Nutrient-holding Capacity Research Articles

Effects of sowing dates and phosphorus levels on cotton growth and yield: soil analysis and implications

This study assessed the effects of sowing dates and phosphorus levels on cotton performance in Chato-Msilale village in Chato District, Tanzania. The soil analysis revealed that field exhibited slightly acidic soil with normal electrical conductivity but suffered from severe deficiencies in total nitrogen and organic carbon. The same field presents common issue of low cation exchange capacity, indicating limited nutrient-holding capacity. Furthermore, both fields displayed very low levels of total nitrogen (<0.1%), signaling a nitrogen deficiency. Available phosphorus was rated as medium (16.8 mg kg−1 soil). Trace elements fluctuated and could be managed based on specific crop requirements. The factors at different levels were: (1) sowing dates – (i) 25th November 2022, (ii) 15th December 2022, and (iii) 4th January 2023; and (2) Phosphorus levels – (i) control, (ii) 20 kg P ha−1, (iii) 40 kg P ha−1, and (iv) 60 kg P ha−1. Regarding cotton growth and yield, sowing dates significantly (p < 0.001) influenced plant height, gin turnout, lint yield, number of bolls per plant, and boll weight while phosphorus levels did not exhibit significant effects. Earlier sowing dates resulted in higher yields, albeit with variations in yield components. Interactions showed that growth and yields were only numerically higher in the middle sowing date at higher levels of phosphorus applied. Overall, these insights offer valuable guidance for optimizing cotton cultivation in Chato District, emphasizing the importance of selecting appropriate sowing dates for improved yields.

Impact of Cover Cropping on Temporal Nutrient Distribution and Availability in the Soil

Cover cropping is a best management practice that can improve soil quality by reducing soil erosion, building soil organic matter (SOM), and improving soil nutrient availability. Southwest (SW) Florida citrus growers have the challenge of growing citrus in sandy soils characterized by low organic matter (<2%), extremely low water and nutrient-holding capacities, and high sand content (>90%), and therefore are looking for methods to improve SOM and nutrient retention and availability in sandy soils. A trial of two cover crop (CC) mixtures planted in the row middles (RM) of Huanglongbing-affected citrus ‘Valencia’ (Citrus sinensis (L.) Osbeck) orchards in sandy soils in SW Florida was conducted. This study explored how incorporating CCs in the RM of the orchards could affect soil ammonium (NH4+), soil nitrate (NO3−), exchangeable macronutrients, and SOM temporal availability. These parameters were measured under the tree canopy (UC) and within RM of two orchards: South Grove (SG) and North Grove (NG), both located in SW Florida. The two seeded CC mixtures were legume + non-legume (LG+NL) and non-legume (NL) and were compared to a control no-CC grower standard (GSC). Phosphorus, calcium, magnesium, and NH4+ were not statistically significantly different among treatments in either of the two sampling positions (UC and RM). Cover cropping significantly (p < 0.05) increased NO3−-N concentrations in the RM area of the citrus orchards after seven consecutive seasons (brassicas, legumes, and grasses) by 31% in the LG + NL and 29% in the NL with reference to the GSC. In addition to the significant increase in NO3−N, SOM significantly (p < 0.05) increased in the RM in the NG site only in both CCs treatments by 17% and 16% for LG + NL and NL treatments, respectively, compared with GSC.

Comprehensive evaluation of effects of various carbon-rich amendments on overall soil quality and crop productivity in degraded soils

Soil degradation is a global menace to agricultural crop production. Since loss of soil organic carbon (SOC) is a significant characteristic of soil degradation and since SOC underpins nearly all critical soil functions, a broad range of C-rich amendments (CRAs) have been applied to avoid soil degradation. However, little information is available regarding how various CRAs influence overall soil quality. Here, we conducted experimental trials under field conditions simultaneously at two sites (Beijing and Ningxia; the nutrient-holding capacity was much higher in the Beijing soil than in the Ningxia soil) over two consecutive years, to investigate effects of various CRAs (i.e. straw-C, composted straw-C, and humic acid-C) on overall soil quality and tomato yields. The overall soil quality was expressed by the soil quality index (SQI) covering a wide range of soil physical, chemical and microbial properties. In general, straw-C addition enhanced SQI mainly at Beijing site through increasing soil water content and plant beneficial bacterium Myxococcota, and decreasing soil pH (alleviating alkalization). Composted straw-C addition increased SQI primarily at Ningxia site by enhancing soil porosity, nutrient availability and plant beneficial bacterium Firmicutes, and reducing soil pH, harsh environment-adapted bacteria Methylomirabilota and Gemmatimonadota, and plant fungal pathogen Basidiomycota. However, humic acid-C addition had no effect on SQI at any experimental site. The SQI showed a significant positive correlation with either root biomass or tomato yields at both sites. Together, our results demonstrate that straw-C addition is an effective method for enhancing overall soil quality and crop productivity in soils having a high nutrient-holding capacity (Beijing), while composted straw-C addition is beneficial to soils having a low nutrient-holding capacity (Ningxia).

Mounding technique improves physiological performance and yield of oil palm on Spodosols

Spodosols have been widely used for oil palm plantations, specifically in Kalimantan, Indonesia. However, they are sub-optimal for agriculture due to a lack of water and nutrient-holding capacity and a spodic layer that limits plant root development. Therefore, proper agriculture practices are needed for oil palm to enhance its potential yield. This study aims to determine the effect of the mounding technique on the physiological performance and yield of oil palms in spodosol. The study location was well-managed, with eight blocks of oil palm plantations planted in 2008 on spodosols (Typic Haplohumod) in Central Kalimantan. The mounding technique was applied to four blocks of oil palm planted in 2015, while the remaining four were left without mounding. The parameters observed were soil moisture, transpiration, number of bunches, bunch weight, and yield. The results showed that the average moisture in the mounded soil was 4% greater than the control. Additionally, the average daily transpiration of oil palm with the mounding was up to 2.30 mm day<sup>-1</sup> or three times higher than the control. The implication was that the average yield of oil palm increased from approximately 1.84 to 3.71 tons ha<sup>-1</sup> year<sup>-1</sup> compared to no-mounding treatments. Furthermore, the average yield was 19-66% higher than the block without the mounding application.

Land Use Capability and Suitability Classifications of a Plinthic Alfisol of a Derived Savannah Ecology of Nigeria

Background: In derived savanna ecology, the evaluation of soil characteristics for the current and future capability and suitability for crop production is crucial. Therefore, studies were conducted to evaluate the capability and suitability of plinthic soil of a derived savannah ecology of Nigeria for sustainable crop production. Methods: The methodology was essentially Grid using hand-held GPS to determine the coordinates of sampling points for the collection of soil samples. In all, 18 profile pit samples were collected. The profile pits were described morphologically on the field using the FAO guideline on soil profile description. From the various horizons of these profile pits, soil samples were collected. Results: Land assessment indicates that the soils of the area are very fragile and inherently low in nutrients. Mapping unit A is moderately suitable for arable crop production while Units B and C are fairly suitable. For agricultural activities, mapping unit D is marginal for arable crop production. Stoniness, steep slope, and shallow soil depth are the major limitations. Mapping unit E is the most suitable for lowland rice production. Soil fertility management ought to be integrated (organic and inorganic). The land evaluation shows that the soils of the project site are very fragile and poor in native fertility. Also, the soils are generally defined by the plinthite content. Apart from the traditional crops grown in the area, some other crops like sweet potato and cowpea will do well on the soil of the area. Crop residue has to be well managed and adopted. Crop rotation and intercropping should be encouraged and included in the soil management plan. Also, due to the low level of organic carbon in the soils, the soils will benefit optimally from the application of manure. This will improve the soil aggregation, water, and nutrient-holding capacities as well as improve the pH status of the soil. Conclusion: Soil fertility assessments should be undertaken every two years after continuous cropping. ’High-Intensity Detailed Soil Survey’ of this nature should be carried out every ten years.

Nitrogen fertilizer response of dry direct-seeded rice in rainfed lowlands of the Philippines

Dry direct-seeded rice (DDSR) is an adaptive practice used in rainfed lowlands of tropical Asia where insufficient rainfall at the onset of the wet season makes it difficult to successfully transplant rice seedlings. However, basic guidelines for nutrient management to support DDSR are lacking. Here, we evaluated crop growth and yield in DDSR with different N fertilizers (ammonium sulfate, urea, and coated compound fertilizer) applied at different timings. The total N rate was fixed at 100 kg ha−1. On-station trials were conducted at the International Rice Research Institute, in the Philippines, during the wet seasons of 2017 and 2018, and 17 on-farm trials were conducted in nine provinces in 2018 and 2019. In the on-station trials, ammonium sulfate did not increase yield compared with urea and coated compound fertilizer in either year. Application of N fertilizers at sowing promoted plant N uptake and early shoot growth, but the effect of the timing of N application on yield was not significant. The on-farm trials showed that a uniform N management recommendation is unlikely to be effective in DDSR. Yield increased significantly with coated compound fertilizer relative to the uncoated fertilizers in clay and silty clay soils, but not in other soil types. In general, flexible timing of the first application of N, ranging from 0 to 30 days after sowing, had no significant effect on yield, but the omission of N application at sowing reduced yield by 13–25% in two trials on sandy soils with a low nutrient-holding capacity.

Initial Study on Phytoextraction for Recovery of Metals from Sorted and Aged Waste-to-Energy Bottom Ash

Sorted and aged bottom ash from Waste-to-Energy plants, i.e., MIBA (the Mineral fraction of Incinerator Bottom Ash) are potential source of metals that could be utilized to meet the increased demand from society. In this work, sunflowers (Helianthus annuus) and rapeseed (Brassica napus) were cultivated in conventional MIBA to evaluate the possibility for phytoextraction, mainly of Zn, during the period of one cultivation season in the Nordic climate. The results show that metal extraction from MIBA using rapeseed and sunflowers is workable but that neither of the used plants is optimal, mainly due to the inhibited root development and low water- and nutrient-holding capacities of MIBA. The addition of fertilizer is also important for growth. There was a simultaneous accumulation of numerous metals in both plant types, and the highest metal content was generally found in the roots. Calculations indicated that the ash from rapeseed root incineration contained about 2% Zn, and the contents of Co, Cu, and Pb were comparable to those in workable ores. This initial study shows that cultivation in and phytoextraction on MIBA is possible, and that the potential for increased metal extraction is high.

Changes in soil properties and crop performance on stubble-burned and cultivated water-repellent soils can take many years following reversion to no-till and stubble retention

No-tillage and stubble retention have been widely adopted in south-western Australia to protect agricultural soils from erosion, but potentially exacerbate repellency. In a 10-year (2008–2017) field experiment, 4 combinations of tillage (no-till vs cultivation) and stubble management (retention or burning) were applied annually from 2008 to 2011. In 2012, all plots were returned to no-till and stubble retention to determine the recovery of crop performance and soil properties from stubble burning and/or cultivation, and this recovery phase is reported here. Changes to ground cover, soil water repellency, soil water content, soil carbon and crop performance during a 6-year period (2012–2017) were compared with plots where no-tillage and stubble retention had been practised for several decades. At the conclusion of monitoring in 2017, ground cover (average 55%) and soil carbon (average 1.2%) in the previously burned treatments remained significantly (P < 0.05) less than in treatments where stubble had always been retained (average ground cover 68% and soil carbon 1.7%). Soil water repellency (Molarity of Ethanol Drop (MED)) varied with seasonal conditions but was always highest (P < 0.001) in the treatment which had been continuously no-till, stubble retained (MED 1.7 in 2017) compared with the treatment that was previously burned and cultivated (MED 1.0 in 2017), but this did not influence soil water contents which were generally higher (P < 0.05) in the more repellent soils. The effect of previous tillage treatment on soil water contents resolved quickly after the reversion to no-tillage, likely due to the rapid establishment and preservation of root pathways to aid water infiltration. However, the effect of stubble burning on soil water contents remained significant (P < 0.001) with 2% v/v less water in 2017 in previously burned treatments compared with those where stubble had always been retained. Average grain yields where stubble had always been retained were significantly (P < 0.001) greater by 22–33% than where stubbles had previously been burned in 4 of the 6 seasons. The poor recovery in crop performance in the previously stubble-burned treatments was attributed to the slow build-up of soil carbon to support water- and nutrient-holding capacity, and crop residue ground cover to protect soils from water loss and erosion.

Use of Recycled Potting Medium for Containerized Production of Squash

Vegetable growers are keen on cost-cutting measures to increase profitability. Containerized vegetable production can be done in a shade-house or garden, and it often requires commercial potting media. Although expensive, potting media are lightweight and provide high water- and nutrient-holding capacities, and thus they are widely used by growers. Growers often discard or compost the potting media after a single season due to issues such as diseases, pests, and weeds. However, old potting media could be reused for containerized production if appropriately sterilized and amended with fertilizer salts. The current study was conducted to determine the feasibility of using sterilized recycled potting medium amended with fertilizer salts for containerized production of squash. This new 4-page publication of the UF/IFAS Horticultural Sciences Department was written by Marie Dorval, Riphine Mainviel, Vincent Michael, Yuqing Fu, Bala Rathinasabapathi, and Geoffrey Meru.https://edis.ifas.ufl.edu/hs1404

The 3R Principles for Applying Biochar to Improve Soil Health

Amending soil with biochar is a promising approach to persistently improve soil health and promote crop growth. The efficacy of soil biochar amendment, however, is soil specific, biochar dependent, and influenced by the biochar application programs. To maximize the benefits of biochar application, this paper proposes the 3R principles for applying biochar to soils: right biochar source, right application rate, and right placement in soil. The quality of biochar as a soil amendment varies significantly with the feedstock and the production conditions. Biochar products capable of everlastingly sustaining soil health are those with high stable organic carbon (OC) content and high water- and nutrient-holding capacities that are manufactured from uncontaminated biomass materials. Acidic, coarse-textured, highly leached soils respond remarkably more to biochar amendment than other types of soils. Soil amendment with particular biochars at as low as 0.1 mass% (equivalent to 2 Mg ha−1) may enhance the seasonal crop productivity. To achieve the evident, long-term soil health improvement effects, wood- and crop residue-derived biochars should be applied to soil at one time or cumulatively 2–5 mass% and manure-derived biochars at 1–3 mass% soil. Optimal amendment rates of particular biochar soil systems should be prescreened to ensure the pH of newly treated soils is less than 7.5 and the electrical conductivity (EC) below 2.7 dS m−1 (in 1:1 soil/water slurry). To maximize the soil health benefits while minimizing the erosion risk, biochar amendment should be implemented through broadcasting granular biochar in moistened conditions or in compost mixtures to cropland under low-wind weather followed by thorough and uniform incorporation into the 0–15 cm soil layer. Biochars are generally low in plant macronutrients and cannot serve as a major nutrient source (especially N) to plants. Combined chemical fertilization is necessary to realize the synergic beneficial effects of biochar amendment.

Comparing the Missouri Gravel Bed and a Wood Chip Production Method for Tree Growth

Tree root defects from current nursery production practices influence short- and long-term tree performance and survivability. The Missouri Gravel Bed (MGB) system, a production method using gravel as a substrate, has been used to prevent many of these defects from occurring. MGB production involves planting bare root stock into a bed of gravel with frequent drip irrigation in order to produce a root system with relatively few defects. MGB production methods have also been purported to allow for summer transplanting of many species, as opposed to traditional dormant transplanting.Because gravel has low water- and nutrient-holding capacity, biochar (5% by volume) was incorporated into one plot as a possible means of improving both water- and nutrient-holding capacity over gravel alone. Wood chip mulch was also investigated as a growing substrate in place of the gravel in a growing system. In 2015, three species, Quercus bicolor (swamp white oak), Taxodium distichum (baldcypress), and Tilia cordata (littleleaf linden), were studied in pea gravel (PG), biochar-amended pea gravel (BC), and wood chip mulch bed (MB) growing environments. Very few differences occurred over the growing season with above- or belowground parameters indicating that the minimal-to-no-cost, more readily available substrate of wood chip mulch should be considered in these growing systems.

Nutrition and Fertilization of Palms in Containers

Palms growing in containers are susceptible to the same deficiencies that landscape palms experience, but the relative importance of the various deficiencies as well as their causes are different. Container substrates are generally more acidic and have greater nutrient-holding capacity than Florida native soils. Thus leaching and insolubility of nutrients are much less of a problem. Also, container-grown palms are often fertilized with more complete controlled-release fertilizers or regular liquid fertilization, which prevents most deficiencies from occurring. This document is ENH1010, one of a series of the Department of Environmental Horticulture, UF/IFAS Extension. Original publication date September 2005. ENH1010/EP262: Nutrition and Fertilization of Palms in Containers (ufl.edu)

Soil quality and vegetation performance indicators for sustainable rehabilitation of bauxite residue disposal areas: a review

The generation of bauxite residue, the by-product of alumina manufacture from bauxite ore, has increased to a global stockpile of some 3 billion tonnes. In the absence of significant reuse options, the bulk of this residue is contained within bauxite residue disposal areas (BRDAs), which can occupy a significant footprint and pose potential environmental risk. Rehabilitation (amendment and vegetation establishment) is viewed as a significant strategy for eventual closure of the BRDAs. Major limitations to plant growth in residue include high pH, salinity, and sodicity, as well as deficiencies of macro- and micronutrients and potentially elevated levels of trace elements. The physical properties are also problematic as residue mud consolidates to form a solid mass that waterlogs easily or dries to form a massive structure, whereas sand has a very low water- and nutrient-holding capacity. A variety of techniques have been trialled at the pot level and at the field scale to bring about reductions in residue alkalinity and sodicity to promote plant establishment, with gypsum amendment viewed as the most promising. Other amendment strategies include use of organic additions or fertiliser applications, and a combined approach can lead to improved residue properties and successful plant establishment. Few reports have focused on longer term plant growth, self-propagation, and residue interactions under field conditions. There is some evidence that rehabilitated residue can support vegetation growth and soil development in the short to medium term (~15 years), but key issues such as nutrient availability and plant uptake require further study. Although rehabilitated residue can support diverse microbial communities and demonstrate trajectory analogous to soil, the ability of rehabilitated residue to support soil biota and key ecosystem processes warrants further study. The bioavailability of trace elements within rehabilitated sites and potential food chain transfer are relatively unexplored. These areas need careful study before definitive statements can be made regarding the sustainability of residue rehabilitation strategies.

Growth Response, Mineral Nutrition, and Water Utilization of Container-grown Woody Ornamentals Grown in Biochar-amended Pine Bark

Container-grown nursery crops generally require daily irrigation applications and potentially more frequent applications during the hottest part of the growing season. Developing management practices that make more efficient use of irrigation water is important for improving the sustainability of nursery crop production. Biochar, a byproduct of pyrolysis, can potentially increase the water-holding capacity and reduce water and nutrient leaching. In addition, the development of sensor-based irrigation technologies has made monitoring substrate moisture a practical tool for irrigation management in the nursery industry. The objective of this research was to determine the effect of switchgrass biochar on water and nutrient-holding capacity and release in container substrates of Buxus sempervirens L. × Buxus microphylla (‘Green Velvet’ boxwood) and Hydrangea paniculata (Pinky Winky® hardy hydrangea). Containers were filled with pine bark and amended with 0%, 10%, or 25% volume of biochar. Plants were irrigated when the volumetric water content (VWC) reached the water-buffering capacity set point of 0.25 cm3·cm−3. The sensor-based irrigation in combination with the low cost biochar substrate amendment increased substrate water-holding capacity and reduced irrigation requirements for the production of hydrangea, a high water use plant. Biochar application rate influenced irrigation frequency, which likely affected plant biomass for hydrangea, but boxwood dry weight was unaffected by biochar rate. Total irrigation applied was decreased by 32% in 10% biochar treatment without reducing hydrangea dry weight. However, in the 25% biochar treatment, total irrigation applied was reduced by 72%, whereas dry weight decreased by 50%. Biochar application reduced leaching volume and leaching fraction in both plants. Leachate analysis over the course of the 8-week experiment showed that the average mass of phosphate (PO4), potassium (K), and total carbon was greater in the leachate from containers that received 25% biochar compared with those receiving 0% or 10% biochar for both plant species. For hydrangea, mass of total nitrogen (TN) and nitrate (NO3) in leachate was not significantly affected by increasing the biochar rate. However, for boxwood, the mass of NO3 and TN was greater in the 25% biochar treatment leachate, whereas the mass of ammonium (NH4) was unaffected. In hydrangea, total nutrients lost from the containers was lower in biochar-amended containers (both 10% and 25% biochar) because of receiving a lower total volume of water. Amendment with biochar also affected concentration of phosphorus (P) and K, with the highest concentration in both leaf tissue and substrate from the 25% biochar application rate.

Understanding Nitrogen Transformations and Cycling for Sweet Corn Production in Sandy Soils

Because sandy soils have low water and nutrient-holding capacities and Florida experiences high rainfall periodically, optimizing fertilizer use efficiency for sweet corn production is challenging. The preparation of nitrogen budgets and the implementation of effective management strategies can help farmers overcome these obstacles. This 4-page fact sheet discusses major concerns which call for nitrogen management in sweet corn production, nitrogen budget preparation and interpretation, and important differences between farm-gate and soil system budgets. Written by Rishi Prasad and George Hochmuth, and published by the UF Department of Soil and Water Science, May 2015.&#x0D; SL430/SS643: Understanding Nitrogen Transformations and Cycling for Sweet Corn Production in Sandy Soils (ufl.edu)

Resource use and efficiency, and stomatal responses to environmental drivers of oak and pine species in an Atlantic Coastal Plain forest.

Pine-oak ecosystems are globally distributed even though differences in anatomy and leaf habit between many co-occurring oaks and pines suggest different strategies for resource use, efficiency and stomatal behavior. The New Jersey Pinelands contain sandy soils with low water- and nutrient-holding capacity providing an opportunity to examine trade-offs in resource uptake and efficiency. Therefore, we compared resource use in terms of transpiration rates and leaf nitrogen content and resource-use efficiency including water-use efficiency (WUE) via gas exchange and leaf carbon isotopes and photosynthetic nitrogen-use efficiency (PNUE) between oaks (Quercus alba, Q. prinus, Q. velutina) and pines (Pinus rigida, P. echinata). We also determined environmental drivers [vapor pressure deficit (VPD), soil moisture, solar radiation] of canopy stomatal conductance (GS) estimated via sap flow and stomatal sensitivity to light and soil moisture. Net assimilation rates were similar between genera, but oak leaves used about 10% more water and pine foliage contained about 20% more N per unit leaf area. Therefore, oaks exhibited greater PNUE while pines had higher WUE based on gas exchange, although WUE from carbon isotopes was not significantly different. For the environmental drivers of GS, oaks had about 10% lower stomatal sensitivity to VPD normalized by reference stomatal conductance compared with pines. Pines exhibited a significant positive relationship between shallow soil moisture and GS, but only GS in Q. velutina was positively related to soil moisture. In contrast, stomatal sensitivity to VPD was significantly related to solar radiation in all oak species but only pines at one site. Therefore, oaks rely more heavily on groundwater resources but have lower WUE, while pines have larger leaf areas and nitrogen acquisition but lower PNUE demonstrating a trade-off between using water and nitrogen efficiently in a resource-limited ecosystem.

English

Characterization of soils is helpful in the appraisal of soil productivity. The study investigated detailed physico-chemical characterize of the soils developed on basaltic parent materials on the Jos plateau, Nigeria. The aim was to assess appropriate management practice for their sustainability in agricultural production. Four profiles pits were dug and studied, soil samples collected from pedogenetic horizons were analysed for particle size distribution, pH, fertility related properties. Results indicated that the soils were deep, clayey and reddish in colour (2.5YR 3/3-5YR 3/4). In terms of chemical characteristic, the soils are acidic (pH ranged between 4.6 and 5.6) with low to high CEC values (between 4.3 and 14.8 cmol (+) kg-1) and generally low in organic matter on the average (&lt;1.5%) and exchangeable bases. The four profiles developed on basaltic parent materials on the Jos Plateau of Nigeria were characterized and classified as Typic Haplustusts and Andic Haplustepts. All the soils were well drained in spite of high percent clay above 40% and silt fraction of 20 to 30%, which is apparently kaolinitic, with moderate to high aluminium saturation. Higher agricultural productivity of these soils is constraint by low nutrient-holding capacities and strong acidity. Ways to ameliorate these problems include; to raise the exchangeable Al3+ above toxicity and to supply Ca and Mg contents besides improving soil physical conditions. &nbsp;&nbsp; &nbsp; Key words: Basaltic, typic haplustusts, andic haplustepts, kaolinitic, aluminium toxicity. &nbsp

Sugarcane Yield Response to Furrow-Applied Organic Amendments on Sand Soils

Organic amendments have been shown to increase sugarcane yield on sand soils in Florida. These soils have very low water and nutrient-holding capacities because of the low content of organic matter, silt, and clay. Because of high costs associated with broadcast application, this field study was conducted to determine sugarcane yield response to furrow application of two organic amendments on sand soils. One experiment compared broadcast application (226 m3 ha−1) of mill mud and yard waste compost, furrow application (14, 28, and 56 m3 ha−1) of these materials, and no amendment. Another experiment compared furrow applications (28 and 56 m3 ha−1) of mill mud and yard waste compost with no amendment. There were significant yield (t sucrose ha−1) responses to broadcast and furrow-applied mill mud but responses to furrow applications were not consistent across sites. There were no significant yield responses to yard waste compost suggesting that higher rates or repeated applications of this amendment will be required to achieve results comparable to mill mud. Results also suggest that enhancing water and nutrient availability in the entire volume of the root zone with broadcast incorporation of organic amendments is the more effective approach for low organic matter sands.

Effectiveness of Squid Hydrolysate as a Home Lawn Fertilizer

Consumer demand for cleaned squid generates a substantial amount of waste that must be properly disposed of, creating an economic burden on processors. A potential solution to this problem involves converting squid byproducts into an organic fertilizer, for which there is growing consumer demand. Organic fertilizers are reputed to offer advantages that synthetic fertilizers cannot provide, such as increasing soil water- and nutrient-holding capacity and promoting the growth of beneficial soil organisms. To evaluate the effectiveness of hydrolyzed squid waste as an organic fertilizer, we quantified soil fertility and turfgrass quality on perennial ryegrass turf (Lolium perenne L.) amended with two types of fertilizer: squid-based (SQ) or synthetic (SY). Field plots were established on an Enfield silt loam in Kingston, RI, and liquid (L) or granular (G) fertilizer formulations of squid or synthetic fertilizers were applied at 0, 48, 146, and 292 kg nitrogen/ha/year. Soil physical, chemical, and biological properties were determined monthly and turfgrass quality was determined periodically during the growing season in 2008 and 2009. Squid hydrolysate applied as a liquid (SQL) and granular (SQG) fertilizer consistently provided high-quality, uniform turf when compared with synthetic fertilizer applied at the same rate. Soil concentrations of NO3, NH4, PO4, pH, moisture, soil organic matter, C:N ratio, and levels of trace metals were unaffected by fertilizer type, formulation, or rate throughout the two-year study. Both squid-based organic fertilizer formulations gave significantly higher microbial activity rates than their synthetic counterparts regardless of application rate. Conversion of squid processing byproducts into fertilizer has the potential to improve turfgrass quality while providing a sustainable solution to waste disposal problems in the seafood processing industry.

The effect of compost application on physical properties of sandy soil

The sewage sludge compost is suitable to improve the colloid-poor sandy soils, which are common characteristics of poor water- and nutrientholding capacity. The general characteristics of sandy soils are the light mechanical composition, the low content of humus and mineral colloids, large pore size and a bad aggregate stability. They have a poor nutrient supply capacity, due to its high porosity the organic matter is degraded very quickly to mineral colloids (Stefanovits et al., 1999).&#x0D; By the compost application the soil is enriched mineral and organic colloids, thereby improving the soil structure. The effect of addition of compost to soil the water- and nutrient-holding capacity and porosity could be increased and the bulk density could be decreased (Martens and Frankenberger, 1992).&#x0D; The aim of our experiment is to carry out physical measurements to determine the effects of compost treatment. In this study the results of the first year are presented.