Nitrogen Availability for Maize from a Rolling Pampa Soil After Addition of Biosolids

Abstract

The objective of this paper was to evaluate the influence of different rates of biosolids on the soil nitrogen (N) availability for maize and its residuality. A field experiment was developed in a typic Argiudol located in the NE of the Buenos Aires Province. Maize was sown for two consecutive years 1997–1999. Biosolids from a sewage treatment plant of Buenos Aires outskirts were superficially applied to the soil and incorporated by plowing. There were eight treatments: Check; 8, 16, and 24 Mg of dry biosolid ha^?1; 8 and 16 Mg of dry biosolid ha^?1 applied one year before, 100 and 150 kg N ha^?1 of calcium ammonium nitrate (CAN). The sampling and determinations were done during the second maize cycle. At presowing (PS), sowing (S), 6 expanded leaves (V6), 12 expanded leaves (V12), and Flowering (Fl) composite soil samples from 0–40 cm depth were obtained to determine ammonium and nitrate contents. At Fl maize plants were sampled in order to determine total biomass and N content. The N‐nitrate content in the soil was significantly increased by the biosolids application (p < 0.05), and varied for each increment depending on the biosolids rates and the phenological stage. After 30 days from the incorporation the increases of 1.19, 1.34, and 2.05% were observed for N‐nitrates for 8, 16, and 24 Mg ha^?1, respectively. The contribution of mineral N from the biosolids was 2.48, 6.46, and 5.01 kg N Mg^?1 when the rates were incremented from 0–8, 8–16, and 16–24 Mg ha^?1, respectively. The nitrogen mineralization followed a release pattern with a maximum value of 296 kg N‐nitrate ha^?1 at sowing for 24 Mg ha^?1. Since then, the release of mineral nitrogen decreased significantly till Fl. The N‐nitrates values variation with the temperature adjusted to polinomic functions. The mineral N released from the biosolids increased as a response to the increment of soil temperature and then decreased due to the maize nitrogen absorption and the potentially mineralized nitrogen exhaustion. The application of 150 kg N ha^?1 as CAN incremented significantly the soil N‐nitrate content and equalized 16 and 24 Mg of dry biosolids ha^?1 at V6. But, no synchronism between the high nitrate releasing from biosolids and the increment in the nitrogen absorption by maize was observed. This fact generates a surplus of nitrate that incremented the potential of nitrogen loss by lixiviation. We observed a residual effect from the biosolids that were applied the previous year. This contribution represented the 35% of the maize requirements and was similar to the nitrate content observed in Bio 16. The biosolids might be a valuable source of nitrogen for maize crop if the synchronism between the soil supply and maize demand is observed in order to avoid nitrates surplus.     

Effect of biochar and phosphorus fertilizer application on soil fertility: soil physical and chemical properties

This study evaluated the effect of biochar and phosphorus fertilizer application on selected soil physical and chemical properties in two contrasting soil types: Rhodic Ferralsols (clay) in Thohoyandou and Leptic Cambisols (loamy sand) in Nelspruit, South Africa. Field experiments were conducted in summer and winter. Treatments consisted of a factorial combination of four biochar levels (0, 5, 10 and 20 t ha^?1) and two phosphorus fertilizer levels (0 and 90 kg ha^?1) arranged in a randomized complete block design with three replicates. Chickpea was the test crop. Soil bulk density, aggregate stability, porosity, total C, total N, C:N ratio, K and Mg were determined. Biochar (10 t ha^?1) and phosphorus increased bulk density and decreased porosity at 0–5 and 15–20 cm soil depth on a loamy sand soil in both seasons. The interaction between biochar and phosphorus increased total C and total N on a clay soil in the summer sowing. However, in the loamy sand soil, biochar (10 t ha^?1) increased total C, C:N ratio, K and Mg in the summer sowing. The effect of biochar was more evident in the loamy sand soil than the clay soil suggesting that the influence of biochar may be soil-specific.     

Soil management for raising crop water productivity in rainfed production systems in Lao PDR

This study investigated the impacts of organic- and clay-based soil amendments, and their combinations on crop water productivity (CWP) using maize as a test crop. On-station field trials were established over two consecutive years at the Naphok and Veunkham sites in Laos. At each site, 10 treatments were applied in a randomized complete block design with three replications. The treatments were control, rice husk biochar (10 t ha^?1), bentonite clay (10 t ha^?1), compost (4 t ha^?1), clay-manure compost (10 t ha^?1), rice husk biochar compost (10 t ha^?1), bentonite clay + biochar, bentonite-clay + compost, biochar + compost, and bentonite clay + biochar + compost. All treatments were applied in 2011. Significant (p < 0.05) treatment effects in CWP and growing period evapotranspiration were determined. At Naphok, differences between the amended and control plots in CWP varied between 0.1 and 0.6 kg m^?3 in 2011 and from 0.1 to 0.4 kg m^?3 in 2012, whereas differences at Veunkham varied between 0.3 and 1.0 kg m^?3 in 2011 and from 0.05 to 0.29 kg m^?3 in 2012. At both sites, CWP in 2012 was significantly lower than 2011. Our results illustrate that organic- and clay-based soil amendments improve CWP, indicating that soil-based interventions could be suitable options for improving agricultural productivity.     

Effect of biochar amendment on soil physical,chemical and biological properties and groundnut yield in rainfed Alfisol of semi-arid tropics

The aim of this study was to evaluate the effect of biochar and organic soil amendments on soil physicochemical and microbial load, carbon sequestration potential, nutrient uptake and yield of groundnut in acidic red soil under rainfed condition. Biochar was prepared from red gram, cotton, maize stalk and mesquite wood using pilot scale slow pyrolysis biochar unit. The above sources of biochar at the rate of 2.5 and 5 t ha^?1 and enriched farmyard manure 0.75 t ha^?1, composted coir pith 10 t ha^?1 and arbuscular mycorrhizae 100 kg ha^?1 were applied as basal with required nitrogen, phosphorous and potassium fertilizer. Biochar amendment at the rate of 5 t ha^?1 reduced the bulk density from 1.41 to 1.36 g cm^?3 and increased the soil moisture 2.5%. With respect to soil chemical changes, it raised soil pH from 5.7 to 6.3; increased the cation exchange capacity 1.4 cmol⁺ kg^?1 and enhanced the carbon buildup 4.4 t ha^?1. The significant differences in bacteria, fungi and actinomycetes population were observed between biochar and control. The nitrogen, phosphorous and potassium were better utilized under biochar and composted coir pith, which was 21, 5 and 20 kg ha^?1 higher than control. The experimental results suggested that application of biochar to acidic red soil favoured good soil physical, chemical and biological environment, and these positive changes influenced growth and yield attributes and enhanced pod yield 29% over control.     

Long‐Term Application of Biosolids on Apricot Production

Abstract

The use and disposal of biosolids, or wastewater treatment sludge, as a fertilizer and soil amendment is becoming increasingly widespread. We evaluated the multiyear use of biosolids in apricot (Prunus armeniaca L.) production, grown on productive agricultural soils. Class A biosolids were initially applied annually at rates of 0, 1.9, 5.8, and 11.7 Mg · ha^?1 (dry basis) to a 2‐year‐old apricot orchard on the USDA‐ARS research site on the eastern side of the San Joaquin Valley, CA. These application rates provided estimated rates of 0 (control), 57, 170, and 340 kg total N · ha^?1 yr^?1, respectively. Compared to the control treatment, the applications of biosolids significantly increased soil salinity (electrical conductivity from 1:1 soil–water extract) and total concentrations of nutrients [e.g., calcium (Ca), magnesium (Mg), sulfur (S), phosphorus (P), zinc (Zn), and copper (Cu)] after 7 years but did not increase the concentrations of selected metals [cadmium (Cd), chromium (Cr), cobalt (Co), nickel (Ni), and lead (Pb)] between 0‐ and 60‐cm soil depths. Mean concentrations of total nitrogen (N) and carbon (C) in soils (0‐ to 15‐cm depth) ranged from a low of 1.3 g kg^?1 to a high of 5.2 g · kg^?1 and from 14.1 g · kg^?1 to 45.7 g · kg^?1 for the control and high biosolids treated soils, respectively.

Biosolids applications did not lead to fruit yield reductions, although fruit maturation was generally delayed and more fruits appeared at picking times at the high rate of application. Yellow fruits collected from all biosolids applications were significantly firmer than were fruit collected from control trees, and they had higher concentrations of Ca, potassium (K), S, iron (Fe), and Zn in the fruit. Among the fruit quality parameters tested, the juice pH, total acidity, and fruit skin color were not significantly affected by biosolids applications. Malic acid concentrations decreased most of the time, while citric acid concentrations increased with increasing rates of biosolids applications. Overall, our results suggest that nonindustrial biosolids applied at an annual rate at or less than 11.7 Mg N · ha^?1 (340 kg N · ha^?1) can be safely used for apricot production on sandy loam soils.     

On-Site Assessment of Extractable Soil Nutrients after Long-Term Biosolid Applications to Perennial Forage

The objective of this study was to evaluate soil nutrient loading and depth distributions of extractable nitrogen (N), phosphorus (P), and potassium (K) after long-term, continuous annual surface applications of anaerobically digested class B biosolids at a municipal recycling facility in central Texas. Commercial forage production fields of coastal bermudagrass (Cynodon dactylon L.) were surface applied at 0, 20, 40, or 60 Mg dry biosolids ha^?1 y^?1 for 8 years. Application duration was evaluated in fields treated with 20 Mg dry biosolids ha^?1 y^?1 for 0, 8, or 20 years. Total soil loads of extractable inorganic N and P increased linearly with application rate, but only extractable P increased with duration. Neither total load nor soil distribution of extractable K was affected by biosolid applications. Mineralization of biosolid-derived organic N and P likely contributed to elevated concentrations of nitrate throughout the soil profile (0–110 cm) and orthophosphate in surface soils (0–40 cm).     

Predicting Biosolids Application Rates for Dryland Wheat across a Range of Northwest Climate Zones

We evaluated dryland wheat (Triticum aestivum L.) response to biosolids applications in the inland Pacific Northwest and compared agronomic application rates predicted from yield curves with those predicted from Extension guidance. We applied biosolids rate treatments during the fallow year in 10 on‐farm experiments and determined grain yield, protein, and postharvest soil nitrate. Nitrogen (N) rates were calculated from Extension guidance and compared with biosolids agronomic rate estimates based on yield regressions generated for each site. Eight of the 10 sites had quadratic yield responses. The agronomic biosolids rate at the responsive sites averaged 315 kg ha^?1 more grain than the farmer inorganic N rate. At responsive sites, a mean biosolids application rate of 4.7 dry Mg ha^?1 (226 kg total N ha^?1) was required for 95% of maximum grain yield. Results showed that Extension fertilizer guidance together with calculations for biosolids available N gave reasonable estimates for biosolids application rates.     

Biochar amendment changes temperature sensitivity of soil respiration and composition of microbial communities 3 years after incorporation in an organic carbon-poor dry cropland soil

Topsoil samples were collected from plots in a dry cropland in the North China Plain 3 years after a single incorporation of biochar at 20 and 40 t ha^?1 and analyzed for abundances and composition of microbial community and for respiration under controlled laboratory conditions at 15, 20, and 25 °C. The addition of biochar generally reduced soil respirations at the three temperatures and the temperature sensitivity (Q₁₀) at 15–20 °C. Biochar amendment significantly increased bacterial 16S rRNA gene abundances and fungal ITS gene diversity and induced clear changes in their community compositions due to improvements in soil chemical properties such as soil organic C (SOC) and available N contents and pH. Illumina Miseq sequencing showed that the relative abundances of Actinobacteria, Gammaproteobacteria, Firmicutes, and Alternaria within Ascomycota, capable of decomposing SOC, were significantly decreased under biochar at 40 t ha^?1. The Q₁₀ values at 15–20 °C were significantly correlated with fungal diversity and dehydrogenase activity. Our results suggest that after 3 years a single biochar amendment could induce a shift in microbial community composition and functioning towards a slower organic C turnover and stability to warming, which may potentially reduce soil C loss in dryland under climate warming in the future.     

Towards sustainable production of peppermint (Mentha piperita L.) through integrated use of vermicompost and cowpea green manuring with synthetic nitrogen fertilization

A field experiment with peppermint (Mentha piperita L.) was conducted in a sandy loam (Typic ustifluvent) soil during 2007 and 2008 at Lucknow, India. Ten treatments consisting of control (no synthetic or organic nitrogen fertilization), synthetic nitrogen fertilization (SN) 75, 150 and 225 kg ha^?1 alone, vermicompost (VC) 3 t + 37.5 kg SN ha^?1, VC 6 t + 75 kg SN ha^?1 and VC 9 t + 112.5 kg SN ha^?1 and intercropping of one, two and three rows of cowpea for green manuring in combination with 50, 100 and 150 kg SN ha^?1, respectively, were evaluated in a randomized block design. Integrated use of VC 9 t with 112.5 kg SN ha^?1 produced maximum essential oil (94.3 kg ha^?1), increased the herb and essential oil yields by 104 and 89%, respectively, over control and reduced SN use by 50%, without affecting the quality of essential oil. Application of VC and intercropping of cowpea for green manuring significantly improved the organic carbon, available N, P and K content in soil over SN alone. To get sustainable production of peppermint, application of VC 9 t ha^?1 along with 112.5 kg N ha^?1 through synthetic fertilizer is recommended for light textured sandy loam soils.     

Bacterial diversity as affected by application of manure in red soils of subtropical China

A plot experiment was conducted to understand the response of the soil bacterial community to manure application rates and the relationship between the composition of bacterial community and soil chemical properties. The experiment involved gradients of manure combined with chemical fertilizer in red soils from granite, red sandstone and red clay between 2013 and 2015. The soil bacterial community composition was significantly affected by different manure rates. The relative abundances of Burkholderiaceae, Micrococcaceae and Streptomycetaceae were higher at low manure rates (1.75 to 3.5 t·ha^?1·yr.^?1), whereas the relative abundance of Xanthomonadaceae was higher at high manure rates (7 to 28 t·ha^?1·yr.^?1). Manure application increased the bacterial abundance but decreased the diversity when its rates were higher than 7, 14 and 14 t·ha^?1·yr.^?1 in soils from granite, red sandstone and red clay, respectively. Redundancy analysis revealed that soils from different parent materials had different bacterial communities with soil pH and available phosphorus (AP) being determinant factors. The peanut yields exhibited significantly positive correlations with the bacterial diversity in soil, implying the importance of bacterial diversity for soil productivity. Soil AP was correlated with bacterial diversity by parabolic equations and probably AP may be an indicator of declining bacterial diversity at high manure rates. The critical value were 39.71, 65.75 and 90.16 mg·kg^?1 in soils from granite, red sandstone and red clay, respectively. This study suggests the importance of maintaining soil bacterial diversity under moderate and balanced applications of manure.     

Suitability of Lime,Green Leaf,and Farm Yard Manure and Inorganic Fertilizers for Sustaining Green Gram Yield and Rainwater Use Efficiency Under Moist Sub-Humid Alfisols in India

Field experiments were conducted to assess the effect of nutrients management practices on yield and rainwater use efficiency of green gram (Vigna radiata), and soil fertility under moist sub-humid Alfisols at Phulbani, India, during 2005–2008. Ten treatment combinations of lime @ 10% and 20% of lime requirement (LR) @ 8.3 t ha^?1, farmyard manure (FYM) @ 5 t ha^?1, green leaf manure @ 5 t ha^?1, and nitrogen, phosphorus, and potassium (N–P–K) (20–40–20 kg ha^?1) were tested. The analysis of variance indicated that treatments differed significantly from each other in influencing yield and rainwater use efficiency. Application of lime @ 20% LR + FYM @ 5 t/ha + 40 kg P + 20 kg K ha^?1 was superior with maximum mean yield of 531 kg ha^?1, while lime @ 10% LR + FYM @ 5 t ha^?1 + 40 kg P + 20 kg K ha^?1 was the second best with 405 kg ha^?1 and maintained maximum soil fertility of nutrients. The superior treatment gave maximum sustainability yield index of 67.5%, rainwater use efficiency of 0.49 kg ha^?1 mm^?1, improved soil pH, electrical conductivity, and soil nutrients over years.     

Mudflat soil amendment by sewage sludge: Soil physicochemical properties,perennial ryegrass growth,and metal uptake

Abstract

The fast pace of cropland loss in China is causing alarm over food security and China’s ability to remain self-reliant in crop production. Mudflats after organic amendment can be an important alternative cropland in China. Land application of sewage sludge has become a popular organic amendment to croplands in many countries. Nevertheless, the land application of sludge to mudflats has received little attention. Therefore, the objective of the present work was to investigate the impact of sewage sludge amendment (SSA) at 0, 30, 75, 150 and 300 t ha^?1 rates on soil physicochemical properties, perennial ryegrass (Lolium perenne L.) growth and heavy metal accumulation in mudflat soil. The results showed that the application of sewage sludge increased organic matter (OM) content by 3.5-fold while reducing salinity by 76.3% at the 300 t ha^?1 rate as compared to unamended soil. The SSA reduced pH, electric conductivity (EC) and bulk density in mudflat soil, increased porosity, cation exchange capacity (CEC) and contents of nitrogen (N), phosphorus (P), exchangeable potassium ions (K⁺), sodium ions (Na⁺), calcium ions (Ca²⁺) and magnesium ions (Mg²⁺) in comparison to unamended soil. There were 98.0, 146.6, 291.4 and 429.2% increases in fresh weight and 92.5, 132.4, 258.6 and 418.9% increases in dry weight of perennial ryegrass at 30, 75, 150, and 300 t ha^?1, respectively, relative to unamended soil. The SSA increased metal concentrations of aboveground and root parts of perennial ryegrass (p < 0.05). The metal concentrations in perennial ryegrass were Zn > Cr > Mn > Cu > Cd > Ni, and the metal concentrations in roots were significantly higher than aboveground parts. The metal accumulation in perennial ryegrass correlated positively with sludge application rates and available metal concentrations in mudflat soil. Land application of sewage sludge was proved to be an effective soil amendment that improved soil fertility and promoted perennial ryegrass growth in mudflat soil. However, heavy metal accumulation in plants may cause food safety concern.     

Reclamation of a Badarkhali hot spot of acid sulfate soil in relation to rice production by basic slag and aggregate size treatments under modified plain–ridge–ditch techniques

Abstract

A field experiment was conducted for the reclamation of a Badarkhali hot spot of acid sulfate soil manipulated by flash leaching followed by basic slag (BS) at 10 t ha^?1 (BS₁₀) and 20 t ha^?1 (BS₂₀) and aggregate sizes (A) of soil less than 20 mm (A₂₀) and less than 30 mm (A₃₀) treatments under two different techniques (Tech 1: pyrite layer at top, jarosite layer at middle and topsoil at the bottom of the ridge; Tech 2: topsoil at top, pyrite layer at middle and jarosite layer at the bottom of the ridge). Responses to two cultivars of rice (Pizam [local cultivar] and BR 14 [high yielding cultivar]) with the treatments were evaluated. The initial soil had a very low pH(H₂O) 4.0 and a high electrical conductivity (EC) of 1.4 m S^?1, and the pyrite content was 68 g kg^?1. The exchangeable Mg content of the soil was approximately twice that of Ca and the Al content was at a highly toxic level. The average soil data of all the treatments, except for the control plots (where no amendment was applied), after harvesting of rice increased by 1.1 units for soil pH and 17–524% for the contents of N, P, Ca and Mg, while the concentrations of Fe, Al, Na, Cl^? and SO₄ ^2– decreased by 30–94% compared with the initial soil. The maximum growth and yield of rice grains (4.4 t ha^?1) were obtained by the Pizam compared with the BR 14 (4.0 t ha^?1) in the A₂₀BS₂₀ treatment in the ridges of Tech 2. The lowest grain yields of 0.02 (BR 14) and 0.07 t ha^?1 (Pizam) were recorded for the control plots. The other treatments also resulted in significantly (P ≤ 0.05) improved performance on rice production. The highest N, P, K, Ca and Mg contents in the shoots of BR 14 and Pizam rice were obtained under the A₂₀BS₂₀ treatment followed by the A₂₀BS₁₀ ≥ A₃₀BS₂₀ treatments. Application of A₂₀BS₂₀ under Tech 2 is the most appropriate reclamation option and the local Pizam is the most suitable rice for this soil.     

Soil Quality Assessment under Restorative Soil Management Practices in Soybean (Glycine Max) after Six Years in Semi-Arid Tropical Black Lands of Central India

Vertisol soils of central India are heavy in texture, with high clay content and low organic matter. These soils are prone to degradation and the soil loss is due to poor management practices including excessive tillage. Based on a long-term study conducted for improving the quality of these soils, it was found that management practice such as low tillage (LT) + 4 t ha^?1 compost + herbicide (Hb) recorded significantly higher organic carbon (OC) (6.22 g kg^?1) and available N (188.5 kg ha^?1) compared to conventional tillage (CT) + recommended fertilizer (RF) + off-season tillage (OT) + hand weeding (HW) (OC: 4.71 g kg^?1, available nitrogen (N) (159.3 kg ha^?1). Among the physical soil quality parameters, mean weight diameter (MWD) was significantly higher under LT + 4 t ha^?1 straw + Hb (0.59 mm). The practice of LT + 4 t ha^?1 straw + HW recorded significantly higher microbial biomass carbon (MBC) (388.8 μg g^?1). The order of key indicators and their contribution towards soil quality was as follows: OC (29%) >, MBC (27%) > available zinc (Zn) (22%) > MWD (9%) > available boron (B) (8%), > dehydrogenase activity (DHA) (5%). The order of the best treatment which maintained soil quality index (SQI) values reasonably good (>1.5) was as follows: LT + 4t ha^?1 compost + HW (1.65) > LT + 4 t ha^?1 compost +Hb (1.60) > LT + 4t ha^?1 straw + HW (1.50). Hence, these treatments could be recommended to the farmers for maintaining higher soil quality in Vertisols under soybean system. Correlation studies revealed stronger relationship between key indicators like OC (R² = 0.627), MBC (R² = 0.884), available Zn (R² = 0.739) and DHA (R² = 0.604) with Relative Soil Quality Index (RSQI). The results of the present study would be highly useful to the researchers, farmers and land managers.     

Effect of Primary Biomethanated Spentwash on Soil Properties,Nutrient Uptake,and Yield of Wheat on Sodic Soil

The experiment on the effect of primary biomethanated spentwash (PBSW) on soil properties, nutrient uptake and yield of wheat on sodic soil was carried out at a research farm of Post Graduate Institute, Mahatma Phule Krishi Vidyapeeth, Rahuri, Maharashtra state, India, during the post-monsoon season. The experimental soil was sodic calcareous having Sawargaon series of isohyperthermic family of Vertic Haplustepts. The experiment was laid out in a randomized block design with nine treatments and three replications. The treatments consisted of varying doses of PBSW (100, 200, 300, 400 and 500 m³ ha^?1), absolute control, farmyard manure (FYM) 5 t ha^?1 + RDF-AST (recommended dose of fertilizer as per soil test), FYM 5 t ha^?1 + 50% GR (gypsum requirement) + RDF-AST and FYM 5 t ha^?1 + 100% GR + RDF-AST. The results revealed that the physical properties, namely bulk density and hydraulic conductivity, were improved in sodic soil due to the application of increased doses of PBSW. A significant reduction in pH, calcium carbonate and exchangeable sodium percentage (ESP) and an increase in organic carbon, cation-exchange capacity (CEC) and electrical conductivity (EC) were observed in the soil, due to the addition of PBSW. The available soil nitrogen (N), phosphorus (P), potassium (K) and micronutrient iron, manganese, copper and zinc (Fe, Mn, Cu and Zn) content after the harvest of wheat was the highest in the 500 m³ ha^?1 treatment compared with all the other treatments. The exchangeable calcium (Ca²⁺), magnesium (Mg²⁺) increased significantly and exchangeable Sodium (Na⁺) reduced significantly with increased doses of PBSW. The saturation paste extract analysis also showed the same trend. A significant increase in the EC of the saturation paste of extract of the soil was observed in all PBSW treatments and it was the highest (4.75 dS m^?1) in PBSW application @ 500 m³ ha^?1. The application of PBSW @ 500, 400, 300 and 200 m³ ha^?1 resembled the treatments of FYM + gypsum @ 100 GR + RDF-AST, FYM + gypsum @ 50 GR + RDF-AST and FYM + RDF-AST, respectively, regarding the biological properties of sodic soil. The PBSW application @ 500 m³ ha^?1 had recorded the highest grain (47.33 q ha^?1) and straw (72.72 q ha^?1) yield and the maximum total uptake of N, P, K, Fe, Mn, Cu, and Zn by wheat, which was at par with the treatment of FYM (5 t ha^?1) + gypsum @ 100% GR + RDF-AST.     

Assessment of Environment-friendly Usage of Spent Wash and its Nutritional Potential for Sugarcane Production

Excessive and inappropriate use of fertilizers is a key factor of low sugarcane yield and degradation of soil. A two-year (2013–14 and 2014–15) field study was conducted to assess the impact of combined application of organic and inorganic fertilizers on sugarcane at research farm of Shakarganj Sugar Research Institute, Jhang, Pakistan. Experiment was conducted under randomized complete block design with three replications. Treatments were used as control (no exogenous application), spent wash (160 t ha^?1), (nitrogen, phosphorus and potassium) NPK (168:112:112 kg ha^?1), spent wash (120 t ha^?1) + NPK (42:28:28 kg ha^?1), spent wash (80 t ha^?1) + NPK (84:56:56 kg ha^?1), spent wash (40 t ha^?1) + NPK (126:84:84 kg ha^?1), and spent wash (160 t ha^?1) + NPK (42:28:28 kg ha^?1). Application of spent wash @ 80 t ha^?1 + NPK @ 84:56:56 kg ha^?1 resulted maximum crop growth rate (11.35 g m^?2 d^?1), leaf area index (7.78), and net assimilation rate (2.53 g m^?2 d^?1). Maximum number of millable canes (14), weight per stripped cane (0.90 kg), stripped cane yield (117.60 t ha^?1) and unstripped cane yield (141.25 t ha^?1) were observed with spent wash @ 80 t ha^?1 + NPK @ 84:56:56 kg ha^?1, followed by sole fertilizer application @ 168:112:112 kg NPK ha^?1 and spent wash @160 t ha^?1 + NPK @ 42:28:28 kg ha^?1. Similar trend was observed regarding quality parameters. The maximum benefit–cost ratio (1.80) was achieved with integrated application of spent wash @ 80 t ha^?1 + NPK @ 84:56:56 kg ha^?1.     

Influence of organic amendments on dissipation kinetics of two different pesticides in soil: a case study

A study was undertaken to investigate the remedial effect of some soil amendments (farmyard manure (FYM), press mud compost (PMC), cereal straw (CS) at 5 t ha^?1 and fresh cow dung slurry (FCD) @ 0.5 t ha^?1) on dissipation kinetics of imidacloprid and sulfosulfuron under laboratory conditions. Incorporation of CS or FCD was found to be most effective in degrading both the pesticides at faster rates. Dissipation of both the pesticides could be well accounted by two component (1 + 1) first order kinetics. The computed values of parameters revealed that use of organic amendments increased the dissipated fraction of imidacloprid and sulfosulfuron. Incorporation of CS or FCD in soil maintained relatively higher dissipation rate constants for both faster and slower dissipation processes of pesticides in comparison to control. Hence, eco-friendly practices of CS or FCD incorporation as soil amendment in soil can play a vital role in preventing soil and water pollution.     

Effect of Municipal Solid Waste Compost and Farmyard Manure Application on Heavy‐Metal Uptake in Wheat

The risks related to municipal solid waste compost application in comparison to farmyard manure and mineral fertilizers on durum wheat were investigated on a short‐term experiment. Compost was applied at 40 t ha^?1 and 80 t ha^?1 with or without chemical fertilizers. Analogously, farmyard manure was applied at 40 t ha^?1. Both compost and farmyard manure improved plant growth and nutrient uptake. However, compost amendment showed more effectiveness, especially at 80 t ha^?1. Alternatively, this dose of compost involved an increase of plant copper, cadmium, and zinc concentrations in plant tissues. Metal accumulation did not thwart the enhancement of wheat yield. Furthermore, grain translocation factor reached 1 only in the case of copper; however, it showed a significant decrease following compost application (ranged between 0.57 and 0.69). Bioconcentration factor showed a significant decrease with municipal solid waste compost supply, constituting an internal detoxification mechanism.     

Effects of Biosolids Based Soil Products on Soil Physical and Chemical Properties in Urban Gardens

A study was conducted to evaluate the effect of two biosolids based soil products on soil physical properties in urban community gardens in Tacoma, Washington. The Tagro soil product is made from Class A biosolids cake mixed with sand and sawdust. The GroCo biosolids compost is produced from biosolids cake and sawdust. Both products meet regulatory requirements for unrestricted use and are locally available to gardeners. Plots were established in 3 community gardens and maintained for 2 growing seasons. Amendments were applied at 200 Mg ha^?1 dry weight in the first year of the study. Plots were split for the 2^nd year with half of the amendment plots receiving an additional 200 Mg ha^?1 of amendments. Although lower in most metals than the soils they were added to, biosolids did not have a significant effect on total soil metal concentrations. Biosolids addition increased the water infiltration rate from 10.1 ± 0.95 ml min^?1 in control soils to between 51 ± 6.1 and 212 ± 34 ml min^?1, depending on the product used. Bulk density was decreased from 1.07 ± 0.01 g cm^?3 to between 0.51 ± 0.08 and 0.77 ± 0.03 g cm^?3. Total carbon, nitrogen and available phosphorus were increased in the biosolids amended plots in comparison to the control plots. Biosolids addition resulted in decreased pH (5.35-5.75) in comparison to the control soils (6.43). The results from this study indicate that biosolids-based soil amendments can be a suitable amendment for urban community gardens.     

Effects of cotton (Gossypium hirsutum L.) straw and its biochar application on NH3 volatilization and N use efficiency in a drip-irrigated cotton field

Reducing ammonia (NH₃) volatilization is a practical way to increase nitrogen (N) fertilizer use efficiency (NUE). In this field study, soil was amended once with either cotton (Gossypium hirsutum L.) straw (6 t ha^?1) or its biochar (3.7 t ha^?1) unfertilized (0 kg N ha^?1) or fertilized (450 kg N ha^?1), and then soil inorganic N concentration and distribution, NH₃ volatilization, cotton yield and NUE were measured during the next two growing seasons. In unfertilized plots, NH₃ volatilization losses in the straw-amended and biochar-amended treatments were 38–40% and 42–46%, respectively, less than that in control (i.e., unamended soil) during the two growing seasons. In the fertilized plots, NH₃ volatilization losses in the straw-amended and biochar-amended treatments were 30–39% and 43–54%, respectively, less than that in the control. Straw amendment increased inorganic N concentrations, cotton yield, cotton N uptake and NUE during the first cropping season after application, but not during the second. In contrast, biochar increased cotton N uptake and NUE during both the first and the second cropping seasons after application. Furthermore, the effects of biochar on cotton N uptake and NUE were greater in the second year than in the first year. These results indicate that cotton straw and cotton straw biochar can both reduce NH₃ volatilization and also increase cotton yield, N uptake and NUE. In addition, the positive effects of one application of cotton straw biochar were more long-lasting than those of cotton straw.