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Author: Terry J. Logan Publisher: ISBN: Category : Agricultural pollution Languages : en Pages : 36
Book Description
This report examines and summarizes published and some unpublished data on the relative effects of conservation tillage (primarily no till) versus conventional tillage on surface runoff, soil loss and phosphorus loss. The data show that conservation tillage increased runoff relative to conventional tillage on soils with poor internal drainage and reduced runoff on more permeable soils. Conservation tillage greatly reduced soil loss and total particulate P (TPP) loss, but the percent reduction of TPP was only 89% of the percent reduction in soil loss. Conservation tillage increased soluble P (OP) losses in all cases. Conservation tillage was less effective in reducing plant-available (Bray P1) phosphate than in reducing TPP. P fertilization in excess of crop needs increased soluble P losses in runoff, and the effect of P fertilization on soluble P losses was greatest with no till because of P accumulation at the surface. (Author).
Author: Terry J. Logan Publisher: ISBN: Category : Agricultural pollution Languages : en Pages : 36
Book Description
This report examines and summarizes published and some unpublished data on the relative effects of conservation tillage (primarily no till) versus conventional tillage on surface runoff, soil loss and phosphorus loss. The data show that conservation tillage increased runoff relative to conventional tillage on soils with poor internal drainage and reduced runoff on more permeable soils. Conservation tillage greatly reduced soil loss and total particulate P (TPP) loss, but the percent reduction of TPP was only 89% of the percent reduction in soil loss. Conservation tillage increased soluble P (OP) losses in all cases. Conservation tillage was less effective in reducing plant-available (Bray P1) phosphate than in reducing TPP. P fertilization in excess of crop needs increased soluble P losses in runoff, and the effect of P fertilization on soluble P losses was greatest with no till because of P accumulation at the surface. (Author).
Author: Kent Lee Martin Publisher: ISBN: Category : Corn Languages : en Pages : 588
Book Description
A number of questions are being raised concerning phosphorus (P) management as producers switch to minimum or no-tillage cropping systems. Benefits of P application are site specific and potential advantages need to be evaluated for each location. Deep band application effects on crop yield and soil P distribution have been studied, but conclusive results are lacking because of the complexity of environment and P placement interactions, particularly in moisture limited environments. Challenges in soil test sampling and interpretation have also affected P management in these reduced and no-tillage systems because of decreased confidence in soil test P data. The objectives of this research were to evaluate crop responses to P application rate and placement and to study the distribution of soil P concentration, both vertically and laterally at a number of locations in Kansas. This research shows that crop growth at the sites evaluated was not negatively affected by P stratification, which was present at all sites at the beginning of the study. Phosphorus placement methods (broadcast and deep band) did not have significant effects on P responses. However, P application was required to achieve maximum yields at sites with low soil P, but high P sites did not consistently respond to P application. When P fertilizer was broadcast, shallow soil depths continued to have high soil test P, while deep band application increased soil P in the 7.6 to 15 cm depth. The addition of starter application with deep banding of P generally resulted in a more even vertical distribution of soil P. Soil test P data also demonstrated that the presence of bands can be confirmed through soil sampling, but the confidence of soil test P data in a vertical and lateral stratified soil was decreased. Soil samples taken from the band area had highly variable P (high coefficient of variation) concentrations likely due to an inability to sample from within the P band or variability in P application. Soil sampling in these management systems proves to be challenging and will need further research to identify improved methods for soil test P sampling and interpretation.
Author: Terry J. Logan Publisher: ISBN: Category : Pesticides Languages : en Pages : 40
Book Description
A major shift from conventional tillage to conservation tillage will be required to reduce soil loss and diffuse sources of phosphorus in the Lake Erie drainage basin. This shift will require some changes in the kinds and amounts of pesticides used and may change the losses of these compounds in runoff. Alachlor, atrazine and butylate account for about 77% of the herbicide used in Indiana, Michigan and Ohio, and carbofuran, fonofos and terbufos represent about 86% of the insecticide use. Most of the pesticides in use in the basin today are relatively nonpersistent and have low mammalian and fish toxicities. A major shift to conservation tillage will increase use of paraquat and glyphosate herbicides and reduce the use of soil-incorporated materials such as butylate and trifluralin. About 1% of applied pesticide is lost in runoff, much of it in the first event after the compound is applied. Pesticide losses are reduced with increased surface cover, but this effect decreases with pesticides that are water-soluble and have only moderate to low affinity for soil particles. Losses of pesticides from agricultural land in the Lake Erie basin are not expected to measurably change with a shift to conservation tillage. (Author).
Author: Publisher: ISBN: Category : Languages : en Pages : 134
Book Description
Part A of this report describes a study initiated to compare soil & nutrient losses from three tillage practices on a clay loam soil under intensive agriculture in Essex County, south-west Ontario. The tillage practices were: fall plough, spring disk, and one mid-season cultivation (conventional tillage); ridge tillage reformed in mid-season; and no tillage other than that associated with planting and fertilizer incorporation. Samples from surface runoff and drain discharge were analyzed for suspended sediment, nutrients, and herbicides. The crop planted was corn, and yield & moisture content were determined at harvest. Part B describes a study to provide data on herbicide losses from the three types of tillage for corn culture on a poorly drained, level plane soil. Total transport losses, seasonal distribution, and source of losses were measured for the three tillage practices for atrazine, its dealkylated analogue des-ethyl atrazine, and metolachlor.
Author: Ashani Thilakarathne Publisher: ISBN: Category : Agricultural systems Languages : en Pages : 0
Book Description
Corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) production in Illinois has a significant impact on the economy and environmental footprint in the state and the Midwest region. Nutrient leaching from Midwestern agricultural fields is one of the major reasons for the hypoxic zone developed in the Gulf of Mexico. Winter-fallow and early spring (after fertilizer application) are the two most critical periods for nutrient leaching due to increased precipitation and availability of nutrients. Cover crops (CCs) in these seasons are a promising best management practice (BMP) to reduce nutrient leaching in the winter-fallow season. No-till (NT) and reduced tillage (RT) are some other BMPs that farmers in Illinois adopt to reduce erosion. The adoption of CCs is limited due to the lack of knowledge and data on the yield and environmental benefits of CCs in different climatic and soil regimes. Thereby, this doctoral dissertation addresses several critical questions about CC and tillage impacts in claypan soils of southern Illinois with four principal projects with multiple objectives. Research study 1 was a field experiment conducted from 2013-to 2021 to understand the effect of CCs (CCs vs. noCC) and two tillage (NT and RT) practices on soil nitrate-N leaching. The experimental design was a complete randomized design with CC treatments that had two levels (two crop rotations) corn-cereal rye (Secale cereale L.)-soybean-hairy vetch (Vicia villosa R.) [CcrShv] and corn-noCC-soybean-noCC [CncSnc] and tillage treatments with two levels (NT and RT) replicated three times in the field. Each plot had a pan lysimeter installed below the A horizon (22-30 cm depth) to collect water samples weekly or biweekly depending on the rainfall. The corn yield was significantly greater in RT rotations compared to NT rotations with a 36% increase in the yield in 2019 and 2021 corn rotations. The yield was significantly greater in CcrShv rotations compared to the CncSnc rotations. The greatest yield was observed in the interaction of CcrShv-RT in all years. This increase in yield is inversely correlated to the remaining soil N values when the N credit from CCs was not accounted for. Soil nitrate-N leaching was significantly greater in CcrShv rotations compared to the CncSnc rotation in 2021 indicating vetch CC biomass decomposition can lead to increased leaching losses if the window between CC termination and corn planting is not minimized. Precipitation during the early spring can play a vital role in flushing the newly applied fertilizer as well as the N released from decomposing CC residue. The excessively wet year of 2019 showed that N losses are dominated by both nitrate-N leaching and nitrous oxide emissions, but in a typical growing season N losses are dominated by leaching compared to emissions. Research study 2 was designed to better understand the N cycling and fate of applied N in a complete corn-soybean rotation in southern Illinois with CCs and tillage practices. The research was overlayed in the same field with the same crop rotation and tillage practices. In this study, 15N labeled urea fertilizer (9.2% atom) was applied before the corn and soybean seasons. Soil, water, and biomass samples were collected to understand N distribution in each pool. In the corn season in 2017 a significantly greater 15N recovery was observed in CC (CcrShv) plots compared to the noCC plots in the sample collected seven days after planting (DAP). In the CC and depth interaction, a significantly greater 15N recovery was observed in 15-30 cm depth showing that the increased macropores due to CCs can lead to subsurface movement of N through the topsoil. The 15N recovery in water samples was high in CncSnc rotations in the cereal rye season but was significantly greater in CcrShv rotations (8.95 kg ha-1) in hairy vetch seasons. In the two years of complete rotation, the cumulative 15N recovery (quantity derived from fertilizer in water) was significantly greater in CC rotation. In the corn plants, the 15N recovered from the soil was greater than the 15N recovered from fertilizer. This shows the importance of the residual N from prior fertilizer and organic matter input. In the cereal rye season, CCs recovered significantly greater 15N from fertilizer compared to noCC rotations, assuring that cereal rye is an effective nutrient scavenger. A similar pattern was observed in the hairy vetch season as well. However, the soybean 15N recovery was greater in noCC rotations compared to CC rotations. The third study was a field trial on CCs and tillage to understand their individual and combined impact on soil physical parameters. Soil physical parameters were first measured in 2014 and were repeated in 2021. Bulk density at the 0-5 cm depth was 5% lower in 2021 compared to 2014 with the lowest BD in CC rotations with RT practices. For the depth of 0-15 cm, the lowest BD was observed in CC rotation with RT but, the largest reduction was observed in the CC rotation with NT. The wet aggregate stability was improved from 15-28 % over the years in all rotations. The lowest percentage improvement was observed in noCC rotation with RT practice. Penetration resistance was significantly lower in CC plots for the depth of 0-2.5 cm. CCs further improved the time to runoff in plots even though the infiltration rates were not affected. Chemical soil health indices were not significant overtime for CCs or tillage practices. However, a large number of earthworm counts were observed in NT systems compared to RT systems. The final project was a field trial to identify the soil P response to the CC and tillage practices. For this study, three different CC rotations, [corn-cereal rye-soybean-hairy vetch / corn-cereal rye-soybean-oats+radish / corn-noCC-soybean-noCC] and two tillage practices (NT and RT) were used. Soil samples were collected after the corn harvest in 2015 and 2021 and were analyzed for soil Phosphorus (P), inorganic P fractions by Chan and Jackson method, and dissolved reactive phosphorus (DRP) in leachate. The soil Mehlich-3 and Bray-1 P values indicate a great concentration of P in 0-15 cm depth for both years. More refined sampling in 2021 showed that the majority of P in 0-15 cm depth concentrates at the near-surface soil, in 0-5 cm depth irrespective of the CC and tillage treatment. Inorganic soil P fractions were not significantly different between CCs or tillage practices over time. Yet, irrespective of the treatment the non- labile P forms increased in 2021in the soil compared to 2015. The average and cumulative DRP values were highly dependent on the precipitation amounts and timing. However, in general, NT systems had greater average and cumulative DRP leaching compared to RT in both years. In general, CCs in the winter-fallow season is a good recommendation for farms that seek to maximize their production with a minimal environmental footprint. In the long run, CCs can improve soil physical and chemical properties which ultimately can increase the yield potential for corn and soybean. The added benefit of N credit due to leguminous CCs can reduce the fertilizer inputs. The CC benefits including the reduction in nutrient leaching depend on the type of CCs used in the field. More importantly, the CC termination time will be critical to obtain the maximum benefit of CCs. Even though the NT practices improve soil physical properties, long-term NT can increase the risk of soil P stratification in near-surface soils and can ultimately lead to more P loss via erosion, runoff, and soil water leaching. However, the combined use of CC and NT practices can help minimize the potential for erosion and runoff.
Author: Terry J. Logan
Author: Terry J. Logan
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Author: Kent Lee Martin
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Author: James M. Kraus
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Author: James Clyde Wilborn
Author: Terry J. Logan
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Author: Ashani Thilakarathne