Rodale Institute

Limited phosphorus (P) availability and declining soil biological health are major constraints in intensive rice (Oryza sativa L.)—wheat (Triticum aestivum L.) systems. Rock phosphate–enriched compost (REC), combined with microbial inoculants, offers a sustainable strategy for improving soil biological functioning. A field experiment was conducted under a randomized block design with seven treatments involving different combinations of REC, chemical fertilizers, phosphate-solubilizing bacteria (PSB), and arbuscular mycorrhizal fungi (AMF). Post-harvest soil samples from rice and wheat were analyzed for microbial biomass carbon (MBC), microbial biomass phosphorus (MBP), enzymatic activities, microbial populations, root colonization, yield, and P uptake. The combined application of REC with PSB and AMF significantly enhanced soil biological parameters compared with recommended fertilizer doses. Under the REC + PSB + AMF treatment, dehydrogenase, acid phosphatase, and alkaline phosphatase activities increased by 77.4%, 24.8%, and 18.1%, respectively, while MBC and MBP improved by 51.6% and 106.6%. Bacteria, fungi, and actinomycete population increased by 55.0%, 76.7%, and 82.8%, respectively, as well as mycorrhizal root colonization increased by 18.7%. Grain yield of rice and wheat increased by 16% and 6%, respectively, along with higher P uptake. The integrated use of REC with PSB and AMF improved soil enzymatic activity, microbial biomass, and nutrient acquisition, leading to higher crop productivity. These results indicate that REC combined with PSB and AMF is an effective nutrient management strategy for improving soil biological health, P utilization, and crop productivity in rice–wheat systems.

Organic annual vegetable farming systems often rely on intensive tillage for weed management due to the prohibition of synthetic herbicides. Regenerative organic agriculture aims to improve soil health and reduce the frequency and intensity of soil tillage by using cover crops as high-residue mulches to suppress weeds. In southern coastal California, the moderate climate supports year-round vegetable production, discouraging many growers from integrating cover crops into their operation and leaving sustainability-minded growers with few strategies to produce organic vegetables outside of reliance on tillage. This study evaluates standard organic tillage practices versus high-residue cover-crop mulch system on squash, peppers, and eggplant over two seasons. We assessed treatment effects on soil health indicators, weed pressure, and crop production. Soil under the cover-crop system improved soil organic matter, organic carbon and nitrogen, microbially active carbon, and water infiltration compared to bare soil. Weed biomass was substantially lower under the high-residue mulch due to persistent surface cover. Crop yield was 82%, 169%, and 189% higher in the cover-crop plots for squash, pepper, and eggplant, respectively. These findings demonstrate that high-residue cover-crop systems can enhance soil health, reduce weed pressure, and substantially increase yields, providing evidence-based strategies for implementing regenerative organic practices in vegetable systems.

Abstract Industrial hemp (Cannabis sativa L.), displaying more than 25,000 products, has been grown in North America since the 16th century. However, knowledge gaps persist in optimizing agronomic practices, including precision nitrogen (N) management, which is crucial for yield and phytochemical quality, for example, delta‐9‐tetrahydrocannabinol (THC) and cannabidiol (CBD). Addressing these gaps, a 2‐year field trial (2022 and 2023) was conducted at the Rodale Institute‐Pocono Organic Center in Blakeslee, PA, aiming to optimize CBD hemp production through precision N management. Forty experimental plots were established, with each assessing two main factors: (i) N rate: 0, 56, 112, 168, and 224 kg N ha−1 using an OMRI‐listed fertilizer, blood meal (12% N) and (ii) application method: banding and broadcasting. The 3‐week‐old hemp seedlings were transplanted into main plots, followed by fertilizer application and drip irrigation. Parameters including plant height, bud weight, biomass, and CBD yield were assessed, alongside CBD and THC concentrations in floral components and N concentration in leaves and flowers. There was a significant interaction of N rate and application method, impacting biomass yield, while the N rate also influenced CBD concentration. Blood meal supplied at 224 kg N ha−1 yielded the highest biomass and elevated CBD and THC concentrations; however, this did not differ significantly from 168 kg N ha−1 application. Therefore, the recommended optimal N fertilizer rate for Northeastern CBD hemp production is 168 kg N ha−1, with an upper limit of 224 kg N ha−1. Furthermore, the banding method of fertilizer application was more effective than broadcasting.

Soil nitrous oxide (N2O) emissions exhibit high variability in intensively managed cropping systems, which challenges our ability to understand their complex interactions with controlling factors. We leveraged 17 years (2003–2019) of measurements at the Kellogg Biological Station Long‐Term Ecological Research (LTER)/Long‐Term Agroecosystem Research (LTAR) site to better understand the controls of N2O emissions in four corn–soybean–winter wheat rotations employing conventional, no‐till, reduced input, and biologically based/organic inputs. We used a random forest machine learning model to predict daily N2O fluxes, trained separately for each system with 70% of observations, using variables such as crop species, daily air temperature, cumulative 2‐day precipitation, water‐filled pore space, and soil nitrate and ammonium concentrations. The model explained 29%–42% of daily N2O flux variability in the test data, with greater predictability for the corn phase in each system. The long‐term rotations showed different controlling factors and threshold conditions influencing N2O emissions. In the conventional system, the model identified ammonium (>15 kg N ha−1) and daily air temperature (>23°C) as the most influential variables; in the no‐till system, climate variables such as precipitation and air temperature were important variables. In low‐input and organic systems, where red clover (Trifolium repens L.; before corn) and cereal rye (Secale cereale L.; before soybean) cover crops were integrated, nitrate was the predominant predictor of N2O emissions, followed by precipitation and air temperature. In low‐input and biologically based systems, red clover residues increased soil nitrogen availability to influence N2O emissions. Long‐term data facilitated machine learning for predicting N2O emissions in response to differential controls and threshold responses to management, environmental, and biogeochemical drivers.

Biochar, widely recognized for its capacity to counteract climate change impacts, has demonstrated substantial benefits in agricultural ecosystems. Nevertheless, empirical studies exploring its efficacy during climatic aberrations such as heavy rainfall are limited. This study investigated the effects of compost and biochar addition on corn growth attributes, yield, and soil CO2 and N2O fluxes under heavy rain (exceeding 5-yr average) and waterlogging conditions. Here, treatments included compost (CP, 7.6 t ha−1); rice husk biochar (RB, 7.6 t ha−1); wood biochar (WB, 7.6 t ha−1); and control (Cn). Under high rainfall and waterlogging, the CP treatment manifested a pronounced enhancement in corn biomass and productivity, exceeding biomass and productivity of Cn treatment by 12.6 and 32.2%, RB treatment by 120 and 195%, and WB treatment by 86.1 and 111%, respectively. Corn yield increased in the order: CP > Cn > WB > RB. Intriguingly, negligible disparity occurred between the RB and WB treatments in straw yield, grain yield, grain index, and corn productivity but both treatments recorded distinctively lower values than CP treatment. Also, the CO2 and N2O fluxes remained largely similar for two biochar treatments but lower than CP treatment. Overall, CP increased corn yield, straw, and grain yield whereas biochars reduced N2O flux during waterlogging. Although derived from a short-term experimental window, these pivotal findings furnish invaluable insights for devising soil amendments for yield and environmental benefits in contexts of extreme climatic perturbations. Our findings offer a robust foundation for refining nutrient management strategies confronted with waterlogging challenges, but long-term studies are necessary for definitive conclusions.

Abstract Parasite infection is a common problem in organic pig production. Pastures grazed by infected pigs can become sources of parasite transmission because parasite eggs can survive in soil for several years. Biofumigation is a method used by farmers to reduce plant pathogens and nematodes in soil by incorporating plant residues into the soil that rapidly release toxic isothiocyanates. This study explored whether grazing crops with biofumigation properties affects parasite fecal egg counts of pigs managed organically, and subsequent parasite eggs in organic pasture soil after biofumigation. A study was conducted using 66 pigs (BW = 72.6 kg ± 21.2 SD) that were raised organically in two blocks. Within each block, pigs were housed in four pens (8 to 9 pigs/pen) and provided feed ad libitum in a hoop barn. Each pen had access to a pasture (0.5 acres). Each pasture was subjected to one of four management treatments: control pastures (Ladino clover) or biofumigation pastures (Rapeseed), each with or without incorporating plant residues. Each pasture was split into four paddocks (9.1m × 10.7m) and pigs were given access to each paddock for one week. Fecal samples (n = 198) were collected from each pig before, two and four weeks after grazing. Triple soil samples (n = 480) were collected from each paddock before grazing, immediately after pigs were removed from pasture paddocks, and weekly thereafter for three weeks. Fecal and soil samples were analyzed for Ascaris suum, Trichuris suis, and Oesphagostomum spp. eggs. Data were analyzed using a mixed model with pen or paddock as the experimental unit. Fecal egg counts of the three parasite species did not differ between pigs that grazed on pastures with different management treatments. All pigs had drecreased Ascaris suum (P < 0.01) and Trichuris suis (P < 0.01) fecal egg counts after four weeks of grazing compared with before grazing. Both clover and rapeseed pastures without incorporating plant residue had decreased Ascaris suum egg counts in the soil compared with incorporating plant residue (both P < 0.05). Rapeseed pastures without incorporating plant residue had reduced (P < 0.05) Trichuris suis egg counts in the soil compared with clover pastures but did not differ from rapeseed pasture with incorporated plant residue. Across pasture management treatments, Ascaris suum and Trichuris suis eggs in the soil were reduced (P < 0.05) two and three weeks after pigs were removed from pastures compared with before, immediately after, and one week after pigs were removed. These results suggest that grazing pastures crops with biofumigation properties did not affect fecal egg counts of pigs. While the number of parasite eggs decreased overtime in pasture soil, biofumigation may not be an effective way to reduce swine parasite eggs in organic pastures.

Semiarid pasture management strategies can affect soil hydraulic and thermal properties that determine water fluxes and storage, and heat flow in unsaturated soils. We evaluated long-term (>10 years) perennial and annual semiarid pasture system effects on saturated hydraulic conductivity (ks), soil water retention curves (SWRCs), soil water thresholds (i.e., volumetric water content (θv) at saturation, field capacity (FC), and permanent wilting point (PWP); plant available water (PAW)), thermal conductivity (λ), and diffusivity (Dt) within the 0–20 cm soil depth. Forage systems included: Old World bluestem (Bothriochloa bladhii) + legumes (predominantly alfalfa (Medicago sativa)) (OWB-legume), native grass-mix (native), alfalfa + tall wheatgrass (Thinopyrum ponticum) (alfalfa-TW), and annual grass-mix (annual) pastures on a clay loam soil; and native, teff (Eragrostis tef), OWB-grazed, and OWB-ungrazed pastures on a sandy clay loam soil. The perennial OWB-legume and native pastures had increased soil organic matter (SOM) and reduced bulk density (ρb), improving ks, soil water thresholds, λ, and Dt, compared to annual teff and alfalfa-TW (P < 0.05). Soil λ, but not Dt, increased with increasing θv. Grazed pastures decreased ks and water retention compared to other treatments (P < 0.05), yet did not affect λ and Dt (P > 0.05), likely due to higher ρb and contact between particles. Greater λ and Dt at saturation and PWP in perennial versus annual pastures may be attributed to differing SOM and ρb, and some a priori differences in soil texture. Overall, our results suggest that perennial pasture systems are more beneficial than annual systems for soil water storage and heat movement in semiarid regions.

Abstract Dual‐purpose wheat (Triticum aestivum L. emend. Thell.) production systems (i.e., graze and grain) are prevalent in the U.S. Southern Great Plains region, though few of them are managed organically and organic research is very limited, particularly on forage and grazing aspects of the system. Therefore, the objective of this 3‐year systems study (2018–2021) conducted near Vernon, TX, was to compare forage production, forage nutritive value, and cattle gains in transitional organic and conventional dual‐purpose wheat systems. Forage data were collected each year during the early‐season dual‐purpose grazing period until maturity. Monthly standing crop biomass, rate of forage production, and forage nutritive value did not differ during the grazing period between systems in any year. Limited early‐season precipitation resulted in slow forage growth in all years and inadequate forage production to support grazing in 2 of 3 years. In the year when grazing occurred (2018–2019), cattle performance did not differ between systems. Following the dual‐purpose grazing period, the organic system trended toward lower forage production and crude protein concentration than the conventional system, suggesting that in a “graze‐out” scenario (i.e., season‐long grazing and no grain production), the organic system might not support as much cattle production. The late‐season divergence between systems could likely be minimized or eliminated by improving N availability in the organic system. Agronomic viability of the organic system, in terms of forage production, nutritive values, and cattle gains, was supported by its overall similarity to the conventional system.