Emerging farmers, including immigrant farmers, play an increasingly important role in the food system of the Upper Midwestern United States but face significant barriers to success. One important barrier is the lack of culturally relevant and system-specific training and technical assistance, particularly related to soil health and nutrient management. A team of researchers and farm support professionals was convened to conduct a farmer engagement process consisting of a survey and focus groups to better understand the experiences and wisdom that emerging farmers already have, and their educational needs related to soils. The broader goal was to inform the development of culturally relevant tools and training. Here we identify key takeaways related to content needs and learning style preferences. While emerging farmers are already skilled in assessing physical and biological aspects of soil health, they often need support in understanding chemical properties of soil, how to do soil testing, and how to translate soil test results into actionable practices. Additionally, many emerging farmers have experience in other countries and in agricultural systems based on practices such as shifting cultivation. Supporting farmers as they adapt these practices to a Midwest context requires educators to learn about these systems and value the expertise of farmers from diverse farming backgrounds. There is a particular need for more nuanced and farm scale-specific training about inputs in highly diversified, mostly organic systems, especially related to compost and manure management. In terms of learning styles, farmers preferred hands-on training opportunities with as much mentorship and peer learning as possible. Many Midwestern emerging farmers participate in incubator farm programs for beginning growers. While such programs provide valuable access to land and infrastructure, they often lack the capacity to provide tailored participant mentorship. This leaves program graduates unsure about how to utilize soil health and nutrient management practices when they start their own farms. To improve soil health and nutrient management outcomes for emerging farmers, we propose investing in train-the-trainer type programs for farmer leaders and staff with beginning farmer organizations. These programs should include tailored one-to-one mentorship and peer learning with an emphasis on organic inputs, chemical aspects of soil health, and diversified production systems.

Agricultural extension requires close communication with farmers, and researchers must consider farmers’ perspectives on crop management. Farmers tend to take into account the canopy appearance when they decide on fertilizer application, and this is often neglected in crop management recommendations by researchers. Our objectives were to dissect the growth characteristics that farmers implicitly account for in nutrient management of tropical rice. Farmer participatory trials were conducted in irrigated and rainfed lowlands in the Philippines during the wet seasons of 2014, 2015, and 2016. Each year, 30 participating farmers made decisions on fertilizer management for plots with different seedling ages and planting densities. These treatments greatly changed the canopy appearance, and affected farmer decisions on nitrogen (N) management, particularly in the first year. We found that plant height and leaf greenness were the major determinants of their decisions in irrigated lowlands. Under rainfed conditions, the risk of drought made farmers focus on tillering rather than plant elongation and leaf color during early growth stages, and on canopy cover and plant elongation during later stages. Across years and water regimes, farmers applied 78% more N than researchers without generally increasing grain yield. Since crop diagnosis is a key for successful management by farmers, guidelines for efficient nutrient management should include numerical targets for the traits emphasized by farmers. That will help farmers better understand their crops, and the guidelines will be more user-friendly than providing only a fertilizer application prescription.

The area of dry-season rice (Oryza sativa L.) has rapidly increased in Cambodia owing to the large-scale development of irrigation infrastructure. But little is known of potential productivity and adaptive crop management. The objective of our study was to evaluate potential yield and nutrient requirements of dry-season rice in Cambodia, and the economic feasibility of soil-specific management recommended by the government. Field experiments were conducted on four soil types (Bakan, equivalent to Alfisol; Krakor, Inceptisol; Prateah Lang, Plinthustalfs; and Toul Samroung, Endoaqualfs) in four provinces (Battambang, Kampong Thom, Pursat, and Siem Reap) during the 2016 and 2017 dry seasons to compare 14 (2016) and 8 (2017) N-P-K combinations. Grain yield ranged from 1.0 to 5.5 t ha−1 in 2016 and from 1.3 to 6.7 t ha−1 in 2017. Potential yield from the experiments was 6–7 t ha−1 on Toul Samroung soil, 5–6 t ha−1 on Bakan soil, and 3–5 t ha−1 on Prateah Lang and Krakor soils. A rate of 140-60-60 kg ha−1 of N-P2O5-K2O was more than enough to achieve the best yields on any soil group. On the other hand, modest application rates in soil-specific management (44–78 kg ha−1 of N, 23–28 kg ha−1 of P2O5, 0–30 kg ha−1 of K2O) proved reasonable for resource-poor farmers in Cambodia, since the treatment always provided >75 % of the highest economic profit in high-input plots.

Rice is widely grown in rainfed lowlands during the wet season in the Mekong region. Limited nutrient availability is a common constraint on crop yield, and the optimal rate of fertilizer application depends on the soil type. The objective of our study was to evaluate rice productivity and the economic feasibility of various nutrient management regimes in Cambodia. We conducted field experiments on three soil types (Prey Khmer, Prateah Lang, and Toul Samroung, equivalent to Psamments, Plinthustalfs, and Endoaqualfs, respectively) in four provinces (Battambang, Kampong Thom, Pursat, and Siem Reap) during the 2016 and 2017 wet seasons to compare nine (2016) and seven (2017) N–P–K combinations. Grain yield ranged from 0.9 to 4.8 t ha−1 in 2016 and from 1.0 to 5.2 t ha−1 in 2017, depending on soil type and nutrient management. The Prey Khmer soil contained around 80% sand, and rice yield responded most weakly to nutrient management. The moderate fertilizer input in the current soil-specific recommendation was effective on this soil type. However, on more fertile soils with a higher clay content and a higher cation-exchange capacity (Toul Samroung and Prateah Lang), an additional 20 kg N ha−1 combined with adding 15 kg ha−1 of P2O5 or 20 kg ha−1 of K2O significantly increased yield and economic return. Although P and K use during Cambodia’s wet season is uncommon, our results demonstrate the importance of these nutrients in improving the country’s rice production.

Soluble phosphate availability is a major limiting factor for plant growth, development, and yield. To assure a constant phosphorous supply, plants employ both high- and low-affinity phosphate acquisition mechanisms. Glyphosate is an herbicide widely used throughout the world, and previous studies have suggested that it can be transported across the plasma membrane via phosphate transporters in herbaceous species. The effects of phosphate status on glyphosate uptake were investigated in the tree grand eucalyptus (Eucalyptus grandis W. Hill ex. Maid.). Eucalyptus grandis’s putative phosphate transporters showed differential gene expression in leaves and roots in response to phosphate limitation. Overall, the expression of high-affinity phosphate transporters increased in phosphate-limiting treatments, particularly in roots. More [14C]glyphosate was absorbed and translocated in phosphate-limiting plants compared with control plants grown in phosphate-replete treatments. In leaf mesophyll protoplast assays, rapid uptake of [14C]glyphosate into protoplasts was observed, and addition of phosphate to the assays competed with [14C]glyphosate uptake. These data indicate that phosphate transporters represent one mechanism of glyphosate uptake in E. grandis. These results have implications for best management practices for weed control and glyphosate application under phosphate application regimes.

Great technological advances have been made in Precision Agriculture (PA) in the past decade, yet adoption of PA in intensive grassland areas in North West Europe is low. This is despite the fact that in these areas the market structures are suitable and there are highly developed agricultural and food industries offering great potential for the application of new technology. Specific inefficiencies in plant nutrient management in soil exist, which are not only limiting grass yields but are also causing environmental deterioration. Soil nutrient management efficiency could be greatly improved using PA techniques, but the complexity of grassland systems, coupled with a lack of calibration of sensors specific to grassland, together with local barriers, appear to be the reasons why PA adoption is poor in these areas. This paper reviews new and existing technology including soil and crop sensors, navigation devices, remote sensing and unmanned aerial vehicles. The suitability and readiness of these technologies for adoption in grassland areas is discussed, along with data interpretation issues, future perspectives and research opportunities.

Cover crops and living mulches bring many benefits to crop production. Interest in winter annual cover crops such as winter rye and hairy vetch for ground cover and soil erosion control has been increasing in the last 30 yr in some areas. The integration of cover crops into a cropping system by relay cropping, overseeding, interseeding, and double cropping may serve to provide and conserve nitrogen for grain crops, reduce soil erosion, reduce weed pressure, and increase soil organic matter content (Hartwig and Hoffman 1975). Hairy vetch has increased availability of nitrogen to succeeding crops, increased soil organic matter, improved soil structure and water infiltration, decreased water runoff, reduced surface soil temperature and water evaporation, improved weed control, and increased soil productivity (Frye et al. 1988). More recent research with perennial living mulches, such as crownvetch (Hartwig 1983), flatpea, birdsfoot trefoil, and white clover (Ammon et al. 1995), has added a new dimension to the use of ground covers that eliminates the need to reseed each year. Cropping systems with the use of ground covers have been worked out for vineyards, orchards, and common agronomic crops, such as corn, small grains, and forages. Legume cover crops have the potential for fixing nitrogen, a portion of which will be available for high-nitrogen–requiring crops such as corn. In areas where excess nitrogen is already a problem, the use of ground covers may provide a sink to tie up some of this excess nitrogen and hold it until the next growing season, when a crop that can make use of it might be planted (Hooda et al. 1998). Even legumes tend to use soil nitrogen rather than fixing their own, if it is available. It is these possibilities that provide the incentive for looking at the effect of various kinds of cover crops on soil erosion, nitrogen budgets, weed control, and other pest management and environmental problems.

Off-farm income as a share of total farm household income has been increasing. Previous studies found inconsistent results regarding the impact of off-farm income on adoption of conservation practices. We test the hypothesis that off-farm employment has a positive impact on adoption of capital incentive practices and a negative impact on adoption of labor-intensive practices. The results confirm that adoption of injecting manure into the soil, a capitalintensive practice, is positively and significantly impacted by off-farm employment of the operator. However, off-farm employment variables had no effect on adoption of record keeping.

Nitrous oxide is a powerful greenhouse gas that is emitted from cropland treated with nitrogen fertilizer. Reducing such emissions through nutrient management might be able to produce offsets for sale in a cap and trade program aimed at reducing greenhouse gases. We use the Nitrate Leaching and Economic Analysis Program (NLEAP) model and data from the Agricultural and Resource Management Survey to examine what changes in rate, timing, or method of application a farmer would take to produce offsets. We find that reducing the application rate is the most favored approach for producing offsets. We also find that some management choices may increase nitrate losses to water.

Farmers and taxpayers would benefit from more cost-effective agricultural nutrient pollution control measures. The objectives of our study are (1) to assess compliance costs and reductions in phosphorus loadings from implementation of nutrient management and riparian buffers; and (2) to estimate how the spatial scenario, which is the method of representing farms within the watershed, affects estimated compliance costs and reductions in phosphorus deliveries. Estimated compliance costs are quite sensitive to the spatial scenario. Buffers are more cost-effective than nutrient management under one of the two spatial scenarios, whereas nutrient management is more cost-effective under the other scenario. Shifts to more erosive crops reduce the effectiveness of both pollution control measures.

The effects of considering variable within-farm soil runoff and leaching potential on costs of reducing nitrogen losses are analyzed for a Virginia dairy. Manure applications may cause nitrogen losses through runoff and leaching because of factors such as uncertain nitrogen mineralization. Farmers can reduce nitrogen control costs by applying manure on soils with less nitrogen loss potential. Ignoring within-farm soil variability may result in overstating the farm's costs of reducing nitrogen losses.

Requiring that crop applications of manure be based on phosphorus content (P-standard) could increase poultry litter disposal costs. Microbial phytase reduces litter P content and could reduce litter disposal costs under a P-standard. For a representative Virginia turkey farm, phytase costs $2,500 and could increase value of litter used for fertilizer on the turkey farm by $390 and reduce supplemental P feed costs by $1,431. Based on assumed litter demand and supply, estimated litter export prices with phytase could exceed export prices without phytase by $3.81 per ton. Phytase net returns to the farm are an estimated $1,435.

We utilize a treatment effects model to examine if there are differences in costs/profits for manure-using corn producers versus non-users. We find that manure users have lower peracre operating costs via reductions in fertilizer and soil conditioner costs; however, the use of manure reduces grain yields and ultimately leads to no difference in profit. Separate results indicate that manure-use restrictions do not affect costs or profits; thus policies could be in place to regulate manure usage without impacting the costs/profit structure of the farm.

Using manure as a substitute for commercial fertilizer could potentiallyreduce fertilizer costs and also reduce non-point source pollution.Livestock farmers in Missouri and Iowa were surveyed regarding their manuremanagement practices. Eighty-one percent of turkey farmers versus 5% of beeffarmers transferred manure to other farmers. Fifty-one percent of farmerswho transferred manure indicated it had been tested. Factors decreasingadoption included higher off-farm incomes, solid versus liquid manure, andmore animal units per acre. Factors increasing adoption included distancetransferred, a contract for the manure, payment, and thinking that manuretesting was profitable.

Organic grain cropping systems can enhance a number of ecosystem services compared with conventional tilled (CT) systems. Recent results from a limited number of long-term agricultural research (LTAR) studies suggest that organic grain cropping systems can also increase several ecosystem services relative to conventional no-till (NT) cropping systems: soil C sequestration and soil N fertility (N mineralization potential) can be greater while global warming potential (GWP) can be lower in organic systems that use animal manures and cover crops compared with conventional NT systems. However, soil erosion from organic systems and nitrous oxide (N2O, a greenhouse gas) emissions from manure-based organic systems appear to be greater than from conventional NT systems, though data are limited. Also, crop yields, on average, continue to be lower and labor requirements greater in organic than in both tilled and NT conventional systems. Ecosystem services provided by organic systems may be improved by expanding crop rotations to include greater crop phenological diversity, improving nutrient management, and reducing tillage intensity and frequency. More diverse crop rotations, especially those that include perennial forages, can reduce weed pressure, economic risk, soil erosion, N2O emissions, animal manure inputs, and soil P loading, while increasing grain yield and soil fertility. Side-dressing animal manures in organic systems may increase corn nitrogen use efficiency and also minimize animal manure inputs. Management practices that reduce tillage frequency and intensity in organic systems are being developed to reduce soil erosion and labor and energy needs. On-going research promises to further augment ecosystem services provided by organic grain cropping systems.

EPA's new restrictions on land application of manure nutrients by concentrated animal feeding operations (CAFOs) could decrease the net return of 6–17% of the medium and large dairy farms with lagoon systems in the southwestern United States. Many of the other dairy CAFOs in the region could achieve higher net income under the restrictions if they reduce feed costs by better utilizing manure and expanding homegrown feed production.

Organic farming systems differ fundamentally from conventional ones in their primary focus on management practices that promote and enhance ecological harmony. Organic farmers also tend to have a different socioeconomic profile. In this study, we summarize average socioeconomic characteristics and production practices of a national sample of about 300 certified organic vegetable growers from 14 states and compare them to a large sample of about 6,900 conventional vegetable growers. We also examine the specific materials used by organic growers for pest and nutrient management.

Organic vegetable growers tend to be younger, more educated, less experienced in farming, and less likely to have grown up on a farm than conventional vegetable growers, and tend to operate smaller farms. Over three-quarters of the organic vegetable growers surveyed have small operations (less than 10 acres of vegetables), and they are much younger and work fewer days in off-farm jobs than conventional small growers. In contrast to conventional marketing practices, nearly half the surveyed organic growers, and the majority of small ones, market their vegetables directly to consumers through farmers' markets and other direct marketing channels.

The organic growers rely primarily on traditional organic processes such as green manuring (legumes), animal manuring, composting, and crop rotation to supply crop nutrients, and on cultural and biological tools, including pest-resistant plant varieties, water management techniques, adjustment of planting and harvesting dates, and beneficial organisms, for pest management. Animal meal, fish products, and lime are their most frequently reported supplemental nutrient sources (14, 20 and 28%, respectively, reported using these materials), and Pyrellin EC and petroleum-based soaps were the most frequently reported supplemental pest management materials (used by 6 and 8%, respectively). The pest and nutrient materials used by the organic growers are generally consistent with current guidelines of major certification organizations that provide services to organic growers, and there is high consistency among those guidelines and national recommendations for most of these materials.

Livestock production and manure handling decisions often have been treated in the literature as separate enterprises. Policymakers, too, have ignored the interactive nature of manure management by focusing on land application for nutrient disposal. This study outlines a systems approach to describe the interrelated decisions producers face, using examples from North Carolina and Iowa that show how producers' attitudes toward manure management lead them to handle manure differently in different regions. In North Carolina, nutrients in manure are “not wanted.” There are economic incentives to treat manure, thus reducing its nutrient content, and to apply it on as little land as possible. In Iowa, nutrients are “not wasted.” Producers conserve the nutrients in manure and use them more fully, applying manure to higher value crops such as corn. Policies that influence manure management can be made more effective by accounting for the differences in producers' incentives to waste or want the nutrients.