The Texas Blackland Prairie is one of the most productive agricultural regions in Texas. This region provides a long growing season coupled with soils that have a high water holding capacity. However, the soils also provide significant challenges to producers because the high water holding capacity is a product of a high clay percentage. This research was aimed to develop and test an expert-based trafficabililty index, based upon soil moisture, for planting cotton (Gossypium hirsutum L.) and corn (Zea mays L.) on the Texas Blackland Prairie. Testing the index focused on quantify the potential effect of high soil moisture at planting on seed furrow sidewall compaction and associated plant growth response. Once the trafficability index was developed, three workable soil moisture regimes were recreated in no-tillage and conventional tillage plots at the Stiles Farm Foundation in Thrall, Texas. The index nomenclature included: "Dry-Workable", "Optimal" and "Wet-Workable". After planting corn and cotton into conventional and no tillage plots, 0.45 x 0.20 x 0.15 m intact soil blocks were removed from each plot and kept in a controlled environment. At 28 days, each block was destructively harvested to quantify plant root and shoot growth responses. Each of the three soil moisture indexes was replicated thrice per crop, and the whole experiment was replicated twice in time, n = 48 blocks. The trafficability index was created using three producer experts, and over 10 interviews to collect a range in soil moisture samples. From "Wet Workable" to "Dry Workable", the gravimetric soil moistures were 0.17, 0.22, and 0.26 g g-1. For corn and cotton, a positive relationship between plant growth factors and planting at soil moisture existed. Plants planted at the highest soil moisture emerged faster and developed more root and shoot biomass than those planted at the lowest soil moisture. No evidence of a detrimental plant response because of seed furrow, sidewall compaction from planting at too high a soil moisture content could be quantified. Furthermore, the cotton plants in no-tillage performed better than in conventional tillage, but corn performed better in conventional tillage. Because the results showed an advantage to plant growth by planting in the "Wet Workable" index, the tillage practice that allows the producer to enter the field with a planter at higher moisture contents appears to have an advantage.

It is well documented that increases in soil organic matter (SOM) improve soil physical properties and increase the overall fertility and sustainability of the soil. Research in SOM storage has recently amplified following the proposal that agricultural soils may provide a significant carbon (C) sink that may aid in the mitigation of increasing atmospheric carbon dioxide. Observed differences in lint yield and nitrogen response from a cotton performance study at the Texas A&M University Experimental Farm near College Station, TX prompted us to examine the effects of tillage and rotation on soil organic C (SOC), soil microbial biomass C (SMBC), 38-day cumulative C mineralization (38-day CMIN), hot-water extractable organic C (hot-WEOC), carbohydrate C, and total glomalin. The treatments examined included conventional-till continuous cotton (CT), reduced-till continuous cotton (RT), and conventional-till cotton after corn rotation (CC) treatments. In pre-plant soil samples, SOC, SMBC, and 38-day CMIN in the top 5 cm were 33, 58, and 79 % greater in RT and 29, 32, and 36 % greater in CC vs. CT. Comparable differences were observed for hot-WEOC and carbohydrate C. Little seasonal variation was observed for labile-C pools throughout the growing season, suggesting minimal C input from cotton roots. Water-stable aggregation was not significantly affected by management, and did not correlate with labile-C pools or total glomalin. Labile-C pools were generally more responsive to management vs. SOC and were strongly correlated with one another. Carbohydrate C of hot-water extracts exhibited the strongest relationships with SMBC and 38-day CMIN, even though it comprised only 3 and 5 % of these pools, respectively. Our data suggest that increasing SOC in Texas cotton-cropping systems through conservation management is possible. Long-term data are still needed to fully address SOC storage potentials in Texas, but increases in labile-C pools resulting from conservation management are attainable and have the potential to positively impact soil fertility.

The experiment was exsecuted in Experimental station of Lithuanian university of agriculture in 2005. The objectives of field experiment was to evaluate effect of reduced tillaged and no tillaged on soil physical properties: bulc density, sheare strength, moisture content, fore volume. Five different tillage treatments were arranged: deep ploughing (GA), shallow ploughing (SA), deep coultivation and discing (GP), shallow discing (SP), no tillage, direct drilling (ND). Change of common soil tillage with simplificated soil tillage and direct sowing to no tillaged soil had not fundamental hold to the soil physical properties: bulc density, moisture content, fore volume. But shallow discing in comparison with deep ploughing slumped sheare strength 10.17 %. Common and simplificated soil tillage had not fundamental holdfor earth worms biomass in barley. In shallow disced soil (SP) earth worms biomass increased to 43.7 %. In no tillage soil biomass of earth worms increased 133.5 %. Shallow discing and sowing to no tillage soil fundamentally increased weed-grow in bushing-out stage. Spread of weeds in simplificately tillaged soil possible to escape with spraying the crop with herbicides. But in no tillaged soil it was not enough. Simplificated soil tillage and sowing to no tillaged soil had not hold for energy of barley germination and for number of productive stems. In no tillaged soil in comparison with deep ploughing, yield of barley slumped 14.5 %.

This thesis investigates the sensitivity and separability of post-harvest tillage conditions using polarimetric Synthetic Aperture RADAR in southwestern Ontario. Variables examined include: linear polarizations HH, HV, and VV and polarimetric variables: pedestal height, co-polarized complex correlation coefficient magnitude, left and right co-polarized circular polarizations and co-polarized phase difference. Six fine-quad polarimetric, high incidence angle (49°) RADARSAT-2 images acquired over three dates in fall 2010 were used. Over 100 fields were monitored, coincident with satellite overpasses. OMAFRA’s AgRI, a high-resolution polygon network was used to extract average response from fields. Discrimination between tillage practices was best later in the fall season, due to sample size and low soil moisture conditions. Variables most sensitive to tillage activities include HH and VV polarizations and co-polarized complex correlation coefficient magnitude. A supervised support vector machine (SVM) classifier classified no-till and conventional tillage with 91.5% overall accuracy. These results highlight the potential of RADARSAT-2 for monitoring tillage conditions.

Magistrantūros studijų baigiamajame darbe pateikiami pasėlio sudygimo, tankumo, piktžolėtumo tyrimo duomenys skirtingo intensyvumo žemės dirbimo, padengimo šiaudais ir žaliąja trąša laukeliuose. Stacionarus dviejų veiksnių eksperimentas vykdomas nuo 1999 metų. Tyrimai buvo vykdomi nuo 2011 - 2012 m. Eksperimentas buvo vykdomas pagal tokią schemą: A veiksnys: Šiaudų įterpimas: šiaudai pašalinti (-Š), šiaudai susmulkinti ir paskleisti (+Š). B veiksnys: Žemės dirbimo sistemos. Atlikus tyrimus nustatyta, kad miežių daigų skaičiui trečią dieną nuo dygimo pradžios esminės įtakos turėjo žemės dirbimo intensyvumas. Fone, kur šiaudai buvo susmulkinti ir paskleisti (+Š) esmingai didesnis daigų skaičius, palyginti su giliu arimu (GA), nustatytas laukeliuose, kurie buvo sekliai purenti kultivatoriumi plokščiapjūviais noragėliais ir lėkštiniais padargais (KL) ir laukeliuose su žaliąja trąša (ŽTRK). Fone be šiaudų (-Š), palyginus su giliu arimu (GA), esmingai daugiau miežių daigų sudygo sekliai artuose (SA), sekliai purentuose kultivatoriumi plokščiapjūviais noragėliais ir lėkštiniais padargais (KL) ir neįdirbtos ražienos (ND) laukeliuose. Dešimtąją dieną nuo dygimo pradžios, tiek fone su susmulkintais ir paskleistais šiaudais, tiek fone be šiaudų esmingai mažiau miežių daigų rasta laukeliuose, kurie buvo sekliai purenti rotoriniu kultivatoriumi (RK). Fone su šiaudais taip pat esminiai skirtumai nustatyti laukeliuose kur sėta į neįdirbtą ražieną (ND). Produktyvių stiebų skaičiui neturėjo... [toliau žr. visą tekstą] / Master's thesis presents data of a study of crop germination, density, weed and earthworm population in fields varying in intensity of tillage, straw and green fertilizer coverage. Stationary two-factor experiment is being carried out since 1999. Studies were carried out from 2011 – 2012 . The experiment was carried out according to the following scheme: factor A: Straw incorporation: straw removal (-Š), straw shredded and spread out (+ Š). Factor B: tillage systems. The research found that the number of barley sprouts on the third day from the beginning of germination is essentially influenced by tillage intensity. In area, where the straw were chopped and spread (+Š) substantially increased the number of sprouts in comparison with deep plowing (GA), has been determined in the fields that have been consistently levelled using harrow tines and flatcutting disc implements (KL). Area without straw (-Š) in comparison with deep ploughing (GA), substantially more barley seeds germinated in shallow ploughed (SA), shallow tine cultivator tines and flatcutting disc implements (KL) and the uncultivated stubble (ND) fields. Tenth day after the beginning of germination area with chopped or spread straw and area without straw in the background substantially less barley plants found in fields that have been consistently leveled harrow (RK). In the area with straw as well as in the area where sown in no-till stubble (ND) substantial differences were dicovered. Number of productive stems... [to full text]

Lauko eksperimentas atliktas 2010–2012 m. Akmenės rajone, Kruopių seniūnijoje, Kruopių km. ūkininko Valiaus Ąžuolo ūkyje. Eksperimento lauko dirvožemis yra tipingas pasotintasis rudžemis (Eutric Cambisol). Tyrimų objektas – žieminių rapsų (Brassica napus var. oleifera DC) linijinės ir hibridinių veislių, pasėtų, į supaprastintai ir tradiciniu būdu dirbtą dirvą, pasėliai. Darbo metodai: ligų ir kenkėjų paplitimas vertintas naudojantis moksliniu metodiniu leidiniu ,,Žemės ūkio augalų kenkėjai, ligos ir jų apskaita“ (2002). Darbo rezultatai. Žemės dirbimas turėjo esminės įtakos fomozės pažeistų augalų proc. linijinės veislės žieminių rapsų pasėliuose. Fomozės pažeistų augalų dalis ir ligos intensyvumas buvo didesni hibridinių veislių pasėliuose. Žemės dirbimas ir veislė neturėjo esminės įtakos juodosios dėmėtligės paplitimui pasėliuose. Mažiau juodosios dėmėtligės pažeistų ankštarų buvo linijinės veislės pasėliuose, tačiau hibridinių veislių pasėliuose šios ligos intensyvumas buvo mažesnis. Žieminių rapsų pasėliuose verticiliozei mažiau atsparūs buvo hibridinės veislės rapsai. Žemės dirbimas turėjo esminės įtakos žieminių rapsų sėklų derlingumui. Didžiausias tirtų veislių žieminių rapsų sėklų derlingumas gautas taikant supaprastintą žemės dirbimą. 2010–2012 m. nenustatyta statistiškai patikimų priklausomumų tarp juodosios dėmėtligės, fomozės bei verticiliozės paplitimo pasėliuose ir sėklų derliaus. Nustatytas silpnas statistiškai patikimas tiesinis priklausomumas tarp... [toliau žr. visą tekstą] / Field experiment was conducted on 2010–2012 in the farm of Valius Ąžuolas in Kruopiai village, Kruopiai municipality, Akmene district. Soil of the experimental field – Eutric Cambisol. Object of the work – Winter rape (Brassica napus var. oleifera DC) crops of conventional and hybrid cultivars sown in the soil under traditional and reduced soil tillage. Method of the work – spreading of pests and diseases was evaluated using scientifical-methodical publication ,,Žemės ūkio augalų kenkėjai, ligos ir jų apskaita“ (Pests, diseases and their accouting in agricultural crops) (2002). The results of the work. Soil tillage significantly influenced the number of plants damaged by Leptospaeria spp. in crop of conventional winter rape cultivar. The percentage of plants damaged by Leptospaeria spp. and disease intensity was higher in crops of hybrid cultivars. Soil tillage and cultivar had no significant influence on the spreading of Alternaria brassica in winter rape crops. Lower amount of siliques damaged by Alternaria brassica was established in crops of conventional cultivar, but the intensity of this disease was lower in crops of hybrid cultivars. Winter rape of hybrid cultivars was less resistent for Verticillium dahliae. Soil tillage significantly influenced seed yield of winter rape. The highest seed yield of winter rape was obtained under reduced soil tillage. No significant correlations were established between seed yield of winter rape and diseases spreading in crops... [to full text]

Soil organic matter (SOM) is a dynamic soil property, sensitive and responsive to many factors. The possibility of increasing soil carbon (C) sequestration by changing land use and management practices has been of great interest recently due to concerns with global changes in the atmospheric carbon dioxide (CO2) balance. Nonetheless, as a result of the complex dynamics of SOM, there is still the need for SOM characterization procedures capable of monitoring SOM stabilization, taking into account all the factors involved. This study characterized SOM stabilization as affected by management practices in three long-term field experiments, considering physical, chemical and biological components. The field experiments are located near Lexington, Kentucky, on a Maury silt loam (fine, mixed, mesic Typic Paleudalfs). The first experiment evaluates tillage and nitrogen (N) rate effects. The second experiment studies manure and N rate effects. The third experiment evaluates the five corn components of three crop rotations [continuous (monoculture) corn, corn-wheat/double crop soybean, and hay-hay-corn-corn-corn]. Soil organic matter content, stability, and composition, for physically separated fractions, were assessed using δ13C natural abundance and diffuse reflectance Fourier transformed infrared (DRIFT) spectroscopy. In addition, management effects on microbial biomass and microbial function as indicated by phenol oxidase enzyme activity were evaluated. The results indicate that management practices affect SOM content, stability, and composition, and these effects differ by the soil aggregate fraction. No-tillage (NT), N fertilization, manure application and increased corn in crop rotations enhanced SOM levels. However, the effect of NT was observed mainly at the soil surface. Soil organic matter storage was determined by the aggregate size distribution. The proportion of recently deposited C was generally positively related to aggregate size, especially for the first and third experiments. Most of the recently deposited C was stabilized in microaggregates within macroaggregates, across the management treatments and field experiments. In addition, this fraction consistently exhibited low to medium SOM reactivity. These results suggest that SOM stabilization, as influenced by management practices, required achieving a specific composition and location within the soil matrix. This implies that soil C forms and aggregate size and stability are closely interrelated.

To evaluate the strip tillage in organic bell pepper (Capsicum annuum L.) production as an integrated system for sustainable vegetable cropping two-years of field trials were conducted in 2011 and 2012. The field trials were conducted to determine the viability of strip tillage in conventional and organic bell pepper production systems by comparing plant growth, water status, and fruit yield to plastic mulch grown plants application under different irrigation regimes. The two-year field data demonstrated that organic pepper with strip tillage application was a viable combination that produced comparable yield to conventional plastic mulch system and utilized water more economically. In 2011 and 2013, strip-tilled rows and plastic mulched rows were used to evaluate the impact of tillage on soil hydraulic conductivity and water internal drainage characteristics. Results indicated that strip-tilled plots had significantly higher in-row penetration resistance compared to the plastic mulch system at depths up to 20 cm, but no differences between the systems were found for layers below 25 cm. In addition, there were no differences in hydraulic conductivity between strip tillage and plastic mulch in both study years over a 30-day period. Also, significant main effects were found for soil layer and time scale on hydraulic conductivity in the first 24 hour of the study in 2013. During field trials in 2011 and 2012, plant tissues were sampled for endophytic bacteria isolation and identification. Differences in endophytic bacteria were obtained among different production combinations. In 2013, endophytic bacteria isolates from 2011 and 2012 trials were re-inoculated to bell pepper grown in greenhouse to assess plant growth. Two Pseudomonas sp. and one Bacillus thioparans strain were screened to evaluate their affects on plant growth under both drought and non-drought conditions. After growth comparisons, the three endophytic strains were used to subsequently study the impacts of endophyte inoculation on regulating plant drought-linked gene expressions in 2014 by conducting real-time PCR. Results demonstrated that plant drought-linked genes, which especially involved plant ethylene biosynthesis, were significantly down-regulated after inoculating the endophytic bacterial strains.

Reduced tillage and living mulches are alternative management strategies that can improve soil quality by minimizing disturbance and building soil organic matter. Weed suppression by these two practices alone is often insufficient to avoid crop yield losses, but their performance in an integrated system is not well understood. This project investigated the production of bell pepper (Capsicum annuum L.) and dry bean (Phaseolus vulgaris L.) in conventional tillage and strip tillage with a living mulch of teff (Eragrostis tef Zucc.) and Korean lespedeza (Kummerowia stipulacea Maxim.). Yields of pepper and bean were generally higher under conventional tillage without living mulch. Weed biomass was not influenced by tillage, and was adequately suppressed by teff in a year when conditions for teff growth were favorable. Mowing appeared to suppress weed growth but not living mulch growth. Soil nitrate and ammonium concentration was generally higher under conventional tillage without living mulch. Delaying living mulch seeding by 15 days after crop establishment generally did not affect weed suppression or crop yield. Soil aggregate stability was not consistently affected by tillage or living mulch. Increased mowing frequency, living mulch planting delay, or distance between the crop row and the living mulch may be necessary to achieve acceptable yields with living mulches.

No description available.