Soil Health Management Enhances Microbial Nitrogen Cycling Capacity and Activity

ABSTRACT Soil microbial transformations of nitrogen (N) can be affected by soil health management practices. Here, we report in situ seasonal dynamics of the population size (gene copy abundances) and functional activity (transcript copy abundances) of five bacterial genes involved in soil N cycling (ammonia-oxidizing bacteria [AOB] amoA, nifH, nirK, nirS, and nosZ) in a long-term continuous cotton production system under different management practices (cover crops, tillage, and inorganic N fertilization). Hairy vetch (Vicia villosa Roth), a leguminous cover crop, most effectively promoted the expression of N cycle genes, which persisted after cover crop termination throughout the growing season. Moreover, we observed similarly high or even higher N cycle gene transcript abundances under vetch with no fertilizer as no cover crop with N fertilization throughout the cover crop peak and cotton growing seasons (April, May, and October). Further, both the gene and transcript abundances of amoA and nosZ were positively correlated to soil nitrous oxide (N2O) emissions. We also found that the abundances of amoA genes and transcripts both positively correlated to field and incubated net nitrification rates. Together, our results revealed relationships between microbial functional capacity and activity and in situ soil N transformations under different agricultural seasons and soil management practices. IMPORTANCE Conservation agriculture practices that promote soil health have distinct and lasting effects on microbial populations involved with soil nitrogen (N) cycling. In particular, using a leguminous winter cover crop (hairy vetch) promoted the expression of key functional genes involved in soil N cycling, equaling or exceeding the effects of inorganic N fertilizer. Hairy vetch also left a legacy on soil nutrient capacity by promoting the continued activity of N cycling microbes after cover crop termination and into the main growing season. By examining both genes and transcripts involved in soil N cycling, we showed different responses of functional capacity (i.e., gene abundances) and functional activity (i.e., transcript abundances) to agricultural seasons and management practices, adding to our understanding of the effects of soil health management practices on microbial ecology.

Download Full-text

605 Evaluation of How Cover Crop, Tillage, and N Fertilization Affect Nitrogen Sufficiency in Watermelons

HortScience ◽

10.21273/hortsci.34.3.551d ◽

1999 ◽

Vol 34 (3) ◽

pp. 551D-551

Author(s):

Anthony F. Silvernail ◽

Gary R. Cline

Keyword(s):

Cover Crop ◽

Citrullus Lanatus ◽

N Fertilization ◽

Soil N ◽

Inorganic N ◽

Vicia Villosa ◽

Testing Procedures ◽

Foliar N ◽

No Till ◽

Spad Readings

The effects of cover crop, tillage, and N fertilization on yields of `Paladin' watermelon (Citrullus lanatus) were analyzed by determining available soil N levels, foliar N content, and relative greenness with a SPAD-502 chlorophyll meter. Analyses from all three analytical procedures identified N deficiencies in watermelon with their respected measurements. Available soil N analyses indicated that soil N levels below 40 mg·kg–1 at vining caused dramatic decreases in yields, while the level needed to ensure maximal yields during the same period was 100 mg·kg–1. Results from foliar and SPAD tests indicated that plants with foliar N levels below 42 g·kg–1 and SPAD readings below 40 SPAD units at anthesis will have suppressed yields. Optimal foliar N levels and SPAD readings required for maximum yields were 50 g·kg –1 and 48 SPAD units, respectively. The main difference among all three N testing procedures was that available soil N analysis was able to detect possible deficiencies two to three weeks before either the foliar or SPAD analysis. Differences in yield between plants from conventionally tilled plots and no-till plots were not significant. However, inorganic N fertilization significantly increased yields in watermelon following both rye (Secale cereale) and mix cover crop treatments. Watermelon yields of plants following the hairy vetch (Vicia villosa) cover crop treatment showed no response to inorganic N fertilization. Of the three cover crop treatments, the addition of N fertilizer had the most effect in the rye treatment.

Download Full-text

Dynamics of nitrogen and dry-matter partitioning and accumulation in broccoli (Brassica oleracea var. italica) in relation to extractable soil inorganic nitrogen

Canadian Journal of Plant Science ◽

10.4141/p98-056 ◽

1999 ◽

Vol 79 (2) ◽

pp. 277-286 ◽

Cited By ~ 9

Author(s):

P. A. Bowen ◽

B. J. Zebarth ◽

P. M. A. Toivonen

Keyword(s):

Dry Matter ◽

N Fertilization ◽

N Fertilizer ◽

Organic N ◽

Soil N ◽

Inorganic N ◽

N Accumulation ◽

Spring Planting ◽

Extractable Soil ◽

Soil Inorganic

The effects of six rates of N fertilization (0, 125, 250, 375, 500 and 625 kg N ha−1) on the dynamics of N utilization relative to extractable inorganic N in the soil profile were determined for broccoli in three growing seasons. The amount of pre-existing extractable inorganic N in the soil was lowest for the spring planting, followed by the early-summer then late-summer plantings. During the first 2 wk after transplanting, plant dry-matter (DM) and N accumulation rates were low, and because of the mineralization of soil organic N the extractable soil inorganic N increased over that added as fertilizer, especially in the top 30 cm. From 4 wk after transplanting until harvest, DM and N accumulation in the plants was rapid and corresponded to a rapid depletion of extractable inorganic N from the soil. At high N-fertilization rates, leaf and stem DM and N accumulations at harvest were similar among the three plantings. However, the rates of accumulation in the two summer plantings were higher before and lower after inflorescence initiation than those in the spring planting. Under N treatments of 0 and 125 kg ha−1, total N in leaf tissue and the rate of leaf DM accumulation decreased while inflorescences developed. There was little extractable inorganic soil-N during inflorescence development in plots receiving no N fertilizer, yet inflorescence dry weights and N contents were ≥50 and ≥30%, respectively, of the maxima achieved with N fertilization. These results indicate that substantial N is translocated from leaves to support broccoli inflorescence growth under conditions of low soil-N availability. Key words: N translocation, N fertilizer

Download Full-text

Tillage and Planting Date Effects on Weed Dormancy, Emergence, and Early Growth in Organic Corn

Weed Science ◽

10.1614/ws-d-14-00112.1 ◽

2015 ◽

Vol 63 (2) ◽

pp. 477-490 ◽

Cited By ~ 7

Author(s):

John R. Teasdale ◽

Steven B. Mirsky

Keyword(s):

Cover Crop ◽

Dominant Species ◽

Management Practices ◽

Crop Management ◽

Planting Date ◽

Hairy Vetch ◽

Planting Dates ◽

Weed Biomass ◽

Giant Foxtail ◽

Smooth Pigweed

Insufficient weed control is a major constraint to adoption of reduced-tillage practices for organic grain production. Tillage, cover crop management, and crop planting date are factors that influence emergence periodicity and growth potential of important weed species in these systems. We assessed two hairy vetch cover crop management practices, disk-kill and roll-kill, across a range of corn planting dates from early May to late June in three experiments in Beltsville, MD. Patterns of seed dormancy, emergence, and early weed growth were determined for overseeded populations of common ragweed, giant foxtail, and smooth pigweed, three important species in the Mid-Atlantic states that represent early to late emergence. Common ragweed emergence was lowest and dormancy was highest of the three species across all planting dates. Giant foxtail emergence was higher than the other species in roll-killed hairy vetch and included a significant number of seeds that germinated before rolling operations in late June. Smooth pigweed had the highest emergence and lowest dormancy in disk-killed hairy vetch in June. Individual giant foxtail plant weight was higher in roll-killed than disk-killed hairy vetch in 2 of 3 yr, whereas that of smooth pigweed plants was higher in disk-killed than roll-killed vetch in 2 of 3 yr. Giant foxtail was the dominant species in roll-killed hairy vetch (averaged 79% of total weed biomass at corn silking), probably because of early germination and establishment before rolling operations. Smooth pigweed was the dominant species in disk-killed hairy vetch at June planting dates (averaged 77% of total weed biomass), probably because of high growth rates under warm conditions in tilled soil. This research demonstrated that cover crop management practices and the timing of planting operations can shift the dominant species of weed communities in organic farming systems and must be considered in long-term weed management planning.

Download Full-text

Knowledge Level on Soil Health Management among Soil Health Card Holders of Namakkal District, India

Asian Journal of Agricultural Extension Economics & Sociology ◽

10.9734/ajaees/2021/v39i1030720 ◽

2021 ◽

pp. 455-459

Author(s):

N. Dhivya ◽

R. Rajasekaran ◽

T. Dhamodaran ◽

R. Pangayar Selvi

Keyword(s):

Management Practices ◽

Health Management ◽

Soil Health ◽

Modern Technology ◽

Knowledge Level ◽

Human Beings ◽

Health Card ◽

Structural Deterioration ◽

Ex Post ◽

Four Blocks

Aims: Soil structural deterioration and degradation is a major concern in the present-day agriculture scenario. Poor soil health directly affects the health of the plant and its productivity; indirectly the health of human beings as well as animals. So, scientific knowledge of soil management on the part of the farmer-producers is necessary. So, the main aim of the study is to identify the knowledge level on soil health management among the soil health card holders. Study Design: Ex-post facto research. Place and Duration of Study: The study was carried out in the Namakkal district of Tamilnadu during the months of July-August 2021. All the selected respondents were the holders of soil health card as it contains physical and chemical characteristics of soil, they have a working knowledge of research problem and were able to provide responses. Methodology: Data were collected by using a pre-tested and structured questionnaire through a face-to-face interview method. The sample size is 120 selected from four blocks of Namakkal district. The statistical analysis applied were frequency distribution, percentage analysis, mean, and standard deviation. Results: The study shows that more than half of the soil health card holders (55.83 percent) had an overall high level of knowledge about soil health management practices. Conclusion: The soil health card scheme was brought to bring improvement of soil health in the long run by farmers all over the country. Thus, the knowledge of soil health management practices including modern technology can be disseminated to a greater extent for the benefit of the farmers including non-holders of soil health cards through formal and informal meetings and training.

Download Full-text

Soil health for improved food securities : an extension professional perspective

10.32469/10355/61955 ◽

2017 ◽

Author(s):

◽

Todd Elmer Lorenz

Keyword(s):

Diffusion Of Innovation ◽

Management Practices ◽

Health Management ◽

Age Groups ◽

Soil Health ◽

Small Sample ◽

Rural Sociology ◽

Management Tool ◽

Limiting Factor ◽

Professional Perspective

This trial study examines barriers to the diffusion and adoption of an agricultural concept surrounding soil health as an improved management tool which has most recently been introduced into production agriculture. For this study, a small sample set of perceived early adopters of soil health management practices were interviewed for their perspective on the subject of diffusion of innovation in soil health. Rogers' (1995) diffusion of innovation serves as the theoretical underpinning for this study. Where "an idea, practice or object that is perceived as new by an individual or other unit of adoption". H. F. Lionberger from the Department of Rural Sociology at University of Missouri was one of the contributing authors and had previous publications (Lionberger, 1957, 1960; Lionberger and Gwin, 1991). While diffusion of innovation has provided an overview of how information is diffused and adopted for Extension professionals, academia, and students, its use in discerning the adoption of soil health management practices has not been examined previously. There were both differences and similarities in what experiences, attitudes, and beliefs shaped the early adoption of Soil Health practices and how each interviewee perceived the most limiting factor 38 of adoption from other producers. Similarities included 1) family farm lived in diffusion of innovations. 2) economic concerns and 3) education is key while differences included perception of older folks as slow adopters. Even though the number sampled was small, N=2 for this study, the differences between the young and older age groups were characterized as "Blinding Energy" and "Earned Wisdom" respectively.

Download Full-text

Fresh Market Tomato Yield and Soil Nitrogen as Affected by Tillage, Cover Cropping, and Nitrogen Fertilization

HortScience ◽

10.21273/hortsci.35.7.1258 ◽

2000 ◽

Vol 35 (7) ◽

pp. 1258-1262 ◽

Cited By ~ 10

Author(s):

Sidat Yaffa ◽

Bharat P. Singh ◽

Upendra M. Sainju ◽

K.C. Reddy

Keyword(s):

Soil Erosion ◽

N Uptake ◽

N Fertilization ◽

N Leaching ◽

Hairy Vetch ◽

Inorganic N ◽

Cover Cropping ◽

Tomato Yield ◽

Soil Inorganic N ◽

Soil Inorganic

Sustainable practices are needed in vegetable production to maintain yield and to reduce the potential for soil erosion and N leaching. We examined the effects of tillage [no-till (NT), chisel plowing (CP), and moldboard plowing (MP)], cover cropping [hairy vetch (Vicia villosa Roth) vs. winter weeds], N fertilization (0, 90, and 180 kg·ha-1 N), and date of sampling on tomato (Lycopersicon esculentum Mill.) yield, N uptake, and soil inorganic N in a Norfolk sandy loam in Fort Valley, Ga. for 2 years. Yield was greater with CP and MP than with NT in 1996 and was greater with 90 and 180 than with 0 kg·ha-1 N in 1996 and 1997. Similarly, aboveground tomato biomass (dry weight of stems + leaves + fruits) and N uptake were greater with CP and MP than with NT from 40 to 118 days after transplanting (DAT) in 1996; greater with hairy vetch than with winter weeds at 82 DAT in 1997; and greater with 90 or 180 than with 0 kg·ha-1 N at 97 DAT in 1996 and at 82 DAT in 1997. Soil inorganic N was greater with NT or CP than with MP at 0- to 10-cm depth at 0 and 30 DAT in 1996; greater with hairy vetch than with winter weeds at 0- to 10-cm and at 10- to 30-cm at 0 DAT in 1996 and 1997, respectively; and greater with 90 or 180 than with 0 kg·ha-1 N from 30 to 116 DAT in 1996 and 1997. Levels of soil inorganic N and tomato N uptake indicated that N release from cover crop residues was synchronized with N need by tomato, and that N fertilization should be done within 8 weeks of transplanting. Similar tomato yield, biomass, and N uptake with CP vs. MP and with 90 vs. 180 kg·ha-1 N suggests that minimum tillage, such as CP, and 90 kg·ha-1 N can better sustain tomato yield and reduce potentials for soil erosion and N leaching than can conventional tillage, such as MP, and 180 kg·ha-1 N, respectively. Because of increased vegetative cover in the winter, followed by increased mulch and soil N in the summer, hairy vetch can reduce the potential for soil erosion and the amount of N fertilization required for tomato better than can winter weeds.

Download Full-text

Nutrient Management with Cover Crops and Compost Affects Development and Yield in Organically Managed Sweetpotato Systems

HortScience ◽

10.21273/hortsci.43.5.1423 ◽

2008 ◽

Vol 43 (5) ◽

pp. 1423-1433 ◽

Cited By ~ 4

Author(s):

Danielle D. Treadwell ◽

Nancy G. Creamer ◽

Greg D. Hoyt ◽

Jonathan R. Schultheis

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Organic Fertilizer ◽

Total Yield ◽

Hairy Vetch ◽

Inorganic N ◽

Available N ◽

Soil Inorganic N ◽

Organically Managed ◽

Soil Inorganic

A 3-year field experiment was initiated in 2001 to evaluate different organic sweetpotato production systems that varied in cover crop management and tillage. Three organic systems: 1) compost and no cover crop with tillage (Org-NCC); 2) compost and a cover crop mixture of hairy vetch and rye incorporated before transplanting (Org-CCI); and 3) compost and the same cover crop mixture with reduced tillage (Org-RT) were compared with a conventionally managed system (Conv) with tillage and chemical controls. Yield of No. 1 sweetpotato roots and total yield were similar among management systems each year, except for a reduction in yield in Org-RT in 2002. The percentage of No. 1 grade roots was at least 17% and 23% higher in Org-CCI and Org-NCC than Org-RT in 2001 and 2002, respectively, and similar to Conv in 2001 and 2004. Organic and conventional N sources contributed to soil inorganic N reserves differently the 2 years this component was measured. In 2002, soil inorganic N reserves at 30 DAT were in the order: Org-CCI (90 kg·ha−1) > Org-NCC (67 kg·ha−1) > Org-RT (45 kg·ha−1), and Conv (55 kg·ha−1). No differences in soil inorganic N reserves were observed among systems in 2004. Sweetpotato N, P, and K tissue concentrations were different among systems only in 2004. That year, at 60 days after transplanting, tissue N, P, and K were greatest in Org-CCI. In 2001 and 2004, N (4.09% to 4.56%) and K (3.79% to 4.34%) were higher than sufficiency ranges for N (3.2% to 4.0%) and K (2.5% to 3.5%) defined by North Carolina Department of Agriculture and Consumer Services recommendations for all treatments. No tissue macronutrient or micronutrient concentrations were limiting during this experiment. Reduced rainfall during the 2002 sweetpotato growing season may have contributed to the low microbially mediated plant-available N from the organic fertilizer sources. Despite differences in the nutrient content of organic and conventional fertility amendments, organically managed systems receiving compost with or without incorporated hairy vetch and rye produced yields equal to the conventionally managed system.

Download Full-text