The impact of fallowing and green manuring on soil conditions and the growth of sugarcane

There are currently concerns within some sugar industries that long-term monoculture has led to soil degradation and consequent yield decline. An investigation was conducted in Swaziland to assess the effects of fallowing and green manuring practices, over a seven-month period, on sugarcane yields and the physical properties of a poorly draining clay soil. In the subsequent first sugarcane crop after planting, yields were improved from 129 t ha(-1) under continuous sugarcane to 141-144 t ha(-1) after fallowing and green manuring, but there were no significant responses in the first and second ratoon crops. Also, in the first crop after planting, root length index increased from 3.5 km m(-2) under continuous sugarcane to 5.2-6.8 km m(-2) after fallowing, and improved rooting was still evident in the first ratoon crop where there had been soil drying during the fallow period. Soil bulk density, total porosity and water-holding capacity were not affected by the fallowing practices. However, air-filled porosity increased from 11% under continuous sugarcane to 16% after fallowing, and steady state ponded infiltration rates were increased from 0.61 mm h(-1) to 1.34 mm h(-1), but these improvements were no longer evident after a year back under sugarcane. Levels of soil organic matter were reduced in all cases, probably as a result of the tillage operations involved. In the plant crop, root length was well correlated with air-filled porosity, indicating the importance of improving belowground air supply for crop production on poorly draining clay soils.

Participatory Farm Management methods for assessing the suitability of potential innovations. A case study on green manuring options for tomato producers in Ghana

This paper examines the potential of using Participatory Farm Management methods to examine the suitability of a technology with farmers prior to on-farm trials. A study examining the suitability of green manuring as a technology for use with wet season tomato producers in Ghana is described. Findings from this case-study demonstrate that Participatory Budgeting can be used by farmers and researchers to analyse current cultivation practices, identify the options for including green manures into the system and explore the direct and wider resource implications of the technology. Scored-Causal Diagrams can be used to identify farmers' perceptions of the relative importance of the problem that the technology seeks to address. The use of the methods in this examine evaluation process appears to have the potential to improve the effectiveness and efficiency of the adaptive research process. This ensures that technologies subsequently examined in trials ate relevant to farmers' interests, existing systems and resources, thereby increasing the chances of farmer adoption. It is concluded that this process has potential for use-with other technologies and in other farming systems. (C) 2002 Elsevier Science Ltd. All rights reserved.

Presubmergence and green manure affect the transformations of nitrogen-15-labeled urea under lowland soil conditions

The effect of presubmergence and green manuring on various processes involved in [N-15]-urea transformations were studied in a growth chamber after [N-15]-urea application to floodwater. Presubmergence for 14 days increased urea hydrolysis rates and floodwater pH, resulting in higher NH3 volatilization as compared to without presubmergence. Presubmergence also increased nitrification and subsequent denitrification but lower N assimilation by floodwater algae caused higher gaseous losses. Addition of green manure maintained higher NH4+-N concentration in floodwater mainly because of lower nitrification rates but resulted in highest NH3 volatilization losses. Although green manure did not affect the KCl extractable NH4+-N from applied fertilizer, it maintained higher NH4+-N content due to its decomposition and increased mineralization of organic N. After 32 days about 36.9% (T-1), 23.9% (T-2), and 36.4% (T-3) of the applied urea N was incorporated in the pool of soil organic N in treatments. It was evident that the presubmergence has effected the recovery of applied urea N.

Farming with green manures, on Plumgrove farm.

Mode of access: Internet.

Leguminous cover crops differentially affect maize yields in three contrasting soil types of Kakamega, Western Kenya

Maize production in smallholder farming systems in Kenya is largely limited by low soil fertility. As mineral fertilizer is expensive, green manuring using leguminous cover crops could be an alternative strategy for farmers to enhance farm productivity. However due to variability in soil type and crop management, the effects of green manure are likely to differ with farms. The objectives of this study were to evaluate Mucuna pruriens and Arachis pintoi on (i) biomass and nitrogen fixation (^15N natural abundance), (ii) soil carbon and nitrogen stocks and (iii) their effects on maize yields over two cropping seasons in Kakamega, Western Kenya. Mucuna at 6 weeks accumulated 1–1.3 Mg ha^{-1} of dry matter and 33–56 kg ha^{-1} nitrogen of which 70% was nitrogen derived from the atmosphere (Ndfa). Arachis after 12 months accumulated 2–2.7 Mg ha^{-1} of dry matter and 51–74 kg N ha^{-1} of which 52-63 % was from Ndfa. Soil carbon and nitrogen stocks at 0–15 cm depth were enhanced by 2-4 Mg C ha^{-1} and 0.3–1.0 Mg N ha^{-1} under Mucuna and Arachis fallow, irrespective of soil type. Maize yield increased by 0.5-2 Mg ha^{-1} in Mucuna and 0.5–3 Mg ha^{-1} in Arachis and the response was stronger on Nitisol than on Acrisol or Ferralsol. We concluded that leguminous cover crops seem promising in enhancing soil fertility and maize yields in Kenya, provided soil conditions and rainfall are suitable.

Soil fertility management in the mid-hills of Nepal: Practices and perceptions

Sustaining soil fertility is essential to the prosperity of many households in the mid-hills of Nepal, but there are concerns that the breakdown of the traditional linkages between forest, livestock, and cropping systems is adversely affecting fertility. This study used triangulated data from surveys of households, discussion groups, and key informants in 16 wards in eastern and western Nepal to determine the existing practices for soil fertility management, the extent of such practices, and the perception of the direction of changes in soil fertility. The two principal practices for maintaining soil fertility were the application of farmyard manure (FYM) and of chemical fertilizer (mainly urea and diammonium phosphate). Green manuring, in-situ manuring, slicing terrace risers, and burning plant residues are rarely practiced. FYM usage was variable with more generally applied to khet land (average 6053 kg fresh weight manure ha(-1)) than to bari land (average 4185 kg fresh weight manure ha-1) with manure from goats and poultry preferred above that from cows and buffaloes. Almost all households (98%) apply urea to khet land and 87% to bari land, with 45% applying diammonium phosphate to both types of land. Application rates and timings of applications varied considerably both within and between wards suggesting poor knowledge transfer between the research and farming communities. The benefits of chemical fertilizers in terms of ease of application and transportation in comparison with FYM, were perceived to outweigh the widely reported detrimental hardening of soil associated with their continued usage. Among key informants, FYM applied in conjunction with chemical fertilizer was the most popular amendment, with FYM alone preferred more than chemical fertilizer alone - probably because of the latter's long-term detrimental effects. Key informant and householder surveys differed in their perception of fertility changes in the last decade probably because of differences in age and site-specific knowledge. All key informants felt that fertility had declined but among households, only about 40% perceived a decline with the remainder about evenly divided between no change and an increase. Householders with small landholdings (< 0.5 ha) were more likely to perceive increasing soil fertility while those with larger landholdings (> 2 ha) were more likely to perceive declining fertility. Perceived changes in soil fertility were not related to food self-sufficiency. The reasons for the slow spread of new technologies within wards and the poor understanding of optimal use of chemical fertilizers in conjunction with improved quality FYM may repay further investigation in terms of sustaining soil fertility in this region.

Crop rotation scheduling with adjacency constraints

In this article we propose a 0-1 optimization model to determine a crop rotation schedule for each plot in a cropping area. The rotations have the same duration in all the plots and the crops are selected to maximize plot occupation. The crops may have different production times and planting dates. The problem includes planting constraints for adjacent plots and also for sequences of crops in the rotations. Moreover, cultivating crops for green manuring and fallow periods are scheduled into each plot. As the model has, in general, a great number of constraints and variables, we propose a heuristics based on column generation. To evaluate the performance of the model and the method, computational experiments using real-world data were performed. The solutions obtained indicate that the method generates good results.

Efeitos da subsolagem e da adubação verde nas propriedades físicas do solo em pomar de citros

O presente trabalho teve por objetivo avaliar o efeito da subsolagem e da adubação verde nas propriedades físicas de um Latossolo Vermelho distrófico típico, cultivado com citros (laranjeira Valência). Os tratamentos empregados foram: manejo mecânico das plantas invasoras com roçadora (Testemunha); subsolagem em um lado da planta na entrecopa; subsolagem nos dois lados da planta na entrecopa, e semeadura direta de Crotalaria spectabilis na entrecopa. As propriedades físicas do solo avaliadas foram: porosidade total, macroporosidade, microporosidade, densidade, resistência mecânica à penetração vertical e condutividade hidráulica. Na avaliação efetuada na safra 2001-2002, obtiveram-se os maiores valores de densidade do solo e resistência do solo à penetração vertical, e os menores valores de macroporos e condutividade hidráulica do solo nas entrecopas com e sem tráfego no pomar, em relação à região da copa, principalmente na camada de 0,0-0,2 m de profundidade. Os tratamentos aplicados não surtiram efeitos positivos significativos nas propriedades físicas do solo.

Períodos de interferência de Mucuna aterrima (Piper & Tracy) em cana-de-açúcar e seu controle químico

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Sistemas de cultivo em área de reforma de cana-de-açúcar e a sucessão de culturas na composição da comunidade infestante

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Plantas de cobertura em pré-safra e adubação nitrogenada no milho em plantio direto

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Seletividade dos herbicidas Bentazon e Nicosulfuron para Crotalaria juncea e Crotalaria spectabilis em consórcio com a cultura do milho

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Die Entwicklung der Mesofauna eines Weinberges im nordöstlichen Rheinhessen im Vergleich zum Lennebergwald und weiteren Agrarflächen

ZusammenfassungrnrnrnDer Köderstreifentest, die Auswertung der Minicontainer und die Erfassung der Bodenlebewesen mit Hilfe der Bodenstechkerne ergeben zusammen eine gut standardisierte Methode zur Darstellung und Beurteilung der Mesofauna. Unter der Vorraussetzung gleicher abiotischer Faktoren ist es problemlos möglich, selbst unterschiedliche Standorte wie Agrarflächen, Weinberge und Waldböden vergleichend zu untersuchen.rnrnAuf den verschiedenen Versuchsflächen des Laubenheimer Weinberges gelingt es deutlich zu zeigen, wie wichtig eine naturnahe Begrünung für den Boden ist. Dies betrifft nicht nur die Entwicklung der Humusschicht und damit die Bodenlebewesen, sondern auch die Schaffung von Kapillaren und Poren, die durch schwere landwirtschaftliche Geräte im Rahmen der Bo-denverdichtung reduziert werden. Erosionserscheinungen kommen vollständig zum Stillstand. Das Ökosystem Boden sollte auch so gut wie keine Belastung durch Herbizide, Insektizide und Pestizide erfahren. Ähnliches gilt auch für agrarisch genutzte Flächen. rnrnDer Lennebergwald als Naherholungsregion von Mainz ist besonders schützenswert, da dieser durch intensiven Immissionseintrag aufgrund der Nähe zu den Autobahnen und durch die Eutrophierung über die Haustiere stark belastet wird. Die immer größere Ausdehnung des Siedlungsgebietes und die damit verbundene steigende Anzahl an Waldbesuchern, die durch Verlassen der vorgegebenen Wege den Boden zerstören, gefährden zusätzlich das Ökosystem.rnrnÜber Sinn und Zweck einer Flurbereinigung zu diskutieren ist hier nicht angebracht. Aus bo-denkundlicher Sicht ist sie nicht zu befürworten, da hiermit alle bodenbewahrenden Maßnah-men ignoriert werden. Wichtig ist es, bei den Landwirten Aufklärungsarbeit zu leisten, was bodenschonende und bodenweiterentwickelnde Bearbeitungsmethoden bedeuten. Mit Hilfe sachgemäßer Aufklärung und richtiger Umsetzung kann durch Begrünungsmaßnahmen der zum Teil sehr stark strapazierte Boden erhalten, gefördert und auf lange Sicht stabilisiert wer-den.rnrnAufgrund der festgestellten Tatsachen wurde ab 2008 auf eine flächige Dauerbegrünung um-gestellt, so dass es auch in den unbegrünten Rebzeilen zu einer Bodenverbesserung kommen kann. Mit großer Wahrscheinlichkeit dürfte diese schneller voranschreiten, da die Mesofauna von den benachbarten begrünten Rebzeilen einwandern kann. rnDie Mesofauna landwirtschaftlich genutzter Flächen und Waldgebiete kann, obwohl extrem unterschiedlich, miteinander verglichen werden.rnrnBrachflächen und Waldgebiete lassen sich aufgrund der unberührten Bodenstrukturen sogar gut miteinander vergleichen. Temperatur- und Niederschlagsverhältnisse müssen dabei über-einstimmen. Die Azidität der jeweiligen Böden gilt es zu berücksichtigen, da verschiedene Tiergruppen damit unterschiedlich umgehen. Collembolen bevorzugen neutrale Böden, wäh-rend Acari als Räuber mit den Lebewesen in sauren Böden besser zurechtkommen. Die Streu-auflage ist dabei von großer Bedeutung.rnrnIm Rahmen von Bearbeitungsmaßnahmen kommt es durch jeglichen Maschineneinsatz zu ei-ner mehr oder weniger starken Veränderung der Bodenstruktur und somit auch der darin le-benden Mesofauna. Bis sich diese erholt hat, steht meist schon die nächste Bodenbewirtschaf-tung an. Die Bodenverdichtung spielt auch eine Rolle. Bei herkömmlichem Ackerbau ist eine Fruchtfolge mit eingeschalteter Brache oder Gründüngung mit Klee oder Luzerne angebracht, um die Mesofauna nicht zu stark zu strapazieren. Organische Düngegaben leicht abbaubarer Streu sind deutlich zu bevorzugen gegenüber sehr zellulose- und ligninhaltigen Pflanzenresten. Die Einbringung von Stoppeln nach Aberntung von Getreidefeldern ist sinnvoll, solange dabei nicht zu tief in die Bodenstruktur eingegriffen wird (ZIMMER 1997).rnrnIm Rahmen der Sonderkultur Wein, bei der eine Bodenbearbeitung aus den aufgezeigten Gründen eigentlich nicht notwendig wäre, sind Dauerbegrünungsmaßnahmen generell von Nutzen: der Erosion wird vorgebeugt, die Bodenfeuchte konstant gehalten, der anfallende Mulch als Gründüngung genutzt. Dies sind alles entscheidende Faktoren, die die Meso- und Makrofauna fördern. Nur die Bodenverdichtung durch schweres Gerät, wie Schlepper und Vollernter, sind für den Boden nicht förderlich (HEISLER 1993, EHRENSBERGER 1993). Nie-derdruckreifen und Verringerung der Befahrung sind geeignete Gegenmaßnahmen. rnrnEntgegen landläufiger Winzermeinung, stellen die Pflanzen einer Begrünung eigentlich keine Konkurrenz für die Weinstöcke dar. Die Vorteile einer Begrünung sind nicht nur die Förde-rung der einheimischen Flora in ihrem standortgerechten Artenreichtum, sondern auch Ver-vielfältigung von Meso- und Makrofauna aufgrund der dadurch mehr anfallenden und ein-zuarbeitenden leicht abbaubaren Streu (GRIEBEL 1995).rn

Effects of cereal species, legume species, and nitrogen on no-till winter wheat and rye grown with perennial forage legume living mulches /

Thesis (Ph. D.)--Cornell University, May, 1988.

Agriculture /

Vol. 1. Soils, formation, physical and chemical characteristics and methods of improvement, including tillage, drainage & irrigation -- v. 2. Manures, fertilizers & farm crops, including green manuring and crop rotation -- v. 3. Animal husbandry, including the breeds of live stock, the general principles of breeding, feeding animals; including discussion of ensilage, dairy management on the farm and poultry farming.