First Years Of Cultivation Research Articles

Vegetative reproduction and yield of bear garlic (<i>Allium ursinum</i> L.) in field cultivation

Bear garlic (<i>Allium ursinum</i> L.) and its value for human health have been known for centuries. Its leaves, flowers, and bulbs contain many health-promoting compounds, and can be essential raw materials for the production of food and dietary supplements of natural origin. The purpose of the study was to evaluate the possibility of growing bear garlic in field conditions that differed significantly from those required by this plant, using unconventional treatments: catch crops (phacelia), shade plant (turnip rape), and biopreparations (Bio-Algeen S90 and Kelpak SL). The plowing of phacelia biomass had a beneficial effect on the number of <i>A. ursinum</i> progeny bulbs, the unit weight of bulbs and their yield per unit area, and the leaf yield not only in the first year of cultivation but also in the follow-up. Winter turnip rape applied as a shade crop caused a slight increase in the unit weight of bulbs and their yield in the first and second years of cultivation and in the number of progeny bulbs in the second and third years of cultivation. The cultivation of <i>A. ursinum</i> with turnip rape increased the percentage of garlic root weight and leaf yield. There was a positive effect of the applied biopreparations on the studied traits of <i>A. ursinum</i> bulb yield and leaf yield and on the formation of progeny bulbs in relation to the control object. The analysis of the interaction of the factors of the experiment showed that the combination with the application of the phacelia catch crop and the simultaneous cultivation of the shade crop had the most favorable effect on <i>A. ursinum</i> progeny bulb formation, bulb unit weight, root system development, and leaf yield. In all years of the study, the worst effect was obtained in the control object, i.e., in the cultivation without the catch crop, rapeseed, and application of biopreparations.

Effect of cover crops and tillage systems on soil quality and sugarcane yield

AbstractThe management adopted in the establishment and replanting of sugarcane fields, with conventional tillage followed by fallow, is one of the main causes of soil quality degradation. In this context, the soil quality index (SQI) is an important tool to guide the use of more sustainable practices and management. This study aimed to monitor the effect of different cover crops in association with different tillage systems on sugarcane yield based on key indicators and an SQI developed using the Soil Management Assessment Framework (SMAF). The experiment was carried out on a sugarcane expansion area located in the municipality of Ibitinga, São Paulo, Brazil. The following soil physical and chemical attributes were analyzed: soil bulk density, macroaggregates, available phosphorus and potassium. Soil carbon content was also analyzed and used to calculate the SQI. Productivity over the 4 years of sugarcane cultivation was also analyzed. The use of subsoilers for soil tillage proved efficient in managing compaction by providing lower soil bulk density values in the first years of cultivation (1.59 and 1.63 g cm−3); however, these effects occurred in the short term with a 10% increase in later years. The use of millet in association with subsoiling showed the best results for soil quality (0.59), reflected in the maintenance of yields at 100 Mg ha−1 over time. Thus, our study reinforces the importance of using soil conservation systems in sugarcane replanting areas to achieve production longevity.

Productivity and quality of paulownia wood in the Right Bank Forest Steppe of Ukraine

Purpose. To determine the effect of application of fertilizer, cryoprotectant and foliar feeding on the formation of yield and quality of paulownia. Methods. The research was conducted in 2021–2023 at the experimental plot of the Bila Tserkva National Agrarian University located in the forest plantations in the Right Bank Forest Steppe of Ukraine (Kyiv region). Design of the experiment: factor A – fertilization: 1) without fertilizers, 2) application of organic fertilizer Vermykompost before planting (400 kg/ha); factor B – application of cryoprotectant: 1) without cryoprotectant, 2) cryoprotectant Mars-EL (0.5 l/ha) applied at the beginning of leaf growth; factor B – foliar application of fertilizers: 1) no treatment, 2) Quantum-AmiNoFrost (1.5 l/ha), 3) SmartGrow Recovery (2.0 l/ha). Results. At the end of the first, second and third years of paulownia cultivation, the average diameter of the trunk was 8.8; 12.2 and 17.3 cm, respectively. The application of organic fertilizer contributed to the average annual increase in this indicator by 3.0, 1.5, and 1.7 cm, and application of cryoprotector – by 0.3, 0.3, and 0.4 cm per year, respectively. The highest values of the trunk diameter in the experiment were obtained under combined application of Vermykompost, cryoprotectant and foliar fertilizer Quantum-AmiNoFrost or SmartGrow Recovery: in the first year – 10.5–10.6 cm, in the second – 13.1–13.2 cm, and in the third year – 18.4 cm. During the first, second and third years of vegetation, dry matter content of paulownia biomass per plant averaged to 3.0, 12.9, and 26.7 kg, respectively. At the same time, the application of fertilizer provided an increase in the dry matter content of 0.7, 1.7, and 3.8 kg per plant, while application of cryoprotectant provided 0.3, 0.6 and 1.2 kg per plant, respectively. Similarly to the diameter of the trunk, dry matter accumulation per plant was the highest under combined action of all factors of the experiment: in the first year – 3.58–3.60 kg, in the second – 14.1–14.2 kg, and in the third – 29.4 kg. Conclusions. The yield of dry matter of paulownia in the first year of cultivation averaged 1.88 t/ha. Application of fertilizer provided dry matter increase of 0.45 t/ha, and cryoprotectant – 0.19 t/ha in the first year; 8.04 t/ha in the second year, with increases by factors of 0.45 and 0.19 t/ha, respectively, and in the third year – 16.68 t/ha, with increases by factors of 2.40 and 0.73 t/ha, respectively. In all years of the experiment, the highest dry matter yield was recorded in the combined treatment with the use of organic fertilizer, cryoprotectant and foliar fertilization: in the first year, dry matter yield was 2.24–2.25 t/ha, in the second 8.80–8.90 t/ha, and in the third year 18.40 t/ha. The average content of cellulose in paulownia biomass over the years of research was 43.8% and lignin – 20.3%. The use of organic fertilizer provided an increase in these indicators by 1.05 and 0.29%, respectively, and cryoprotectant – by 0.41 and 0.24%. The highest content of cellulose (44.5%) and lignin (20.7%) were noted for the combined action of all three factors of the experiment. As to the ash content, the average indicator for the experiment was 1.1%, and the deviations of his parameter did not depend on the influence of the experimental factors (the difference was within the experimental error).

AGROBIOLOGICAL EVALUATION ALLIUM AMPELOPRASUM VAR. AMPELOPRASUM L.

The article presents the results of studies of biological and morphological features of introduced forms of Elephant garlic (Allium ampeloprasum var. ampeloprasum L.) in comparison with garlic cultivars (Allium sativum L.) Sofiivskyi and Prometei. Research on collection samples began in 2016. Samples of Elephant garlic were obtained by expeditionary method (from Greece and Khmelnytsky region). Several plants with long dark green, broad and leathery leaves, pink inflorescences with microcloves (bulbils), large bulbs were selected and vegetatively (clonally) propagated to create a population of homogeneous plants. The study used field, laboratory, statistical, computational and analytical methods. The research was conducted in the training and production department of Uman National University of Horticulture during 2020-2021, using collection varieties of different ecological and geographical origin (Ukraine and Greece). Cultivars/varieties were evaluated according to the following parameters: plant height, leaf area, and indicators of individual productivity (bulb weight, number of teeth and bulbils, etc.), yield and nutritional value. It was found that varieties of Аllium ampeloprasum var. ampeloprasum L. react more sharply to changes in growing conditions than cultivars of Allium sativum L. Winter hardiness of cultivars of Elephant garlic was in the range of 98,0–100%, but they had low adaptability, where the coefficient of adaptability (CA) was 0,45–0,49, and in winter garlic CA = 0,95–0,97. Plants of Аllium ampeloprasum var. ampeloprasum L. do not form air bubbles, but on the bottom and under the covering scales of the bulb is formed from 3-5 to 10 pcs. bulbils. Varieties № 2 and № 3 have 7.1 and 5.1 large teeth in their structure, respectively. The weight of the bulb without removal of the flowering scape in the cultivar Sofiivskyi was less than the samples № 2 and № 3, respectively, by 28.4-53.3 g. With the removal of the flowering scape, the difference increased to 60.5-68.6 g. Yield of Аllium ampeloprasum var. ampeloprasum L. without removal of the flowering scape № 2 was lower than the standard by 1.7 t/ha, at the same time the variety № 3 exceeded the standard by 1.1 t/ha. With the removal of the flowering scape, the yield of cultivars № 2 and № 3 exceeded the cultivar Sofiivskyi by 1.6 and 2.2 t/ha. As a result of research it was found that the introduced forms of Аllium ampeloprasum var. ampeloprasum L. have high indicators of economic value, but they are limited in the first years of cultivation, the period of adaptation to new soil and climatic conditions, which creates some difficulties in their cultivation and reproduction.

Comparing Different Methods for Pruning Pitaya (Hylocereus undatus)

Recently there have been new trends in global consumption toward fresh foods that are sources of healthy bioactive compounds, as is the case with pitaya. However, pitaya cultivation is a relatively recent phenomenon and little is known about its management. The objective of this work is to determine the most appropriate annual fruiting pruning method for pitaya in order to obtain a regular annual yield of quality fruit and an intense shoot renewal that guarantee future production. This study compared the response of Hylocereus undatus to spur, cane, and combined pruning. As control plants, we left some plants where only sanitary pruning was performed. The results indicate that spur pruning greatly reduced flowering (seven times less than controls) and did not promote intense vegetative growth. Cane pruning, on the contrary, allowed greater flowering which is compatible with a higher number of new shoots (8% more than controls). The vigor of the new shoots was equal in all treatments. Fruit size and quality did not differ either among treatments. Spur pruning only seems applicable as a rejuvenation pruning. Combined pruning gave an intermediate response and seems of no interest given the good shoot renewal provided by cane pruning. Performing sanitary pruning alone may be an interesting option, but only in the first years of cultivation.

Impact on the soil and the infiltration as a consequence of oil palm cultivation (Elaeis guineensis jacq) in Tabasco

Objective: To evaluate the possible negative impacts on soil fertility, as a result of the soil use change from the grassland to oil palm. Design/methodology/approach: The following variables were evaluated: soil organic matter (SOM), bulk density (BD), mechanical penetration resistance (MPR), root system distribution, and infiltration in 5-, 11- and 25-year-old oil palm plantations, as well as in an adjoining grassland —whose land use had not changed to oil palm cultivation. Results: During the first years of cultivation, the substitution of the grassland for oil palm caused SOM losses, increased BD and MPR, and reduced infiltration levels. After 11 years, these effects became stable and were reversed. Therefore, in mature plantations of >25 years, the soil and infiltration conditions improved, even surpassing the grassland. These changes occur at a depth of 40 cm and are attributable to the SOM provided by the root system; consequently, root distribution does not block infiltration, becoming a beneficial factor, particularly in mature plantations. Study limitations/implications: The research must be replicated under other soil conditions, in order to observe the fertility behavior. Findings/conclusions: After the grassland is replaced by oil palm, soil fertility deteriorates during the first years; fertility becomes stable and recovers after 11 years. Meanwhile, the effect reverses and surpasses grassland fertility levels after 25 years.

Farmyard Manure as K-Fertilizer Modulates Soil Biological Activities and Yield of Wheat Using the Integrated Fertilization Approach

Potassium fertilization is often ignored by assuming alluvial soils have sufficient K reserves in the North West Plain Zone of India under cereal-based cropping systems. There is scanty information on the impact of integrated K fertilization on soil enzymes, nutrients availability, microbial population, and wheat yield cultivated in the corn–wheat cropping system. The current study exhibits that treatment (T7) applied with a dose of 90 kg K ha−1 [30 kg K by farmyard manure (FYM) and 60 kg K by muriate of potash (MOP)] significantly enhances the various microbial populations from 48.00 to 123.10% and 39.00 to 124.00%, soil enzymatic activities from 70.31 to 180.00% and 102.42 to 175.68%, and available nutrients from 2.43 to 8.44% and 14.79 to 22.87% for the first and second years of wheat cultivation, respectively. It also improved various yield parameters (12.39–41.71% and 18.24–41.14%) during both the consecutive years of cultivation. Statistical analyses revealed that the treatments (T4, T5, and T7) applied with integrated fertilization of wheat cultivation through FYM and MOP were more promising for improving soil enzymatic activities (11.59–57.22%), microbial populations (5.14–15.70%), available nutrients in soil (7.60–16.54%), and crop yield (1.06–5.85%) during the second year of cultivation as compared to the first year of cultivation. This study might be helpful to reclaim soil health and reduce chemical fertilizers used in agricultural lands.

Avaliação financeira e desempenho produtivo de Sistemas Agroflorestais Agroecológicos

Os Sistemas Agroflorestais (SAFs) surgem para potencializar a produtividade dos agroecossistemas e melhorar os ganhos financeiros da agricultura familiar. Questiona-se neste estudo a efetividade do uso de SAFs ampliarem a produtividade e o rendimento financeiro de pequenas áreas. Assim, o objetivo do estudo é avaliar o desempenho produtivo, a demanda de mão de obra e a eficiência financeira dos SAFs. A metodologia baseou-se em um Estudo de Caso, onde durante o período de seis meses foram coletadas informações por meio de entrevistas semiestruturadas, bem como foi acompanhado o cotidiano de três agricultores que estão inseridos no contexto do assentamento Contestado, no município da Lapa, Paraná. Para realizar o prognóstico da análise financeira foi utilizado a planilha AmazonSAF 8.1. No modelo otimizado, dos três agricultores acompanhados, o SAF-3 apresentou o melhor desempenho produtivo financeiro, ultrapassando 17ton/0.5ha/ano de alimento, que corresponde a um VPL de R$ 339,123.40 mil reais durante o período analisado com garantia de venda pelo Plano Nacional de Alimentação Escolar (PNAE). A demanda de mão de obra, em todos os SAFs, se concentra no cultivo das espécies de ciclo curto, atingindo mais de 200 diárias por ano. Conclui-se que os indicadores financeiros oficiais demonstram viabilidade financeira para os três SAFs. Mas o fluxo de caixa não demonstra regularidade da rentabilidade a partir do oitavo ou nono ano até o 15, pois as receitas das hortaliças foram tão altas nos primeiros anos de cultivo que conseguiram manter os indicadores financeiros positivos para todo período.

AGROCLIMATIC RISK ZONING FOR GUAVA (Psidium guajava L.) IN PARANÁ RIVER BASIN 3

Fruticulture constitutes an important sector of the Brazilian agricultural industry. Despite technological and scientific advances, climate is still the most important variable defining crop productivity. Because of this, agroclimatic zoning should be one of the first factors to consider when starting to plant a particular crop. The objective of this work was to conduct climate risk zoning for guava (Psidium guajava L.) in Paraná river basin 3, Paraná, Brazil, using meteorological data from 43 stations collected between 1976 and 2018. The climate risk analysis was based on the climatic factors that impact the species, such as rainfall, annual water deficit, average annual temperature, coldest month temperature, and risk of frost. The findings of this study suggest that the basin has areas with a low climate risk for guava cultivation. Precipitation and water balance were sufficient under all tested scenarios. The most limiting factor for production was frost, but with risk only present during the first years of cultivation. Despite this, planting restrictions were only predicted to occur in the far west portion of the basin. Agricultural techniques that reduce the risk of frost and avoiding areas with greater frost incidences are the two most important aspects to consider to ensure greater success for guava in the region.

Scaled Semivariogram in the Sample Planning of Soils Cultivated With Sugarcane

Sugarcane cultivation has expanded in areas previously occupied by degraded pastures. In the first years of cultivation, besides the physical and chemical restrictions of the soils, other factors can make impossible the maximum productive expression of the crop, like the climatic and edaphic factors. The objective of this work was to evaluate the ideal sampling density and spatial variability of the physical and chemical attributes of soils cultivated with sugarcane. Georeferenced data provided by the Sugarcane Technology Center (STC) of an area of approximately 19,000 hectares located in the northwest region of São Paulo were evaluated. The granulometric fractions of the soils and organic matter contents and base saturation were determined at depths of 0.00-0.25 and 0.25-0.50 m. An index named edaphic environment (ENV) was calculated based on the records of rainfall of the areas and the productivity of the sugarcane, being represented with aptitude scores ranging from 0 (worst condition) to 10 (best condition). The results showed a strong correlation between clay and organic matter attributes with ENV index. Regions with aptitude ≥ 6.65 of ENV index corresponded to sites with clay (CL) and organic matter (OM) content above 335 g kg-1 and 30 g kg-3, respectively. Only 10.86% of the area presented base saturation (V%) concentration ≥ 68%, correlating positively with CL and ENV. Through the scaled semivariogram it was possible to verify that a density of sampling of a sample to each 18 ha can be used for a mapping in macroscale of the evaluated attributes in the northwest region of the state of São Paulo.

Особливості росту сосни кедрової сибірської різного географічного походження у культурах 17-46-річного віку

Охарактеризовано особливості інтенсивності росту сосни кедрової сибірської 17-46-річного віку в загущених посадках залежно від місця збору насіння. Дослідження проведено у Караульному дільничному лісництві Навчально-дослідного лісгоспу Сибірського державного технічного університету (зелена зона м. Красноярська), 56°00` пн.ш., 92°30` сх.д., висота над рівнем моря становить 300 м. Дослідну ділянку створено садінням шестирічних сіянців за схемою 2 х 1 м. Сіянці вирощено з насіння, зібраного в популяціях Алтаю, Хакасії, Красноярського краю, Іркутської і Читинської областей. Середня висота дерев у 17-річному біологічному віці становила 2,2 м, у 28-річному – 7,1 м, у 46-річному – 15,9 м. Встановлено, що лідерські позиції за висотою і діаметром стовбура дерев змінюються залежно від віку. Так, 17-річні деревні рослини відрізнялися найбільшими показниками в шуміхінскому (місцевому) і північно-єнісейському варіантах. Дерева 28-46-річного віку мали перевищення за висотою та діаметром стовбура в шуміхінскому, алтайському, черемхівському, читинському варіантах (висота над рівнем моря становить 500-1000 м, пн.ш. – від 50°22` до 56°00`, сх.д. – 86°54`-108°43`). Відношення висоти дерева до діаметра стовбура змінювалося від 0,83 у 17-річному віці до 1,16 – у 46-річному. Відзначено збільшення співвідношення між висотою дерева і діаметром стовбура з віком, що свідчить про підвищену конкуренцію дерев. Кореляція між висотою, діаметром стовбура насіннєвого потомства і показниками материнських популяцій в перші роки вирощування відсутня; у 46-річному віці тіснота зв’язку між висотою, діаметром дерев і класом бонітету материнських популяцій помірна. До 46-річного віку в дослідних посадках відбувався природний відбір і збережені екземпляри, незалежно від географічного походження, відрізнялися кращими біометричними показниками. Проведено відбір кращих дерев для вирощування селекційного садивного матеріалу.
 До групи швидкорослих віднесено дерева читинського, алтайського, черемхівського і шумихінського походжень. Відсталі в рості дерева представляють північно-єнісейське, слюдянське і сонське походження. Відмінності підтверджуються показником достовірності (tф > t05).

Land-use change affects the functionality of soil microbial communities: A chronosequence approach in the Argentinian Yungas

Land-use change has drastically reduced the area of pristine forests in tropical and subtropical regions. In NW Argentina, Yungas forests were among the most affected by deforestation for the implementation of agricultural crops. Conversion of forests to croplands modified the structure and function of soil microbial communities, but its effects on soil functionality across time after land-use change are understudied. Therefore, the objective of this study was to analyze the impact of land-use change and time under cultivation on the functionality of microbial communities in these soils. We established a 30-year old chronosequence comprising 4 stages (forest and short-, mid- and long-term agriculture) in 3 independent farms. Together with soil physicochemical properties, we measured microbial biomass carbon, basal respiration, ammonification, acid and alkaline phosphomonoesterase activities, and community-level physiological profiling (CLPP). During the first years of cultivation, the functionality and biomass of soil microbial communities were strongly affected. Compared to forest soils, short-term agricultural soils exhibited a reduction on microbial biomass (∼45%), ammonification (∼67%) and acid phosphomonoesterase activity (∼41%). Moreover, increased basal respiration (up to 94%) and metabolic quotient in those soils suggested radical changes in functionality at the beginning of the chronosequence. However, CLPP evidenced that older agricultural sites had an increased global catabolic response per unit biomass, while it detected no differences in physiological diversity of soil microbial communities along the chronosequence. The lack of differences detected between mid- and long-term agricultural sites, in addition to a reduced inter-site variability, evidences an apparent stabilization and homogenization of soil microbial communities towards the end of the chronosequence. In contrast with physicochemical variables, microbiological variables had a greater performance for characterizing the different stages of the agricultural chronosequence and the impact of land-use change on soil functionality.

Sixteen Years of Bt Maize in the EU Hotspot: Why Has Resistance Not Evolved?

The majority of Bt maize production in the European Union (EU) is concentrated in northeast Spain, which is Europe’s only hotspot where resistance might evolve, and the main target pest, Sesamia nonagrioides, has been exposed to Cry1Ab maize continuously since 1998. The cropping system in northeast Spain has some similar characteristics to those that probably led to rapid resistance failures in two other target noctuid maize pests. These include repeated cultivation of Bt maize in the same fields, low use of refuges, recurring exposure of larvae to non-high dose concentrations of Cry1Ab toxin during the first years of cultivation, low migratory potential, and production concentrated in an irrigated region with few alternative hosts. Available data reveal no evidence of resistance in S. nonagrioides after 16 years of use. We explore the possible reasons for this resistance management success using evolutionary models to consider factors expected to accelerate resistance, and those expected to delay resistance. Low initial adoption rates and the EU policy decision to replace Event 176 with MON 810 Bt maize were key to delaying resistance evolution. Model results suggest that if refuge compliance continues at the present 90%, Bt maize might be used sustainably in northeast Spain for at least 20 more years before resistance might occur. However, obtaining good estimates of the present R allele frequency and level of local assortative mating are crucial to reduce uncertainty about the future success of resistance management.

Long-term decline in soil fertility and responsiveness to fertiliser as mitigated by short fallow periods in sub-Sahelian area of Togo

Using 40-year experiment data from a mono-modal rainfall area of northern Togo, we analyzed soil fertility dynamics when 2 and 3-year fallows were alternated with 3-year rotation of groundnut, cotton and sorghum. The control treatment consisted to continuous cultivate the soil in a rotation of groundnut/cotton/sorghum without fallow periods. For each rotation, two fertilisation rates were applied: no fertilisation and mineral fertiliser application during the cropping and/or the fallow periods. Yields of unfertilised crops, which averaged 1 t ha−1 during the first years of cultivation, were often nil in the long-term. In the long-term, yields of fertilised cotton and sorghum decreased by 32 and 50 %, respectively compared to the average of 2.4 and 1.6 t ha−1 obtained during the first decade of cultivation. The long-term decline in crop productivity was mitigated when fallow periods were alternated with cropping periods, and consequently there was partial compensation in terms of production for the unproductive fallowed plots. Long-term yields of fertilised cotton and sorghum in the periodically fallowed plots were 40 and 50 % higher than those in continuously cropped plots, respectively; they were 90 and 60 % higher than those in continuously cropped plots without fertilisation. Like for crop productivity, soil C, N and exchangeable Ca and Mg decreased less in periodically fallowed plots than in continuously cropped plots. The limited soil C decline when fallows were alternated with crops appears to be the consequence of no-tillage period rather than the effect of the highest C inputs to the soil.

Stream water nutrient and organic carbon exports from tropical headwater catchments at a soil degradation gradient

Carbon and nutrient losses were quantified from four small headwater catchments in western Kenya in the year 2008. They include a forested catchment and three catchments under maize continuously cultivated for 5, 10 and 50 years following forest conversion. The C isotopic composition of dissolved organic C (DOC) in stream discharge suggested that soil organic C (SOC) derived from the original forest rather than OC from maize may have contributed to a large extent to watershed OC losses, even 50 years after the forest was removed. Flow-weighted stream water concentra- tions of DOC and coarse particulate OC, all N species, total P, K and Na significantly (P \ 0.05) increased in streams after forest conversion and long-term cultiva- tion. Solute concentrations increased despite the fact that soil contents decreased and total water flow increased indicating mobilization of C and N, P and K from soil with progressing cultivation. In contrast, Ca and Mg concentrations in stream water did not system- atically change after deforestation and cultivation, and may be controlled by geochemical weathering rather than by changing water flow paths or topsoil contents. All OC and nutrient exports increased with longer cultivation over decadal time scales (P \ 0.05) to the same or greater extent than through deforestation and the first years of cultivation. Fluvial OC and total N losses were 2 and 21 % of total SOC and total N decline, respectively, in the top 0.1 m over 50 years. Fluvial OC losses therefore played a minor role, and SOC losses were mainly a result of microbial mineralization. Resulting total N losses by stream discharge, however, were large with 31 kg ha -1 year -1 after 50 years of continuous cropping in comparison to fertilization of 40 kg N ha -1 year -1 . Most (91 %) of the N losses occurred as NO3 - . In contrast, P losses by stream discharge were negligible in comparison to plant uptake. Water losses should be managed to reduce soil fertility declines especially through large N export from agricultural headwater catchments. However, stream concentrations of both P (0.01-0.15 mg L -1 )

Root distribution in young olive trees (Olea europaea cv. Chétoui) and agronomic application

The study was carried out to have a comprehensive view of the root system behavior of young olive trees cultivated under field conditions. The experiment involved irrigated trees (Olea europaea L., cv., Chetoui) cultivated at 6x6 m2 spacing in Mornag (36.5°N, 10.2°E), northern Tunisia. The way in which roots explore the soil volume during the first years after planting was explored through ‘in situ’ root system drawings and estimation of root densities. The relationship between canopy and root growth parameters was also investigated. The last section of this paper proposes a methodological approach for determining irrigation requirements of young olive trees and how water supply could be linked to the development of canopy and root system during the first years of cultivation when ground cover and the root system are not completely developed. Some agronomic applications were then deduced concerning water and fertilizers for such orchards. Results show that the main development of the olive root system occurs during the two to four first years of cultivation confining most roots (70%) to the top soil layers (20-40 cm). Maximum root densities were observed at this depth at a distance of 0.4 m from trunks. For young trees, water and fertilizers should be supplied at these depths and distances from trunk to allow easy and efficient root absorption. Obtained results also show a significant relationship between canopy and root areas which can be approximated by a linear model (r = 0.94). The root-canopy ratio estimated from their areas decreased rapidly beginning from the second year after planting, resulting from the establishment of competition between vegetative growth and fruiting. The optimum ratio root length/leaf canopy area of 2.3 km m-2 was found for the six-year-old tree indicating good equilibrium between the above and underground parts. The mathematical model developed on the basis of canopy cover and root extension allows precise esti- mation of water needs taking into account the actual root surface. However, while the canopy cover measurement was relatively easy to carry out, it was much more difficult to determine the surface covered by the root system. Results obtained in the present work also show an over-estimation of water needs when the FAO method is adopted to estimate the evapotranspiration of young trees.

A hybrid approach to mapping land-use modification and land-cover transition from MODIS time-series data: A case study from the Bolivian seasonal tropics

This study uses a combination of satellite imagery and GIS data, a vegetation map, interview data, and on-site field studies to map detailed natural vegetation to land-use conversion pathways (~ 22,000 possible combinations) in the seasonal tropics of Santa Cruz Department in southeastern Bolivia from 1994 to 2008. We mapped a suite of land-use classes based on the seasonal phenology of double- and single season cropping regimes; pasture; and bare soil cropland (fallow). Analyses focus specifically on the Corredor Bioceánico, which bisects some of the most sensitive and poorly understood ecosystems in the world and indirectly creating one of the most important agricultural region-deforestation hotspots in South America at the present time. Training data to predict class membership were based on MODIS NDVI annual mean, maximum, minimum, and amplitude derived from field observations, semi-structured interviews, and aerial videography. Results show that over 8,000 km 2 of forest was lost during the 14-year study period. In the first years of cultivation, pasture is the dominant land use, but quickly gives way to cropland. The main findings according to forest type is that transitional forest types on deep and poorly drained soils of alluvial plains have lost the most in terms of percentage area cleared. The resulting transition pathways can potentially provide decision-makers with more detailed insight as to the proximate causes or driving forces of land change in addition to the most threatened forests remaining in the Tierras Bajas and those most likely to be cleared in the Brazilian Shield and Pantanal.

Change in Olive Tree Height Growth During the First Years of Cultivation

Change in Olive Tree Height Growth During the First Years of Cultivation

Changes in carbon storage in temperate humic loamy soils after forest clearing and continuous corn cropping in France

Soil samples from forest and agricultural sites in three areas of southwest France were collected to determine the effect of forest conversion to continuous intensive corn cropping with no organic matter management on soil organic carbon (C) content. Soils were humic loamy soils and site characteristics that may affect soil C were as uniform as possible (slope, elevation, texture, soil type, vegetation). Three areas were selected, with adjacent sites of various ages of cultivation (3 to 35 yr), and paired control forest sites. The ploughed horizon (0-Dt cm) and the Dt-50 cm layer were collected at each agricultural site. In forest sites, each 10 cm layer was collected systematically down to 1 meter depth. Carbon concentrations were converted to total content to a given depth as the product of concentration, depth of sample and bulk density, and expressed in units of kg m-2. For each site and each sampled layer, the mineral mass of soil was calculated, in order to base comparisons on the same soil mass rather than the same depth. The pattern of C accumulation in forest soils showed an exponential decrease with depth. Results suggested that soil organic carbon declined rapidly during the first years of cultivation, and at a slower rate thereafter. This pattern of decrease can be fitted by a bi-exponential model assuming that initial soil organic carbon can be separated into two parts, a very labile pool reduced during the first rapid decline and more refractory fractions oxidizing at a slower rate. Sampling to shallow depths (0-Dt cm) resulted in over-estimation of the rate of carbon release in proportion to the initial amount of C, and in under-estimation of the total loss of C with age. The results for the 0–50 cm horizon indicated that losses of total carbon average about 50% in these soils, ranging in initial carbon content from 19 to 32.5 kg m-2. Carbon release to the atmosphere averaged 0.8 kg m-2 yr-1 to 50 cm depth during the first 10 years of cultivation. The results demonstrate that temperate soils may also be an important source of atmospheric carbon, when they are initially high in carbon content and then cultivated intensively with no organic matter management.

A influência de dois tipos de consórcios de fruteiras na incidência de broca do tronco (Cratosomus sp) na graviola (Annona muricata L.) (*)

O objetivo principal deste trabalho foi estudar a incidência e intensidade de ataque da praga "Broca do tronco" (Cratosomus sp.) na graviola (Annona muricataL.) em um sistema de dois tipos de consórcio de fruteiras. 0 estudo foi realizado na área do projeto "Sistema de Produção Comerciado de Fruteiras", instalado em /977 e se encontra localizado na E.E.S.T. do INPA, Km 41 da BR - 774 no Município de Manaus, foram utiliza das 6 espécies de fruteiras: graviola (Annona muricataL.), côco (Cocos nucíferaL.), pupunha (Bactris gasipaesH.B.K.), caju (Anacardium ocidentaleL.) birlbá (Rollinia mu cosa (Jacq.) Baill e o mapati (Pouroma cecropiazfoliaMart.). Os sistemas comerciados empregados são: Consórcio simples constituído pelas 6 espécies de fruteiras com 16 plantas cada subparcela e o Consórcio misto as 6 espécies de fruteiras foram plantadas al-ternadamente usando o mapati para separar as demais: neste consórcio contém o seguinte número de plantas: 8 graviolas, 8 biribás, 8 cajus, 14 cocos, 14 pupunhas e 98 mapati. 0 delineamento empregado é bloco casualizados com 20 repetições. Avaliaram-se o grau de infestação pelo inseto (Cratosomussp.) e número de plantas atacadas em cada tipo de consórcio, na qual uma planta foi considerada atacada apenas quando apresentou um ata -que ativo, ataques velhos não foram considerados. Os dados sobre o ataque foram coleta dos nos meses de junho/79 a julho/80. Concluiu-se que, apesar da hipótese de que plantas comerciadas sofreriam menor incidência de ataque em plantas de graviola nas parcelas heterogêneas nos primeiros anos do desenvolvimento da plantação. Entretanto, reconhece-se a necessidade de estudos mais especializados sobre o ciclo biológico desta pra ga e sobre diferentes tipos de comércios para fornecer recomendações mais seguras sobre quais são os sistemas de plantio economicamente mais viáveis.