Reduce Nutrient Leaching Research Articles

Nutrients Leaching from Tillage Soil Amended with Wheat Straw Biochar Influenced by Fertiliser Type

The co-application of biochar and fertiliser has emerged as a strategy for improving soil quality and crop growth; however, the impact of the type of fertiliser added with biochar to the soil on leaching and retention of nutrients is not well studied. In this study, a leaching experiment was undertaken using a series of column lysimeters incorporating a wheat straw biochar (WSB) and two fertiliser types—chemical fertiliser (CF), or rock mineral fertiliser (MF). The results showed that CF and MF leached a similar amount of NH4+ with or without WSB, but the NO3– leaching occurred from CF-treated soil which was decreased by CF + WSB application. In contrast, NO3– leaching was not affected by WSB in MF-treated soil. Both CF and MF with or without WSB increased the cumulative leaching of P and K. Nevertheless, WSB application increased soil P and K contents after leaching, which was attributed to intrinsic nutrient release from biochar. Shoot growth and P and K uptake also increased with biochar amendment, whereas root growth and N uptake did not change. Therefore, the results highlight that biochar addition can improve nutrient retention and plant growth by reducing nutrient leaching, mainly dependent on biochar and fertiliser type combination used. It suggests that the adsorption properties of biochar for nutrient retention and subsequent release need to know before their broad application to soils as amendments.

Assessing variability of soil water balance components measured at a new lysimeter facility dedicated to the study of soil ecosystem services

Diversifying annual crop rotations is postulated to promote soil ecosystem services throughreduction of greenhouse gas emissions, control of soil evaporation, moderation of soil freeze-thaw cycles, increases in soil organic carbon, and reduced nutrient leaching, all of which are processes that are impacted by the waterbalance. A newly-installed facility with large monolithic weighing soil lysimeters dedicated to studying changes in soil ecosystem services induced by rotation diversification was installed in June 2016 in Elora, ON, Canada. The high-precision lysimeters, nine for each of two different soils (silt loam, loamy sand) are a closed system to fully evaluate water balance components.In the first year of operation, the lysimeters were not subject to any diversification treatments. This provided an opportunity to study water budget components (precipitation, P; evapotranspiration, ET; change is soil storage,ΔS; drainage, D) measured by the 9 replicate lysimeters for each soil type. The objectives of this study were to1) determine the total uncertainty of P, ET,ΔS and D induced bydatasmoothing and gap fillingdataprocedures; and 3) characterize the spatial variability of water budget components for the baseline year. Cumulative sums of water balance variables from data processing procedures found that the adaptive window and adaptive threshold (AWAT) data smoothing method introduced minimal errors (0.2 to 1.9%). Filling missing data gaps using data from replicate lysimeters, i.e., lysimeters of the same soil type and agronomy, introduced errors of only 0.3 to 0.5% for P and ET (120-day sums). There was greater uncertainty for D andΔS (10.8% and 2.1%, respectively) because of the variability in D. P showed a small degree of spatial variation across all 18 lysimeters, with variations being 1.5% of the mean cumulative sums when using data with no gaps, which demonstrated the high precision of the lysimeter measurements. Spatial variability of evapotranspiration (ET) was higher (6.1% for the silt loam and5.7% for the loamy sand), but within the range of variability estimated for similar lysimeter facilities. The differences in plant cover on individual lysimeters were the main source of variation forETandΔS. Results inform future comparisons of water budget componentsfor other lysimeter sitesand demonstratethe suitability of this facility for examining the complex impacts of crop diversification on soil ecosystem services, providing a basis for future evaluations of water balance components.

​Nutrient Release Pattern of a Fortified Manure Disc and its Implication on Yield of Tomato in Sandy Soils

Background: Development of fortified organic formulations using various organic sources and fertilizers for soil application will ensure efficient nutrient management in homestead vegetable production systems. Fortified organic formulations will help in preventing nutrient leaching also. Hence, the present study has been undertaken during 2019-20 to develop low cost fortified organic manure discs using various biodegradable agro waste materials and NPK fertilizers and to study its effect on growth and yield of tomato in sandy soils of Kerala. Methods: A fortified manure disc was developed by combining local biodegradable agro waste materials with conventional NPK fertilizers. Organic manures like rice husk ash, cow dung, rice husk, coirpith compost, vermicompost, neem cake and clay were used to develop the manure disc. The combination of organic manures was fortified with fertilizers at various proportions of manure: fertilizer viz., 1:1, 2:1, 0.5:1 and manure alone and used for incubation for a period of two months to study the nutrient release pattern of N, P and K.The 2:1(manure: fertilizer) formulation was selected based on the highest peak of nutrient availability of N, P and K even after 2 months. Effect of fortified manure disc was evaluated by using tomato variety Anagha as test crop in a pot culture experiment. Result: Growth, yield and quality of tomato increased significantly due to the application of fortified manure disc. The highest yield per plant of 0.97 kg was recorded for T8 (50% recommended dose fortified manure disc in 2 splits) and lowest yield was recorded for T9 (Manure alone). The fortified manure disc had a significant influence on nutrient use efficiency also. The highest NUE of 45.5% was recorded in treatment T8 (50% fertilizer fortified discs in 2 splits). Study revealed that fortified manure disc is a promising technology to reduce nutrient leaching and enhancing the nutrient use efficiency in sandy soils. Fifty percentage reduction in the recommended dose of NPK fertilizers were achieved by fortifying the manure disc with fertilizers.Thus the cost of fertilizers and fertilizer load per unit area can be reduced by the application of fortified manure disc which will act as slow release fertilizer.

Closing nutrient loops in a maize rotation. Catch crops to reduce nutrient leaching and increase biogas production by anaerobic co-digestion with dairy manure

Three catch crop species, ryegrass, forage rape and black oat, were grown between successive rotations of maize to reduce nitrogen leaching due to maize fertilization with digested dairy manure. Catch crops showed a high nutrient uptake, but with a wide range, depending on the year and the specie. Ensiling was shown to be a feasible storing method increasing catch crop methane production per hectare between 14–36% compared with fresh catch crop. In semi-continuous co-digestion experiments, methane production was increased between 35–48%, in comparison with anaerobic digestion of dairy manure alone. Catch crops were shown to be a good co-substrate, being a sustainable option to prevent leaching of nutrients to the environment, thus closing the loops from production to utilization by optimal recycling measures.

Multi-temporal estimation of vegetable crop biophysical parameters with varied nitrogen fertilization using terrestrial laser scanning

Estimation of biophysical parameters at various crop growth stages is vital for precision agricultural crop production. Spatial delineation of crops’ responses to various levels of nutrients helps optimise resources and reduce nutrient leaching. This paper explores the potential of 3D terrestrial laser scanning (TLS) for the estimation of plant height, crown area, and biomass of vegetable crops at various N levels. Experimental setup of growing three vegetable crops: tomato (Solanumlycopersicum L.), eggplant (Solanummelongena L.) and cabbage (Brassica oleracea L.) with three levels of N fertilization was laid out at the University of Agricultural Sciences, Bengaluru, India in 2017. LiDAR point clouds using a terrestrial laser scanner were collected at different growth stages. A methodology which included, among other processing steps, adaptive spatial filtering, canopy height modelling, watershed segmentation, and support vector regression has been adapted for the estimation of plant height, crown area, and biomass. Validation with ground measurements show high prediction accuracies for plant height (lowest coefficient of determination (R2), 0.96; highest symmetric mean absolute percentage error (SMAPE) of 3.18), and crown area (lowest R2, 0.82; highest SMAPE, 8.82) for all the three crops across growth stages. The combined use of plant height and the crown area has enabled accurate and consistent estimation of biomass (lowest R2, 0.92; highest SMAPE, 7.53) throughout the growing season. However, the mapping of a specific range of biomass to a specific N level is ambiguous due to wider variations in the crop growth due to rainfall, and wind interferences.

Correction to: Long-term application of manure reduced nutrient leaching under heavy N deposition

Correction to: Long-term application of manure reduced nutrient leaching under heavy N deposition

Arbuscular mycorrhizal fungus-induced decrease in nitrogen concentration in pore water and nitrogen leaching loss from red soil under simulated heavy rainfall.

Arbuscular mycorrhizal fungus (AMF) is generally colonized in plant roots and influences the migration of mineral elements such as nitrogen (N) in soils. However, its effect on N leaching loss in red soils is limited. In the present study, red soils were collected from wasteland, farmland, and slopeland in the Yunnan Plateau. Maize, as a host plant, was cultured in a dual-compartment cultivation system. There were mycorrhizal and hyphal compartments for the AMF inoculation treatment and root and soil compartments for the non-inoculation treatment. The N concentration and uptake in maize, N concentration in pore water within two depth (0-20 and 20-40 cm), and N leaching losses from soil under simulated heavy rainfall (40 and 80 mm/h) were analyzed. Results showed that AMF inoculation significantly enhanced the biomass and N uptake in maize. Compared with the root and soil compartments, the N concentrations in pore water and their leaching losses from the mycorrhizal and hyphal compartments were decreased by 48-77% and 51-74%, respectively. Moreover, significant or extremely significantly positive correlations were observed between the N concentrations in pore water with the N leaching losses from soil. The three-way ANOVA showed that AMF highly significantly decreased N concentrations in pore water and their leaching losses from wasteland, farmland, and slopeland; rainfall intensity had strong influences on the N concentration in pore water from farmland and N leaching losses from wasteland and farmland, whereas the maize root's effect was insignificant. The study indicated that the AMF-induced decreases in the N leaching loss from red soils were caused by increased N uptake by maize and decreased N concentrations in pore water. These results have implications for reducing nutrient leaching loss through the management of beneficial microorganisms in soils.

Long-term application of manure reduced nutrient leaching under heavy N deposition

Little is known about the importance of long-term fertilization in crop production and nutrient leaching under heavy wet nitrogen (N) deposition from the atmosphere (WNDA) in tropical and subtropical soils. Thus, a 15-year (2004–2018) field experiment was established on a yellow soil (Orthic Arisols) near Zunyi, Southwest China, to compare the effects of fertilization on maize yields and nutrient leaching in a rotation system of summer maize-winter wheat-summer flue-cured tobacco (or sometimes sweet potato). All crops in this system received no fertilizers (CK), only chemical fertilizers (CF), or manure plus chemical fertilizers (MCF). MCF achieved higher yield and economic efficiency of fertilizers than CF after the first four maize cropping seasons. These results suggested a positive interaction between manure and chemical fertilizers. Maize plants used residual nutrients in the soil from the previous fertilizer management, which may interfere with manure efficiency. MCF alleviated soil acidification and increased soil organic matter (OM), available nutrients, microbial biomass, and enzyme activities (urease and phosphatase compared with CK and invertase and catalase compared with CF). The stimulation of microbial growth and activities may lead to OM depletion in the CF soil, while OM added into the soil in the MCF treatment may exceed microbial OM consumption. During the maize growing season, MCF decreased N and K leaching losses compared with CF. WNDA accounted for 10–12% of N fertilized to maize and 32–69% of maize N uptake in the unfertilized soil. WNDA may thus be an important N source of maize in N-poor soils.

Soil Nitrogen in Response to Interseeded Cover Crops in Maize–Soybean Production Systems

Improved agronomic management strategies are needed to minimize the impact that current maize (Zea mays L.) and soybean (Glycine max (L.) Merr.) production practices have on soil erosion and nutrient losses, especially nitrogen (N). Interseeded cover crops in standing maize and soybean scavenge excess soil N and thus reduce potential N leaching and runoff. The objectives were to determine the impact that pennycress (Thlaspi arvense L.) (PC), winter camelina (Camelina sativa (L.) Crantz) (WC), and winter rye (Secale cereale L.) (WR) cover crops have on soil N, and carbon (C) and N accumulation in cover-crop biomass. The cover crops were interseeded in maize at the R5 growth stage and in soybean at R7 in four replicates over two growing seasons at four locations. Soil and aboveground biomass samples were taken in autumn and spring. Data from the maize and soybean systems were analyzed separately. The results showed that cover crops had no effect on soil NH4+-N under both systems. However, winter rye decreased soil NO3−-N up to 76% compared with no-cover-crop treatment in the soybean system. Pennycress and WC scavenged less soil N than WR. Similarly, N and C accumulation in PC and WC biomass were less than in WR, in part because of their poor growth performance under the interseeding practice. Until PC and WC varieties with improved suitability for interseeding are developed, other agronomic practices may need to be explored for improving N scavenging in maize and soybean cropping systems to reduce nutrient leaching and enhance crop diversification.

Soil Organic Matter Mineralization as Driven by Nutrient Stoichiometry in Soils Under Differently Managed Forest Stands

Nutrient contents of soil organic matter in forests vary with regional differences in soil types, and can be modified by forest management. Variation of organic carbon (OC)-to-nutrient ratios in soils supposedly alters microbial carbon and nutrient use efficiencies and the rates of OC-to-nutrient mineralization. Here, we studied mineralization rates of carbon (C), nitrogen (N), phosphorus (P) and sulfur (S) for topsoil samples from differently managed forest plots in Germany. Samples were incubated for two weeks in microlysimeters under controlled conditions. CO2 respiration, leachable dissolved organic carbon (DOC), nitrate (NO3-), ammonium (NH4+), sulphate (SO42-) and phosphate (PO43-) were determined as net organic C (OC) and nutrient mineralization rates. We hypothesized that in soils with high C-to-nutrient ratios, soil microbes may mobilize relatively more OC as CO2 or DOC than nutrients to meet their nutrient and that forest type influences the stoichiomertry of SOM mineralization by altering the ratios of C-to-nutrients in soils. Results showed that CO2-release rates were proportional to soil OC, but when normalized to microbial biomass C, they increased, similar to DOC leaching rates, with soil OC-to-N ratios. However, higher soil OC-to-nutrient ratios did not go along with reduced nutrient leaching. Instead, when normalized to soil OC, the largest amounts of N, P and S were leached in the most nutrient poor region, so that sites with highest soil OC-to-nutrient ratios had the smallest OC-to-nutrient mineralization ratio. Forest type affected soil stoichiometry only in the most nutrient poor region with smaller OC-to-nutrient ratios and OC-normalized DOC leaching rates under deciduous than coniferous forest sites. However, in the two other study regions tree species had a significant effect on N and S leaching rates and the ratio of OC-to-nutrient leaching despite similar stoichiometry. Overall, our study suggests that increasing nutrient scarcity enhances microbial based CO2 and DOC production, possibly because of increased energy demand for enzyme production to reach and mobilize nutrients, thereby allowing for high nutrient leaching rates despite small total stocks. Forest management affected OC-to-nutrient mineralization rates mostly via tree species selection, but differences were not caused by soil stoichiometry but rather other ecological differences between forest types.

Biochar Effects on Nutrients Retention and Release of Hydroponics Growth Media

Applying biochar (BC) to broad acre crops is an effective way to sequester carbon while improving soil fertility and reducing nutrient leaching. Adopting a similar approach in a hydroponic environment, BC may enhance nutrient availability and reduce natural fluctuations in the nutrient solution. This study monitored the effect of BC addition to peatmoss growth media with ratios of 0%, 5%, 25% and 50% on pH, electrical conductivity (EC) and macronutrient retention, over 15 days using hydroponic nutrient solution controls. Deionised water was used to measure nutrient releases in the closed loop hydroponic system, showing that biochar increased pH level in both retention and release stages. As expected, the pH increased by a maximum of 1.5 units with the highest biochar to growth media ratio due to the natural liming nature of the BC. The EC was also affected, as BC increased in the media EC reduced. With regards to retention of nutrients, BC recovered nitrate, phosphate, calcium and sulphate but did not affect magnesium. Potassium levels increased in solution with increasing BC ratio. In terms of outcomes relevant to global agriculture, the results show that the same level of production can nominally be obtained with around half the nutrient requirements.

Development of Carbon Based NPK Slow Release Fertilizer using Biochar from Oil Palm Empty Fruits Bunch

Biochar is a solid material produced by thermochemical conversion of biomass under oxygen-limited conditions. It has a wide surface and contains many pores so that it can be used as a material for making fertilizer. Biochar based slow release NPK fertilizer was formulated and developed to reduce nutrient leaching and greenhouse gas emissions. In this research, biochar which was a by-product of biomass gasification using oil palm empty fruit bunches was processed to make slow release biochar NPK fertilizer. Sources of nitrogen (N) were derived from urea, phosphate (P) from diamonium phosphate (DAP) and potassium (K) derived from potassium chloride (KCl). Zeolite was added as a matrix to improve fertilizer characteristics. All materials were formulated to make slow release biochar NPK fertilizer used for red onion (Allium sepa) plant applications. Several micronutrients were also added including Mg (MgSO4 fertilizer) and S (ZA fertilizer) to support plant growth. The characterization of fertilizer products was carried out by using SEM, BET etc. to determine physical properties including surface area, pore volume, morphology and composition. Furthermore, biochar NPK fertilizer was applied to the red onion plant which was a high-value crop in Indonesia. The application of NPK biochar fertilizer on red onion plant showed its superiority compared to commercial NPK fertilizers. In addition, the use of Magnesium and sulfur micronutrients could support the growth of red onion bulbs so that they produced more and bigger bulbs.Keywords: biomass, gasification, oil palm empty fruit bunches, biochar, slow release fertilizer*The paper has been selected from a collaboration with IPST and 7th ICFCHT 2019 for a conference entitled "Innovation in Polymer Science and Technology (IPST) 2019 in Conjunction with 7th International Conference on Fuel Cell and Hydrogen Technology (ICFCHT 2019) on October 16th - 19th at The Stones Hotel Legian, Bali, Indonesia"

Farmers' preferences for nutrient and climate-related agri-environmental schemes: A cross-country comparison.

We use data from a survey of 2439 farmers in 5 countries around the Baltic Sea (Denmark, Estonia, Finland, Poland and Sweden) to investigate their preferences for adopting agricultural practices aimed at reducing nutrient leaching and greenhouse gas emissions. The measures considered are set-aside, catch crops and reduced fertilization. Contracts vary with respect to the area enrolled, contract length, possibility of premature termination, availability of professional advice and compensation. We quantitatively describe farmers' preferences in terms of their willingness-to-accept compensation for specific attributes of these contracts, if implemented. The results vary substantially between farm types (farmers' characteristics) and between the 5 countries, and support differentiation of contract obligations and payments to improve the uptake of Agri-Environmental Schemes. The results can be readily used to improve the design of country-specific nutrient reduction policies, in accordance with the next Common Agricultural Policy.

Incorporating Poultry Litter Ash as a Pre-plant Fertilizer to Reduce Nutrient Leaching during Bermudagrass Establishment

ABSTRACTPre-plant fertilizers are used to adjust soil fertility for nutrients such as phosphorus (P) during turfgrass establishment. However, nutrient applications of water-soluble sources in coarse-textured soils are prone to leaching compared to slow-release sources. Poultry litter ash (PLA), a by-product of poultry litter combustion, concentrates macronutrients into less water-soluble forms. The objective of this study was to evaluate PLA with triple superphosphate (TSP), in ratios of P in PLA to that in TSP of 0:100, 25:75, 50:50, 75:25; 100:0 as a pre-plant fertilizer incorporated into a 90:10 (v/v) sand and peat mixture seeded with bermudagrass (Cynodon dactylon L.) ‘Sahara’. Bermudagrass groundcover, shoot, and root biomass were measured at 6 weeks. Leachate was captured weekly and analyzed for P, K, Ca, and Mg. Bermudagrass groundcover and biomass accumulation were similar across all treatments at 6 weeks after planting (WAP). The benefit of PLA compared to TSP was the reduction in P, K, Ca, and Mg leached during the first two WAP. As the percentage of PLA increased relative to TSP, nutrient leaching decreased, with 100% PLA resulting in the lowest cumulative nutrient masses leached. Application of 100% PLA as a pre-plant fertilizer can limit nutrient leaching in coarse-textured media compared to more water-soluble nutrient sources, particularly TSP, without delaying bermudagrass establishment.

The influence of extensive green roofs on rainwater runoff quality: a field-scale study in southwest China.

Green roofs of young age (≤ 5 years old) have boomed in China since the Sponge City Construction initiative was implemented. To use green roofs for better urban stormwater management, it is necessary to investigate the runoff quality of field-scale young green roofs as well as to examine common plant-media combination in green roof projects of China. The influence of two Sedum-vegetated extensive green roofs of different designs at the early stage of operation on runoff water quality was investigated by a field-scale study in Chengdu, southwest China. The water quality parameters of pH, suspended solids (SS), chemical oxygen demand (COD), total phosphorus (TP), and total nitrogen (TN) of rainwater (that is, input water for roofs), runoff from the two green roofs, and runoff from a conventional concrete control roof were compared. The results indicate that both green roofs mainly act as pollutant sources with greater concentrations of SS, COD, and TP when compared with rainwater quality. When compared with runoff quality from the control roof, greater TP concentrations in runoff from one green roof with commercially available substrate were observed. Attention should be paid to TP leaching in runoff for retrofitted green roofs with imported commercial substrates in that region. Adoption of pre-cultivated S. lineare mats of low fertility and localized soils may reduce nutrient leaching in green roof runoff. A nitrogen-rich substrate is not recommended for a plant community of a single species. Investigation of the effect of green roofs on water quality involving various pollutants in the long run is recommended.

Biochar prepared at different pyrolysis temperatures affects urea-nitrogen immobilization and N2O emissions in paddy fields.

BackgroundFood safety has become a major issue, with serious environmental pollution resulting from losses of nitrogen (N) fertilizers. N is a key element for plant growth and is often one of the most important yield-limiting nutrients in paddy soil. Urea-N immobilization is an important process for restoring the levels of soil nutrient depleted by rice production and sustaining productivity. The benefits of biochar application include improved soil fertility, altered N dynamics, and reduced nutrient leaching. However, due to high variability in the quality of biochar, the responses of N loss and rice productivity to biochar amendments, especially those prepared at different pyrolysis temperatures, are still unclear. The main objectives of the present study were to examine the effects of biochar prepared at different pyrolysis temperatures on fertilizer N immobilization in paddy soil and explore the underlying mechanisms.MethodsTwo biochar samples were prepared by pyrolysis of maize straw at 400 °C (B400) and 700 °C (B700), respectively. The biochar was applied to paddy soil at three rates (0, 0.7, and 2.1%, w/w), with or without N fertilization (0, 168, and 210 kg N ha–1). Pot experiments were performed to determine nitrous oxide (N2O) emissions and 15N recovery from paddy soil using a 15N tracer across the rice growing season.ResultsCompared with the non-biochar control, biochar significantly decreased soil bulk density while increasing soil porosity, irrespective of pyrolysis temperature and N fertilizer level. Under B400 and B700, a high biochar rate decreased N loss rate to 66.42 and 68.90%, whereas a high N level increased it to 77.21 and 76.99%, respectively. Biochar also markedly decreased N2O emissions to 1.06 (B400) and 0.75 kg ha−1 (B700); low-N treatment caused a decrease in N2O emissions under B400, but this decrease was not observed under B700. An application rate of biochar of 2.1% plus 210 kg ha−1 N fertilizer substantially decreased the N fertilizer-induced N2O emission factor under B400, whereas under B700 no significant difference was observed. Biochar combined with N fertilizer treatment decreased rice biomass and grain yield by an average of 51.55 and 23.90 g pot–1, respectively, but the yield reduction under B700 was lower than under B400.ConclusionIrrespective of pyrolysis temperature, biochar had a positive effect on residual soil 15N content, while it negatively affected the 15N recovery of rice, N2O emissions from soil, rice biomass, and grain yield in the first year. Generally, a high application rate of biochar prepared at high or low pyrolysis temperature reduced the N fertilizer-induced N2O emission factor considerably. These biochar effects were dependent on N fertilizer level, biochar application rate, and their interactions.

Evaluation of Soil Water and Nitrogen Distribution by Site‐Specific Irrigation Scheduling Method in Tomato Crop Grown on Sandy Soil

Core Ideas SmartIrrigation is a smartphone‐based crop irrigation scheduling method using real‐time and location‐specific (RT‐LS) weather information. The RT‐LS irrigation scheduling method improved irrigation water savings and increased crop yield. The RT‐LS model can reduce nutrient leaching by maintaining water and nutrient within crop root zone. Efficient irrigation scheduling can improve crop performance and increase production efficiencies. Irrigation scheduling based on a real‐time and location‐specific (RT‐LS) model increases irrigation water savings and yield. The RT‐LS irrigation scheduling models have been developed as smartphone applications and have been used for crop‐specific irrigation requirements. Although many RT‐LS irrigation models have been tested and used in several agronomic and horticultural crops in Florida, none of these irrigation‐scheduling models has been tested for their impacts on nutrient distribution in Florida's sandy soils. A two‐season (fall 2015 and spring 2016) study was conducted to determine the effects of an RT‐LS–based irrigation scheduling on soil water, NO3‐–N, and NH4+–N distributions during a tomato cropping season. In both seasons, an RT‐LS model for tomato was evaluated at three irrigation application rates (66, 100, and 150% RT‐LS–suggested amounts) and compared with a historic evapotranspiration (ET)‐based irrigation schedule (Historic ET) currently recommended in Florida. This study suggests that the RT‐LS model improves water savings by 20 and 17% for the fall and spring seasons, respectively, compared with the Historic ET irrigation scheduling method. No specific pattern was observed for soil NH4+–N concentration between scheduling methods, but the RT‐LS model maintained a higher soil NO3‐–N concentration within the crop root zone and hence could reduce NO3‐–N leaching potential. In each season, compared with the Historic ET irrigation method, the RT‐LS improved both nitrogen recovery and irrigation water use efficiency in the open‐field fresh‐market tomato production system. Results obtained in this study clearly demonstrate that irrigation applications using the RT‐LS irrigation scheduler improved irrigation scheduling accuracy by maintaining nutrients within the tomato root zone and hence could reduce nutrient leaching potential in sandy soil.

Pasture chemoscapes and their ecological services.

Ruminant livestock-production systems are between a rock and a hard place; they are experiencing increasing societal pressure to reduce environmental impacts in a world that demands increased food supply. Recent improvements in the understanding of the nutritional ecology of livestock by scientists may help livestock producers respond to these seemingly contradictory demands. Forages are nutrition and pharmacy centers with primary (nutrients) and plant secondary compounds (PSC; pharmaceuticals, nutraceuticals), which can provide multiple services for the proper functioning of agroecosystems. Legumes with lower contents of fiber and higher contents of nonstructural carbohydrates, coupled with different types and concentrations of PSC (e.g., condensed tannins, terpenes), create a diverse array of chemicals in the landscape (i.e., the “chemoscape”) with the potential to enhance livestock nutrition, health and welfare relative to foodscapes dominated by grasses and other conventional feeds. These PSC-containing plants may reduce methane emissions and nitrogen (N) excretion from animals while increasing animal growth rate compared with swards dominated by grasses, and provide meat quality that appeals to consumers. Condensed tannins from sainfoin and saponins from alfalfa and manure of cattle consuming these forages also reduce N mobilization in soils, reduce nutrient leaching, and increase plant-available N stores for future use. The challenge for future pastoral production systems is to design multifunctional spatiotemporal arrangements of forages with “ideal” chemical diversity for specific ecoregions, aiming to achieve sustainability while increasing production goals and improving ecosystem services. Thus, the objective of this review is to stimulate the quest for chemically and taxonomically diverse pastoral feeding systems that optimize overall productivity; reduce environmental impacts; and enhance livestock, soil, and human health.

Effects of biochar-based fertilizers on nutrient leaching in a tobacco-planting soil

Biochar is a soil amendment for increasing soil quality and decreasing nutrient leaching. However, there is little information on the impact of biochar-based fertilizer (BF) on soil nutrient leaching in agricultural soils. We conducted a soil column leaching experiment to study the effects of BF on the leaching of total nitrogen (TN), total phosphorus, and total potassium (TK) in tobacco soils. The distribution characteristics of NH4+-N, available P, and available K in soil profiles were analyzed after the application of BF. Biochar was prepared by pyrolysis of flue-cured tobacco stems. It was applied at four levels, 0%, 3%, 9%, and 15% (w/w), respectively, to the compound fertilizer. Compared with the control, the leaching loss of soil TN decreased by 8.36%, 6.72%, and 6.45%, and the loss of soil TK decreased by 9.18%, 9.31% and 11.82% in the 3%, 9%, and 15% BF treatments, respectively. However, BF had no significant effect on the P leaching due to the low movement of P in the soil profile. In addition, the BF addition increased the immobilization of NH4+-N, available P, and available K in the soil profile. These results indicate that addition of BF to a tobacco-planting soil reduced nutrient leaching, and suggest that BF could be an effective method of applying biochar to agriculture fields.

Physical and mechanical characteristics of oil palm leaf and fruits bunch stalks for bio-mulching

This paper discusses specifically on physical and mechanical characteristics of oil palm leaf and FFB stalks as parameter used to select appropriate method for size reduction of materials which will give optimum performance as bio-mulch. Physical and mechanical properties of oil palm leaf and fresh fruit bunch (FFB) stalks are basic data in determining the appropriate method of size reduction in order to find optimum size of material for bio-mulching. The output of this research were (1) the physical characteristics i.e. size (length, width, thickness), and moisture content; (2) mechanical propertiesi.e. shear strength, tensile strength, and hardness. Previous researches showed that the use of mulches, both organic and synthetic mulches were able to maintain soil moisture, reduce nutrient leaching, to maintain soil organic matter, soilaggregates, reduce runoff/erosion, and prevent weed growth. Oil palm frond collected after harvesting activities is generally placed on a “gawanganmati” under oil palm trees. The materials are expected to decompose naturally. However, currently, the materials are not fully managed and just remain in the field which takes space and disturb the field operation during production of oil palm. In fact the materials are potential as bio-mulch if it is in proper size that can be well distributed in the field. In this study, the materials used for mulchingareoil palm leaf and FFB stalks. Toshorten the decomposition time of the mulch, one of the aspects that should be suppressed is the size of the mulch. In terms of achieving optimumimpact of materials as bio-mulch, it is necessaryto determine the shape, dimensions, moisture content, strength and hardness of materials.