Manure Sources Research Articles

Source contribution to phosphorus loads from the Maumee River watershed to Lake Erie

Coastal eutrophication is a leading cause of degraded water quality around the world. Identifying the sources and their relative contributions to impaired downstream water quality is an important step in developing management plans to address water quality concerns. Recent mass-balance studies of Total Phosphorus (TP) loads of the Maumee River watershed highlight the considerable phosphorus contributions of non-point sources, including agricultural sources, degrading regional downstream water quality. This analysis builds upon these mass-balance studies by using the Soil and Water Assessment Tool to simulate the movement of phosphorus from manure, inorganic fertilizer, point sources, and soil sources, and respective loads of TP and Dissolved Reactive Phosphorus (DRP). This yields a more explicit estimation of source contribution from the watershed. Model simulations indicate that inorganic fertilizers contribute a greater proportion of TP (45% compared to 8%) and DRP (58% compared to 12%) discharged from the watershed than manure sources in the March–July period, the season driving harmful algal blooms. Although inorganic fertilizers contributed a greater mass of TP and DRP than manure sources, the two sources had similar average delivery fractions of TP (2.7% for inorganic fertilizers vs. 3.0% for manure sources) as well as DRP (0.7% for inorganic fertilizers vs. 1.2% for manure sources). Point sources contributed similar proportions of TP (5%) and DRP (12%) discharged in March–July as manure sources. Soil sources of phosphorus contributed over 40% of the March–July TP load and 20% of the March–July DRP load from the watershed to Lake Erie. Reductions of manures and inorganic fertilizers corresponded to a greater proportion of phosphorus delivered from soil sources of phosphorus, indicating that legacy phosphorus in soils may need to be a focus of management efforts to reach nutrient load reduction goals. In agricultural watersheds aground the world, including the Maumee River watershed, upstream nutrient management should not focus solely on an individual nutrient source; rather a comprehensive approach involving numerous sources should be undertaken.

Growth and Performance of Baby Spinach (Spinacia oleracea L.) Grown under Different Organic Fertilizers

Spinacia oleracea L. (baby spinach) is a relatively new leaf vegetable crop in Zimbabwe, so the agronomic performance is unknown. A 3-year field experiment was done at the Seke Teachers College research farm, Zimbabwe. The research evaluated the response of baby spinach to different types of organic manure sources, days after fertilizer application (DAS), and growing season. A 3 × 2 factorial in a completely randomized block design (CRBD) with three replicates was used. Baby spinach cultivar, Dash, was grown on three organic manures (goat applied at 14.894 t ha−1, cattle at 17.789 t ha−1, and poultry at 13.807 t ha−1) in winter 2018, 2019, and 2020. Compound D (7% N, 14% P, and 7% K) at 300 kg ha−1 was included as a control. Crop growth rate, leaf area index, leaf area ratio, net assimilation rate, total dry matter production, and harvest index were measured on 7-day intervals from 14 to 35 days after transplanting. Analysis of variance (ANOVA) to compare the effects of the treatments on the baby spinach growth parameters was done. Significant p < 0. 05 interactions on the type of organic manure × DAS × growing season were observed on all the measured response variables. There were varied effects of organic manures on growth performance at 14 to 28 DAS where poultry manure had higher growth performance compared to cattle and goat manure. Generally, there was a significant p < 0. 05 gradual increase in growth from 14 to 35 DAS on the organic manures and a decline from day 28 to 35 DAS under compound D. Low quality (large C/N) cattle and goat manure had lower effects than high quality (small C/N) poultry manure at early growth stages of the baby spinach. Unlike compound D, organic manure continuously supplied adequate nutrients throughout the life cycle (35 DAS) of the baby spinach.

Effects of Organic Manure Source and Weeding Frequencies on Growth Parameters of Jute Mallow (Corchorus olitorious)

Field trials were carried out during 2018 and during 2019 dry season periods at Federal College of Forestry and Mechanization Afaka Kaduna, located between latitude 10° 35”N and longitude 007° 21”E at altitude 644 m above sea level, to determine the effects of organic manure source and weeding frequencies on growth parameters of jute mallow (Corchorus olitorious). The experimental treatments consists of ten combinations of poultry manure + weed free, cow dung + weed free, goat dropping + weed free, poultry manure + weeding at 2 WAT, cow dung + weeding at 2 WAT, goat dropping + weeding at 2 WAT, poultry manure + weeding at 4 WAT, cow dung + weeding at 4 WAT, goat dropping + weeding at 4 WAT and no organic manure application + no weeding which were laid out in a randomize complete block design (RCBD) and replicated 3 times The growth parameters observed and measured were crop vigour score, plant height, shoot diameter, number of leaves and number of primary branches. Result of the study showed that at harvest (8 WAT) all the treatments significantly affected the vigour of jute mallow crop and gave comparable score than the least observed with no nutrient + no weeding as control. The result revealed that plant growth at harvest exhibited significantly taller plant with application of poultry manure + weeding at 2 WAT. In conclusion the result obtained from the study showed that poultry manure at 4 tons /ha + weeding at 4 WAT resulted in taller plant height, wider shoot diameter, increased number of leaves, number of branches than all other treatment due to lower weed infestation, it is therefore recommended as the best treatment combination to obtained the best growth rate of jute mallow.

Quality Parameters of Snap Bean Plant as affected by Compost Town Refuse, K-Levels and Bacillus cerculans

Field experiment was conducted out during season of 2017 as a randomized complete block with 9 treatments and replicated three times. The experiment location is located in the Experimental Farm of the Faculty of Agric. El-Mansoura Univ. to study the effect of compost town refuse and K-levels in presence of Bacillus cerculans on the growth, yield and pods quality snap bean plant.The obtained results could be summarized as average values of vegetative growth parameters, chemical content, yield and its component, quality of snap bean seeds and available K were realized with using CTR+ 75%K +BS. While concentrations of heavy metals in seeds, available N,P, K, DTPA-extractable Pb, Ni and Cd mg.kg-1 were recorded with using CTR as source of organic manure all comparing with control.

Agronomic and productivity efficiency of two animal manure sources on intercropped maize-groundnut in the derived savannah

Abstract Two animal manure sources (swine and sheep / goat manures) each at 5 Mt·ha−1, were applied in mono- and intercropped maize (Zea mays L.) and groundnut (Arachis hypogea L.). A general control (no manure treatment of the component crops was established) for productivity assessment. The trial, conducted at the Federal College of Agriculture, Ishiagu (04º 30′ N, 06º 45′ E, 150 m above sea level), in the derived savannah plains, Ishiagu, Nigeria in 2012 and 2013 mid-cropping seasons used a randomised complete block design with three replications. It assessed the agronomic performance, cropping system (CS) and plant nutrient (PN) productivity of maize-groundnut in mono-and intercrop as influenced by two animal manure sources. The two-year combined analysis indicated that animal manure sources significantly (P < 0.05) increased growth and yield components of the crop species in the systems. Swine manure application gave the significantly (P < 0.05) highest maize grain yield in both mono- and intercropped strategies in contrast to sheep / goat manure that had the highest grain yield in both cropping strategies in groundnut. The biological and economic productivity indices of the cropping system (CS) and plant nutrient (PN) indicated that the application of sheep / goat manure in the maize / groundnut mixture exhibited greater intercrop advantage whose total CS and PN land equivalent ratios (LERs) were higher by 4.79% and 13.57%, respectively, relative to swine manure application. Therefore, the application of animal manure demands encouragement in maize-groundnut intercrop, especially sheep / goat manure as it enhances crop yield, food security and protein intake of people living in Sub-Saharan Africa practicing different strokes of farming system technology. The results of this study showed that intercropping system exhibited positive growth, yield, biological and economic advantages over monocropping of the component species. The study further indicated that intercropped maize / groundnut that received sheep / goat manure exhibited the highest cropping system and plant nutrient yield advantage and agronomic efficiency compared to swine manure alone under the same environment.

Effects of the construction of fertile and cultivated upland soil layer on soil fertility and maize yield in black soil region in Northeast China.

Organic amendment return could enhance soil fertility, improve soil structure, and increase crop yield. However, how construction of soil layers can affect soil fertility and crop yield are not fully understood. We examined the effects of constructions of fertile and cultivated soil layer on soil fertility and maize yield in the upland black soil region in Northeast China, to provide theoretical guidance in increasing soil fertility and sustainable development of agriculture. Based on the combination of field plot experiments and demonstration regions, nine study sites with different ecological characteristics were selected from Heilongjiang, Jilin and Liaoning provinces from northeast China, covering dark brown, black, meadow, chernozem, albic, brown and cinnamon soils. There were three treatments in each study site, including maize straw return within 0-35 cm soil layer (CFⅠ), the combination of maize straw and organic manure return within 0-35 cm soil layer (CFⅡ) and conventional agricultural practice without organic amendmentas control (CK). The rate of straw return in CFⅠ and CFⅡ treatments were 10000 kg·hm-2, and full straw for demonstration regions. The rate of organic manure in CFⅡ treatment was 30000 kg·hm-2. Considerable difference in soil fertility were recorded among the nine study sites with the trend of tillage layer > sub-tillage layer, especially for dark brown soil and albic soil. Soil fertility of tillage layer and sub-tillage layer was relatively low both for brown soil and cinnamon soil. The heavy clay and plow pan were pivotal limiting factors of soil fertility for the black soil and the meadow soil. Compared with CK, the concentrations of soil organic matter (SOM), available nitrogen (AN), available phosphorous (AP), and available potassium (AK) in tillage layers was increased on average by 1.85 g·kg-1, 20.16 mg·kg-1, 1.56 mg·kg-1 and 17.2 mg·kg-1 in the CFⅠ and CFⅡ treatments in five study sites with more than two years of treatments. The contents of SOM, AN, AP and AK in sub-tillage layer increased by 2.09 g·kg-1, 12.06 mg·kg-1, 2.18 mg·kg-1 and 3.84 mg·kg-1, compared with tillage layer. CFⅠ treatment significantly enhanced the contents of SOM and AP in both tested soil layers, while CFⅡ treatment significantly enhanced all fertility indices in both tested soil layers. This indicated that the increase of organic amendment return is an effective way to improve soil fertility. Maize yield fluctuated under the combined effect of climatic conditions and soil types. The significant differences in maize yield under CK, CFⅠ and CFⅡ treatments were observed with a trend of CFⅡ > CFⅠ > CK. This result indicated that the construction of fertile and cultivated soil layer could significantly increase maize yield independent of soil types. The construction of fertile and cultivated soil layer based on maize straw return or maize straw and organic manure combined return within 0-35 cm soil layer, could simultaneously increase soil fertility in both tillage and sub-tillage layer, as well as maize yield. We suggested that the selection of approaches of the constructions of fertile and cultivated soil layer should consider soil types and the sources of organic amendments. It should also give priority to soil layers rich in organic manure source to construct fertile and cultivated soil layers.

Effect of organic manures and liquid organic formulations on wheat (Triticum aestivum L.) economics

A field experiment was conducted during Rabi season of last week of December 2019 at the certified organic experiment farm of the SHIATS Model of Organic Farm (SMOF) in NAI, Prayagraj to study the response of wheat under different sources of organic manures and liquid organic formulation on yield attributes of wheat (Triticum aestivum L.). The experiment consists 10 treatments with 3 replications laid out in a randomized block design. Organic manures i.e., Control 16 t/ha, M1: FYM 25% (4 t/ha) + Vermicompost 75% (4.5 t/ha), M2: FYM 50% (8 t/ha) + Vermicompost 50% (3 t/ha), M3: FYM 75% (12 t/ha) + Vermicompost 25% (1.5 t/ha) and Liquid organic formulations i.e., L1: Panchagavya at 2%, L2: Vermiwash at 5%, L3: Panchagavya at 2% + Vermiwash at 5%. The result concluded that the maximum grain yield (2.39 t/ha) and straw yield (3.67 t/ha) was recorded with application of FYM 75% + VC 25% + Panchagavya at 2% + Vermiwash at 5% spray. The economic analysis clearly indicates that higher benefit: cost ratio (2.11) recorded with application of FYM 50% + VC 50% + Panchagavya at 2% spray.

Effect of Different Sources of Organic Manures and Different Levels of Humic and Fulvic Acid on Growth, Flowering, Yield and its Components of Watermelon Plants

Effect of Different Sources of Organic Manures and Different Levels of Humic and Fulvic Acid on Growth, Flowering, Yield and its Components of Watermelon Plants

Physical, chemical and biological properties of soil as influenced by organic sources in cotton under rainfed condition

The field experiment was conducted during 2017-18 to study the Physical, chemical and biological properties of soil as influenced by organic sources in cotton under rainfed condition at Cotton Research Unit, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola during kharif season. The physical, chemical and biological properties were improved with FYM @12.5 t ha-1 followed by seed treatment of biofertilzer + PPFM PGR spray @ 1% + neem cake @ 250 kg ha-1 with cotton + sunhemp GMS (1:1). Soil available nitrogen, phosphorus and potassium after harvest of crop were influenced significantly due to different organic sources of manures. Significantly more nitrogen, phosphorus and potassium were remained in soil where RD of nutrient applied through organics on P equivalent basis (FYM @12.5t ha-1) after second year of study. While minimum soil available nutrients were observed control/no organics. Different organic sources showed numerically higher number microbial population (Bacteria, Fungi and Actinomycetes) was found in FYM and combined application of green manuring and cotton + blackgram and sunhemp intercropping + neem cake application @ 250 kg ha-1 at 50% flowering and 50% boll bursting stage of crop during both the years of study.

Effect of Different Manure Sources on Soil Chemical Properties, Performance and Yield of Maize on a Degraded Land

Application of manure for soil amendment plays important roles in reclaiming and improving soil properties of degraded soils. This study assessed the effects of composted and non-composted manures on a degraded soil under continuous maize production. The treatments applied consisted of composted manures in form of cassava based compost (CBM) and verticompost (VC) at the rate of 0, 30, 60 and 120 tons/ha, non-composted manure (NC) applied as poultry manure (PM), and an un-amended control plot. These treatments were laid out in a randomized complete block design replicated three times. Soil physical and chemical properties were determined for two consecutive seasons, with maize (SUWAN 1-SYR) planted as test crop. The CBM, VC and PM treatments increased the soil organic carbon content by 18.2, 24.1, and 22.3 % respectively. Corresponding increases observed in cation exchange capacity (CEC) were 13.6, 15.7, and 15.2 %. The comparison of the soil chemical properties measured indicated positive effects from the amendments on the soil properties in the order: CBM < PM < VC. The maize grain yield of cassava based fertilized plot consistently and significantly was higher than the other treatments in both cropping seasons. However, both the composted and non-composted manures favored improved maize growth and resulted in higher grain yields (4.62 – 6.03 t ha-1) than the un-amended control treatment (3.69 t ha-1). The study therefore showed that the incorporation of manures, whether composted or non-composted, is beneficial to soils, improving one or more essential soil attributes thus reducing soil degradation.

Reduction of salinity and sodicity of saline-sodic soils under filed condition in Brazilian semi-arid region

The salinization process in irrigated areas in the semi-arid region of Brazil, constantly cause economic, social, and environmental problems. Therefore, the present research aimed at assessing the effect of different amounts of agricultural gypsum and cow manure associated with an artificial drainage system and salt leaching due to the application of amount of water in a saline-sodic soil under field condition. The experiment was carried out at the irrigated perimeter of Jacaré-Curituba, Poço Redondo, with an experimental design split into plots made of doses of gypsum corresponding to 0,0; 4,300.00 and 8,600.00 kg.ha-1 combined with and without organic matter, cow manure with 25,000.00 kg.ha-1 and 0.00 kg.ha-1. Each treatment (six in total) was repeated four times. Thus, 24 plots of 50 m2 were monitored (split plot) with an area of 1.200 m2. All treatments had an artificial drainage system in the center of the plot and the same amount of leach water was then added. The outcomes allowed us to understand that all treatments had the salinity and sodicity soil values reduced at the studied site. Moreover, the treatments with cow manure (source of organic matter) presented the best results, because soil electrical conductivity values (< 4 dS m-1) reached the normal level to agricultural yield.

Redox Chemistry and Nutrient Release from Organic Amended Terrace Soil under Anaerobic Incubation

Aims: To examine the changes in pH and Eh values of terrace soils during anaerobic incubation when amended with different organic materials, and to study N, P and S release from different manure and bio-slurry in terrace soil under anaerobic condition.
 Study Design: The experiment was carried out following Complete randomized design (CRD) with two replications.
 Place and Duration of Study: A laboratory incubation study was conducted in Soil Science Laboratory, Bangladesh Agricultural University, Mymensingh in December 2014 for 98 days.
 Methodology: The surface (0-15 cm) soil sample was collected from rice growing field of a selected area of Bhaluka, Mymensingh. The incubation study was carried out using four different sources of organic manures with two replications and five treatment combinations. The changes in soil pH, Eh and release pattern of N, P, and S from some organic materials in terrace soil under anaerobic incubation were investigated during December 2014 to April 2015. The soil was amended with all the treatments at 2g 100 g-1 (air dry basis) soil and incubated for 14 weeks at 25° C. The N, P and S release were determined by the measurement of NH4-N, phosphate P and SO4-S on destructive sampling at every two weeks.
 Results: The pH values increased at initial stage but gradually decreased over time to neutral and the soil became reduced with the advancement of incubation, it varies (1-3 weeks) depending on the quality of organic matter used. The reduction potential showed a significant variation among the treatments. Overall, when the pH values were averaged over the weeks, the highest pH value was measured in poultry bio-slurry (PB) amended soil followed by poultry manure (PM), cow dung bio-slurry (CDB) and cow dung (CD) amended soils and the lowest was in control. In case of Eh, the most negative (-133.08) Eh value was measured in PM amended soil followed by poultry bio-slurry (PB), CD and CDB amended soils. Control soil had comparatively positive Eh value. At the end of incubation, the highest amount of NH4-N found in CDB followed by CD, PM, PB and the lowest was in control; the highest amount of phosphate P found in PB followed by PM, control, CDB and CD; the highest amount of SO4-S found in PB followed by PM, CD, CDB and the lowest was in control.
 Conclusion: PB is the best source of organic amendment with respect to release of P and S, whereas CDB showed the best performance in release of N. Nutrient release and availability in reduced environment in terrace soil are a function of soil redox chemistry which is influenced by the quality and quantity of organic matter.

Different organic manure sources and NPK fertilizer on soil chemical properties, growth, yield and quality of okra

Use of organic manures to meet the nutrient requirement of crop would be an inevitable practice in the years to come for sustainable agriculture since organic manures generally improve the soil physical, chemical and biological properties. Hence, field experiments were carried out in 2017 and 2018 to compare the impact of different organic manures and NPK fertilizer on soil properties, growth, yield, proximate and mineral contents of okra (Abelmoschus esculentus L.). The treatments each year 2017 and 2018 consisted of: rabbit manure, cow dung, poultry manure, green manure [Mexican sunflower (Tithonia diversifolia Asteraceae)], pig manure, NPK 15-15-15 fertilizer applied at 120 kg N ha−1 and a control (no manure/inorganic fertilizer). The seven treatments were laid out in a randomized complete block design with three replication. Organic manures and NPK fertilizer increased the soil organic matter (OM), N, P, K, Ca and Mg (NPK fertilizer did not increase OM, Ca and Mg significantly), growth, yield, minerals, protein, ash, carbohydrate and mucilage contents of okra fruit as compared with control. Organic manures improved okra yield compared with NPK fertilizer. Okra growth and yield parameters were significantly higher in 2018 compared with 2017. Control, rabbit manure, cow dung, poultry manure, green manure, pig manure and NPK fertilizer in 2018 increased the pod yield of okra by 9.7%, 35.3%, 57.9%, 36.2%, 39.2%, 45.5% and 3.2%, respectively compare with the same treatment in 2017. Amongst various organic manures, poultry manure produced significantly higher plant growth, yield, mineral and proximate composition of okra because of its high soil chemical properties which could be related to its lowest C: N ratio, lignin and lignin: N ratio. Results also showed that okra grown during high intensity rainfall has higher yield but with reduced quality except its mucilage content. Therefore, planting of okra with poultry manure under moderate rainfall will enhance the health benefit from the fruit, however, those that desire its mucilage content planting during high rainfall is recommended.

Chemical identification and insecticidal effect of Tephrosia vogelii essential oil against Cerosipha forbesi in strawberry crop

Botanical insecticides based on oils and plant extracts have proven to be an efficient alternative method for pest control, as required by agroecological systems. Tephrosia vogelii (Hook.f.) has been used in agriculture as a source of green manure and in the control of pests and diseases. However, there are few studies regarding the use of compounds derived from the secondary metabolism of this plant. Chemical compounds present in the essential oil of Tephrosia vogelii flowers were identified, aiming at its use to control the aphid Cerosipha forbesi in the strawberry crop. Bioassays were carried out under laboratory and semi-field conditions, with different concentrations of the essential oil and the lethal concentrations LC50 and LC90 were estimated. Only two groups of terpenic compounds were identified in the essential oil of T. vogelii: monoterpenic hydrocarbons (alpha-pinene; limonene and ocimene) and oxygenated sesquiterpenes (nerolidol, spathulenol and farnesol). The essential oil of T. vogelii presented toxic effect against C. forbesi, with the LC50 and LC90 of the insect population estimated at 0.106 and 0.380 mL/L, respectively. Under semi-field conditions, mortality increased at higher concentrations, and the LC50 and LC90 were estimated at 0.114 mL/L and 0.465 mL/L, respectively. Mortality over 90% was observed after 24 h of the essential oil application, for all of the tested concentrations, showing an insecticidal action of the oil against the aphid C. forbesi.

Co-transesterification of waste cooking oil, algal oil and dimethyl carbonate over sustainable nanoparticle catalysts

Key challenges for the application of biodiesel include their high acid value, high viscosity, and low ester content. It is essential to develop later-generation biodiesel from unexploited non-food resources for a more sustainable future. Reuse of biowaste is critically important to address these issues of food safety and sustainability. Thus, the co-transesterification of waste cooking oil (WCO), algal oil (AO) and dimethyl carbonate (DMC) for the synthesis of fatty acid methyl esters (FAMEs) was investigated over a series of nanoparticle catalysts containing calcium, magnesium, potassium or nickel under mild reaction conditions. Nanoparticle catalyst samples were prepared from biowaste sources of chicken manure (CM), water hyacinth (WH) and algal bloom (AB), and characterized using XRD, Raman and FESEM techniques for the heterogeneous production of biodiesel. The catalyst was initially prepared by calcination at 850 °C for 4 h in a major presence of CaxMgyCO3, KCl and K2CO3. The WCO and AO co-conversion of 98% and FAMEs co-selectivity of 95% were obtained over CM nanoparticle catalyst under the reaction conditions of 80 °C, 20 mins and DMC to oil molar ratio of 6:1 with 3% catalyst loading and 3% methanol addition. Under the optimum condition, the density, viscosity, and cetane number of the biodiesel were in the range of diesel standards. Nanoparticle catalysts have been proven as a promising sustainable material in the catalytic transesterification of WCO and AO with the major presence of calcium, magnesium and potassium. This study highlights a sustainable approach via biowaste utilization for the enhancement of biodiesel quality with high ester content, low acid value, high cetane number, and low viscosity.

Life Cycle Assessment of Struvite Precipitation from Anaerobically Digested Dairy Manure: A Wisconsin Perspective.

Recovering valuable nutrients (e.g., P and N) from waste materials has been extensively investigated at the laboratory scale. Although it has been shown that struvite precipitation from several manure sources contributes to nutrient management practices by recovering valuable nutrients and preventing them from reaching water bodies, it has not been widely applied in commercial (i.e., farm) scales. The purpose of this study is to evaluate the potential environmental impacts of the struvite recovery process from the liquid portion of the anaerobically digested dairy cow manure generated in Wisconsin, USA, dairy farms using life cycle assessment methodology for both bench- and farm-scale scenarios. The struvite precipitation process involves the use of additional chemicals and energy; therefore, investigating upstream impacts is crucial to evaluate the environmental costs and benefits of this additional treatment process. Results indicate that up to a 78% impact decrease in eutrophication potential can be achieved when P and N are recovered in the form of struvite and are applied in lieu of conventional fertilizers, rather than using the liquid portion of the anaerobically digested dairy manure as a fertilizer. Additionally, significant differences are identified in the majority of environmental impact categories when the struvite precipitation process is modeled and evaluated in a farm-scale setting. Future work should expand to evaluate the overall environmental impacts and trade-offs of struvite recovery application, including the anaerobic digestion system itself at the farm scale. Integr Environ Assess Manag 2021;17:292-304. © 2020 SETAC.

Discrimination of Nitrogen Sources in Karst Spring Contributing Areas Using a Bayesian Isotope Mixing Model and Wastewater Tracers (Florida, USA)

ABSTRACT Many springs in Florida have experienced a proliferation of nuisance algae and alteration of trophic structure in response to increases in nitrate concentration concurrent with rapid population growth and land use intensification beginning in the mid-20th century. While loading targets and remediation plans have been developed by state agencies to address excess nitrogen inputs, further confirmation of the relative contribution of nitrogen sources to groundwater is necessary to optimize the use of resources when implementing projects to reduce nitrogen loads. In the present study, stable isotopes of nitrate and wastewater indicators were used to discriminate sources of nitrogen in wells and springs in central Florida. Sampling was performed in 50 wells at 38 sites and at 10 springs with varying levels of agriculture and urban development. Nitrate isotope values were used to develop Bayesian mixing models to estimate the probability distribution of the contributions of nitrate sources in wells. Prior probabilities for the fractional contribution of each source were adjusted based on land use and density of septic tanks. Sucralose and the Cl:Br mass ratio were used as confirmatory indicators of wastewater sources. In residential areas, mixing model results indicated that fertilizer or mixed fertilizer and wastewater (septic tank effluent and reuse water) were the primary sources, with sucralose detections corresponding to wells with elevated contributions from wastewater. Sources of nitrogen in pasture and field crop areas were primarily fertilizer and manure; however, model posterior distributions of δ15N indicated that manure sources may have been overpredicted. The present study demonstrates the utility of a multi-tracer approach to build multiple lines of evidence to develop locally relevant remediation strategies for nitrogen sources in groundwater.

Impact of Cropping Systems and Resource Conservation Techniques on Productivity and Profitability of Systems

Background: A suitable cropping system seem to be the possible solution to meet the continuous increase in demand for food, stability of income and diverse requirement of food grains. Selection of suitable cropping system for conservation of resources has prime importance now a day. The cropping systems selected in study have higher potential of production along with incorporable residues during winter. The residues of cotton, castor and mustard crops (Crops in selected cropping systems) have more potential to feed nutrients to soil as compared to burning. So incorporation of such crop residues in to soil helps to recycle the nutrients to correct their deficiencies. Farmyard manure is being used as major source of organic manure in field crops. Thus to maintain the soil health, integrated nutrient management approaches involving FYM and mineral source need to be standardized. So there is need to find out agronomically efficient and economically viable cropping system which can perform better for increasing productivity and profitability with association of conservation of natural resources. Methods: The experiment was laid out in split plot design with three replications. Sixteen treatment combinations comprising of four cropping system treatments viz, C1 : Cotton- Summer Pearlmillet, C2 : Greengram + Kharif Castor (Relay), C3 : Greengram - Mustard - Summer Pearlmillet and C4 : Greengram - Rabi Castor and two residue incorporation treatments viz, R0 : No residue incorporation and R1 : Residue incorporation as well as two fertilizer doses viz, F1 : 100% RDN through inorganic fertilizer and F2 : 75% RDN through inorganic fertilizer + 25% RDN through FYM were evaluated in the study. Result: Cotton - summer pearlmillet cropping system found significantly superior by recording higher pearlmillet equivalent yield, system productivity and system profitability while, total weed count/m2 and total weed dry weight were found the lowest under greengram- kharif castor (relay) cropping system. Residue incorporation secured top position by recording significantly the highest pearlmillet equivalent yield, system productivity and system profitability as well as lowest total weed count/m2 and total weed dry weight. Application of 75% RDN through inorganic fertilizer + 25% RDN through FYM recorded significantly highest pearlmillet equivalent yield, system productivity and system profitability. In case of weed count and weed dry weight, 100% RDN through inorganic fertilizer found significantly superior by recording lowest total weed count/m2 and total weed dry weight.

Effect of Combined Organic and Inorganic Fertilizer Application on Soil Attributes, Yield and Quality of Sweet Potato (Ipomoea batatas L.)

The use of organic fertilizers in adequate doses is an alternative to reduce the use of inorganic inputs, improving the soil chemical attributes, and increasing the production and quality of sweet potato. In this perspective, the objectives of this study were: (i) to evaluate the effects of fertilization with poultry and bovine manure, Ribumin®, and of conventional fertilization on soil attributes, production, and quality of sweet potato; and (ii) to evaluate the residual effect of organic fertilization on the production components and quality of sweet potato, in the second crop cycle. The two experiments were developed in the 2018/2019 crop year at the Agrotechnical School of the Federal University of Roraima (UFRR), Brazil. The treatments were arranged in a randomized block design with three replications, using a (2 × 5 × 2) + 1 factorial arrangement referring to two manure sources (bovine and poultry manure) and five doses, aiming at increasing the content of soil organic matter (1.35%) to 2.35; 3.35; 4.35, and 5.35%, in the absence and presence of Ribumin®, and an additional treatment referring to organomineral fertilization. For the evaluation of the second cycle, the residual effect of the manure was evaluated by applying only Ribumin® and conventional fertilizers. In the first cycle, the addition of 50.4 t ha-1 of bovine manure without Ribumin® provided the highest values of total (14.7 t ha-1) and marketable yield (14.6 t ha-1). However, the addition of poultry manure associated with the application of Ribumin® provided no increments in the sweet potato production components. Under the same experimental conditions, chemical fertilization can be replaced by fertilization with organic sources.

Application of Response Surface Methodology in Optimization of the Yields of Common Bean ( Phaseolus vulgaris L.) Using Animal Manures

The objective of design and analysis of experiments is to optimize a response variable which is influenced by several independent variables. In agriculture, many statistical studies have focused on investigating the effect of application of organic manure on the yield and yield components of crops. However, many of these studies do not try to optimize the application of the manures for maximum productivity, but select the best treatment among the treatment range used. This is mainly due to design and analysis of experiments applied. Therefore, there is a need to apply a statistical method that would establish the effect of the application of organic manures on crop production and in addition optimize the levels of application of these manures for maximum productivity. This study aimed at application of response surface methodology for optimization of the yields of common bean (Phaseolus vulgaris L.) using animal manure. The study was conducted at Chuka University Horticultural Demonstration Farm. The experiment was laid down in a Randomized Complete Block Design. The treatments consisted of three organic manure sources (cattle manure, poultry manure and goat manure) each at three levels (0, 3 and 6 tonnes per ha). Data was collected from six weeks after sowing to physiological maturity. Data was collected on the weight of the grain yield harvested in each experimental plot measured by use of a weighing scale. The data collected was analysis using the R-statistical software. The study findings indicated that animal manures had a significant effect (p -1, 12.7213 t ha-1 and 4.1417 t ha-1 cattle manure, poultry manure and goat manure, respectively. These were the optimum levels that would lead to maximum yield of common beans without an extra cost of input.