Research objective. The study was aimed to establish the competitive peculiarities of the multi-component agrocenose (maize, living mulches, weeds) and its effects on soil properties under sustainable farming conditions. Research tasks. To accomplish the research objective the following tasks were set - to study: 1. The influence of living mulches, grown in a maize monocrop, on soil physical properties (soil moisture dynamics, shear resistance, penetration resistance, soil structure and its stability), chemical characteristics (total nitrogen, available phosphorus and potassium content, pH) and biological characteristics (urease and saccharase activity); 2. The dynamics of biomass accumulation of living mulches and weeds; 3. The impact of living mulches on weed infestation in a maize crop and on weed seed contamination in a ploughlayer; 4. Maize crop irradiance conditions and their influence on different components of the agrophytocenose; 5. Projection coverage of maize inter-rows; 6. Maize productivity and biometric indicators; 7. The relationships between the factors tested. / Tyrimų tikslas – įvertinti daugiakomponentės agrocenozės – kukurūzų, tarpinių augalų, piktžolių – konkurencinius ypatumus ir jos poveikį dirvos savybėms tvaraus ūkininkavimo sąlygomis. Tyrimų uždaviniai. Tyrimų tikslui pasiekti numatyta ištirti: 1. Įsėlinių tarpinių augalų, augusių kukurūzų monopasėlyje, poveikį dirvos fizikinėms (dirvos drėgnio dinamikai, šlyties pasipriešinimui, kietumui, dirvos struktūrai ir jos patvarumui), cheminėms (suminio azoto, judriojo fosforo ir kalio kiekiui, pH), biologinėms (ureazės ir sacharazės aktyvumui) savybėms; 2. Įsėlinių tarpinių augalų ir piktžolių biomasės kaupimosi dinamiką; 3. Įsėlinių tarpinių augalų poveikį kukurūzų pasėlio piktžolėtumui bei armens užterštumui piktžolių sėklomis; 4. Kukurūzų pasėlio apšvitos sąlygas ir jų poveikį skirtingiems agrofitocenozės komponentams; 5. Kukurūzų tarpueilių projekcinį padengimą; 6. Kukurūzų produktyvumo ir biometrinius rodiklius; 7. Tiriamųjų veiksnių sąsajas ir poveikio priežastingumą.

Darbo tikslas – įvertinti įsėlinių tarpinių augalų, piktžolių ir kaupiamųjų augalų konkurencingumą ekologinio ūkininkavimo sąlygomis bei mulčiavimo technikos pritaikymas tarpueilių mulčiavimui. Įsėlinių tarpinių augalų („gyvojo mulčio") ir piktžolių konkurencingumo dėsningumai kaupiamųjų augalų pasėliuose nėra išsamiai ištirti. Pasaulyje šia linkme tyrimai yra tik pradėti. Mėginta mūsų iškeltas problemas spręsti daržininkystėje ir auginant kai kuriuos grūdinius javus. Gauti pirmieji teigiami rezultatai. Mūsų tyrimuose bandymo schema buvo išplėsta, tiriama daugiau rūšių įsėlinių augalų, įvertinamas dirvoje esančių maisto medžiagų balansas. Taip pat buvo įvertintas kaupiamųjų augalų mulčiavimas, piktžolių - įsėlinių augalų konkurencingumas. Šios srities tyrimai Lietuvoje vykdyti, tačiau dažniausiai buvo tirtas posėlinių ir įsėlinių augalų poveikis juos panaudojant žaliajai trąšai. Mūsų tyrimuose buvo atskleisti unikalios kaupiamųjų augalų auginimo technologijos ekologinio ūkininkavimo sąlygomis ypatumai – vietoj įprasto tarpueilių purenimo taikyti tarpueilių mulčiavimą tarpiniais augalais. Atlikus eksperimentinius tyrimus skirtingais kukurūzų vystymosi tarpsniais, kukurūzų tarpueiliuose nustatyta gyvojo mulčiaus ir piktžolių masė (g∙m-2) bei kaupiamųjų augalų konkurencingumas, taip pat nustatyta fotosintetinė aktyvioji spinduliuotė (FAR), tenkanti augalams žemės paviršiuje bei dirvos drėgnis 0–10 cm ir 10–20 cm gylyje. / The aim of the research was to assess the competiveness of the undercrops, weeds and row crops under the conditions of organic farming using the interrow mulching techniques. There is no thorough research on the peculiarities of the undercrops (living mulch) and weed competitiveness in the row crops. Scientists all over the world have only started investigating this subject. The study attempts to utilize the researched subject in gardening and growing some of the grain crops. The first positive results were obtained. The testing scheme of our research was extended by investigating more species of undercrops, assessing the balance of the soil nutrients. The competitiveness of cumulative plants mulching with weeds and undercrops was evaluated. There is some research on this subject in Lithuania, but most of it deals with the investigation of aftercrop and undercrop plants and implications for their use as green manure. The studies revealed the unique technologies of the row crop production under the conditions of organic farming moreover, instead of the usual loosening the interrow mulching was applied. The experimental research has identified the living mulch and weed weight (g∙m-2)in the interrows at different stages of maize growth, row crop competitiveness, photosynthetic active radiation (PAR), which falls on plants and soil surface humidity in 0 to 10 cm and 10–20 cm depth.

Control of water erosion of soil at mine sites requires an ability to predict the effects of different management practices on soil loss. Using soil loss models such as the Revised Universal Soil Loss Equation (RUSLE) requires calibration of the model for materials and situations that are not defined in the model’s handbook or software. The outer slopes of bauxite residue disposal areas are potentially highly erodible surfaces, and a recent evaluation of previous rehabilitation practices at Worsley Alumina, Collie, Western Australia, identified areas on the bauxite residue disposal areas where vegetation establishment and management of long term soil loss could be improved. Field experiments commencing in April 2000 at Worsley Alumina’s bauxite refinery, Collie, and laboratory tilting flume experiments run at the University of Queensland, were designed to quantify the effectiveness of different surface treatments on reducing short-term soil loss, and to model long-term erosion risks. Crushed ferricrete caprock – rock-pitch – and different types of mulches, seed mixes and fertiliser rates were applied to the compacted clay batter slopes used to contain bauxite residue, with runoff, soil loss and vegetation establishment monitored periodically over 27 months. Laboratory tilting flume results were related to the field data using the soil erosion models MINErosion, the Modified Universal Soil Loss Equation (MUSLE) and RUSLE to predict event-based and annual soil loss for different treatments. Turbo-mulch, a blocky, coarse pine bark, was the most effective surface treatment for promoting vegetation establishment, reducing rill formation and reducing soil loss, a result supported in both the field and laboratory results. Turbo-mulch and vegetation did not reduce runoff, but resulted in decreased soil loss. This shows the importance of protecting soil from raindrop impact and of the soil holding capacity of vegetation. Increased seed and fertiliser rates did not significantly affect native plant numbers or foliage cover on topsoil without turbo-mulch. Rock-pitch was found to be resistant to erosion and mass movement along a rock-pitch/compacted clay interface. Field erosion measurements ranged from 0.87 t/ha/yr for turbo-mulched treatments to 7.41 t/ha/yr for a treatment with a different seed mix, lacking turbo-mulch and lacking underlying rock-pitch. RUSLE soil loss predictions based on soil properties and soil loss estimates from the MINErosion model ranged from 0.27 to 60.0 t/ha/yr. RUSLE predictions based on tilting flume data ranged from 0.14 to 81.1 t/ha/yr. RUSLE overpredicted soil loss for treatments without turbo-mulch, and underestimated soil loss for turbo-mulched treatments, necessitating calibration based on the unique materials trialed in this study. The relative soil loss measured in the field was best represented by RUSLE predictions based on tilting flume data rather than the MINErosion model. MINErosion did not adequately describe the effect of bulk density and infiltration on soil loss of compacted/consolidated materials. MUSLE and RUSLE are adequate models for the Western Australian conditions of this study, but further research is required to calibrate the C factor for turbo-mulched surfaces and calibrate the P factor for rock-pitch.

Universiẗat, Diss.--Duisburg-Essen, 2004. / Zsfassung in engl. und span. Sprache.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 57-59). Also available on the World Wide Web.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-12-19T12:40:50Z No. of bitstreams: 1 Eduardo Jose Bezerra da Costa.pdf: 2331435 bytes, checksum: 889c0217916ac47c2b9deaf17ea42d8d (MD5) / Made available in DSpace on 2016-12-19T12:40:50Z (GMT). No. of bitstreams: 1 Eduardo Jose Bezerra da Costa.pdf: 2331435 bytes, checksum: 889c0217916ac47c2b9deaf17ea42d8d (MD5) Previous issue date: 2013-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In Northeast Brazil, more than 70.000 small dams retain superficial run off and underground water flow, creating small reservoirs. Flood recession agriculture consists of cropping the margins of the reservoirs, on slight slopes, while the water level progressively decreases, and it is a widespread cropping system in this region. It is characterized as a means of survival and self-sustenance that comes from the beginnings of agriculture, and that persists to this day, especially in semiarid. Few studies have been conducted on flood recession agriculture, particularly with regard characterization of hydraulic parameters and models that describe this specific condition of unsaturated soils. This proposed research aims to evaluate the physical-hydric characteristics of soil on flood recession agriculture cropped with sorghum and subjected to two ground cover conditions: with and without mulch. This study also sought to examine the behavior of four sorghum varieties (IPA 2502, IPA4202, IPA and IPASF 25467-4-2) submit them to the conditions of absence and presence of mulch. The sorghum crop was chosen for its ability to survive and produce under conditions of limited waters up plies over long periods of dry conditions usually found at the end of the flood recession agriculture. Cattail (Typha domingensis), plant of the flooded regions, typical of wetlands and floodplains, also found in semiarid, but is essentially cosmopolitan, was chosen as mulch depending on the availability of abundant biomass and by not being a food source human and / or animal of the region. The effects of flood recession agriculture on the physical - hydric properties of the soil, conserving water in the soil and consequently yield of sorghum were evaluated in 2012 at the Experimental Station of the Agronomic Institute of Pernambuco - IPA, region of Pajeú, semiarid of the Pernambuco. It was essential to the study and understanding of water dynamics in soils for proper management and obtaining better yields of crop cultivation ebb. Sorghum was cultivated with spacing of 0.8 m between rows and 0.15 m between plants. The design was a randomized block design with four replications arranged in a factorial design (4x2). The physical-hydric properties were evaluated water hydraulic conductivity, bulk density, resistance to penetration, porosity and water content in the soil. To determine the hydraulic conductivity was used infiltrometer with controlled suction disc 8 cm in diameter and the measurements soils penetration resistance (RP) was used impact penetrometer Model (IAA-Planalsucar). The measurements were performed between plants in the central rows of cultivation. Parallel data were evaluated for plant height, flowering initial percentage of surviving plants and biomass production. For data analysis we used the statistical program Sisvar, being employed the Tukey test at 5% probability to compare the treatment means. The measures of the physical and hydraulic properties of soil have been realized on two times: at the beginning of cultivation, after treatment installation in the experimental area (1st test campaign) and between reproductive and maturity stages of grains (2st test campaign). In the first measurement campaign, the hydraulic conductivity values (K(h)) were higher in the soils without mulch for all cultivars, except in the soils cropped with sorghum varieties IPA 4202 and IPA 467-42 in the soil water pressure head h (0 and -2 cm). In the second measurement campaign, the mulch offers a decrease for hydraulic conductivity (K(h)) for all treatments, except for K(h) values in the soil water pressure head h (-12, -6 and -2 cm) of soils cropped whit sorghum variety IPA 2502. The highest yields of biomass are obtained for the cultivars IPA 467-42 and IPA SF-25. Mulching effect was significant in dry matter for the IPA SF-25variety. Mulched sorghum plants (IPA SF-25 variety) produced more dry matter than the unmulched plants. The average yield of 12.85 t DM / ha of the experiment indicates that the growing tide is an excellent alternative to sorghum production in the dry season. / No Nordeste do Brasil, mais de 70 mil pequenas barragens retém a água proveniente do escoamento superficial e do fluxo de água subterrânea criando pequenos reservatórios. A agricultura de vazante consiste em cultivar os solos nas margens desses reservatórios, em declives leves, enquanto que o nível de água diminui progressivamente, sendo um sistema de cultivo bastante utilizado na região. É caracterizada como uma alternativa de convivência com a seca e de auto-sustento das famílias. Praticada desde os primórdios da agricultura até o presente, principalmente no semiárido. Poucos estudos têm sido realizados sobre a agricultura de vazante, sobretudo no que se refere a caracterização dos parâmetros hidráulicos e dos modelos que descrevem a condição específica dos solos não saturados das vazantes. Esta pesquisa objetivou avaliar o comportamento das características físico-hídricas do solo de vazante cultivado com sorgo, submetido a duas condições de cobertura do solo: presença e ausência de cobertura morta. Neste estudo, buscou-se também analisar o comportamento de quatro cultivares de sorgo (IPA 2502, IPA 4202, IPA 467-42 e IPA SF 25) ao submetê-las as condições de solos com e sem cobertura morta, utilizando-se cinco toneladas/ha de matéria seca da palhada. A cultura do sorgo foi escolhida por sua capacidade de sobreviver e produzir em condições de limitado suprimento de água em períodos longos de seca, condições normalmente encontradas no final do cultivo de vazante. A palhada de taboa (Typha domingensis), planta cosmopolita de regiões alagadas, típica de brejos e várzeas, encontrada também no semiarido, foi escolhida como cobertura morta em função da farta disponibilidade de biomassa e pelo fato de não ser fonte de alimento humano e/ou animal da região. Os efeitos do cultivo em vazante nas propriedades físico-hídricas do solo, na conservação da água no solo e consequentemente no rendimento do sorgo foram avaliados em 2012, na Estação Experimental do Instituto Agronômico de Pernambuco - IPA, Sertão do Pajeú, Semiárido pernambucano. Para isso foi imprescindível o estudo e a compreensão da dinâmica da água nos solos para um manejo adequado e obtenção de melhores rendimentos da cultura em cultivo de vazante. O sorgo foi cultivado com espaçamento de 0,8 m entre linhas e 20 plantas/metro linear. O delineamento foi em blocos ao acaso, com quatro repetições, arranjado no esquema fatorial (4x2). As propriedades físico-hídricas avaliadas foram a condutividade hidráulica, a densidade do solo, a resistência a penetração, a porosidade e o conteúdo de água no solo. Para determinar a condutividade hidráulica foi utilizado o infiltrômetro a disco com sucção controlada de 8 cm de diâmetro e para a resistência a penetração foi utilizado o penetrômetro de impacto (modelo IAA-Planalsucar). As medidas foram realizadas entre plantas nas fileiras centrais de cultivo. Paralelamente, avaliaram-se dados de altura da planta, floração inicial, percentagem de plantas sobreviventes e a produção de biomassa. Para análise dos dados utilizou-se o programa estatístico Sisvar, sendo empregado o teste Tukey, em nível de 5% de probabilidade, para a comparação entre as médias dos tratamentos. As medidas das propriedades física-hidricas do solo foram realizadas em dois momentos: no início do cultivo, logo após a instalação dos tratamentos na área experimental (1ª campanha de testes) e entre a reprodução e maturação de grãos (2ª campanha). Na primeira campanha de testes de infiltração, percebeu-se que os valores de condutividade hidráulica (K(h)) foram maiores nos solos cultivados com sorgo sem cobertura morta, exceto para os solos com as variedades de sorgo IPA 4202 e IPA 467-42, nos potenciais h (0 e -2 cm). Já na segunda campanha, os valores de condutividade hidráulica dos solos com e sem cobertura morta só diferiram estatisticamente quando cultivados com a variedade de sorgo IPA 2502, submetidos aos potencias h (-12, -6 e -2 cm). As maiores produções de biomassa são obtidas para as cultivares IPA 467-42 e IPA SF-25. O efeito da cobertura morta foi significativo na produção de MS para a variedade IPA SF-25. Plantas de sorgo (variedade IPA SF-25) com cobertura morta produziram mais matéria seca do que as plantas cultivadas sem cobertura morta. A produtividade média de MS de 12,85 t/ha do experimento indica o cultivo de vazante como uma excelente alternativa para produção de sorgo em período de seca.

2 p. / Originally Published: 2006 / Techniques and tips on watering trees and shrubs efficiently. Topics include weather, plant type, soil type and signs of under and over watering. Originally published 2006

Production of hot peppers, Capsicum spp., in Jamaica is constrained by the aphid-transmitted potyviruses, tobacco etch virus (TEV) and potato virus Y (PVY). The virus epidemiology was not understood and no effective virus management system existed for these viruses. This study sought to identify possible management strategies for aphid-transmitted viruses of hot peppers in Jamaica, using TEV and Capsicum chinense, var. 'Scotch Bonnet' and 'West Indian Red', as models. Field spread of TEV to pepper was mainly by secondary spread from primary infections. Secondary infections were spatially correlated to primary infections for up to 25 meters. Natural infections of TEV were associated with aphid flight activity. Over 30 species of aphids were collected on pepper farms in St. Catherine parish. These aphids included five known vectors of TEV, Aphis gossypii Glover, A. craccivora Koch, A. spiraecola Patch, Lipaphis erysimi Hille Ris Lambers and M. persicae (Sulzer), and 12 new records for Jamaica, Aphis amaranthi Holman, Brachycaudus helichrysi (Kaltenbach),Capitophorus hippophaes (Walker), Geopemphigus floccosus (Moreira), Hysteroneura setariae (Thomas), Lipaphis erysimi Hille Ris Lambers, Rhopalosiphum padi (Linnaeus), Schizaphis graminum (Rondani), Schizaphis rotundiventris (Signoret), Trichosiphonaphis poligoni (van der Goot), Uroleucon ambrosiae complex (Thomas) and Uroleucon pseudoambrosiae (Olive). A. amaranthi and U. ambrosiae were associated with TEV spread. Weeds on and near farms influenced the abundance and species of aphids captured. West Indian Red pepper showed tolerance to TEV. Scotch Bonnet pepper yield reduction was greater if plants were infected with TEV during the vegetative stage through flower initiation rather than after the start of fruit set. Stylet oil and reflective mulch used together delayed the incidence of TEV in pepper plots for over two months. TEV management programs should aim to delay the virus from infecting peppers during the first two months after transplanting. A risk analysis is proposed for management of TEV and other aphid-borne viruses. / Ph. D.

Situated on the western edge of Africa's harsh Sahel region, Senegal faces a number of agricultural production constraints. Limited rainfall, poor soil fertility, and insufficient agronomic inputs all contribute to low yielding millet production systems. This study was initiated to assess the potential for intercropping either cowpea (Vigna unguiculata (L.) Walp.) or mungbean (Vigna radiata (L.) Wilczek) into traditional pearl millet (Pennisetum glaucum (L.) R. Br.) cropping systems. During the 2013 and 2014 growing seasons two varieties of cowpea (upright and viney), and one variety of mungbean (upright) were grown in monoculture and subsequently intercropped with millet to evaluate the potential for increasing millet and overall yields. Millet was also planted with a mulch (2 t/ha of neem leaves) to test the effectiveness of increased ground cover on millet yields. In addition to yield data, soil moisture and plant NDVI data were also collected. Millet grain yields increased when intercropped with either cowpea or mungbean compared to millet that was grown alone, with grain yield increases of up to 55%. Additionally, the combined grain yields (millet + bean) were up to 67% higher than the traditional monoculture millet. The addition of mulch was the most effective treatment and increased millet grain yields up to 70%. Soil moisture increased up to 14% in mulched treatments over millet monoculture treatments. All yield increases were achieved without the addition of fertilizers or nutrient amendments. In an attempt to mimic local practices our experiment was rainfed and no soil amendments were introduced. / Master of Science

The contribution of non-point source pollution to degrading surface water quality is considerable throughout Virginia and beyond. While research on agricultural best management practices in nutrient management and nutrient and soil stabilization has made progress in reducing agricultural contributions to nutrient and sediment loading of watersheds, little is known about how land covers of different vegetation representative of urban areas (e.g., bare soil versus turfgrass lawns versus urban forest) influence the potential for non-point source pollution. Ambient rainfall volumes were manipulated to provide 50%, 100%, and 150% of natural precipitation to plots with landscape covers of bare soil, shredded wood mulch, turfgrass, and simulated urban forest (complete pin oak canopy with shredded hardwood leaf mulch). Precipitation amounts, runoff volumes, and eroded sediment masses for ten rain events between July and December 2004 were measured. Runoff was analyzed for nitrate and orthophosphate concentrations for three rain events. Turfgrass was found to be the most effective of the land covers tested at reducing components of non-point source pollution from stormwater. Turfgrass plots produced, on average, the least runoff and sediment, and lower nitrate concentrations in runoff water as compared to the other land covers tested. Results from urban forest plots apparently reflected the disturbance of tree planting, even six months later. This study contributes to a sparse body of knowledge about the influences of urban landscapes on water quality, and will inform land use policy and urban Best Management Practices. / Master of Science