Restoration of a degraded area using soil tillage systems in Campinas, São Paulo, Brazil

In Brazil the intensive agriculture use, mainly pasture, is the main cause of the presence of extensive areas of degraded lands. This study aimed to assess the impact of different soil management practices in a pasture degraded area used as garbage disposal. The experiment was performed at the Faculdade de Engenharia Agrícola, Universidade Estadual de Campinas - UNICAMP, in Campinas, state of São Paulo, Brazil, from 1990 to 1996. This area has undergone a process of recovery through removal of trash deposited on the surface, in 1985, levelling of soil, followed by application of limestone, subsoiling, planting of legumes (Crotalaria juncea) and crop rotation (soybean and maize). Since 1990 only popcorn maize was grown and established plots managed with different soil tillage systems, including harrow, chisel plow, moldboard plow, no tillage, disk plow and revolving hoe. One plot was planted exclusively with guinea grass (Panicum maximum) to serve as a reference for minimum loss of soil and another grown on a downhill direction to correspond to the expected maximum erosion. There were differences in sediment loss, nutrient loss and productivity of the popcorn maize in the period analyzed. The chisel plow and no tillage treatments caused the slightest loss of soil and nutrients, compared to other tillage systems. The results show that the soil management systems influenced the physical and chemical characteristics of soil, allowing an economical and environmental recovery of the area, providing the conditions for grain agricultural production.

Mume clonal rootstocks for 'Aurora-1' peach in São Paulo State, Brazil

In spite of significant results achieved with scion genetic improvement in stone fruits, the peach culture in Brazil still needs studies and new technologies regarding the use of rootstocks. A wide research project has being developed at the Faculdade de Ciências Agrárias e Veterinárias (FCAV/UNESP), Jaboticabal, Brazil, dealing with the use of mume clones (Prunus mume) as rootstocks for peach trees, which has produced promising results. In this research, two mume genotypes propagated by herbaceous cuttings were tested as rootstocks for peach cultivar Aurora-1. Three different tree spacing were used: 6 x 2 m, 6 x 3 m and 6 x 4 m. The experiment was carried out at Vista Alegre do Alto (21°10'14 S, 48°37'45 W, 700 m of altitude), São Paulo State, Brazil. Growing field conditions included Hapludalfs soil with medium sandy texture and using micro sprinkler irrigation. The region has an average chilling accumulation 17.9 hours per year. The evaluations were taken in 2005 and 2006 (2nd and 3rd year after planting, respectively). The trunk diameter was evaluated every three months, from the 24th to the 41st month after planting, totalizing seven evaluations. Plants on 'Rigitano' had higher trunk diameter on the 33rd, 39th and 41st month after planting (May/06, November/06 and February/07, respectively). No significant differences were observed in the other evaluations. The diameter at 5 cm above to the graft point was larger than below, but no incompatibility symptoms were observed between rootstocks and scion. Spacing tested did not influence trunk diameter, phenology and flower bud production in 'Aurora-1' scion. In conclusion, 'Rigitano' and 'Clone 15' are recommended for high density plantings of peach 'Aurora-1' in Brazil, and the 6 x 2 m spacing can be recommended, with productivity advantages for peach under low air relative humidity and mild winter conditions. © ISHS 2012.

Development of a support vector machine-based navigation system for driving a mobile robot through paths in plantations

The use of mobile robots turns out to be interesting in activities where the action of human specialist is difficult or dangerous. Mobile robots are often used for the exploration in areas of difficult access, such as rescue operations and space missions, to avoid human experts exposition to risky situations. Mobile robots are also used in agriculture for planting tasks as well as for keeping the application of pesticides within minimal amounts to mitigate environmental pollution. In this paper we present the development of a system to control the navigation of an autonomous mobile robot through tracks in plantations. Track images are used to control robot direction by preprocessing them to extract image features. Such features are then submitted to a support vector machine in order to find out the most appropriate route. The overall goal of the project to which this work is connected is to develop a real time robot control system to be embedded into a hardware platform. In this paper we report the software implementation of a support vector machine, which so far presented around 93% accuracy in predicting the appropriate route. © 2012 IEEE.

Recovery of degraded areas using topsoil in the Amazon rainforest

This study is aimed at evaluating the effect of placing the top soil cover areas, such as tailings degraded by tin mining, in the Amazon rainforest in Brazil. The evaluations of the planting sites occurred in areas where tin mining was carried out, basically planting native trees over a period of seven years. This work did not come from a pre-decreed methodology of experimental design, and data was collected only seven years after planting. Thus, it was not possible to identify all variables that contributed to a better recovery of the areas. Sampling was done about seven years after placing the top soil and is determined: pH, organic matter content, P, K, Ca, Mg, Al, cation exchange capacity (T), base saturation (V%), B, Fe, Zn, Cu and Mn. The native forest species existing at the site were evaluated in relation to height (in meters) and diameter of the base. For all sites where the surface layer of soil was applied, there were significant differences in the growth of native species. A fundamental aspect in the rehabilitation of areas degraded by mining, in general, is the knowledge about the soil where that recovery must be conducted. The specific procedures in the rehabilitation of those areas depend essentially on the physical, chemical, biological and mineralogical properties of the soil, which must present conditions for the adequate development of the plants. The initial idea of implanting a project of recovery of soils degraded by mining in the Amazon Forest emerged from a first visit to the field, carried out in 1998. The conditions of the already mined areas, in comparison to the exuberant forest of the surroundings caught our attention. The mining company that acts in the area had already been trying for some time to implant a plan of recovery of these mining areas, however without reaching any significant positive results. The loss of organic matter is one of the main problems of degraded areas in Brazil. The storage and reuse of a blanket of soil (topsoil) produce excellent results, but most of the miners consider this technique expensive and difficult because of operational costs and the sharp topographical condition of the mine site. Therefore, a research project was elaborated prioritizing the recovery of the soil degraded by the tin mining as a prior step to the recovery activities with native forest species. The formation of a superficial pseudo-horizon that supported the vegetation and the time that it would take for its establishment became the main objective of this research. The objective of this work is to verify the levels of elements and their traces in areas where top soils were applied for the remediation of degraded areas with local re-vegetation. © 2011 WIT Press.

Classification of crucifer cultivars based on the life-history of diamondback moth (Plutella xylostella)

We compared different cultivars and hybrids of crucifers in relation to development and life-history of diamondback moth (Plutella xylostella) to classify the plants according to their resistance to the pest. The plants used were Manteiga da Geórgia kale, Bola de Neve cauliflower, Ramoso Piracicaba Precoce broccoli, Chato-de-quintal cabbage, and the hybrid cabbages Midori, TPC668, TPC308, and TPC681. We evaluated performance daily until the pupal stage. Pupae were assessed individually to determine the pupal weight, performance, and pupal period. We determined the sex ratio, fecundity, fertility, and longevity of the emerged adults and calculated their reproductive potential. Cabbage hybrids TPC668, TPC308, and TPC681 do not support the development and reproduction of the diamondback moth. These hybrids show a level of resistance that is similar to that found the commercially available hybrid Midori and cultivar Chato de Quintal, which are known to be resistant to the diamondback moth. This finding implies that the capitata (cabbage) cultivars are the most suitable for planting because they are more resistant to pest than the cultivar's moth, acephala (kale). © 2013 Copyright Taylor and Francis Group, LLC.

Carbon dioxide emissions under different soil tillage systems in mechanically harvested sugarcane

Soil tillage and other methods of soil management may influence CO 2 emissions because they accelerate the mineralization of organic carbon in the soil. This study aimed to quantify the CO2 emissions under conventional tillage (CT), minimum tillage (MT) and reduced tillage (RT) during the renovation of sugarcane fields in southern Brazil. The experiment was performed on an Oxisol in the sugarcane-planting area with mechanical harvesting. An undisturbed or no-till (NT) plot was left as a control treatment. The CO2 emissions results indicated a significant interaction (p < 0.001) between tillage method and time after tillage. By quantifying the accumulated emissions over the 44 days after soil tillage, we observed that tillage-induced emissions were higher after the CT system than the RT and MT systems, reaching 350.09 g m-2 of CO2 in CT, and 51.7 and 5.5 g m-2 of CO2 in RT and MT respectively. The amount of C lost in the form of CO2 due to soil tillage practices was significant and comparable to the estimated value of potential annual C accumulation resulting from changes in the harvesting system in Brazil from burning of plant residues to the adoption of green cane harvesting. The CO 2 emissions in the CT system could respond to a loss of 80% of the potential soil C accumulated over one year as result of the adoption of mechanized sugarcane harvesting. Meanwhile, soil tillage during the renewal of the sugar plantation using RT and MT methods would result in low impact, with losses of 12% and 2% of the C that could potentially be accumulated during a one year period. © 2013 IOP Publishing Ltd.

Irrigation management in pruned coffee tree crop

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Adubação de cobertura na batata-doce com doses combinadas de nitrogênio e potássio

Balanced fertilizations with N and K often increase the performance of crops, however, when there is absence of one of these nutrients in poor soils, can reduce crop response to fertilization with the other. The objective of this work was to evaluate the productivity of sweet-potato, the amount of sweetpotato without quality, and leaf nutrients analysis, of sweet-potato crop fertilized with N and K. The trial was conducted in farming for commercial production, in Presidente Prudente, São Paulo State, during February-June 2007, in a dystrophic Ultisol of medium texture. The experimental design was a randomized complete block design, with four replications, on factorial 4 x 4: levels of 0, 30, 60 and 120 kg N ha-1 (urea source) combined with levels of 0, 30, 60 and 120 kg K2O ha-1 (KCl source), applied to 39 days after planting of the crop. The sweet-potato is responsive to topdressing application with nitrogen and potassium, however, the greatest increases in productivity occur when doses of N and K are combined. Fertilization with N and K not increase the amount of sweet-potato without quality marketing. The highest increase in productivity of sweet-potato is reached with topdressing combined with 100 kg N ha-1 plus 120 kg K2O ha-1.

Nitrogênio e idade de corte na qualidade da biomassa de capimelefante para fins agroenergéticos cultivado em Latossolo

Nowadays one of the major challenge for research is the production of alternative agrifuels energy material derived from plant biomass. Allied to this, the proper management of nitrogen, becomes fundamental for productivity gains and improvement in quality of elephant grass biomass. Thus, the objective was to evaluate the effect of nitrogen fertilization and plant age effect on the quality of elephant grass biomass for energy purposes. The experiment was performed with genotype Paraíso, grown in a dystrophic Oxisol in the southern state of Tocantins. The design was randomized blocks with subdivided plots, situating plots as nitrogen rates (0, 50, 100 and 150 kg ha-1) and the subplots cutting age (120, 150 and 180 days after planting ) four replicates. We evaluated the relationship carbon/nitrogen (C:N) and leaf/stem (L:S), levels of neutral detergent fiber (NDF) and ash contents in dry biomass produced. The application of nitrogen increased by 12% to C:N ratio of the plant. The advanced age of cut forage was increased 9% in the C:N plant, however, decreased by 12 and 14% levels of ash produced in the stem and leaves, respectively. The production of elephant grass for agrifuels is feasible with management system proposed, quality characteristics desirable, such as high C:N ratio, above 40% and higt fiber content, above 50%.

Eficiência de utilização de nutrientes por cultivares de batata

The use of cultivars efficient in nutrient use is essential to increase yield and reduce production costs. The objective of this study was to evaluate absorption and nutrients use efficiency on five potato cultivars. The experiment was conduced in Itaí, São Paulo State, Brazil, in winter cropping season of 2008 on Oxisol. The experimental design was randomized blocks with split-plots and four replications. Plots comprised the five potato cultivars and subplots were established by sampling times, performed at planting and every seven days after emergence. At 97 DAP was calculated the nutrients use efficiency for dry matter production and at 122 DAP were calculated the nutrients use efficiency for fresh tuber and tuber dry matter yield. Mondial and Asterix cultivars showed greater dry matter production, higher fresh tubers yield and nutrients accumulation. Nutrients use efficiency for total dry matter and tubers dry matter, was similar among cultivars, but Ágata was more efficient in nutrients use efficiency for fresh tubers yield.

Estratégias para produção de mudas de tomateiro utilizando paclobutrazol

The modern tomato production, either for fruit table production or for processing, has required quality seedlings, able to withstand environmental adversities after planting and maintaining the standard genotype productive. The aim of this study was to evaluate the effect of three concentrations of PBZ (0, 50 and 100 mg L-1) and two methods of application (seed treatment and watering seedlings) on seedling emergence and seedling production of tomato growth indeterminate. We adopted a completely randomized in a 2x3 factorial scheme with four replications. We evaluated the seedling emergence, the rate of speed of emergence, seedling height and diameter of hypocotyl and their absolute growth rate (TCA), leaf area, dry weight of shoots, roots and total, and reason leaf area (RAF). Results were subjected to analysis of variance and the mean levels of the factor methods of application compared by Tukey test at 5% and the mean levels of the factor concentrations subjected to regression analysis. The application of paclobutrazol via seedlings watering did not affect seedling emergence, significantly reduced the rate of seedling growth and, consequently, the size of the seedlings without affecting the diameter of hypocotyl, plus allow accumulation of dry roots. A concentration of 50 mg L-1 was shown to be sufficient to obtain seedlings more compact, subject to leaf area, the application via watering, beyond allowing an increase of about 37% in dry weight of roots.

Qualidade de mudas seminais de eucalipto em função dos substratos e fertilização de liberação controlada

For the production of quality seedlings, depending on the physical characteristics of each substrate, more rational nutritional managements, from the of economic-environmental point of view, should be sought. This study aimed to evaluate the development and quality of Eucalyptus grandis × E. urophylla seedlings in terms of substrates and doses of controlledrelease Osmocote® fertilizer. The experiment was conducted with a completely randomized, factorial design, using as substrates: vermiculite+carbonized rice chaff+coconut fiber (1:1:1); vermiculite+coconut fiber (1:1) and vermiculite+coconut fiber (2:1) and doses of 2, 4, 6 and 8kg·m -3 of substrate. The substrates with higher water holding capacity allow seedlings to reach their maximum development in most parameters using lower doses of controlled-release fertilizer. We recommend the application of the controlled-release fertilizer at a dose of 6.0kg·m-3 in vermiculite+carbonized rice chaff+coconut fiber (1:1:1) and vermiculite+coconut fiber (2:1) substrates, and in substrate vermiculite+coconut fiber (1:1) at a dose of 7.0kg·m-3. In each substrate there is a dose range that promotes a greater formation of suitable root systems for planting in the field, which consequently results in seedlings with greater morphological development at nursery.

Adubação com torta de filtro e micronutrientes no plantio da cana-de-açúcar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Acúmulo de nutrientes no colmo de cana-de-açúcar em função de fontes e doses de manganês

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Variação genética em progênies de jacaranda cuspidifolia mart. Utilizando o delineamento sistemático tipo leque

Knowledge of genetic variation in native tree species has helped direct strategies of genetic ex situ conservation, based on provenances and progenies tests. These tests use fixed spacing, not allowing evaluating the behavior of different progenies under this management variable. One way to evaluate simultaneously the genetic variation and different spacing in a small planting area is to use a systematic design. The aim of this study was to estimate the genetic variation and to evaluate its performance in Jacaranda cuspidifolia under different spacing. We used a progeny test in a systematic fan design, arranged in a system of 30 concentric rays, with one progeny per ray, randomly, at angles of 12°. The plants were arranged in rays in geometric progression of ratio 1.21, corresponding to nine for plant spacing: 1,95 m2; 2,86 m2; 4,18 m2; 6,12 m2; 8,96 m2; 13,12 m2; 19,21 m2; 28,13 m2; e 41,19 m 2 installed in Selvíria/MS. The traits height, height diameter of 30 cm to soil (DA3) and survival were evaluated at 12 and 24 months of age. Estimates of genetic parameters and spacing were evaluated using the procedure REML/BLUP (restricted maximum likelihood / best linear unbiased prediction). The progenies showed genetic variation, showing that the sample strategy to ex situ conservation was efficient. The species showed good adaptability inthe field and the best performance in treating five, equivalent to a 3 × 3 m spacing, with 8,96 m2;/plant for all traits. The fan systematic design permitted to evaluate in a small area the silvicultural behavior of J. Cuspidifolia plants in spacing varying from 2 to 42 m2/plant (5.000 to 238 trees/ha); which could hardly be evaluat by the traditional designs.