Reliance on Biological Nitrogen Fixation Depletes Soil Phosphorus and Potassium Reserves

AbstractLimited nutrient availability is one of the major challenges in organic farming. Little is known about nutrient budgets of organic farms, the underlying factors or effects on soil fertility. We therefore assessed farm gate nutrient budgets for nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg) and sulfur (S) of 20 organic farms in Germany and analyzed their soil nutri-ent status. In average, the budgets showed a surplus of N (19 kg ha−1), K (5 kg ha−1), S (12 kg ha−1), and Mg (7 kg ha−1), and a deficit of P (−3 kg ha−1). There was, however, high variability between farms (e.g. standard deviation up to ± 36 kg N ha−1), which was mainly explained by different degrees of reliance on biological N fixation (BNF) as N source. When farms obtained more than 60% of their N input through BNF, they had deficits of P (mean −8 kg P ha−1) and K (mean −18 kg K ha−1). Nutrient status of most soils was within the ad-vised corridor, but for P, K and Mg, 10–15% of fields were lower and 45–63% were higher than advised. Extractable soil nutrient contents did not correlate with the nutrient budgets, inputs or outputs. Only extractable soil P increased with increasing P inputs and outputs. Fur-thermore, a decrease in extractable soil P was detected with a prolonged history of organic farming, indicating a risk of soil P mining in organic farming systems. In conclusion, the study revealed nutrient imbalances in organic farming and pointed to P and K scarcity as a major challenge for organic farms with high reliance on BNF in the long term.

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Crop yield and soil nutrient status on 14 organic farms in the eastern portion of the northern Great Plains

Canadian Journal of Plant Science ◽

10.4141/p00-089 ◽

2001 ◽

Vol 81 (2) ◽

pp. 351-354 ◽

Cited By ~ 96

Author(s):

M. H. Entz ◽

R. Guilford ◽

R. Gulden

Keyword(s):

Crop Rotation ◽

Great Plains ◽

Green Manure ◽

Soil Nutrient ◽

Nutrient Status ◽

Northern Great Plains ◽

Organic Farms ◽

Soil Nutrient Status ◽

Canadian Prairies ◽

Soil P

Cropping records from 13 organic farms in the eastern Canadian prairies and one in North Dakota (1991 to 1996) were surveyed to determine crop rotation pattern, yields and soil nutrient status. Major crops included cereal grains, forages, and green manure legumes. Organic grain and forage yields averaged from one-half to almost double conventional yields. Soil N, K and S levels on organic farms were generally sufficient; however, levels of available soil P were deficient in several instances. Key words: Crop rotation, weeds, forages, green manure crops

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Rekomendasi Pemupukan Fosfor dan Potasium berdasarkan Analisis Hara Tanah pada Tanaman Sayuran

Jurnal Hortikultura Indonesia ◽

10.29244/jhi.1.2.81-87 ◽

2014 ◽

Vol 1 (2) ◽

pp. 81

Author(s):

Lutfi Izhar ◽

Anas D. Susila

Keyword(s):

Soil Type ◽

Agricultural Development ◽

Soil Analysis ◽

Soil Nutrient ◽

Nutrient Status ◽

Vegetable Crops ◽

Soil P ◽

Fertilizer Recommendation ◽

Fertilizer Recommendations ◽

Low K

ABSTRACT Vegetables are important agricultural commodities. Productivity of vegetables in Indonesia is still low. One effort that can be done is an application of specific fertilizer recommendations. Fertilizer recommendation based on soil analysis is still rarely for vegetable crops and need further development. The purpose of this paper is to describe some fertilizer recommendations based on soil analysis for vegetable crops. Three stages to consider in the assessment of the research such as soil incubation, correlation test, calibration test and fertilizer recommendation statue. Application all this stages of soil method recommendation in Indonesia is still not widely applied. Two researches which were completed until the entire stage has been done for yard long beans and tomatoes. Recommendations for tomatoes on Inceptisols soil type with very low nutrient status of soil K was 180 kg K2O ha- 1, a low K soil nutrient status was 131.4 kg K2O ha-1, soil K nutrient status was 82.2 kg K 2O ha-1. Yard long bean that planted on Ultisol soil type with low soil P nutrient status was recommended by an application of 185.8 kg P2O5 ha-1, medium soil P nutrient status was added 174.9 kg P2O5 ha-1. Development of fertilizer recommendation based on soil testing to support agricultural development in Indonesia still has some problems and need some strategies for further research, application and dissemination in the future.Key words: vegetables, soil test, fertilizer recommendation

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Weed Species Diversity in the Czech Republic Under Different Farming and Site Conditions

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201563030741 ◽

2015 ◽

Vol 63 (3) ◽

pp. 741-749 ◽

Cited By ~ 1

Author(s):

Michaela Kolářová ◽

Luděk Tyšer ◽

Josef Soukup

Keyword(s):

Czech Republic ◽

Organic Farming ◽

Chenopodium Album ◽

Arable Land ◽

Farming Systems ◽

Weed Species ◽

Organic Farms ◽

Standard Size ◽

The Czech Republic ◽

Winter Cereals

The aim of this study was to explore the composition of weed vegetation on arable land in selected areas of the Czech Republic and to determine the level of γ-diversity. Our survey was conducted at 27 conventional and 35 organic farms from 2006–2008. In each sampled field, one phytocoenological relevé of a standard size of 100 m2 was recorded in the central part of the field. The species cover was estimated. The total γ-diversity was expressed as the total number of weed species recorded. γ-diversity of different farming systems, altitudes and crops was calculated. Subsequently, the species were divided on the basis of their perenniality. In total, 172 weed species were found – 123 and 162 in conventional and organic farming, respectively. The highest number of species was found in winter cereals and at medium altitudes. Chenopodium album was recorded as the species with the highest constancy in both types of farming. In total, 89 annuals, 17 biennials and 15 perennials were observed in conventional farming, and 109 annuals, 23 biennials, 28 perennials and 2 semiparasitic annuals were found in organic farming.

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Agricultural intensification reduces microbial network complexity and the abundance of keystone taxa in roots

10.1101/416271 ◽

2018 ◽

Cited By ~ 1

Author(s):

Samiran Banerjee ◽

Florian Walder ◽

Lucie Büchi ◽

Marcel Meyer ◽

Alain Y. Held ◽

...

Keyword(s):

Organic Farming ◽

Mycorrhizal Fungi ◽

Agricultural Intensification ◽

Soil Phosphorus ◽

Farming Systems ◽

Wheat Root ◽

Plant Performance ◽

No Till ◽

The Impact ◽

Root Microbiota

AbstractRoot-associated microbes play a key role in plant performance and productivity, making them important players in agroecosystems. So far, very few studies have assessed the impact of different farming systems on the root microbiota and it is still unclear whether agricultural intensification influences network complexity of microbial communities. We investigated the impact of conventional, no-till and organic farming on wheat root fungal communities usingPacBio SMRT sequencingon samples collected from 60 farmlands in Switzerland. Organic farming harboured a much more complex fungal network than conventional and no-till farming systems. The abundance of keystone taxa was the highest under organic farming where agricultural intensification was the lowest. The occurrence of keystone taxa was best explained by soil phosphorus levels, bulk density, pH and mycorrhizal colonization. The majority of keystone taxa are known to form arbuscular mycorrhizal associations with plants and belong to the ordersGlomerales,Paraglomerales, andDiversisporales. Supporting this, the abundance of mycorrhizal fungi in roots and soils was also significantly higher under organic farming. To our knowledge, this is the first study to report mycorrhizal keystone taxa for agroecosystems, and we demonstrate that agricultural intensification reduces network complexity and the abundance of keystone taxa in the root microbiota.

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Nutrient balances and nutrient availability of organic cash crop farms in Austria

10.5194/egusphere-egu21-11456 ◽

2021 ◽

Author(s):

Juergen K. Friedel ◽

Anne Leonhard ◽

Christopher Schöpf

Keyword(s):

Organic Farming ◽

Nutrient Management ◽

Phosphorus Availability ◽

Available Phosphorus ◽

N Fixation ◽

Nutrient Balances ◽

Organic Farms ◽

Cash Crop ◽

Class B ◽

Class C

For stockless organic farms an adequate nutrient supply is in many ways a challenge. In order to assess the nutrient management of Austrian organic stockless farms, farm gate-balances for nitrogen, potassium and phosphorus of 15 organic stockless farms located in Austria&#8217;s main arable production areas were calculated. Two of the farms were located in Wald- und M&#252;hlviertel (Northern Upper and Lower Austria), two in the Carinthian Basin (Carinthia), two in the Pre-alpine Region (Southern Upper and Lower Austria), two in the South-Eastern Lowlands (Eastern Styria and Burgenland), four in the Marchfeld region (Eastern Lower Austria) and three in the Weinviertel (North-Eastern Lower Austria). The farms were managed according to organic farming guidelines for at least five years at the time of assessment. Nutrient balances were calculated over a period of five years, subtracting all farm outputs (nutrients in sold products) from all farm inputs (seeds and fertilizers, biological N fixation). Yields were assessed in questionnaires from the farmers, nutrient contents were taken from standardized tables.Nitrogen balances (n = 14 farms) were -14.6 kg N ha-1 yr-1 on average, ranging from -61 to +34 kg N ha-1 yr-1. Nitrogen balances were strongly negative for one farm, slightly negative for 10 farms, even for one farm and slightly positive for 2 farms. Phosphorus balances (n = 15 farms) were -8.3 kg P ha-1 yr-1 on average, ranging from -23 to -3 kg P ha-1 yr-1. Phosphorus balances were strongly negative for one farm, slightly negative for 12 farms and even for 2 farms. Potassium balances (n = 15 farms) were -15.6 kg K ha-1 yr-1 on average, ranging from -31 to -8 kg K ha-1 yr-1. Potassium balances were slightly negative for 5 farms and even for 10 farms.Plant available potassium contents (KCAL) on the farm fields ranged from 74 to 378 mg K kg-1. Two farms were moderately supplied (class B of the Austrian classification scheme), 10 farms were optimally supplied (class C) and 3 farms were over-supplied (class E). Plant available phosphorus contents (PCAL) on the farm fields ranged from 21 to 102 mg P kg-1. Two farms were classified as undersupplied (class A), 5 farms were moderately supplied (class B) and 8 farms were optimally supplied (class C).Potassium availability and potassium balances on the farms were not correlated (r = 0.192, P = 0.899), phosphorus availability and phosphorus balances neither (r = -0.210, P = 0.881). Potassium and phosphorus availability were not significantly correlated to the duration of organic farming as well.Stockless organic farms in Austria are very diverse, concerning their production conditions and nutrient management. The results indicate no adverse short-term effects on soil fertility for most of the farms. In the long term though, nutrient management should be improved to secure yields and to ensure the sustainability on organically managed cash crop farms. Meaningful options are e.g. farm partnerships with fodder-manure exchange and the use of recycled fertilizers like struvite. This, however, requires an adjustment of organic farming guidelines.

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Effect of introducing frogs and fish on soil phosphorus availability dynamics and their relationship with rice yield in paddy fields

Scientific Reports ◽

10.1038/s41598-019-56644-z ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 2

Author(s):

Kaimiao Lin ◽

Jianping Wu

Keyword(s):

Best Practice ◽

Rice Yield ◽

Soil Phosphorus ◽

Farming Systems ◽

Paddy Fields ◽

Rice Grain ◽

P Availability ◽

Soil P ◽

Labile P ◽

Rice Fish

AbstractThe long-term impacts of introducing frogs and fish on rice yield and soil P availability are largely underestimated and undervalued. A 9-year field experiment compared the soil phosphorus fraction dynamics and their relationship with rice yield in rice-frog-fish (RFF) cultures, rice-fish (RF) cultures and rice-only (RO) cultures in southeastern China paddy fields. The yields in the RFF and RF cultures were notably higher than those in the RO culture, by 22.1% and 6.8%, respectively. Soil total P ranged from 345.5 to 385.6 mg kg−1 among all the farming systems, with the smallest amount found in the RO culture. There were only slight changes in the distribution of soil phosphorus fractions with time. The concentrations of NaHCO3-Pi and NaHCO3-Po were significantly higher in the RFF and RF cultures compared with those in the RO culture, and most of the NaOH-Pi and NaOH-Po fractions were greater in the RFF and RF cultures compared with those in the RO culture. The rice grain yield was significantly correlated with labile P and slowly cycling P. Introducing frogs and fish might be useful for increasing soil active P supplies and meeting rice nutrient requirements. This study concluded that RFF is the best practice for improving rice grain yields and soil fertility in paddy fields.

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Pronounced surface stratification of soil phosphorus, potassium and sulfur under pastures upstream of a eutrophic wetland and estuarine system

Soil Research ◽

10.1071/sr16144 ◽

2017 ◽

Vol 55 (7) ◽

pp. 657 ◽

Cited By ~ 3

Author(s):

Megan H. Ryan ◽

Mark Tibbett ◽

Hans Lambers ◽

David Bicknell ◽

Phillip Brookes ◽

...

Keyword(s):

Soil Phosphorus ◽

Dairy Farm ◽

Soil Surface ◽

Plant Litter ◽

Nutrient Concentrations ◽

Estuarine System ◽

Soil P ◽

Extractable P ◽

High Concentrations ◽

Extractable Soil

High concentrations of nutrients in surface soil present a risk of nutrient movement into waterways through surface water pathways and leaching. Phosphorus (P) is of particular concern because of its role in aquatic system eutrophication. We measured nutrients under annual pastures on a beef farm and a dairy farm in the Peel–Harvey catchment, Western Australia. Soils were sampled in 10-mm increments to 100mm depth in March, June and September. Plant litter contained approximately 300–550mg kg–1 Colwell-extractable P. Extractable soil P was strongly stratified, being approximately 100–225mg kg–1 (dairy) and 50–110mg kg–1 (beef) in the top 10mm and <40mg kg–1 at 40–50mm depth. Total P and extractable potassium were also highly stratified, whereas sulfur was less strongly stratified. Shoot nutrient concentrations indicated that nitrogen was often limiting and sulfur was sometimes limiting for pasture growth: concentrations of P were often much greater than required for adequate growth (>4mg g–1). We conclude that high P concentrations at the soil surface and in litter and shoots are a source of risk for movement of P from farms into waterways in the Peel–Harvey catchment.

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Soil Nutrient Status of Organic Farms in Flanders: An Overview and a Comparison with the Conventional Situation

Biological Agriculture & Horticulture ◽

10.1080/01448765.2006.9755023 ◽

2006 ◽

Vol 24 (3) ◽

pp. 217-235 ◽

Cited By ~ 5

Author(s):

Stefaan De Neve ◽

Annemie Van Den Bossche ◽

Steven Sleutel ◽

Georges Hofman

Keyword(s):

Soil Nutrient ◽

Nutrient Status ◽

Organic Farms ◽

Soil Nutrient Status

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Genetic Diversification and Selection Strategies for Improving Sorghum Grain Yield Under Phosphorous-Deficient Conditions in West Africa

Agronomy ◽

10.3390/agronomy9110742 ◽

2019 ◽

Vol 9 (11) ◽

pp. 742

Author(s):

Chiaka Diallo ◽

H. Frederick W. Rattunde ◽

Vernon Gracen ◽

Aboubacar Touré ◽

Baloua Nebié ◽

...

Keyword(s):

Grain Yield ◽

Agronomic Traits ◽

Soil Phosphorus ◽

Central Africa ◽

Farming Systems ◽

Recurrent Parent ◽

Soil P ◽

Nested Association Mapping ◽

Design Selection ◽

Sorghum Grain

Sorghum, a major crop for income generation and food security in West and Central Africa, is predominantly grown in low-input farming systems with serious soil phosphorus (P) deficiencies. This study (a) estimates genetic parameters needed to design selection protocols that optimize genetic gains for yield under low-phosphorus conditions and (b) examines the utility of introgressed backcross nested association mapping (BCNAM) populations for diversifying Malian breeding materials. A total of 1083 BC1F5 progenies derived from an elite hybrid restorer “Lata-3” and 13 diverse donor accessions were evaluated for yield and agronomic traits under contrasting soil P conditions in Mali in 2013. A subset of 298 progenies were further tested under low-P (LP) and high-P (HP) conditions in 2014 and 2015. Significant genetic variation for grain yield was observed under LP and HP conditions. Selection for grain yield under LP conditions was feasible and more efficient than the indirect selection under HP in all three years of testing. Several of the BCNAM populations exhibited yields under LP conditions that were superior to the elite restorer line used as a recurrent parent. The BCNAM approach appears promising for diversifying the male parent pool with introgression of diverse materials using both adapted Malian breed and unadapted landrace material from distant geographic origins as donors.

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Meta-analysis of nutrient budgets in organic farms across Europe

Organic Agriculture ◽

10.1007/s13165-020-00300-8 ◽

2020 ◽

Vol 10 (S1) ◽

pp. 65-77 ◽

Cited By ~ 1

Author(s):

Marie Reimer ◽

Kurt Möller ◽

Tobias Edward Hartmann

Keyword(s):

Meta Analysis ◽

Soil Surface ◽

Nutrient Status ◽

Farming System ◽

Nutrient Budgets ◽

Organic Farms ◽

Comprehensive Overview ◽

Farm Type ◽

Organic Farming System ◽

Farm Types

AbstractNutrient supply to organic farms is a highly discussed topic in Europe, due to the restricted availability of external fertilizer resources and the use of contentious inputs. To optimize the flow of nutrients throughout the organic farming system, it is firstly necessary to obtain valid data on the nutrient status of organic farms. Nutrient budgets are a valid tool to investigate the nutrient demand or surplus of a system. However, there is currently no comprehensive overview of nutrient budgets of European organic farms. We therefore carried out a meta-analysis on 56 individual studies that reported either farm-gate or soil surface budgets. The analysis showed an imbalance between nutrients, a general surplus of nitrogen (45 kg N ha−1 year−1 [95% confidence interval (CI) 30, 61]), magnesium (16 kg Mg ha−1 year−1 [− 9, 40]) and sulfur (45 kg S ha−1 year−1 [− 29, 118]), a balanced phosphorus budget (0 kg P ha−1 year−1 [− 2, 2]), and a deficit for potassium (− 12 kg K ha−1 year−1 [− 21, − 3]). We observed large differences between farms that could be partly explained by farm type and budgeting method. Arable and mixed farms showed lower nitrogen, phosphor, magnesium, and sulfur budgets than dairy/beef farms or even vegetable farms, while all farm types besides dairy/beef farms showed deficits for K budgets. Further, farm-gate budget studies yielded higher budgets than soil surface budgets. Variations between studied countries could also be detected, but the coverage and comparability are low due to differences in studied farm types and budgeting method.

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