Comparisons between subsurface trickle-(drip) and furrow-irrigated leaf lettuce, scheduled by AZSCHED and by tensiometers were made to evaluate their effects on crop coefficient, crop water use, nitrogen uptake and nitrogen leaching. A field experiment with four treatments and five replications was conducted during the fall-winter 1994-95 growing season at The University of Arizona's Campus Agricultural Center. Results showed that there was no significant difference at 95% confidence level among treatments, with respect to crop coefficients. A Fourier series was fitted to represent the Growing Degree Days (GDD)--Crop coefficient (Kc) relationship that can be recommended for irrigation scheduling of leaf lettuce at any geographical situation and planting date. A table of Kc for "days after thinning" was derived for Tucson-AZ. Marketable yield averaged 25.0 Mg ha⁻¹ with crop water use efficiency of 9.8 Kg of marketable yield per cubic meter of water (including rainfall). The 1994-95 growing season was not typical for Tucson-AZ. There was 181 mm of rainfall compared to the long term average of 91 mm. Based on the studied condition we could also conclude that, for supplementary irrigation, that is typical of humid areas, there is no difference if one irrigate leaf lettuce by short-end-closed furrow or subsurface - trickle irrigation, scheduled either by tension of 20 kPa or AZSCHED software, concerning yield and nitrogen uptake. The risk of nitrogen leaching is higher for furrow irrigation systems than for drip.

Biochar is a carbon sequestration technology that has shown potential to inhibit greenhouse gas (GHG) emission and nutrient leaching from soils, however the majority of biochar research thus far has focused on arable cropland rather than livestock systems or grasslands. Livestock production is an important agricultural system, and manure generated from livestock systems is a source of GHG emission as well as nutrient loading to surface- and groundwater. The high environmental impact of livestock production in the very areas that biochar has shown potential may suggest that this would be an ideal system for biochar incorporation. However, as grassland systems in the context of livestock production often receive high nutrient inputs in the form of manure which increases the potential for nutrient leaching or runoff, the high-nutrient ash content of biochar may potentially exacerbate this problem rather than suppress nutrient loss from soils. As private companies and government-funded programmes discuss the possibility of scaling the global manufacturing and soil-incorporation of biochar to a rate of gigatonnes per year, understanding the potential of biochar for use within a livestock system could be crucial in helping to develop an appropriate deployment plan for this material. This thesis is therefore focused on the use of biochar in grassland and livestock systems. It first examines the nutrient release from biochar in a sequential leaching experiment. Phosphorus (P) release indicated that provision of soil P (though quantitatively small) may be sustained over time whilst potassium (K+) release was quantitatively large but declined rapidly following the first extraction. An incubation study was then carried out using soil columns amended with farmyard manure, liquid manure (slurry) or fertiliser (plus an unamended control), each with and without biochar, which sought to determine the impact of biochar on N2O release and N and P leaching from soils with diverse nutrient sources. N2O emission from the columns was significantly suppressed by the presence of biochar, as was the leaching of mineral N. However, the amount of PO4 3--P in leachate was increased in biocharamended columns, relative to their unamended counter-parts. A slurry incubation study was then conducted, with a control slurry and four biochar-amended treatments, which explored whether biochar could suppress GHG and NH3 emission from manure prior to land application. The resulting data indicated that biochar demonstrates potential for GHG suppression but does not demonstrate potential for NH3 suppression from slurry in storage. Finally, a one-year field-based experiment was completed which analysed the impact of biochar on CH4, N2O, and NH3 emission as well as nutrient leaching from grassland soils that had been amended with a high rate of manure application (151.4 m3 ha-1 or 409 kg N ha-1). In this study, biochar demonstrated the potential to suppress each of the three types of gaseous emissions from manure-amended soil, though the differences between mean values were not statistically significant. Extracts from ion exchange resins indicated that annual cumulative K+ leached from biochar-amended plots was significantly higher than the control, and that P and NH4 + leached from biochar-amended plots was higher than the control at the time of the first rain event following biochar and manure application. Together, the results of these component studies indicate that biochar may indeed have potential to suppress GHG emissions from livestock systems, most likely through suppression of microbial activity by organic compounds that are sorbed to the char, though (as the mechanisms of GHG suppression by biochar are thus far not well understood) the capacity of biochar to do so may vary based on the type of biochar used, the soil characteristics, and other factors. Overall, the results of these studies suggest that some types of biochar should be used with caution in systems with high rates of nutrient application, unless the ash is removed prior to soil application.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 4 uppsatser.

Application of biosolids as an alternative source of Nitrogen (N) is becoming a common silviculture practices on loblolly pine forest. However, little is known about how biosolids type, application rate, and timing affect forest floor and soil N availability in pine plantations. The objectives of this study were to determine the effect of different types, rates, and season of application of biosolids on forest floor and soil N. The study was established in a 17-year-old loblolly pine plantation in Amelia County, VA. Anaerobically digested (AD225), lime stabilized (LS225), and pelletized (Pellet225) biosolids and a conventional inorganic urea plus diammonium phosphate fertilizer (U+DAP225) were surface applied at a rate of 225 kg ha-1 based on Plant Available Nitrogen (PAN) between March 5th and 10th, 2006. Anaerobically digested biosolids were also surface applied at the rates of 900 kg PAN ha-1 and 1800 kg PAN ha<sup>-</sup¹ (AD900 and AD1800). Anaerobically digested biosolids at the rate of 900 kg PAN ha⁻¹ were also applied on November 5th, 2005 (AD900F). Surface application of different type of biosolids in a loblolly pine plantation increased soil N availability and mineralization when biosolids were applied at the permitted rate of 225 kg PAN ha⁻¹. Surface soil NH₄-N and NO₃-N availability and N mineralization was significantly different among biosolids type over time. N release from different type of biosolids depends on the initial inorganic N content, and N mineralization in biosolids. The average soil N availability and mineralization was significantly greater in the Pellet225 treatments than in all the other treatments. Soil N availability decreased in winter in all the treatments but remained generally higher than the control until the end of the second growing season. Nitrate-N concentrations in lysimeters were below water quality standard limits in all the treatments applied at the rate of 225 kg PAN ha⁻¹. Accumulation of N, C, and Ca in the forest floor was well correlated with the amount of biosolids applied on each treatment. The surface application of different type of biosolids had minimal impact upon total N and C in the mineral soil. Increasing application rates of anaerobically digested biosolids directly increased soil N availability and mineralization. Nitrate-N concentrations in lysimeters were above water quality standards limits during several months in the AD900 and AD1800 treatments. Significant differences in the forest floor total N, C and Ca were observed with increasing application rates of biosolids. Total C accumulation was significantly higher in the forest floor in the AD1800 treatment. However, we observed no effect on soil total C with increasing application rates of biosolids. We found that biosolids application during spring significantly increased soil extractable N, N mineralization, NO₃-N leaching, and total C in the mineral soil in comparison to the fall application. Fall application significantly increased NH₄-N leaching and soil extractable Ca. We observed no significant effect on ion exchangeable N measured on membranes, total N, C, Ca, and pH measured in the forest floor, and soil total N and pH in the mineral soil. Our results demonstrated that permitted surface application of biosolids at the rate of 225 kg PAN ha⁻¹ in a loblolly pine plantation increased surface soil N availability without increasing the potential for NO₃-N groundwater pollution. / Ph. D.

A utilização de inibidores de nitrificação pode ser uma alternativa interessante para aumentar a eficiência do uso do fertilizante nitrogenado em diversas culturas, porém, essa alternativa vem sendo pouco estudada em condições de solo e clima do Brasil. Assim, objetivou-se com esse trabalho avaliar a eficiência do inibidor de nitrificação fosfato de 3,4-dimetilpirazol (DMPP) em três solos com gradiente textural, bem como avaliar o destino do nitrogênio (N-NO3-, N-NH4+ e 15N) no solo, a absorção e o uso do nitrogênio (N-total e 15N) nas plantas de algodão. Três experimentos foram montados e desenvolvidos. No primeiro foi efetuada a incubação do solo em condições de laboratório para avaliar a inibição da nitrificação pelo DMPP aplicado na forma de ureia e sulfonitrato de amônio (SNA) em três solos (Neossolo Quartzarênico - NQ, Latossolo Vermelho Amarelo - LVA, Latossolo Vermelho - LV). No segundo experimento plantas de algodão foram cultivadas em colunas de lixiviação com os mesmos solos, recebendo ureia e sulfonitrato de amônio, com e sem DMPP como fonte de N. Foram avaliados a produção de matéria seca, o acúmulo de nutrientes nas plantas, a eficiência de uso do N pelo algodoeiro, a lixiviação e a quantidade de N mineral no solo após o cultivo do algodão por 60 dias. No terceiro experimento, plantas de algodão foram cultivadas também em colunas lixiviação, porém, com um solo de textura média (Latossolo Vermelho Amarelo), o qual recebeu três doses de N em cobertura (50, 100 e 150 kg ha-1 de N) na forma de ureia marcada no isótopo 15N, com e sem DMPP. Foram avaliados a produção de matéria seca, teor de N e recuperação do N aplicado na planta, lixiviação de N, teor de N-total, nítrico e amoniacal no solo, e recuperação do N aplicado no solo após o cultivo do algodão, por 90 dias. Melhores resultados foram obtidos com a aplicação do DMPP em ureia em relação ao SNA. No experimento de incubação, o DMPP foi capaz de manter menor o teor de nitrato nos três solos analisados. A nitrificação do N na ureia foi mais rápida comparado ao SNA, o que permitiu melhor desempenho do inibidor na ureia em dois dos três solos estudados. O efeito do DMPP aumentou seguindo a seguinte ordem: NQ>LVA>LV. O inibidor foi mais eficiente nos solos com menor teor de argila e matéria orgânica. O uso do DMPP em ureia aplicada no solo arenoso (NQ) reduziu significativamente a lixiviação de N e aumentou a produção de matéria seca, a eficiência do uso do N e a absorção de fósforo pela planta. No solo de textura média (LVA), sob irrigação intensa, o DMPP reduziu significativamente as perdas de N do sistema e aumentou a recuperação do 15N aplicado na planta e no solo, o que, porém, não se traduziu em maior produção de matéria seca provavelmente pelo N não ter sido limitante, devido à mineralização da matéria orgânica. As atividades das enzimas redutase do nitrato e urease não diferiram entre tratamentos com e sem DMPP / The use of nitrification inhibitors may be an interesting alternative to increase nitrogen fertilizer use efficiency in different crops, although it has been little studied in soil and climate conditions of Brazil. This study aimed to evaluate the efficiency of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) in three soils with textural gradient (represented by clay percentage), as well as to evaluate the fate of soil nitrogen (N-NO3-, N-NH4+ and 15N), nitrogen uptake, and N-use efficiency (total-N and 15N) by cotton plants. Three experiments were set and carried out in a controlled environment. In the first one, a laboratory incubation was performed to evaluate the inhibition of nitrification by DMPP applied to urea and ammonium sulfate nitrate (ASN) in three soils (Typic Quartzipsammnet - NQ, Typic Hapludox - LVA, Rhodic Hapludox - LV). In the second experiment, leaching columns with the same soils were planted with cotton receiving ammonium sulfate nitrate and urea with or without DMPP as nitrogen source. It were evaluated plant dry matter yield (shoot plus roots), nutrient uptake and nitrogen use efficiency by cotton plants, as well as the nitrogen leaching, and mineral nitrogen amount in the soil after cotton growth, for 60 days. In the third experiment, leaching columns with a medium textured soil (LVA) were planted with cotton and received three nitrogen rates in topdressing (50, 100 and 150 kg ha-1) as 15N-urea with and without DMPP. The production of dry matter, nitrogen content and recovery of applied N in the plant and soil, as well as the nitrogen leaching, total nitrogen, nitrate and ammonium in the soil were evaluated after cotton growth for 90 days. Best results were obtained with the application of DMPP to urea than in ASN. In the incubation experiment, the DMPP was able to maintain lower nitrate content in the three soils. The nitrification of nitrogen from urea was faster than the one from ASN, which allowed a better performance of the inhibitor in the urea in two out of three soils analyzed. The effect of DMPP increased in the following order: NQ> LVA> LV. The inhibitor was more effective in soils with lower clay and organic matter contents. The use of DMPP in urea applied on the sandy soil (NQ) significantly reduced N leaching and increased dry matter production, nitrogen use efficiency and phosphorus uptake by cotton plants. In a medium textured soil (LVA) under intense irrigation, DMPP significantly reduced N losses in the system and increased the recovery of applied 15N in plant and soil, which however did not translate into higher dry matter production because nitrogen was probably not limiting. The activity of the enzymes nitrate reductase and urease were not different between treatments with and without DMPP

Unintentional nitrogen (N) loss from agroecosystems produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, adoption of conservation agricultural management practices, such as no-till and cover cropping, has increased. This study assessed N loss via leaching, NH3 volatilization, N2O emissions, and N retention in plant and soil pools of corn conservation agroecosystems across a year. Three systems were evaluated: 1) an unfertilized organic system with cover crops Vicia villosa, Triticum aestivum, or a mix of the two; 2) an organic system with a Vicia cover crop employing three fertilization schemes (0 N, organic N, or a cover crop N-credit approach); 3) a conventional system with a Triticum cover crop and three fertilization techniques (0 N, urea N, or organic N). During cover crop growth, species affected N leaching but gaseous emissions were low across all treatments. During corn growth, cover crop and fertilizer approach affected N loss. Fertilized treatments had greater N loss than unfertilized treatments, and fertilizer type affected gaseous fluxes temporally and in magnitude. Overall, increased N availability did not always indicate greater N loss or yield, suggesting that N conserving management techniques can be employed in conservation agriculture systems without sacrificing yield.

A utilização de inibidores de nitrificação pode ser uma alternativa interessante para aumentar a eficiência do uso do fertilizante nitrogenado em diversas culturas, porém, essa alternativa vem sendo pouco estudada em condições de solo e clima do Brasil. Assim, objetivou-se com esse trabalho avaliar a eficiência do inibidor de nitrificação fosfato de 3,4-dimetilpirazol (DMPP) em três solos com gradiente textural, bem como avaliar o destino do nitrogênio (N-NO3-, N-NH4+ e 15N) no solo, a absorção e o uso do nitrogênio (N-total e 15N) nas plantas de algodão. Três experimentos foram montados e desenvolvidos. No primeiro foi efetuada a incubação do solo em condições de laboratório para avaliar a inibição da nitrificação pelo DMPP aplicado na forma de ureia e sulfonitrato de amônio (SNA) em três solos (Neossolo Quartzarênico - NQ, Latossolo Vermelho Amarelo - LVA, Latossolo Vermelho - LV). No segundo experimento plantas de algodão foram cultivadas em colunas de lixiviação com os mesmos solos, recebendo ureia e sulfonitrato de amônio, com e sem DMPP como fonte de N. Foram avaliados a produção de matéria seca, o acúmulo de nutrientes nas plantas, a eficiência de uso do N pelo algodoeiro, a lixiviação e a quantidade de N mineral no solo após o cultivo do algodão por 60 dias. No terceiro experimento, plantas de algodão foram cultivadas também em colunas lixiviação, porém, com um solo de textura média (Latossolo Vermelho Amarelo), o qual recebeu três doses de N em cobertura (50, 100 e 150 kg ha-1 de N) na forma de ureia marcada no isótopo 15N, com e sem DMPP. Foram avaliados a produção de matéria seca, teor de N e recuperação do N aplicado na planta, lixiviação de N, teor de N-total, nítrico e amoniacal no solo, e recuperação do N aplicado no solo após o cultivo do algodão, por 90 dias. Melhores resultados foram obtidos com a aplicação do DMPP em ureia em relação ao SNA. No experimento de incubação, o DMPP foi capaz de manter menor o teor de nitrato nos três solos analisados. A nitrificação do N na ureia foi mais rápida comparado ao SNA, o que permitiu melhor desempenho do inibidor na ureia em dois dos três solos estudados. O efeito do DMPP aumentou seguindo a seguinte ordem: NQ>LVA>LV. O inibidor foi mais eficiente nos solos com menor teor de argila e matéria orgânica. O uso do DMPP em ureia aplicada no solo arenoso (NQ) reduziu significativamente a lixiviação de N e aumentou a produção de matéria seca, a eficiência do uso do N e a absorção de fósforo pela planta. No solo de textura média (LVA), sob irrigação intensa, o DMPP reduziu significativamente as perdas de N do sistema e aumentou a recuperação do 15N aplicado na planta e no solo, o que, porém, não se traduziu em maior produção de matéria seca provavelmente pelo N não ter sido limitante, devido à mineralização da matéria orgânica. As atividades das enzimas redutase do nitrato e urease não diferiram entre tratamentos com e sem DMPP / The use of nitrification inhibitors may be an interesting alternative to increase nitrogen fertilizer use efficiency in different crops, although it has been little studied in soil and climate conditions of Brazil. This study aimed to evaluate the efficiency of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) in three soils with textural gradient (represented by clay percentage), as well as to evaluate the fate of soil nitrogen (N-NO3-, N-NH4+ and 15N), nitrogen uptake, and N-use efficiency (total-N and 15N) by cotton plants. Three experiments were set and carried out in a controlled environment. In the first one, a laboratory incubation was performed to evaluate the inhibition of nitrification by DMPP applied to urea and ammonium sulfate nitrate (ASN) in three soils (Typic Quartzipsammnet - NQ, Typic Hapludox - LVA, Rhodic Hapludox - LV). In the second experiment, leaching columns with the same soils were planted with cotton receiving ammonium sulfate nitrate and urea with or without DMPP as nitrogen source. It were evaluated plant dry matter yield (shoot plus roots), nutrient uptake and nitrogen use efficiency by cotton plants, as well as the nitrogen leaching, and mineral nitrogen amount in the soil after cotton growth, for 60 days. In the third experiment, leaching columns with a medium textured soil (LVA) were planted with cotton and received three nitrogen rates in topdressing (50, 100 and 150 kg ha-1) as 15N-urea with and without DMPP. The production of dry matter, nitrogen content and recovery of applied N in the plant and soil, as well as the nitrogen leaching, total nitrogen, nitrate and ammonium in the soil were evaluated after cotton growth for 90 days. Best results were obtained with the application of DMPP to urea than in ASN. In the incubation experiment, the DMPP was able to maintain lower nitrate content in the three soils. The nitrification of nitrogen from urea was faster than the one from ASN, which allowed a better performance of the inhibitor in the urea in two out of three soils analyzed. The effect of DMPP increased in the following order: NQ> LVA> LV. The inhibitor was more effective in soils with lower clay and organic matter contents. The use of DMPP in urea applied on the sandy soil (NQ) significantly reduced N leaching and increased dry matter production, nitrogen use efficiency and phosphorus uptake by cotton plants. In a medium textured soil (LVA) under intense irrigation, DMPP significantly reduced N losses in the system and increased the recovery of applied 15N in plant and soil, which however did not translate into higher dry matter production because nitrogen was probably not limiting. The activity of the enzymes nitrate reductase and urease were not different between treatments with and without DMPP

The impact of different agricultural systems used in agriculture on the leaching of nutrients and nitrates first of all depends on many factors that are not noticed and sometimes even underestimated by farmers trying to reach larger yields and better economic results. This article analysis the issue of changes in water regime and nitrate nitrogen leaching under the change of agricultural systems; such issue has not been investigated in Lithuania before. This research is especially relevant under the conditions of the Middle Lithuanian Lowland, where annual crops (cereals and sugar beet) area mainly cultivated, the ground is aerated in-tensely thus increasing the mineralization of organic substances and a lot of fertilizers are used. The change of conventional tillage for reduced tillage resulted in the decrease of the resources of surface soil water by 4,91-5,85 % and after changing it into no-tillage water resources decreased by 23,4 %. Reduced tillage and late ploughing are appropriate environmental means reducing nitrate nitrogen leaching from soil. / Įvairių žemdirbystės sistemų naudojamų žemės ūkyje poveikis maisto medžiagų ir labiausiai nitratų išsiplovimui priklauso nuo daugelio veiksnių, kurių žemdirbiai siekdami didesnių derlių ir geresnių ekonominių rezultatų nepastebi, o kartais ir reikiamai neįvertina. Šiame darbe, nagrinėjamas šalyje netirtas vandens režimo ir nitratų azoto išplovimo pasikeitimų, keičiantis žemdirbystės sistemoms, klausimas. Šie tyrimai ypač aktualūs Lietuvos Vidurio lygumos sąlygomis, kur daugiausia auginama vienmečių augalų (javų ir cukrinių runkelių), kasmet žemė intensyviai aeruojama, taip didinant organinių medžiagų mineralizaciją, naudojama daug trąšų. Pakeitus tradicinį žemės dirbimą į sumažintą žemės dirbimą paviršinio dirvožemio sluoksnio vandens atsargos sumažėjo 4,91-5,85 %, o pakeitus į neariminį žemės dirbimą vandens atsargos sumažėjo 23,4 %. Sumažintas žemės dirbimas bei vėlyvas arimas yra tinkamos aplinkosauginės priemonės, mažinančios nitratų azoto išplovimą iš dirvožemio.

In der vorliegenden Studie wurden zwei Fragestellungen bearbeitet, die beide das Ziel verfolgen, die Stickstoff(N)-Ausnutzungseffizienz in landwirtschaftlichen Systemen zu steigern: 1) Hat die langjährige organische Düngung einen Einfluss auf den Abbau kürzlich applizierter organischer Dünger? Die Hypothese war, dass relevante Effekte nur bei schwer abbaubaren organischen Düngern auftreten während bei leicht abbaubaren organischen Düngern die Düngungshistorie keine Rolle spielt. 2) Können die hohen N-Bilanzüberschüsse im intensiven Freilandgemüsebau durch den Einsatz von Winterzwischenfrüchten (ZF) deutlich reduziert werden? Die Hypothese war, dass ZF die Bilanzüberschüsse der betrachteten zweijährigen Fruchtfolgen um mindestens 30 kg N / ha reduzieren. Die erste Hypothese wurde überprüft, indem der Abbau organischer Dünger in Böden, die sich in ihrer organischen Düngungshistorie unterschieden, gemessen wurde. Es wurden ein Topfversuch im Gewächshaus sowie ein Inkubationsversuch im Labor durchgeführt. Die Ergebnisse deuteten darauf hin, dass es Effekte der Historie auf den Abbau von Stallmist und Kiefernrinde gab, während es keine Effekte bei leicht abbaubarem Kohlmaterial gab. Daher wurde die Hypothese angenommen. Allerdings ergaben die beobachteten Effekte kein konsistentes Bild in Hinblick auf die Richtung der Effekte auf die Kohlenstoff(C)- und N-Mineralisierung und Effekte auf die Netto-N-Mineralisation waren generell sehr klein. Zur Überprüfung der zweiten Hypothese wurden an drei Standorten in Deutschland Feldversuche mit Gemüsefruchtfolgen und unterschiedlichen ZF durchgeführt. Die Ergebnisse ergaben, dass trotz der die mittleren Bilanzüberschüsse der Kontrollen (ohne ZF) von 217 kg N / ha die ZF die N-Bilanz im Mittel um nur 13 kg N / ha reduzierten. Daher wurde die Hypothese abgelehnt. Die Ergebnisse zeigten weiterhin, dass der verlustfreie Transfer der von der ZF aufgenommenen N-Menge an die Folgefrucht ein kritischer Schritt bei dieser Technik ist. / The current study dealt with two questions that target potential options to increase the nitrogen (N) use efficiency of agricultural systems: 1) Does long-term organic fertilization affect the decomposition of recently added organic fertilizers? The hypothesis was that effects only occur for recalcitrant organic fertilizers while for readily decomposable organic fertilizers, the fertilization history does not play a role. 2) Can the N balance surpluses in intensive field vegetable production systems be substantially reduced by cultivation of winter catch crops (CC)? The hypothesis was that the N balance surpluses of the investigated two-year crop rotations can be reduced by more than 30 kg N / ha. The first hypothesis was tested by applying organic fertilizers to soils that only differed in organic fertilization history. A greenhouse pot experiment and a laboratory incubation experiment were conducted. The results indicated that fertilization history had effects on the decomposition of farmyard manure and pine bark, not however on the decomposition of readily decomposable cabbage material. Hence, the hypothesis was accepted in that fertilization history effects depended on the type of fertilizer. However, fertilization history effects showed no consistent trend with respect to increase or decrease in carbon (C) and N mineralization and the effects on net N mineralization were minor in magnitude. The second hypothesis was tested by performing field experiments at three sites in Germany. Vegetable crop rotations were set up, testing different types of CC. The results suggested that in spite of high N surpluses in the control treatments (no CC) of 217 kg N / ha, CC reduced the N balance surplus on average by only 13 kg N / ha. Hence, the hypothesis was rejected. The findings further indicated that the transfer of N taken up by the CC to the succeeding crop is a critical step when adopting this technique.