Effect of Long-Term Integrated Crop and Livestock Systems on Forage Finishing, Soil Fertility, Nitrogen Mineralization, Carbon Sequestration, and Profitability

View the project final report

Commodities

• Agronomic: barley, corn, peas (field, cowpeas), sunflower, wheat
• Animals: bovine
• Animal Products: meat

Practices

• Animal Production: feed/forage, grazing - rotational, stockpiled forages, winter forage
• Crop Production: application rate management, continuous cropping, cover crops, crop rotation, double cropping, intercropping, multiple cropping, no-till, nutrient cycling, relay cropping
• Education and Training: demonstration, extension, farmer to farmer, focus group, networking, on-farm/ranch research, participatory research, technical assistance, workshop, youth education
• Farm Business Management: agricultural finance, budgets/cost and returns, new enterprise development, risk management, value added, whole farm planning
• Natural Resources/Environment: carbon sequestration, GHG emisson (CO2, CH4, N2O)
• Pest Management: allelopathy, chemical control, economic threshold, field monitoring/scouting
• Production Systems: agroecosystems, dryland farming, holistic management, integrated crop and livestock systems
• Soil Management: earthworms, nutrient mineralization, organic matter, soil analysis, soil microbiology, soil quality/health
• Sustainable Communities: public participation, quality of life, sustainability measures

SWCS Merit Award_7-29-19

Minimizing reliance on harvested feeds through grazing and extending the grazing season beyond that which is typical in western ND is a management strategy that enhances economic and environmental stability, especially when grazing is integrated into a diverse crop rotation. Systems integration in LNC11-335 identified that labor and inputs were reduced, soil fertility and crop yield improved, delayed feedlot entry of yearlings reduced days on feed and increased profitability, cow winter feed cost was reduced 2.8 times, and quality of life improved. Consumer demand for forage-finished beef is increasing by 25-30% per year and integrating forage-finished beef with fiber-based supplementation into the established crop rotation is a logical research succession, which needs to be continued to capture the long-term effect of integration on forage-finished beef grazing management, soil quality, nitrogen mineralization, carbon sparing, profitability, and farm family quality of life. The previous project established baseline soil bulk density, OM levels, seasonal soil nitrate-N fertility and end of season ammonium-N and nitrate-N levels. Since soil dynamics change slowly, extending the integrated research into years 7-9, is relevant to measure grazed and ungrazed soil quality dynamics in much greater detail. That is, maintenance of short and long-term carbon pools, water soluble soil organic nitrogen, seasonal soil NO3-N fertility, residual soil nitrogen pools, microbial CO2-C and soil C:N ratio change between crops within the rotation, soil GHG emissions, soil bulk density change, and soil water dynamics. Outreach programming will blend traditional extension and journal publication methods with yearly NCR SARE multi-state webinars, community café meetings, forage-finishing beef production workshops, field walks, high school student field days, exercise-health-service group presentations, YouTube (How-To) videos, DVD documentary, and social media outreach to schedule events, post links, inform, educate, and measure internet response.

Synergy between crop production, grazing, and soil health is complex and constantly evolving. A 10-year integrated crop and livestock study in the semi-arid region of western North Dakota was initiated in 2011 that compared No-Till hard red spring wheat grown continuously (HRSW-C) to hard red spring wheat grown in a No-Till five-crop rotation (HRSW-R). For the rotation, the sequence of crops consisted of HRSW-R, dual winter triticale-hairy vetch (THV) and spring seeded 13-specie cover crop (CC), forage corn (CN), field pea-forage barley mix (PBLY), and sunflower (SF). Beef cattle are integrated into the systems evaluation due to the importance of grazing to soil biological activity and soil health enhancement arising from integration with crop production. As such, the winter cover crop mix is put up as hay, and the other crops: post-hay harvest 13-specie CC, PBLY mix, and CN are grazing crops for yearling beef steers. This project encompasses systems’ response during the second five-year rotation.

Response during this period (2016-2020) has been vastly different and negatively affected by hail, wind, extreme drought, and ensuing soil microbial population fluctuations. Compared to the initial 2016 crop year, control spring wheat yields were 39.6, -3.14, 16.9, and 1.03%, and rotation spring wheat yields were -6.46, -18.7, 24.5, and -3.74% in 2017, 2018, 2019, and 2020, respectively. Rotation crop yields were similar to spring wheat yield declining sharply in 2017, but struggled to recover to pre-drought production levels in 2018; however, the 2019 crop would be considered near normal for most rotation crops, but not all. Compared to the 2016 crop, PBLY and the 13-specie cover crop were-38.8 and -76.0% less whereas THV and SF were 25.4 and 17.7% more. Corn (warm-season grass) dry matter forage yield was 2720 lbs. in 2017. But for 2016 before the drought and 2018 and 2019 after the drought, dry matter corn forage yield did not change appreciably averaging 7,534 lbs. (range: 7,580 -7,640 lbs.). Soil physical property evaluations for water infiltration, wind erodibility, and water stable aggregates for the integrated system compared to the control monoculture system show no significant difference between crops. Numerically higher values for water infiltration, wind erodible fraction, and water stable aggregates were identified for the rotation spring wheat system. This indicates the diverse crop rotation is having an impact on soil quality change such that there are more stable aggregates, indicating soil structure is improving. Nitrogen mineralization between the two spring wheat cropping systems has been evaluated and continues to be evaluated with increasing years and sampling. To date, the relationship between soil organic matter (SOM) and potential mineralized nitrogen (PMN) indicates that crop rotation is supportive for nitrogen mineralization such that approximately 8.4 mg (16.9 lbs.) PMN are mineralized for each 1.0% increase in SOM per kg of soil. nitrogen (PMN) indicates that crop rotation is supportive for nitrogen mineralization such that approximately 8.4 mg (16.9 lbs.) PMN are mineralized for each 1.0% increase in SOM per kg of soil.

Unfortunately, dry soil conditions impede microbial mineralization of soil OM. Haney and phospholipid fatty acid (PLFA) test were conducted in 2017, 2019, and 2020. Differences arising between extremely dry soil conditions and moist soil conditions are dramatic. Lack of sufficient soil water for nutrient solubilization and translocation disrupts a complex system of microbial activity. Across all crops soil pH declined 0.63 basis points and SOM decline to 3.29% in 2017, but recovered to 3.97% in 2019. However, reduced 2020 growing season precipitation contributed to an overall 16.9% microbial biomass decline compared to 2019. Most notably, cover crop following the winter THV mix had the greatest total microbial biomass decline of 37.9%; whereas collectively, SF, HRSW-C, HRSW-R, CN, and PBLY microbial biomass increase 3.9% in 2020 compared to 2019 levels. Although total microbial biomass and percent SOM declined, organism diversity index did not change between drought and moist soil in 2017 and 2019, but 2020 analysis indicates that soil conditions have negatively impacted microorganism diversity index, declining 28.4%. Soil minerals became more concentrated in the soil solution as soil dehydration continued with advancing season. Integrating systems’ molecular analysis of nitrogen cycling genes provides an opportunity to investigate soil nitrogen cycling communities at the molecular level. Quantitative real-time polymerase chain reaction (qPCR) is being used to estimate the quantity of microbes with enzymes capable of performing nitrogen transformations. Nitrogen is often the limiting soil nutrient in dry-land agricultural systems and is known to be converted into different forms by soil bacteria. Analysis for the presence and quantity of nitrogen cycling genes was performed on soil samples from the 2019 sampling period. Genes involved in nitrogen fixation (nifH), nitrification (amoA/B), and denitrification (nirS, nirK, and nosZ) were analyzed via qPCR (quantitative Polymerase Chain Reaction). Nitrogen fixation is the conversion of nitrogen gas from the atmosphere into NH₄⁺, nitrification is the eventual conversion of ammonic (NH₄⁺) to nitrate (NO₃^-), and denitrification is the conversion of NO₃^- to nitrogen gas (released back to the atmosphere). Although analysis is still ongoing, it appears that there is an increased abundance of genes involved in denitrification compared to both nitrogen fixation and nitrification. Suggesting that limited nitrogen nitrification and fixation were possible when soil sampling took place.

Yearling steers (n=144) of similar frame score (5.1) grazed either western North Dakota native range (NR) or a sequence of native range and annual forages in the diverse crop rotation (ANN: PBLY, CN, and CC) to evaluate grazing cover crop bales (12.8% CP, 59.0% TDN) as a management practice for extending the grazing season before feedlot entry or as forage finished steers for the GrassFed industry. For grazing muscling, ANN steer ribeye area (REA) and percent intramuscular fat were greater than NR steers and there was a tendency for ANN steers to have greater marbling score. At the end of bale grazing, ANN steers were heavier and ADG was greater. For the overall 221.5-day study from the start of grazing to the end of bale grazing, ANN steer ending gain weight was greater than NR. In the feedlot, steer ending weight did not differ between treatments, but the ANN steers started heavier and ended heavier than the NR steers. Thus, ANN steers had heavier hot carcass weight resulting in greater gross return for the ANN steers ($2,013.93 vs, $1,921.67). Combining the merits of bale grazing and delayed feedlot entry over three annual data collection periods has resulted in excellent net returns to both the ANN and NR systems. However, grazing systems net return after accounting for annual cow cost, steer pre-grazing wintering cost, grazing and mineral cost, bale grazing and protein supplement cost, and feedlot finishing expenses resulted in a $62.26/steer greater net return to the NR system (ANN: $482.92 vs. NR: $545.18). The final steer grazing investigation in this research is to further evaluate the merits of bale grazing and delayed feedlot entry finishing for marketing ANN and NR system steers as grass-fed beef and compare to similar steers finished in the feedlot. At the time of this final report, grass-fed steers have been marketed, but the feedlot steers remain on feed. Preliminary economic analysis of the grass-fed steers from ANN and NR system treatments show the ANN system steers with a net loss of -$88.25/steer compared to a greater return/steer of $62.70 for the NR system. Without going into detail until the feedlot steers have been closed out, preliminary factors contributing to the loss include, but are not limited to, price, farming cost, no choice quality grade premium, hauling shrink, and light weight carcasses.

At the 74^th Soil and Water Conservation Society Annual Conference held at the Wyndham Grand Hotel in Pittsburgh, PA, July 28-31, the Integrated Crop-Grazing Research Team were awarded the 2019 Soil and water Conservation Society Merit Award for outstanding research. Clare Lindahl, CEO, said, “Their work will encourage producers within the Dakotas and beyond to adopt regenerative and integrated management practices that can both improve profitability and protect our valuable soil and water natural resources.” Crop and livestock producers in the semi-arid region of western North Dakota are listening to the research results and are adopting components of the practices evaluated in this SARE funded research and education project.

Added Objective:

Investigate soil nitrogen cycling communities at the molecular level to determine the quantity of microbes that posses the ability via enzymes to perform nitrogen transformations.