Manure Application Methods Research Articles

Evaluating effects of dairy manure application method on soil health and nitrate

Liquid manures are typically applied via surface broadcasting; however, subsurface injection is an alternative characterized by greater nutrient retention and a spatially distinct application pattern, altering management strategies and nutrient cycling dynamics. Thus, a field study was conducted from spring of 2016 through fall of 2018 on seven sites to assess pre-sidedress nitrate test (PSNT) methodology, seasonal soil nitrate nitrogen (NO3−-N) trends, corn (Zea mays L.) silage and grain yield, estimated milk production via MILK 2006, and biological soil health among surface broadcast and subsurface injection applications of dairy slurry. A weighted sampling method had a coefficient of variation of 37%, ~8% higher relative to random (28%) and equispaced (30%) sampling methods. Soil NO3−-N was greater in 7 out of 25 measurements under subsurface injection and 30% higher under injection on average during the corn PSNT. There were no significant differences in crop yield or milk production between surface and injected slurry applications, but means were always higher for injection. Biological soil health tests were highly variable, and analyzing carbon mineralization (C-min) took considerably more time than other tests. There were no significant differences in C-min between manure application methods; although, mineralization values increased with soil organic matter. Estimated microbial biomass was on average 46% lower under subsurface injection relative to surface broadcast in 2017, but results were inconsistent in 2016 and 2018. Overall, the biological indicators of soil health were not productive in showing differences between application methods. Nevertheless, it is apparent that injection can decrease chemical sidedress N applications, and either the standard method of PSNT soil sampling or an equispaced method can be used in injected fields.

Nitrogen cycling trade-offs with broadcasting and injecting dairy manure

Understanding the fate of nutrients in land-applied manure is key to improving the efficiency of their use in crop production. We developed nitrogen (N) budgets for 2 years of continuously cropped corn fertilized by dairy manure via broadcast application or shallow disk injection. Major pathways and pools of N loss were monitored on 12, 0.04 ha field lysimeters in central Pennsylvania, USA to estimate the impact of manure application method on N fate: gas emissions, off-site runoff (overland and subsurface flow), crop uptake, and, soil storage. The budgets illuminated trade-offs in N cycling with each management strategy. Crop removal accounted for the largest portions of manure N applied in both budgets (16–43%). Injection manure N balances were more difficult to close because balances included a large proportion of ‘unaccounted’ N (49% and 68% of applied N for two accounting periods). Even so, results point to cumulative differences in nutrient use efficiencies that can be attributed to the greater conservation of ammonia-N with manure injection. There was an apparent build-up of soil N with manure injection that was not observed with broadcast application (in pre sidedress nitrogen test measurements). However, these trends were preliminary; over the two growing seasons covered by this study, these findings did not result in significant differences in corn yield or crop N removal.

Development of PLEAD: A Database Containing Event-based Runoff Phosphorus Loadings from Agricultural Fields.

Computer models are commonly used for predicting risks of runoff P loss from agricultural fields by enabling simulation of various management practices and climatic scenarios. For P loss models to be useful tools, however, they must accurately predict P loss for a wide range of climatic, physiographic, and land management conditions. A complicating factor in developing and evaluating P loss models is the relative scarcity of available measured field data that adequately capture P losses before and after implementing management practices in a variety of physiographic settings. Here, we describe the development of the P Loss in runoff Events from Agricultural fields Database (PLEAD)-a compilation of event-based, field-scale dissolved and/or total P loss runoff loadings from agricultural fields collected at various research sites located in the US Heartland and southern United States. The database also includes runoff and erosion rates; soil-test P; tillage practices; planting and harvesting rates and practices; fertilizer application rate, method, and timing; manure application rate, method, and timing; and livestock grazing density and timing. In total, >1800 individual runoff events-ranging in duration from 0.4 to 97 h-have been included in the database. Event runoff P losses ranged from <0.05 to 1.3 and 3.0 kg P ha for dissolved and total P, respectively. The data contained in this database have been used in multiple research studies to address important modeling questions relevant to P management planning. We provide these data to encourage additional studies by other researchers. The PLEAD database is available at .

Influence of Dairy Slurry Manure Application Method, Fall Application‐Timing, and Winter Rye Management on Nitrogen Conservation

Core Ideas Manure application method and timing affected ryelage but not rye cover biomass. Manure injection compared to broadcast conserved manure‐N in ryelage. Manure injection compared to broadcast with rye cover resulted in more corn silage. Late injection compared to early injection conserved more manure‐N in ryelage. Late versus early injection resulted in more manure‐N in soil and more corn after cover crops. Fall manure applications can lead to nutrient losses prior to spring planting. This 2‐yr study evaluated effects of winter cereal rye (Secale cereal L.) crop management (cover crop versus ryelage), and fall, dairy slurry manure application method (broadcasted versus injected) and timing (September vs. November) on manure–N conservation. Nitrogen conservation was calculated from NH3 volatilization, percentage of manure–N in aboveground rye (%ManureN‐R) and soil (%ManureN‐S) in spring prior to corn (Zea mays L.) planting, and subsequent corn yield. Ryelage compared to cover crop conserved more %ManureN‐R (2.6‐fold) and despite reduced corn yield, ryelage‐corn treatments with 3.6‐fold greater rye biomass produced 20% greater total harvested forage than cover crops. Compared to broadcasted manure (BM), injected manure (IM) reduced NH3 losses and increased ryelage biomass (42%) after September (EARLY) applications, %ManureN‐R (50%), %ManureN‐S at multiple depths, and total harvested forage (20%). Corn silage yield with IM compared to BM was also greater after all cover crop treatments (23%), all ryelage treatments in 2015 (35%), and ryelage with a November application (LATE) in 2014 (30%). Compared to EARLY, LATE applications increased %ManureN‐R in ryelage after BM (44%) and IM (50%), %ManureN‐S at multiple depths in both rye treatments, and corn silage yields with IM following cover crops (21%). Following ryelage, corn yields were not larger following greater %ManureN‐S in LATE IM versus BM, suggesting potential for more soil NO3 leaching loss with LATE IM. However, multiple management options reduced fall manure–N losses and conserved manure–N for crop utilization, allowing for farm management flexibility.

Manure Application Decisions Impact Nitrous Oxide and Carbon Dioxide Emissions during Non‐Growing Season Thaws

Core Ideas Manure injection increased N2O emissions vs. broadcast and broadcast + plow application. Winter thaws increased N2O and CO2 emissions, particularly in soils injected with manure. The impacts of manure application decisions may extend beyond the growing season to influence N2O and CO2 fluxes during winter thaw events. Climate and agricultural management are strong drivers of greenhouse gas (GHG) emissions, but little is known about potential interactions among these drivers. Climate change will likely increase the frequency of wintertime thaws in northern agricultural systems, which have been shown to induce large pulses of carbon dioxide (CO2) and nitrous oxide (N2O). We tested the hypothesis that different manure application practices would interact with thaw events to produce GHG emission pulses of different sizes. Specifically, we expected manure injection would increase CO2 and N2O emissions relative to other manure application methods by enhancing subsurface microbial substrate availability. We conducted a laboratory incubation study with frozen, intact soil cores from a continuous corn (Zea mays L.) system under three manure application methods: broadcast, broadcast + plow, and injection. Cores were subjected to three temperature treatments over 8 d: frozen (−7°C), freeze–thaw (alternating −7 and 5°C), and thaw (5°C). In the freeze–thaw and thaw treatments, cumulative N2O emissions were 2 to 20 times greater in injected versus broadcast treatments (6.5 mg N2O‐N m–2 averaged across broadcast treatments); cumulative CO2 emissions were up to two times higher in injected versus broadcast treatments (1017 mg CO2–C m–2 averaged across broadcast treatments). Our results suggest that the impacts of manure application choices extend beyond the growing season to increase N2O and CO2 emissions during wintertime thaws, potentially interacting with a warming climate to increase GHG emissions.

Crop Yield and Nitrous Oxide Emissions following Swine Manure Application: A Meta‐Analysis

Core Ideas Swine manure is a potential nutrient source but may harm environmental quality. Crops fertilized with swine manure matched those using synthetic fertilizer. Swine manure did not increase nitrous oxide compared with synthetic fertilizer. Manure application method and conditions dictate yield and environmental impacts. Swine manure has potential for reuse as fertilizer on cropland and pastureland. Currently, producers may be hesitant to land apply swine manure because information regarding the impacts to crop production and environmental quality has been inconsistent. The objective of this research was to synthesize the literature investigating impacts of swine manure application on crop yield and soil nitrous oxide emissions as compared to synthetic fertilizer. Overall, the meta‐analysis of 39 studies shows that swine manure does not affect either crop yield or nitrous oxide emissions. However, a moderator analysis indicated that crop yield using manure fertilizer may be adversely affected in fine‐textured soils or when applied to the soil surface. While these results suggest that swine manure may be safely applied as fertilizer, producers should still be cautious with how manure is applied to capture its N value without yield losses or detrimental effects to environmental quality.

Effects of wheel traffic and farmyard manure applications on soil CO 2 emission and soil oxygen content

This 2-year field study investigated the effects of different wheel traffic passes, manure amounts, and manure application methods on soil temperature, soil moisture, CO 2 emission, and soil O 2 content. To achieve this purpose, three different wheel traffic applications (no traffic, one pass, and two passes) were used. In the experiments, two different methods of manure applications (surface and subsurface) and three different farmyard manure amounts were used with a control plot (N0), 40 Mg ha -1 (N40), and 80 Mg ha -1 (N80). Manure was applied in both years of the experiment in the first week of April. For the subsurface application, the manure was mixed in at approximately 10 cm of soil depth with a rotary tiller. According to the results, soil temperature, soil moisture, penetration resistance, and bulk density increased with increasing wheel traffic except CO 2 emission for 2014 and 2015. CO 2 emission values decreased with traffic. Subsurface manure application caused more CO 2 emission compared to surface application. The increase in manure amounts led to an increase in CO 2 emission and soil moisture content. The effects on soil O 2 content were observed only during 2015. Maximum oxygen values were obtained in the plots where compaction was not applied. In addition, surface manure application caused more soil O 2 content compared to subsurface application.

Nitrous Oxide Emissions from Surface versus Injected Manure in Perennial Hay Crops

Core Ideas Low‐producing alfalfa and tall fescue stands can benefit from the addition of manure. Injection of manure (slicing of soil) did not reduce yields of alfalfa or tall fescue. Impact of manure injection on N2O emissions is weather and species dependent. When injection of manure does not increase yield, surface application is more economical. Injecting manure can preserve N, but may mechanically damage the root systems of hay crops such as tall fescue (Festuca arundinacea L.) and alfalfa (Medicago sativa L.). Such damage could result in reduced yield. The objective of this study was to compare the effect of disk‐injected versus surface applied liquid dairy manure on (i) alfalfa and tall fescue dry matter (DM) yield and (ii) nitrous oxide (N2O) emissions. Two manure application methods (injection versus surface application) and two no‐manure controls (injection versus no soil disturbance) were replicated six times in 2014 and 2015 on established hay stands. Manure application increased alfalfa yield from 2.9 to 3.7 and from 4.2 to 5.1 Mg DM ha‐1 in 2014 and 2015, respectively, regardless of application method, suggesting no yield penalty or benefit from injection. Nitrous oxide emissions increased two‐ and six‐fold with manure addition, consistent with higher yields under manure application. Compared with the control treatments, manure addition to tall fescue increased yield by 0.8 and 3.3 Mg ha‐1 in 2014 and 2015, respectively, also with no yield benefit or penalty from injection. Injection of manure did not influence N2O emissions in 2014, but increased emissions by 35% compared with surface application in 2015, and this is consistent with differences in soil moisture that year. Our results indicate injection of liquid manure can be implemented without negatively influencing yield in hay crops, while the impact on N2O emissions can be crop and weather dependent. When injection does not increase yield, the surface application of manure to hay crops is more economical.

Impact of interventions on knowledge and adoption of improved technologies in ber (Ziziphus mauritiana) cultivation

The present study was conducted to ascertain the knowledge gain and adoption level of ten specific technologies demonstrated through various interventions during earlier years by the KVK. Barmer, chohtan, Baytoo, Balotra, and Gudamalani blocks of Barmer District were taken for study and 20 beneficiary farmers were randomly selected from each block. The data were collected through personal interview with well-designed questionnaire. The data revealed that the gain in knowledge was more than 50 per cent for technologies viz., time and method of pruning of Ber (72%), use of micronutrient (68%), plant protection techniques and time of planting (65%), method of manure and fertilizer application (58%), drip irrigation (54%) and recommended dose of fertilizer (51%). Similarly, time and method of pruning, plant protection techniques and recommended dose of fertilizer recorded the highest extent of adoption as 63, 56 and 19 per cent, respectively. This could be due to the easiness and effectiveness of technologies at field level application and yield enhancement. Though the acquisition of knowledge for the technologies like value addition (58%), use of micronutrient (68%) and drip irrigation (62%) was high, the number of farmers adopting these technologies were very low i.e., 31, 25 and 13 per cent, respectively.

Relative role of transport and source-limited controls for estrogen, TDP, and DOC export for two manure application methods

Abstract Developing successful mitigation strategies for emerging contaminants can be difficult due to incomplete understanding of factors controlling their fate and transport. A variety of data analysis techniques can be used to assess the fate and transport behavior of pollutants in runoff water. Here, we use concentration-discharge, load-discharge, and coefficient of variation relationships to examine how two methods of dairy manure application (surface broadcast and shallow disk injection) affect the transport dynamics of estrogens, total dissolved phosphorus (TDP), and dissolved organic carbon (DOC). Nine surface runoff events were sampled from Oct 2014–June 2015 from 12 research plots (six with each application method) in Central Pennsylvania after fall application. The plots received inorganic fertilizer for 15 years, but only four manure applications since 2012. Both TDP and DOC exhibited similar transport behavior under both manure application methods that indicate transport-limited control of export, potentially due to legacy sources in soils. However, estrogen loads exhibited dilution responses, a sign of source-limited controls. The strength of the dilution response for estrogens was greater for surface applied manure relative to the injected manure, suggesting that manure application methods can be used to control the mobilization potential of estrogens. Additionally, results suggest the longer-term application history of inorganic fertilizer led to the transport-limited dynamics exhibited by TDP, while the short-term application history of manure caused estrogen transport to be source-limited. Our findings provide insight into how anthropogenic drivers (application type, method, and history) and natural drivers (hydrology, biogeochemistry) are interconnected in agricultural fields, and point to opportunities for protecting downstream water quality.

Effect of the Manure Levels , Depth and Method of Applying Using Ditch Opener and Manure Laying Machine on Some of Soil Physical Properties

A field experiment was carried out in silty loam soil at Agricultural research station, College of Agriculture during the corn growing season of 2015. The aim of study was to determine the effect of manure (cattle residues) levels (0, 20 and 40 ton ha-1), the depth of manure application (10, 20 and 30 cm), and the method ofmanure application (mixing with soil and subsoil laying) on soil bulk density and soil water content. The manure was added at certain treatments by using a ditch opener and manure laying machine which was designed and manufactured in the Agriculture Machines and Equipment Department, College of Agriculture, University of Basrah in 2015. The field was plowed perpendicularly, and the treatments were arranged in RCBD with split-split plot design with three replicated using drip irrigation system. Corn (Zea mays L.) seeds were planted on the manure rows. All plots received NPK fertilization with the same levels. At the end of growing season, soil samples (0-30 cm) were collected to examine soil bulk density and soil water content. The results showed that, lower bulk density and higher water content were obtained at level of 40 ton ha-1compared with the levels of 0 and 20 ton ha-1. The soil bulk density decreased from1.23 to 1.20 Mg m-3 and the soil water content increased from 26.33 to 30.23 % whenthe depth of application increased from 10 to 30 cm. Mixing manure with soil resulted in lower value of bulk density and higher value of water content compared with subsoil laying method. Mixing manure with soil down to the depth of 30 cm amount of 40 ton ha-1 improved the soil bulk density which reached lower value of 1.14 Mg m-3 and soilwater content increased to 36.19% among all other treatments.

Effect of the Manure Levels , Depth and Method of Applying Using Ditch Opener and Manure Laying Machine on Some of Soil Physical Properties

A field experiment was carried out in silty loam soil at Agricultural research station, College of Agriculture during the corn growing season of 2015. The aim of study was to determine the effect of manure (cattle residues) levels (0, 20 and 40 ton ha-1), the depth of manure application (10, 20 and 30 cm), and the method ofmanure application (mixing with soil and subsoil laying) on soil bulk density and soil water content. The manure was added at certain treatments by using a ditch opener and manure laying machine which was designed and manufactured in the Agriculture Machines and Equipment Department, College of Agriculture, University of Basrah in 2015. The field was plowed perpendicularly, and the treatments were arranged in RCBD with split-split plot design with three replicated using drip irrigation system. Corn (Zea mays L.) seeds were planted on the manure rows. All plots received NPK fertilization with the same levels. At the end of growing season, soil samples (0-30 cm) were collected to examine soil bulk density and soil water content. The results showed that, lower bulk density and higher water content were obtained at level of 40 ton ha-1compared with the levels of 0 and 20 ton ha-1. The soil bulk density decreased from1.23 to 1.20 Mg m-3 and the soil water content increased from 26.33 to 30.23 % whenthe depth of application increased from 10 to 30 cm. Mixing manure with soil resulted in lower value of bulk density and higher value of water content compared with subsoil laying method. Mixing manure with soil down to the depth of 30 cm amount of 40 ton ha-1 improved the soil bulk density which reached lower value of 1.14 Mg m-3 and soilwater content increased to 36.19% among all other treatments.

Year‐Round Nitrous Oxide Emissions as Affected by Timing and Method of Dairy Manure Application to Corn

Core Ideas The year × timing interaction affects cumulative N2O emissions. Injection of manure produces the highest cumulative N2O emissions. Injection of manure produces the highest corn yields. Manure application to agricultural soils enhances N2O emissions, but these emissions could be reduced by using improved application methods at the right time. We conducted a 3‐yr study on corn (Zea mays L.) grown in Elora, ON, Canada, to test the effects of timing and method of liquid dairy manure application on year‐round N2O emissions. A randomized complete block design was set up every year evaluating two application times (fall vs. spring) and three methods of manure application (surface broadcasting, incorporation, and injection). Lower cumulative N2O emissions for fall than spring application (mean ± standard error = 1.2 ± 0.3 vs. 2.9 ± 0.3 kg N2O‐N ha−1) were found during the driest year (2012), whereas no differences in emissions occurred between application timing in near‐normal precipitation years (2013 and 2014). Nitrous oxide emissions were not affected by the timing × method of application interaction. Injected manure resulted in cumulative N2O emissions not different than surface broadcast manure (3.6 ± 0.5 vs. 3.0 ± 0.5 kg N2O‐N ha−1) but significantly higher than incorporated manure (2.2 ± 0.3 kg N2O‐N ha−1). Injection resulted in greater corn yields than the other two methods. Our results suggest that (i) method of application affects N2O emissions independently of timing; (ii) including N2O emissions for the non‐growing season avoided biased estimates for the fall application timing since 20 to 60% of total emissions occurred during this period; and (iii) incorporating manure is the best practice to mitigate N2O emissions, although if N rates are optimized, injection could potentially produce yields with low N2O intensity.

Coupling Dairy Manure Storage with Injection to Improve Nitrogen Management: Whole‐Farm Simulation Using the Integrated Farm System Model

Core Ideas Manure storage and injection strategies were simulated using the Integrated Farming Systems Model. Strategies were verified using field data. We compared manure storage in environmental and economic model outputs. Introducing 6 mo of storage on a PA dairy farm decreased whole‐farm NUE without manure injection. Manure injection and 6 mo of storage gave the best combination of profit and environmental outcome. Application of livestock manure to farm soils represents a priority nutrient management concern in the Chesapeake Bay watershed. Historically, strong emphasis has been placed on adding manure storage to dairy operations, with the recognition that manure application methods can be improved. The Integrated Farm System Model was used to simulate manure management on a typical Pennsylvania dairy farm (100 milking cows, 80 ha). Converting the operation from daily haul to 6 mo of storage with broadcast application did not substantially change nitrogen (N) losses to the environment. However, switching to manure injection conserved ammonium N and improved manure N use efficiency by crops, even though it increased N leaching by 27% with 6‐mo storage and 13% with 12‐mo storage. Increasing manure storage from 6 to 12 mo with manure injection reduced nitrate N leaching by 38%, due to better timing of manure application to crop growth, but lowered annual net returns. Overall, manure injection and 6 mo of storage resulted in the best combination of profit and environmental outcome.

Estrogen Transport in Surface Runoff from Agricultural Fields Treated with Two Application Methods of Dairy Manure.

This study compares two methods of dairy manure application-surface broadcast and shallow disk injection-on the fate and transport of natural estrogens in surface runoff from 12 field plots in central Pennsylvania. Ten natural surface runoff events were sampled over a 9-mo period after fall manure application. Results show that the range of estrogen concentrations observed in surface runoff from the broadcast plots was several orders of magnitude higher (>5000 ng L) than the concentrations in runoff from the shallow disk injection plots (<10 ng L). Additionally, the transport dynamics differed, with the majority of the estrogen loads from the surface broadcast plots occurring during the first rainfall event after application, whereas the majority of the loads from the shallow disk injection plots occurred more than 6 mo later during a hail storm event. Total estrogen loads were, on average, two orders of magnitude lower for shallow disk injection compared with surface broadcast. Independent of the method of manure application, 17α-estradiol and estrone were preserved in the field for as long as 9 mo after application. Overall, injection of manure shows promise in reducing the potential for off-site losses of hormones from manure-amended soils.

Standardization of organic manure application in pomegranate (Punica granatum) orchards grown in semi-arid regions

An experiment was conducted at ICAR - National Research Centre on Pomegranate during 2011-12 and 2012-13 on pomegranate (Punica granatum L) cv. Bhagwa plants. The experiment comprises of application of raw and well decomposed farmyard manure in the form of slurry (liquid form, manures mixed with water in 1:10 ratio and kept for 10 to 15 days with intermittent stirring) as a sole or in combination with micronutrients and/or various microbial inoculants. It was compared with normally practiced method of organic manure application in the soil. The results revealed that application of farmyard manure in slurry form decreased electrical conductivity (0.94 to 0.72 dS/m) and increased organic carbon content (0.55 to 1.45 %) in the soil. Combined application of FYM in the form of slurry along with micronutrients and microbial inoculants significantly increased available N (339.7 kg/ha) and P (34.8 kg/ha) and micronutrients content in the soil. Substantially increased plant height (20.8%), plant spread (22.8 %) and produced maximum number of fruits (39.0/ plant). Population of soil microbes, viz. Aspergillus niger, Pseudomonas fluorescence and potash solubilising organisms were significantly highest with the combined application of FYM in slurry form and microbial inoculants. While, Azotobacter population was more in raw FYM slurry along with microbial inoculants. It is recommended that on light textured soils, farmyard manures should be applied in the form of slurry. It reaches in the active root zone of the plants along with percolating water.

Nutrient Runoff Losses from Liquid Dairy Manure Applied with Low‐Disturbance Methods

Manure applied to cropland is a source of phosphorus (P) and nitrogen (N) in surface runoff and can contribute to impairment of surface waters. Tillage immediately after application incorporates manure into the soil, which may reduce nutrient loss in runoff as well as N loss via NH volatilization. However, tillage also incorporates crop residue, which reduces surface cover and may increase erosion potential. We applied liquid dairy manure in a silage corn ( L.)-cereal rye ( L.) cover crop system in late October using methods designed to incorporate manure with minimal soil and residue disturbance. These include strip-till injection and tine aerator-band manure application, which were compared with standard broadcast application, either incorporated with a disk or left on the surface. Runoff was generated with a portable rainfall simulator (42 mm h for 30 min) three separate times: (i) 2 to 5 d after the October manure application, (ii) in early spring, and (iii) after tillage and planting. In the postmanure application runoff, the highest losses of total P and dissolved reactive P were from surface-applied manure. Dissolved P loss was reduced 98% by strip-till injection; this result was not statistically different from the no-manure control. Reductions from the aerator band method and disk incorporation were 53 and 80%, respectively. Total P losses followed a similar pattern, with 87% reduction from injected manure. Runoff losses of N had generally similar patterns to those of P. Losses of P and N were, in most cases, lower in the spring rain simulations with fewer significant treatment effects. Overall, results show that low-disturbance manure application methods can significantly reduce nutrient runoff losses compared with surface application while maintaining residue cover better than incorporation by tillage.

Effect of irrigation water salinity, manure application and planting method on soil ions variation and ions uptake by saffron (Crocus sativus L.)

The objective of the present study is to investigate the effects of irrigation water salinity,cow manure levels and different planting methods on ions variation in soil and their uptake bysaffron. A split-split plot arrangement was conducted in a randomized complete block designwith irrigation water salinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0 (S4) dS m-1)as the main plot, cow manure levels (30 (F1) and 60 (F2) Mg ha-1) as the subplot and plantingmethod (basin (P1) and in-furrow (P2)) as the sub-subplot with three replications. Resultsshowed that the concentration of sodium (Na+), calcium (Ca2+), chloride (Cl-), potassium (K+),sulphate (SO42-) ions in soil was increased significantly with increasing water salinity levels.These variations were in accordance with ECe variations that were 2.6 times in S4 comparedwith S1 treatment. However, the soil nitrate (NO3-N) decreased in the highest irrigation salinitylevel by about 30% compared with the lowest salinity level in two growing seasons. Theseelement concentrations were significantly higher in F2 treatment in comparison with F1 due toaddition of these ions by higher application rate of cow manure to soil. There was no significantdifference between element concentrations in soil for two planting methods. Increasing salinityto the highest level significantly increased the saffron leaf concentration of Na+, Ca2+ and Cl- byabout 4.0, 1.4 and 1.5 times, respectively. Increasing salinity resulted in decrease in K+, nitrogen(N) and phosphorus (P) concentration in saffron leaf by about 30, 20 and 39% under the highestwater salinity level, respectively. The in-furrow planting method significantly led to increase inK+, N and P concentration in plant by about 10, 3 and 8% in comparison with the basin planting,respectively. Also, higher manure application rate as 60 Mg ha-1 significantly increased plant Nand P concentration by about 12 and 20% in two growing seasons, respectively.

Modification of the saffron model for growth and yield prediction under different irrigation water salinity, manure application and planting methods

The Saffron Yield Estimation Model (SYEM) was modified for salinity conditions, cowmanure application and planting methods using two-year experiments data in Badjgah region ofIran. A split-split plot arrangement was conducted in complete randomized block design duringtwo years with irrigation water salinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0(S4) dS m-1) as the main plot, cow manure levels (30 (F1) and 60 (F2) Mg ha-1) as the sub plotand planting method (basin (P1) and in-furrow (P2)) as the sub-sub plot in three replications.Data of the second and first growing season were used to calibrate and validate the modifiedmodel, respectively. In the modified SYEM model, the soil salinity was estimated. Based on theNRMSE and d indices, the modified SYEM model presented a very good to fair estimation ofactual evapotranspiration, evaporation, transpiration, soil water content and salinity, leaf drymatter, corm and saffron yields. The advantage of this model is its simplicity and easycalibration in other climate conditions for saffron crop. Prediction of saffron yield by this modelcan be used for better irrigation salinity management under different manure application levelsand planting methods.

Effect of irrigation water salinity, manure application and planting method on qualitative compounds of saffron (Crocus sativus L.)

The objective of the present study is to investigate the effects of irrigation water salinity,cow manure levels and different planting methods on saffron quality compounds includingcrocin (coloring strength), picrocrocin (bitterness) and safranal (aromatic strength). A split-splitplot arrangement was conducted in complete randomized block design with irrigation watersalinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0 (S4) dS m-1) as the main plot,cow manure levels (30 (F1) and 60 (F2) Mg ha-1) as the sub plot and planting method (basin (P1)and in-furrow (P2)) as the sub-sub plot in three replications. Results showed that the saffroncoloring strength, bitterness and aromatic strength in higher salinity level decreased by 9, 1 3and 18% in comparison with the lowest salinity level, respectively. However, saffron(stile/stigmas) yield declined significantly as about 42% by increasing water salinity to highestlevel. The saffron crocin and picrocrocin concentration for the in-furrow planting method weresignificantly higher than the basin planting method by about 4 and 8%, respectively. Higherapplication rate of cow manure (60 Mg ha-1) did not promote the saffron quality compounds.Furthermore, planting methods showed no significant effect on saffron aromatic strength.Correlation analysis indicated that saffron quality compounds showed negative relationship withleaf calcium, sodium and chloride and positive relationship with leaf phosphorus, nitrogen andpotassium at 0.01 and 0.05 significant levels, Furthermore, a positive correlation between crocinand picrocrocin and saffron yield components (leaf dry matter, corm, flower and saffron yields)was observed; however, there was no significant correlation between safranal and yieldcomponents. Generally, the saffron quality compounds variations were concurrent with thesaffron quantity variations.