (Saccharum spp.) growth and yield are not well understood. To determine the effects of tillage on sugarcane growth and yield, a 3‐yr (plant cane, first ratoon, and second ratoon) field trial was conducted in 2013–2015 with three tillage levels and three varieties (CP 88–1762, CP 89–2143, and CP 00–1101). Tillage levels were conventional tillage, CT (three pre‐planting disc passes and two post‐planting inter‐row cultivations); minimum tillage, MT (two pre‐planting disc passes and one post‐planting inter‐row cultivation); and no‐tillage, NT (no cultivation). Data were collected on Soil Plant Analysis Development (SPAD), stomatal conductance, tillering, and yield parameters. Our results showed that tillage did not affect SPAD and stomatal conductance. Tillering was better in CT than NT in plant cane but it was opposite in second ratoon. Sugarcane yield (tons of cane per hectare, TCH) and sugar yield (tons of sugar per hectare, TSH) were not significantly different in plant cane, but NT had greater TCH than CT and MT in first ratoon, and both NT and MT had greater TCH and TSH than CT in second ratoon. Tillage effects on yield did not vary with the varieties. Our results showed that NT and MT improved yields in ratoon crops with no significant effect on overall sugarcane yields in a 3‐yr crop cycle in a Florida Histosol. Therefore, tillage may be minimized or eliminated in fallow planting to improve soil sustainability without any sugarcane yield penalty in a Florida Histosol.

Influence of Elemental Sulfur on Sugarcane Yield on Histosols with Near-Neutral pH

ABSTRACTSoil subsidence of Florida Histosols caused by microbial oxidation following drainage of these soils has resulted in decreased depth. Soil pH has increased from tillage operations and vertical movement of carbonates from underlying limestone bedrock through evapotranspiration and seepage irrigation. This study was conducted to determine sugarcane (Saccharum spp.) yield response to banded elemental sulfur (S) (granular 90% S and granular 80% S with 5% manganese (Mn)) in soils with unamended pH ranging from 6.5 to 7.2. Four field experiments were established as small-plots on Histosols in the Everglades Agricultural Area (EAA). Each experiment was a randomized complete block design with six replications and elemental S rates of 0, 90, 224, and 448 kg S ha−1. Less than optimum leaf Mn at two locations were associated with Mehlich 3-extractable Mn<5 g m−3. There were no sugarcane yield responses to elemental S with unamended pH<7.2, although S significantly reduced in-row pH.Abbreviations: EAA, Everglades Agricultural Area; ICP, inductively coupled argon plasma; KSM, kg sucrose Mg−1 cane; MAP, monoammonium phosphate; M3-Mn, Mehlich 3-extractable Mn; RCB, randomized complete block; STM5, granular 80% S with 5% Mn; MCH, Mg cane ha−1; MSH, Mg sucrose ha−1

Sugarcane Yield Response to Potassium Fertilization as Related to Extractable Soil Potassium on Florida Histosols

Core Ideas Sugarcane yield responses to K fertilizer were attributable to increases in sugarcane biomass. There was reduced sucrose concentration at higher K rates in 4 of 14 crop years. Maximum K fertilizer requirement determined was 27% less than current recommendation. Soil test K limit for K fertilizer application was within 12% of the current limit. Sugarcane (Saccharum spp.) has a large K requirement and so K fertilizer can be a major cost for growers. Histosols in the Everglades Agricultural Area (EAA) of Florida are shallower with higher pH than when current sugarcane K fertilizer recommendations were established in the 1970s. This study was conducted to determine sugarcane yield response to K fertilizer as related to extractable soil K on Florida Histosols. Six small‐plot (83, 120, or 138 m2) field experiments were established as randomized complete block (RCB) designs (four or six replications) with annual K rates ranging from 0 to 279 kg K ha−1. There were significant sugarcane and sucrose yield responses to K fertilizer and these were attributable to increases in sugarcane biomass. There was evidence of reduced sucrose concentration at higher K rates in 4 of 14 crop years. Orthogonal contrasts determined significant sucrose yield response to K fertilizer compared to the zero rate in 5 of 14 crop years. Nonlinear regression determined that the acetic acid‐extractable soil K value at or above which K fertilization is not required was within 12% of the current value. Maximum K fertilizer requirement determined in the study was 170 kg K ha−1 at an acetic acid‐extractable K value of 20 g K m−3, which is 27% less than the current recommendation. Results of a previously unpublished K rate trial confirmed the results of the current study, which will be used to update K fertilizer recommendations on Florida Histosols.

Sugarcane yield and plant nutrient response to sulfur-amended Everglades histosols

ABSTRACTHigh soil pH causes leaf nutrient deficiencies and reduces sugarcane yield. Soil pH in Florida histosols has been increasing as these soils subside and depth to limestone is decreased. A factorial experiment of four sulfur (S) rates and three added calcium carbonate (CaCO3) levels in soil was designed to determine S-amendment effectiveness in reducing pH and increasing nutrient availability in sugarcane as calcium (Ca) carbonate levels were increased. Sulfur-amendment and increased CaCO3 level had limited effects on yield and leaf nutrient concentrations during the growing season. Most leaf nutrients were within optimum range except nitrogen (N), phosphorus (P), iron (Fe), and manganese (Mn). Unexpected increases in Mn concentrations with added CaCO3 were associated with reducing conditions due to increased soil bulk density. High soil pH caused Mn deficiencies in the plants. Soil pH, P and Mn concentrations were important factors in predicting sugarcane yield.

Sugarcane Response to Phosphorus Fertilizer on Everglades Histosols

Determining sugarcane (Saccharum spp.) yield response to P fertilizer supports the development of agricultural best management practices consistent with Everglades restoration efforts. Field studies were conducted on organic soils to determine sugarcane yield responses to P fertilizer. Four test sites were established on Florida Histosols (water‐extractable P = 1.3, 1.7, 2.1, and 9.0 g P m−3) with annual banded rates of 0, 9, 18, 36, 72, and 144 kg P ha−1 There were a total of 13 crop years with duration of each test ranging from 2 to 4 yr. Linear and quadratic regression and single degree of freedom contrasts were used to determine P fertilizer requirements. There were responses in t cane ha−1 (TCH) and t sucrose ha−1 (TSH) to P fertilizer application at four and three sites, respectively. Annual fertilizer P requirement at the four sites ranged from 18 to 33 kg P ha−1, with no consistent change in P requirement across crop years. Based on measured response (95% of maximum yield) in TCH and TSH up to 33 kg P ha−1, the maximum P recommendation for sugarcane grown on Florida Histosols should be maintained at 36 kg P ha−1 Minimal reductions in sucrose concentration (kg sucrose t−1 cane) were measured at P rates ≤36 kg P ha−1 Water‐extractable P did not predict the measured yield response at all sites, demonstrating the need for an updated soil test calibration that should be applicable over a wide pH range and include both quickly available and reserve soil P.

Nitrogen mineralization in histosols of the everglades agricultural area1

A long‐term soil incubation and column nutrient leaching study was conducted to determine nitrogen (N)‐mineralization rates of selected Florida Histosols with drained and intermittent‐flooded conditions. Five surface soils from the Everglades Agricultural Area (EAA) were packed in columns (5‐cm i.d. containing the 0‐ to 15‐cm depth of each soil) and leached with 0.01M CaC12 followed by distilled water every 25 d for 1 yr. Drained columns were treated with a minus‐nitrogen‐phosphorus (NP) solution followed by applying ‐0.97 MPa tension to remove excess solution. Flooded columns received the same minus‐NP solution, but were flooded to a depth of 3 cm. Both treatments were incubated for 25‐d periods, solution sampled, and treatments reapplied. Because flooding conditions could not be maintained during the sampling period, this treatment is referred to as intermittent flooded. The ammonium‐nitrogen (NH4 +‐N) released from drained soils accounted for less than 6% of the total soluble N released from all soils, compared to more than 30% released from flooded soils. There were no differences in the amounts of soluble organic N from drained and intermittent flooded soils. Total soluble N from the surface 15‐cm of drained soils ranged from 217 to 509 kg‐ha‐1yr‐1, with 50 to 67% released as nitrate‐nitrogen (NO3 ‐‐N). In contrast, total soluble N released from flooded soils ranged from 168 to 345 kg‐ha‐1yr‐1, with less than 3% released as NO3 ‐‐N.

Optimization of solution: Soil ratio and shaking times of the Mehlich‐III soil test on Histosols

Abstract The University of Florida Everglades Soil Testing Laboratory has been determining water‐extractable P in organic soils (Histosols) since 1944. The water extractant has consistently provided reliable correlations for vegetable commodities, but not for agronomic crops. Recent research has suggested that the Mehlich‐III soil test has potential for use on Histosols. However, no information indicated if solution: soil ratios (RAs) and shaking times (SHs) used for mineral soils would be appropriate for organic soils, which have appreciably lower soil bulk densities. A laboratory study with SHs ranging from 1 to 29 min and RAs ranging from 8 to 22 (v/v) arranged in a central composite rotatable design (ccd) was conducted using four Florida Histosols. Nine treatment combinations of RAs and SHs were used. Two replications of the ccd were performed with duplicate extractions for each sample. The fitted second‐degree response surface equations for P and K nutrients with surface contour plots were shown for ...

POTASSIUM AND SODIUM INTERRELATIONS IN CELERY

Recent research suggests that celery (Apium graveolens var. dulce) produced on Florida Histosols does not respond to rates of K fertilizer as high as previously recommended. The soil-test Na levels of Florida Histosols have been increasing as a result of canal dredging which has exposed saline water from shallow aquifers to mixing with surface water used for irrigation. Sand culture and field experiments were conducted to obtain a better understanding of the effect of Na on the K nutritional requirement of celery. The sand culture experiment included factorial combinations of 0, 2, 4, and 8 mM concentrations of K and 0 and 0.5 mM concentrations of Na. The field experiment was a 13 point fractional factorial with K and Na rates ranging from 0 to 400 kg ha-1. The data indicated that Na partially substituted for the K requirement of celery when K was limiting growth and yield. Interestingly, the data also suggested that optimal celery yields were obtained when some Na was present even where K was not limiting.

Nitrogen Fertilization of Radishes on Histosols: Response and 15N Recovery

Experiments were conducted from 1985 to 1989 to evaluate the response of radishes (Raphanus sativus L.) to N fertilization on Histosols. Three of these experiments used 15N-labeled fertilizer to evaluate the recovery of N by radishes. There was no response to N fertilization in seven of the eight experiments, even though some of them were conducted under conditions of high rainfall. The one experiment in which radish yields increased with N was conducted in a poorly drained, waterlogged field that was atypical of normal radish production fields. Recoveries of fertilizer N in the marketable radish roots averaged 19%. The results of N and 15N analysis showed that although fertilizer N was available for uptake, so was an ample amount of soil mineralized N. These results indicate that under typical growing conditions, radishes produced on Florida Histosols do not respond to N fertilization.

Relative Efficiency of Broadcast and Banded Phosphorus for Sweet Corn Produced on Histosols

AbstractHistosols used extensively for crop production are often hydrologically linked to environmentally sensitive wetlands, making it imperative that management strategies be developed to improve the efficiency of fertilizer P. Furthermore, sweet corn (Zea mays L.) produced on Florida Histosols is grown in rotation with sugarcane (Saccharum spp.), which responds negatively to high P. Reduction of the P rates applied to sweet corn would increase the compatibility of this common crop rotation. Studies were conducted across six site‐seasons during 1988 and 1989 to evaluate the relative efficiency of broadcast and banded P for sweet corn. Broadcast and banded P rates were 0, 25, 50, 75, and 100 kg P ha−1. Broadcast P was surface applied and disked into the soil before planting. Banded P was applied ≈3 cm below the corn seeds in bands mixed with soil in an approximate diameter of 5 cm. Sweet corn responded to P when soiltest P levels were below 1.2 g m−3. Total marketable yields, yield of U.S. Fancy, and quality parameters of sweet corn ears were increased by P rate and affected by placement in four of the six site‐seasons. Band placement reduced the amount of P required for a specified sweet corn yield and also appeared to result in higher total yield. The relative efficiency of banded to broadcast P depended on soiltest P level. The relative efficiency was greater than 3:1 (band/broadcast) when soil‐test P was &lt;0.2 g m−3 but approached 1:1 as soil‐test P increased to 1.2 g m−3. Overall, results indicate that banding P is, indeed, a viable strategy to reduce the amount of P used for sweet corn production on Histosols.

Phosphorus Application Constraints Limit Profitability of Sweet Corn and Lettuce Production

The economics of producing sweet corn (Zea mays L.) and head lettuce (Lactuca sativa L.) on Florida Histosols were analyzed with and without P application constraints based upon quadratic response functions derived from two experiments with each crop. At the lower end of the historical price range, production of both crops is unprofitable, especially when P is constrained. At higher prices, net returns for sweet corn under P constraints are relatively small compared with the capital invested; net returns are higher for lettuce. However, an analysis of historical monthly prices showed that those high prices rarely occur. Values for the marginal contribution of the last unit of P show that constraints greatly limit net returns. Many sweet corn and head lettuce producers may be forced out of business if P fertilization rates are arbitrarily lowered below the economic optimal rate.

Sugarcane Response to P, K, and DRIS Corrective Treatments on Florida Histosols1

AbstractNutritional imbalances in sugarcane (a complex trispecies hybrid of Saccharum) on Florida Histosols (Medisaprists) were suggested in earlier studies. In order to eliminate possible imbalances among nutrients, the Diagnosis and Recommendation Integrated System (DRIS) was adapted to monitor the nutritional status of sugarcane in an experiment with varying P and K levels. Standard DRIS reference norms were established for nine nutrients (N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu) in the top visible dewlap leaf laminae of sugarcane. Factorial P and K levels were applied with the seed cane at planting (January). Soil and leaf samples were collected during the grand growth period (July) and the DRIS indices for nutrients in the leaves were calculated. In order to correct nutritional imbalances indicated by DRIS indices at each PK‐treatment, each plot was split into two subplots. One subplot did not receive additional fertilizer while the other subplot was fertilized with the required nutrients as indicated by DRIS indices for that whole plot. Leaf samples were collected again close to the end of the grand growth period (end of September). Sugarcane and sugar yields were not affected by the rates of P applied at planting but were significantly affected by the rates of K applied at planting and by the DRIS treatments. The highest rate of K (560 kg/ha) reduced both sugarcane and sugar yields compared with the other rates. Plots which received 280 kg of K/ha at planting yielded significantly more cane but no more sugar than plots with 0 K at planting. Application of nutrients during the grand growth period (July) as indicated by DRIS indices significantly increased both cane and sugar yields over those obtained from plots which did not receive fertilizers in July. The DRIS indices for leaf nutrients during the grand growth period revealed that a shortage of P and an excess of K had been applied at planting, a fact which would have gone undetected by conventional nutrient level monitoring. The increase in cane and sugar yields from the DRIS corrective treatment resulted primarily from better nutrient balance as revealed by DRIS indices for leaf nutrients late in the season.

Nitrogen Mineralization in Florida Histosols

AbstractThe N‐mineralization rates of several Florida Histosols and the effects of soil moisture tension and organic C amendments on these rates were measured in the laboratory with an 15N‐tracer technique. An enhancement of microbial activity by crop residues was exhibited by greater N mineralization in cropped vs. uncropped soils. Nitrogen mineralization was not affected by soil moisture tension over the range of 0.1 to 3.0 bar. Exogenous C supplies such as glucose or St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntz] stimulated mineralization of native soil organic matter. Mineralization of soil organic N was increased by 91% in glucose amended soil samples. The N‐mineralization rate for a 75‐cm profile of Pahokee muck was estimated to be 686 kg N/ha for each centimeter of soil lost to microbial oxidation.