{"type": "FeatureCollection", "features": [{"id": "10.1007/978-1-4020-5760-1_55", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:14:32Z", "type": "Journal Article", "created": "2006-10-03", "title": "Comparative Short-Term Effects Of Different Quality Organic Resources On Maize Productivity Under Two Different Environments In Zimbabwe", "description": "Major challenges for combined use of organic and mineral nutrient sources in smallholder agriculture include variable type and quality of the resources, their limited availability, timing of their relative application and the proportions at which the two should be combined. Short-term nutrient supply capacity of five different quality organic resources ranging from high to low quality, namely Crotalaria juncea, Calliandra calothyrsus, cattle manure, maize stover and Pinus patula sawdust were tested in the field using maize as a test crop. The study was conducted on two contrasting soil types at Makoholi and Domboshawa, which fall under different agro-ecological regions of Zimbabwe. Makoholi is a semi-arid area ( 750 mm yr\u22121) soils are sandy-clay loams with 220 g kg\u22121 clay. Each organic resource treatment was applied at low (2.5 t C ha\u22121) and high (7.5 t C ha\u22121) biomass rates at each site. Each plot was sub-divided into two with one half receiving 120 kg N ha\u22121 against zero in the other. At Makoholi, there was a nine-fold increase in maize grain yield under high application rates of C. juncea over the unfertilized control, which yielded only 0.4 t ha\u22121. Combinations of mineral N fertilizer with the leguminous resources and manure resulted in between 24% and 104% increase in grain yield against sole fertilizer, implying an increased nutrient recovery by maize under organic\u2013mineral combinations. Maize biomass measured at 2 weeks after crop emergence already showed treatment differences, with biomass yields increasing linearly with soil mineral N availability (R2 = 0.75). This 2-week maize biomass in turn gave a positive linear relationship (R2 = 0.82) with grain yield suggesting that early season soil mineral N availability largely determined final yield. For low quality resources of maize stover and sawdust, application of mineral N fertilizer resulted in at least a seven-fold grain yield increase compared with sole application of the organic resources. Such nutrient combinations resulted in grain harvest indices of between 44% and 48%, up from a mean of 35% for sole application, suggesting the potential of increasing maize productivity from combinations of low quality resources with mineral fertilizer under depleted sandy soils. At Domboshawa, grain yields averaged 7 t ha\u22121 and did not show any significant treatment differences. This was attributed to relatively high levels of fertility under the sandy-clay loams during this first year of the trial implementation. Differences in N supply by different resources were only revealed in grain and stover uptake. Grain N concentration from the high quality leguminous resources averaged 2% against 1.5% from sawdust treatments. We conclude that early season soil mineral N availability is the primary regulatory factor for maize productivity obtainable under poor sandy soils. Maize biomass at 2 weeks is a potential tool for early season assessment of potential yields under constrained environments. However, the likely impact on system productivity following repeated application of high N-containing organic materials on different soil types remains poorly understood.", "keywords": ["0106 biological sciences", "2. Zero hunger", "yields", "fertilizer application", "abonos nitrogenados", "04 agricultural and veterinary sciences", "15. Life on land", "maize", "01 natural sciences", "ma\u00edz", "nitrogen fertilizers", "0401 agriculture", " forestry", " and fisheries", "organic fertilizers", "abonos org\u00e1nicos", "aplicaci\u00f3n de abonos", "rendimiento"]}, "links": [{"href": "https://doi.org/10.1007/978-1-4020-5760-1_55"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Nutrient%20Cycling%20in%20Agroecosystems", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/978-1-4020-5760-1_55", "name": "item", "description": "10.1007/978-1-4020-5760-1_55", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/978-1-4020-5760-1_55"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2006-10-03T00:00:00Z"}}, {"id": "10.1016/j.agee.2010.12.004", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:15:20Z", "type": "Journal Article", "created": "2011-01-27", "title": "Comparison Of Organic Versus Mineral Resource Effects On Short-Term Aggregate Carbon And Nitrogen Dynamics In A Sandy Soil Versus A Fine Textured Soil", "description": "Abstract   Aggregation and stabilization of soil organic C (SOC) and N are highly dependent on soil texture and addition of organic resources (ORs). While OR quality may influence SOC and N stabilization within aggregates, the simultaneous addition of N-fertilizers may enhance OR decomposition resulting in loss of SOC. A mesocosm study was conducted on a clayey soil at Embu and a sandy soil at Machanga in central Kenya to determine the influence of soil texture, OR quality and N-fertilizer on aggregation, SOC and N.  Tithonia diversifolia  (high quality),  Calliandra calothyrsus  (medium quality) and  Zea mays  (maize; low quality) residues, natural abundance or labeled with  15 N, were applied to soil at an equivalent rate of 4\u00a0Mg\u00a0C\u00a0ha \u22121  compared to no input control. Each treatment was fertilized with 120\u00a0kg  14 N or  15 N\u00a0ha \u22121  as (NH 2 ) 2 CO, or not fertilized. Soil samples were collected at installation of the mesocosms (start), and 8 months after installation (end). Soils were separated into different aggregate size fractions by wet sieving and macroaggregates were further fractionated to isolate microaggregates-within-macroaggregates. Total soil and aggregate fractions were analyzed for SOC and N. On average, 20% and 70% of SOC and N was in the macroaggregates in the sandy and clayey soils, respectively. There were no differences among OR quality in both soils but in the clayey soil all ORs resulted in greater SOC and N than in the control. However, proportions of OR-derived N in the macroaggregates, mostly in the microaggregates-within-macroaggregates were greater with sole applied maize in the clayey soil. The addition of N-fertilizer together with maize stover reduced soil N, macroaggregate N, and OR-derived N in the microaggregate and silt and clay fractions within macroaggregates compared to when maize was applied alone. In the sandy soil,  Calliandra  resulted in greater OR-derived N than  Tithonia  in the coarse particulate organic matter (cPOM; i.e., 5% compared to 2% of N applied). Thus, the greater polyphenol concentration in  Calliandra  likely slowed its decomposition compared to that of  Tithonia . In addition, greater proportions of N and residue-derived N in the macroaggregates were observed in the coarse POM in the sandy soil whereas in the clayey soil it was in the microaggregates-within-macroaggregates. We conclude that the preservation of OR-derived N is affected by the chemical recalcitrance of the residues in sandy soils, whereas macroaggregate protection, and not OR quality, is the major factor in clayey soils.", "keywords": ["2. Zero hunger", "soil fertility", "textura del suelo", "enmiendas org\u00e1nicas", "soil texture", "abonos nitrogenados", "04 agricultural and veterinary sciences", "fertilidad del suelo", "15. Life on land", "01 natural sciences", "6. Clean water", "unidades estructurales de suelos", "nitrogen fertilizers", "organic amendments", "0401 agriculture", " forestry", " and fisheries", "ecology", "soil structural units", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://doi.org/10.1016/j.agee.2010.12.004"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Agriculture%2C%20Ecosystems%20%26amp%3B%20Environment", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.agee.2010.12.004", "name": "item", "description": "10.1016/j.agee.2010.12.004", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.agee.2010.12.004"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2011-03-01T00:00:00Z"}}, {"id": "10.1007/s11104-010-0462-7", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:15:04Z", "type": "Journal Article", "created": "2010-06-16", "title": "Agronomic Use Efficiency Of N Fertilizer In Maize-Based Systems In Sub-Saharan Africa Within The Context Of Integrated Soil Fertility Management", "description": "Traditionally, crop production in sub-Saharan Africa (SSA) depends primarily on mining soil nutrients. Integrated Soil Fertility Management (ISFM) is an approach for intensifying agriculture in SSA that aims at maximizing the agronomic efficiency (AE) of applied nutrient inputs. ISFM contains the following essential components: proper fertilizer management, use of improved varieties, the combined application of organic inputs and fertilizer, and adaptation of input application rates to within-farm soil fertility gradients where these are important. This paper evaluates, through meta-analysis, the impact of these components on the AE of fertilizer N (N-AE), defined as extra grain yield per kg fertilizer N applied, in maize-based systems in SSA. Since N-AE is low for excessive fertilizer N application rates or when fertilizer is applied on fertile, unresponsive soil, as was confirmed by scatter plots against control yields and fertilizer N application rates, such values were removed from the database in order to focus on and elucidate the more variable and complex responses under less than ideal conditions typical for SSA. Compared with local varieties, the use of hybrid maize varieties significantly increased N-AE values (17 and 26\u00a0kg (kg\u00a0N)\u22121, respectively) with no differences observed between local and improved, open-pollinated varieties. Mixing fertilizer with manure or compost resulted in the highest N-AE values [36\u00a0kg (kg\u00a0N)\u22121] while organic inputs of medium quality also showed significantly higher N-AE values compared with the sole fertilizer treatment but only at low organic input application rates (40 and 23\u00a0kg (kg\u00a0N)\u22121, respectively). High quality organic inputs (Class I) and those with a high C-to-N ratio (Class III) or high lignin content (Class IV) did not affect N-AE values in comparison with the sole fertilizer treatment. Application of N fertilizer on infields resulted in significantly higher N-AE values [31\u00a0kg (kg\u00a0N)\u22121] compared with the outfields [17\u00a0kg (kg\u00a0N)\u22121]. The obtained information indicates that N-AE is amenable to improved management practices and that the various components embedded in the ISFM definition result in improvements in N-AE.", "keywords": ["germoplasma", "2. Zero hunger", "nitrogen fertilizers", "soil fertility", "0401 agriculture", " forestry", " and fisheries", "abonos nitrogenados", "04 agricultural and veterinary sciences", "germplasm", "fertilidad del suelo", "15. Life on land", "maize", "africa al sur del sahara", "ma\u00edz"]}, "links": [{"href": "https://doi.org/10.1007/s11104-010-0462-7"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Plant%20and%20Soil", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1007/s11104-010-0462-7", "name": "item", "description": "10.1007/s11104-010-0462-7", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1007/s11104-010-0462-7"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2010-06-17T00:00:00Z"}}, {"id": "10.1023/b:fres.0000019043.33580.a6", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:16:59Z", "type": "Journal Article", "created": "2004-03-10", "title": "Nitrogen Fertilizer Equivalencies Of Organics Of Differing Quality And Optimum Combination With Inorganic Nitrogen Source In Central Kenya", "description": "Decline in crop yields is a major problem facing smallholder farmers in Kenya and the entire Sub-Saharan region. This is attributed mainly to the mining of major nutrients due to continuous cropping without addition of adequate external nutrients. In most cases inorganic fertilizers are expensive, hence unaffordable to most smallholder farmers. Although organic nutrient sources are available, information about their potential use is scanty. A field experiment was set up in the sub-humid highlands of Kenya to establish the chemical fertilizer equivalency values of different organic materials based on their quality. The experiment consisted of maize plots to which freshly collected leaves of Tithonia diversifolia (tithonia), Senna spectabilis (senna) and Calliandra calothyrsus (calliandra) (all with %N>3) obtained from hedgerows grown ex situ (biomass transfer) and urea (inorganic nitrogen source) were applied. Results obtained for the cumulative above ground biomass yield for three seasons indicated that a combination of both organic and inorganic nutrient source gave higher maize biomass yield than when each was applied separately. Above ground biomass yield production in maize (t ha\u22121) from organic and inorganic fertilization was in the order of senna+urea (31.2), tithonia+urea (29.4), calliandra+urea (29.3), tithonia (28.6), senna (27.9), urea (27.4), calliandra (25.9), and control (22.5) for three cumulative seasons. On average, the three organic materials (calliandra, senna and tithonia) gave fertilizer equivalency values for the nitrogen contained in them of 50, 87 and 118%, respectively. It is therefore recommended that tithonia biomass be used in place of mineral fertilizer as a source of nitrogen. The high equivalency values can be attributed to the synergetic effects of nutrient supply, and improved moisture and soil physical conditions of the mulch. However, for sustainable agricultural production, combination with mineral fertilizer would be the best option.", "keywords": ["2. Zero hunger", "Organic", "biomass", "N fertilizer equivalency", "yields", "abonos nitrogenados", "04 agricultural and veterinary sciences", "910", "15. Life on land", "maize", "N-sources", "6. Clean water", "ma\u00edz", "12. Responsible consumption", "Inorganic", "zea mays", "nitrogen fertilizers", "biomasa", "0401 agriculture", " forestry", " and fisheries", "organic fertilizers", "inorganic fertilizers", "abonos org\u00e1nicos", "abonos inorg\u00e1nicos", "rendimiento"]}, "links": [{"href": "https://doi.org/10.1023/b:fres.0000019043.33580.a6"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Nutrient%20Cycling%20in%20Agroecosystems", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1023/b:fres.0000019043.33580.a6", "name": "item", "description": "10.1023/b:fres.0000019043.33580.a6", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1023/b:fres.0000019043.33580.a6"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2004-02-01T00:00:00Z"}}, {"id": "10.2134/agronj2008.0188x", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:18:47Z", "type": "Journal Article", "created": "2009-09-01", "description": "<p>Organic resources (ORs) are important nutrient inputs in tropical agriculture. Combined with mineral fertilizers, they form the backbone of integrated soil fertility management. This study was conducted to determine the medium\uffe2\uff80\uff90 to long\uffe2\uff80\uff90term influence of OR quality and quantity on maize productivity and to evaluate the occurrence of additive benefits in terms of extra grain yield produced by the combined application of ORs and N fertilizers. Farmyard manure, high quality Mexican sunflower [Tithonia diversifolia (Hemsl.) A. Gray], intermediate quality calliandra (Calliandra calothyrsus Meisn.) and maize (Zea mays L.), and low quality silky\uffe2\uff80\uff90oak (Grevillea robusta A. Cunn. ex R. Br.) sawdust were incorporated into the soil at equivalent rates of 1.2 and 4 Mg C ha\uffe2\uff88\uff921 yr\uffe2\uff88\uff921 in Embu (clayey) and Machanga (sandy soil), together with a control to which no OR was added. All plots were split, with one half receiving 120 kg N ha\uffe2\uff88\uff921 season\uffe2\uff88\uff921 as CaNH4NO3. The ORs, except sawdust and maize, improved maize grain yields compared with the control at both sites. Greatest mean maize yields (i.e., 4.9 and 2.3 Mg ha\uffe2\uff88\uff921 season\uffe2\uff88\uff921, in Embu and Machanga, respectively) over 10 seasons were observed with the high rate of Mexican sunflower, but was not significantly different from calliandra and manure. Generally, maize yields were greater with higher than lower OR rates, except for maize and sawdust. Although N fertilizer additions to the ORs improved grain yields in Embu, the increase was marginal; resulting in negative interactive effects of applying ORs with N fertilizers, especially with high\uffe2\uff80\uff90N ORs. Thus high\uffe2\uff80\uff90N ORs should not be applied in combination with N fertilizers, especially at such high fertilizer N rates.</p>", "keywords": ["2. Zero hunger", "soil fertility", "abonos nitrogenados", "04 agricultural and veterinary sciences", "fertilidad del suelo", "15. Life on land", "maize", "630", "ma\u00edz", "soil exhaustion", "nitrogen fertilizers", "cultivos tropicales", "0401 agriculture", " forestry", " and fisheries", "agotamiento del suelo", "estiercol", "farmyard manure", "organic fertilizers", "abonos org\u00e1nicos", "tropical crops"]}, "links": [{"href": "https://doi.org/10.2134/agronj2008.0188x"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Agronomy%20Journal", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.2134/agronj2008.0188x", "name": "item", "description": "10.2134/agronj2008.0188x", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.2134/agronj2008.0188x"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2009-09-01T00:00:00Z"}}, {"id": "10.5424/sjar/2008062-320", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:21:22Z", "type": "Journal Article", "created": "2013-11-21", "description": "<p>The aim of this experiment was to evaluate the effects of adding DMPP (3,4-dimethylpyrazole phosphate) to urea on nitrate leaching and maize (Zea mays L.) yield over two growing seasons. Two nitrogen (N) levels (optimum and excessive) were applied to an irrigated maize crop under Mediterranean conditions. There were five treatments: optimal N (as urea) and the same dose plus DMPP; optimal N (as urea plus 40 kg N/ha) and the same N dose plus DMPP; and a control with no added N fertilizer. The maize was irrigated with an overhead mobile-line sprinkler system. EnviroSCAN probes were used to determine drainage and evapotranspiration and ceramic cups to obtain soil solution samples at a soil depth of 1.4 m. The use of DMPP with urea reduced nitrate leaching. No phytotoxic effects were observed due to the DMPP. There were no differences in grain yield between treatments with and without DMPP at the same rate of N. When DMPP was applied, sodium was displaced from the soil exchange complex due to increased NH4+ concentration, which also increased the electrical conductivity of soil in the drainage zone.</p>", "keywords": ["ZEA MAYS; APLICACION DE ABONOS; ABONOS NITROGENADOS; UREA; NITRATOS; LIXIVIACION; POLUCION DE AGUAS SUBTERRANEAS; INHIBIDORES DE LA NITRIFICACION; CONTROL DE LA CONTAMINACION; RENDIMIENTO DE CULTIVOS", "NITRIFICATION INHIBITORS", "INHIBIDORES DE LA NITRIFICACION", "NITROGEN FERTILIZERS", "CONTROL DE LA CONTAMINACION", "LEACHING", "POLLUTION CONTROL", "GROUNDWATER POLLUTION", "NITRATES", "Fertilizing", "RENDIMIENTO DE CULTIVOS", "CROP YIELD", "FERTILIZER APPLICATION", "APLICACION DE ABONOS", "ZEA MAYS", "ZEA MAYS; FERTILIZER APPLICATION; NITROGEN FERTILIZERS; UREA; NITRATES; LEACHING; GROUNDWATER POLLUTION; NITRIFICATION INHIBITORS; POLLUTION CONTROL; CROP YIELD", "POLUCION DE AGUAS SUBTERRANEAS", "2. Zero hunger", "ABONOS NITROGENADOS", "0402 animal and dairy science", "04 agricultural and veterinary sciences", "6. Clean water", "NITRATOS", "0401 agriculture", " forestry", " and fisheries", "LIXIVIACION", "UREA"], "contacts": [{"organization": "D\u00edez L\u00f3pez, J.A., Hernaiz, P.,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.5424/sjar/2008062-320"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Spanish%20Journal%20of%20Agricultural%20Research", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.5424/sjar/2008062-320", "name": "item", "description": "10.5424/sjar/2008062-320", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.5424/sjar/2008062-320"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2008-06-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=ABONOS+NITROGENADOS&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=ABONOS+NITROGENADOS&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=ABONOS+NITROGENADOS&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=ABONOS+NITROGENADOS&offset=6", "hreflang": "en-US"}], "numberMatched": 6, "numberReturned": 6, "distributedFeatures": [], "timeStamp": "2026-09-23T04:56:21.206126Z"}