Narrow Grass Hedge Effects on Nutrient Transport Following Land Application

Transcription

1 Narrow Grass Hedge Effects on Nutrient Transport Following Land Application

2 Production agriculture contributes approximately $10 billion to Nebraska s economy each year.

3 Nebraska s livestock industry accounts for more than 65% of the state s total agriculture receipts.

4 Annual animal manure production in Nebraska is 27 million tons.

5 Manure generated from livestock production is applied to cropland areas

6 LONG TERM RESEARCH GOAL: Develop cropping and management practices that incorporate the use of manure as a valuable nutrient source and soil amendment without causing adverse environmental impacts

7 CURRENT PROJECT OBJECTIVE: Evaluate the effectiveness of a narrow grass edge in reducing runoff nutrient transport

8 EXPERIMENTAL STUDIES INCLUDE: A. Previous Manure Application B. Recent Manure Application

9 Previous Manure Application

10 Objective Determine the effects of a grass hedge, manure application rate, on runoff rate on nutrient transport.

11 Experimental Procedures The investigation was conducted near Lincoln, Nebraska. Beef cattle manure was applied at five rates to a silty clay loam soil and then incorporated by disking. There were three replications of each of the manure application rates.

12 Experimental Procedures A 1.4 m wide switch grass hedge had been established at the site. The grass hedge was located at the down slope portion of 15 of the 30 plots. Experimental plots were 0.75 m wide by 4 m long. Soil samples were collected 242 following manure application.

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19 National Phosphorus Research Project USDA Agriculture Research Service USDA Natural Resources Conservation Service USDA Cooperative Extension Service US Environmental Protection Agency University Cooperators

20 Experimental Procedures Three 30-min rainfall simulation runs were conducted. The simulated rainfall events were separated by 24-hr intervals. The design rainfall intensity was 70 mm/hr. Additional inflow was introduced at the top of the plots after the third simulation run.

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25 Statistical Analyses ANOVA was performed to determine the effects of a) grass hedge and manure application rate on soil characteristics and runoff nutrient transport and b) grass hedge, manure application rate, and runoff rate on nutrient transport rate.

26 Statistical Analyses Bray-1 P (mg kg -1 ) 350 ANOVA was performed to determine the 300 effects of a) grass hedge and compost 250 application rate on soil characteristics and 200 runoff nutrient transport and b) grass 150 hedge, compost application rate, and 100inflow rate on nutrient transport rate Compost Rate (Mg ha -1 ) Hedge Compost Rate (Mg ha -1 ) No-Hedge

27 DP (kg ha -1 ) Compost Rate (Mg ha -1 ) Hedge Compost Rate (Mg ha -1 ) No-Hedge

28 TN (g ha -1 min -1 ) Runoff Rate (kg min -1 ) Hedge Runoff Rate (kg mi n -1 ) No-Hedge

29 Soil Loss (kg ha -1 min -1 ) Runoff Rate (kg min -1 ) Hedge Runoff Rate (kg min -1 ) No-Hedge

30 Conclusions Manure application rate significantly affected soil measurements of WSP, Bray-1 P, and NO 3 -N. Mean runoff rates on the hedge and nohedge treatments were 17 and 29 mm, and erosion rates were 0.12 and 1.48 Mg ha-1, respectively.

31 Conclusions Manure application rate significantly affected the transport of DP, TP, and NO 3 -N in runoff. The transport of DP, TP, NO 3 -N, NH 4 -N, TN, runoff and erosion was reduced significantly on the plots with a grass hedge.

32 Conclusions Differences in soil loss rates were found among runoff treatments, with rates varying from 24.8 to 141 kg ha -1 min -1. The existence of grass hedge, manure application rate, and runoff rate all significantly influenced runoff nutrient transport.

33 Recent Manure Application

34 Objectives Determine the effects of a grass hedge and manure application rate on runoff nutrient load occurring soon after manure application. Compare the effects of a grass hedge, manure application rate, and varying runoff rate on nutrient transport rate.

35 Experimental Procedures The investigation was conducted at the Rogers Memorial Farm near Lincoln, Nebraska. Field tests were conducted on 24 plots. Experimental treatments included the presence or absence of a switch grass hedge, manure application rate, and varying runoff rate. Each of the experimental treatments were replicated 3 times.

36 Experimental Procedures Manure was applied to meet a 0, 1, 2, or 4 year corn N requirement. Experimental plots were 0.75 m wide by 4 m long. The grass hedge was approximately 1.4 m. Three 30-minute rainfall simulation runs were conducted.

37 Experimental Procedures The design rainfall intensity was 70 mm/hr. The simulated rainfall events were separated by 24-hr intervals. Inflow was added in four successive increments at the end of the third run.

38 Statistical Analyses AVOVA was used to determine the effects of a grass hedge and manure application rate on runoff nutrient load. The LSD test was used to determine statistical significance among treatments.

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40 Figure 1. Transport of dissolved phosphorus (DP) in runoff as affected by manure application rate for the hedge and no-hedge treatments.

41 Figure 2. Transport of total phosphorus (TP) in runoff as affected by manure application rate for the hedge and no-hedge treatments.

42 Figure 3. Transport of dissolved phosphorus (DP) in runoff as affected by runoff rate for the hedge and no-hedge condition. Vertical bars are standard errors.

43 Figure 4. Transport of NH 4 -N in runoff as affected by runoff rate for the hedge and no-hedge condition. Vertical bars are standard errors.

44 Conclusions Manure application rate significantly affected the transport of DP and TP in runoff on the treatments without a grass hedge. On the hedge treatments, the transport of DP and TP in runoff was not significantly affected by manure application rate.

45 Conclusions The transport of NO 3 -N, NH 4 -N, and TN in runoff was significantly less on the hedge than the nohedge treatments. Each of the runoff water quality parameters were significantly affected by runoff rate. Stiff-stemmed grass hedges can significantly reduce the transport of nutrients in runoff occurring soon after manure application.

46 Session 33-10:30 AM Wednesday March 27 Nutrient Concentrations of Runoff During the Year Following Manure Application

47 Thank You for Your Attention!