Increase Base Saturation Research Articles

PENGARUH REVEGETASI TERHADAP SIFAT-SIFAT TANAH PADA LAHAN BEKAS TAMBANG TEMBAGA DI NUSA TENGGARA BARAT

Copper mining activities mainly using open-pit techniques, lead to environmental issues such as overburden waste in waste dump areas that have potential to generate acid mine drainage (AMD), which can decrease soil pH and increase heavy metal toxicity. Reclamation efforts, including revegetation using pioneer plants and cover crops are necessary to restore degraded land in waste dump areas. The aim of this research is to analyze soil physical and chemical properties improvement after revegetation on copper post-mining land as an evaluation and to provide recommendations for future reclamation. The research was carried out by analyzing and interpreting laboratory data from soil observations in revegetation areas for the 2016, 2018, 2019 and 2020 planting years, as well as natural forests belonging to PT. Amman Mineral Nusa Tenggara. Revegetation of copper post-mining land does not show a significant improvement in soil physical properties because improving physical properties takes quite a long time, especially in post-mining areas with heavy structural damage. Soil chemical properties analysis shows that revegetation can increase base saturation (BS), cation exchange capacity (CEC), exch-Ca, exch-Mg, and reduce soil Al saturation. In contrast, soil pH, organic-C, total-N, and soil available-P in the revegetation area did not increase as the revegetation age increased. The effect of revegetation appears to be more significant at the age of 2 to 3 years. However, based on the Tukey test, the age of revegetation mostly does not have a significant effect on enhancing soil chemical properties.

Reactivity of two acidity correctives in a medium texture soil

For crops to have good productivity, it is necessary to adopt agricultural practices that ensure an adequate supply of water and nutrients, and neutralize toxic elements in the soil, especially exchangeable aluminum, both in the arable layer and in the subsurface. One of these agricultural practices usually employed in both small and medium and large rural properties is the correction of soil acidity, which aims, in addition to neutralizing exchangeable aluminum, to provide calcium and magnesium for plants. Several materials have been used to correct soil acidity, with carbonates, oxides, hydroxides or silicates as neutralizing components. In the present work, the reactivity of two acidity correctives was evaluated in a soil of medium texture, with high aluminum saturation: 72.96%. The correctives used were a steel slag (calcium silicate), and a dolomitic limestone, applied in doses equivalent to one, one and a half, two, and two and a half times the analytically predicted amount, to raise the base saturation to 60%, using calcium acetate with H+ + Al3+ extractor. The study also included a control treatment, which did not receive acidity correction. The method used to evaluate the reactivity of the two correctives was soil incubation. The block design was used, with six repetitions per concealer dose. The experimental units were plastic bags with 3.0 kg of soil. After mixing the correctives with the soil, in the doses corresponding to each treatment, they were transferred to plastic bags and incubated at 70% of the maximum water retention capacity for ninety days. After the incubation period, the soil was analyzed for pH in CaCl2, pH in H2O, exchangeable aluminum (Al+3), and base saturation (V %). Steel slag and dolomitic limestone had the same efficiency to neutralize aluminum and increase base saturation. The pH in CaCl2 and pH in H2O were highly correlated, with the average pH in H2O being 0.50 units greater than the pH in CaCl2. The equation to relate pH in CaCl2 to pH in H2O was Y= 1.0273 x + 0.4716, with R2 = 0.9730. Complete neutralization of Al+3 occurred when the soil pH was raised to 5.03 (pH in CaCl2) or pH 5.50 (pH in H2O). The extraction of H+ + Al3+ with calcium acetate resulted in an underestimation of the cation exchange capacity at pH 7.0 (CTC T), and consequently of the corrective dose to be applied. On average, there was a need to double the amount of concealer predicted analytically to reach the desired base saturation. The equation to relate base saturation with corrective doses, in CaCO3 equivalents, was Y= 9.1476x + 3.8439, with R2 of 0.9449.

Soil Health: Indicators of Soil Management for Vegetable Cultivation under the Clove Plant

Low soil health indicates poor productivity soil optimal for supporting agricultural businesses because it will reduce the production of agricultural commodities for vegetable crop farmers in Ternate City which are carried out under plantation crops. This study aims to determine the level of soil health of vegetable farms under clove plantations. Field observation methods and laboratory analysis were carried out to observe the characteristics of the land (soil and plants) which became the research variables. The drill and soil profile approach is used in observing and taking soil samples. Research data were analyzed quantitatively and qualitatively by using a scale (scoring value) and then determined the level of soil health of agricultural land in the study location. Soil variables observed were physical properties (including soil morphology), chemical properties soil, and soil biological properties. The results showed that the level of soil health on vegetable farms under clove stands in Tobololo Village was in the medium (53-58%) and high (63-67%) classes. Soil health indicators which are variables that affect the decline in the value of soil health on vegetable farms under clove stands are C-organic, base saturation, total nitrogen, and available potassium. The provision of organic matter, nitrogen, and potassium fertilizers will increase base saturation as well as soil fertility and health.

Assessing characteristics and land suitability of an intercropping between soybeans and juvenile oil palm over peatlands in Riau, Indonesia

Soybean is one of essential food crops targeted for self-sufficiency. Indonesia’s largest oil palm plantation is located in Riau Province. Juvenile plants cover around 17.60 percent of the area. Soybeans can be intercropped with juvenile oil palm plantations. This study aims to determine the suitability of peatland in Muara Kelantan Village, Sungai Mandau District, Siak Regency. We collected data and information from primary observations, measurements, and from published articles recording secondary data including rainfall, annual temperature, and map of the research area. Soil type was classified as Typic Haplosaprist. Land suitability was determined by matching collected data with criteria for each class, resulting the class of marginal (S3), with base saturation and soil acidity (nr) as limiting factors. Lime and fertilization were required to increase base saturation and soil pH. After the improvement, the potential suitability becomes sufficiently suitable (S2) for intercropping between soybean and juvenile oil palm, with the air humidity (tc) and peat thickness (rc) as limiting factors.

Soil fertility, growth, nutrition and production of red pitaya subjected to liming

This study aimed to evaluate the effects of liming on soil fertility, growth, nutrition and production of red pitaya (Hylocereus monacanthus) plants cultivated in pot. The experiment was conducted in blocks, with five doses of limestone (0.0; 0.6; 1.2; 1.8; and 2.5 t ha − 1) and four replicates. Corrective doses were established to achieve base saturation of 20 to 70%. Liming increased soil pH (4.5 to 6.7), Ca concentration (5.36 to 20.11 mmolc dm − 3), Mg concentration (4.36 to 16.53 mmolc dm − 3) and base saturation (23.69 to 72.61%) and reduced potential acidity (37.39 to 15.41 mmolc dm − 3). Liming reduces nitrogen concentration and increased phosphorus, calcium and sulfur concentrations in the cladodes. There was an increase in phosphorus concentration and decrease in boron and iron concentrations in fruit peel according to the increase in limestone doses; in the pulp, there was an increase in boron concentration and decrease in iron and zinc concentrations, from the lowest to the highest dose of limestone. Based on the principal component analysis, the limestone dose of 1.8 t ha − 1 increased base saturation to 59%, providing favorable chemical conditions for the growth and productivity of red pitaya.

Effect of Nanoparticle Phosphate Rock and Phosphate Solubilizing Fungi on Soil P-Potential, P-Retention, Organic Carbon and Base Saturation on Cilembu’s Inceptisols

Intensive agricultural cultivation on Cilembu’s Inceptisols has become several soil properties problem for crop production. Nanoparticle phosphate rock and phosphate solubilizing fungi have ability to increase some soil properties content. The research aimed to observe the effect of nanoparticle phosphate rock and phosphate solubilizing fungi on soil P-potential, P-retention, C-organic and base saturation on Cilembu’s Inceptisols. The experiment arranged in Completely Randomized Design. The nanoparticle phosphate rock consisted of 4 levels. The phosphate solubilizing fungi consisted of 2 levels, and 2 replication. Soil P-Potential, P-Retention, C-organic, and Base Saturation were observed. The factors was observed after one month incubation on soil. Results showed that there were an interaction between nanoparticle phosphate rock and phosphate solubilizing fungi on the C-organic after one month incubation. Nanoparticle phosphate rock had affected on C-organic, P-potential and base saturation significantly, but had not affected on P-retention. Utilization of phosphate solubilizing fungi as soil ameliorant had affected significantly on P-potential and C-organic, but had not affected on P-retention and base saturation. Nanoparticle phosphate rock with a dose of 6% had the best effect on increase P-potential and base saturation

Short-term nickel residual effect in field-grown soybeans: nickel-enriched soil acidity amendments promote plant growth and safe soil nickel levels

ABSTRACT Nickel-enriched soil acidity amendments (SAA) may be advantageous for neutralizing acidity and providing safe/uniform distribution of Ni in soils. We evaluated the short-term effects of Ni application on field-grown soybean yield, growth, and soil chemical attributes using three sources of SAA, two enriched with Ni (Ni-rich mining by-product and Ni-salt) and a commercial SAA. The tested Ni-enriched sources were effective in providing Ni to the soil at safe levels, neutralizing acidity and increasing base saturation. A one-time Ni application resulted in optimal Ni levels in the first cropping season, enhancing grain yield by up to 658 kg ha−1 and improving nitrogen metabolism in soybean. A low residual effect of Ni was observed in the second year, with soil available Ni and plant Ni concentrations decreasing to sub-optimal levels and yield gains not being observed. In conclusion, the application of Ni-enriched SAA is a sustainable technology for agriculture, optimizing soil management practices. The SAA derived from by-products has benefits to the mining sector, meeting the ‘Ensure Sustainable Consumption and Production Patterns’ (SDG 12). Our findings suggest that this micronutrient may require a year-to-year adjustment via Ni-fertilization and the total Ni concentration in the soil should be monitored over the cropping seasons.

Minimizing the impact of climate change through the determination of land and plant technology needs based on the agroecological zone on food crops in Boyolali District of Central Java, Indonesia

The agroecological zone (AEZ) is a land potential information system for land use planning and commodity development. AEZ contains information on landforms, elevation, topography, soil characteristics, temperature, etc. which is useful for determining the suitability of land and commodities. This study aims to determine the technology requirement based on the limiting factors found in each land unit. The methods of determination of land suitability and technology requirement were carried out using the FAO standard land evaluation program, by matching land characteristics with plant growth needs. Through the application of recommendation technology that suitable for land capability, the cultivation system becomes more adaptive to the environment, so that the possible negative impact of climate change can be minimized. The limiting factors found as constraints to the development of food crops in the Boyolali District include (a) temperature conditions, (b) rooting conditions, (c) nutrient retentions, (d) erosion hazard, (e) land preparation, and (f) flooding hazard. Based on existing limiting factors, land management should be focused on (a) using adaptive varieties to local temperatures; (b) providing organic fertilizer to improve soil drainage, organic C and CEC soil; (c) lime and soil ameliorant application to increase base saturation, deep and reverse soil treatment to increase CEC; (d) conservation-oriented planting system and (e) eradication of rocks with minimum tillage.

Efficiency of a mine by-product as agricultural liming material and source of zinc

Most Brazilian soils have restrictions on agricultural use related to acidity and nutrient availability. This study aims to evaluate a zinc (Zn) and lead (Pb) mining by-product (Zincal™), regarding its capacity to correct soil acidity, and to serve as a source of Zn. For evaluation of its efficacy, a comparison with dolomite + Zn sulfate was conducted. The experiment was set up in two soils, a Quartzarenic Neosol and a Red Latosol, and conducted under controlled conditions in the laboratory. Treatments consisted in the application of two doses, aiming at 75 and 95% base saturation of both liming materials, as well as in a control treatment without acidity correction. The effect of said treatments on pH, base saturation, Al3+, H+Al, Ca2+, Mg2+, Zn, Mn and Pb contents were evaluated over 120 days. Similar responses were obtained from both liming materials, regarding their capacity to increase the pH of the soil, reduce Al3+ and potential acidity (H+Al), and increase base saturation. Differences observed in these attributes were dose-related. In regard to Ca and Mg, the content released in soil correlates with the content present in the liming materials. Zincal™ released more Mg and less Ca than dolomite, hence proving to be efficient in releasing Zinc.

Litter share and clay content determine soil restoration effects of rich litter tree species in forests on acidified sandy soils

Many West-European forests are located on degraded and acidified soils. Soil acidification has resulted in hampered ecosystem functioning and lower delivery of ecosystem services. Forest management, particularly the choice of tree species, can accelerate or counteract soil acidification by the quality of litter input. The positive impact of so called ‘rich litter’ on the soil nutrient status and belowground ecosystem functioning has already been evidenced in common gardens. Here, we evaluate the effect of the rich litter species black cherry (Prunus serotina Ehrh.) in mixed forest stands dominated by pedunculate oak (Quercus robur L.). We study the effects using a replicated set-up of 10 established forest stands (age 30 to 90) in Belgium, the Netherlands and Germany along an edaphic gradient in sandy soils on Pleistocene aeolian deposits. We hypothesize that black cherry has a positive effect on the soil nutrient status and aim to answer the following research questions: (i) does admixture of black cherry increase soil pH and base saturation? (ii) what proportion of rich litter admixture is needed in a poor litter matrix to observe significant improvement of the soil nutrient status? and (iii) does the magnitude of the rich litter effect interact with initial soil properties? The results of this study indicate that admixture of black cherry enhances the forest floor turnover and enriches topsoil chemical conditions significantly. Thickness of the litter layer decreases from a mean of 7 cm under oak to a mean of 4.5 cm under cherry and correspondingly base saturation increases to a maximum of 25%, NO3− concentration to 26 mg/mg and organic matter content to 8%. However, large shares of rich litter admixture (>30% basal area) are needed to improve topsoil conditions. Moreover, we find that rich litter effects are more pronounced on sandy soils with higher fine particle (loam + clay) content. This suggests that the actual impact of restoration efforts in acidified forest soils is a product of the trinity “litter quality – litter share – site quality”.

Agronomic performance and water‐use efficiency of F3 soybean populations grown under contrasting base saturation

AbstractMost of the Brazilian soils, especially in Cerrado biome, have high acidity and toxic aluminium, making the application of limestone an indispensable technique to obtain high yield in soybean crop. The hypothesis of this study was that contrasting base saturation provides changes in water‐use efficiency (WUE) and agronomic traits of soybean populations. Thus, we evaluated the WUE and agronomic performance of F3 soybean populations under different base saturation levels. Each experiment was conducted in a randomized complete blocks design with three replicates and 10 F3 populations (P1, P2, P3, P4, P5, P6, P7, P8, P9 and P10) for two crop seasons. Segregating populations were obtained by bulk method. In the first experiment, F3 populations were evaluated without correction of base saturation (V = 30%), while in the second experiment, limestone was applied three months before sowing to increase base saturation to 60%. The traits evaluated were as follows: calcium, magnesium and potassium contents, water‐use efficiency (WUE), plant height, first pod height, main stem diameter and grain yield. Our findings indicate that WUE and agronomic performance of F3 soybean populations depends on the saturation condition. We identified the P4 and P9 populations as the most promising for use in breeding programmes aiming at higher tolerance to abiotic stress caused by low base saturation in soil.

EFFECT OF LIIMING AND PHOSPHOR DOSES ON RADISH CROP IN SAND SOIL/EFEITO DA CALAGEM E DOSES DE FÓSFORO NA CULTURA DO RABANETE EM SOLO ARENOSO

Radish represents a great cultivation alternative for family farmers. The objective of this study was to study the nutritional relationships between phosphorus and limestone, including possible interactions between them. The experiment was carried out in a greenhouse of the Federal University of Goias, cultivating radish (Raphanus sativus L.), variety Crimson Gigante, in pots with 3 kg of sandy soil. A completely randomized design in a 2x5 factorial scheme was used, with two doses of limestone, equivalent to 0 and 3.5 t ha-1, dose necessary to increase base saturation to 80% and five phosphorus doses (P). : 0, 50, 100, 200 and 400 mg kg-1, with three repetitions per treatment. Dry mass was evaluated in relation to phosphorus doses and the nutritional relationship between soil and leaf. There is a nutritional relationship between phosphorus and limestone. The use of liming and phosphate fertilization is recommended for radish production, with a dose of 200 mg phosphorus per kilogram of sandy soil.

Effects of lime and steel slag application on soil fertility and soybean yield under a no till-system

Steel slags can be used in agriculture, as they are composed of CaO, MgO, SiO2, and compounds such as P2O5, FeO, and MnO. The solubility of slag may be higher than that of lime, which can make this residue an excellent source for soil acidity correction in no-till systems. However, there are few studies reporting their benefits when applied to the soil surface. This study evaluated slag amendment effects on soil chemical attributes and on the yield and nutrient uptake of soybean following surface application and/or incorporation of different types of slag, in comparison to lime, on a tropical, acidic soil under a no-till system. The trial was performed in Botucatu, SP, Brazil. Six soil-acidity corrective materials were incorporated or surface-applied, including steel slag, ladle slag, stainless-steel slag, wollastonite, dolomitic lime, and calcined dolomitic lime, plus a negative control. Each material dose was calculated to raise the base saturation to 70%. Slags can be applied in a no-tillage system with efficiency similar to that of lime for the neutralization of soil acidity, for adequate nutrition and yield of the soybean crop. Slags and limes showed similar effects on increased pH, decreased Al3+concentration, and increased base saturation up to the 0.40 and 0.20-m soil layers at 12 and 23 months, respectively, after the application of treatments, regardless of surface or incorporated application. The by-product application has an additional advantage, depending on the type of slag, that is the provision of phosphorus and/or silicon.

Reactive Natural Phosphate in Safflower Fertilization in Cerrado Oxisol

Fertilizer management has a direct influence on crop productivity, especially phosphorus, which is most limiting to the development of crops in tropical soils due to the genesis of these soils. In this sense, it is necessary to use nutrient sources that are agronomically efficient at reduced costs compared to conventional sources. Thus, the objective of the present study was to evaluate the effects of reactive natural phosphate as a source of phosphorus on the development, growth, and yield of safflower in Cerrado Oxisol. The experiment was carried out in a greenhouse at the Federal University of Mato Grosso, Campus of Rondonópolis. The completely randomized design consisted of the following treatments: 0, 100, 200, 400 and 600 mg dm-3 of reactive natural phosphate (Bayóvar reactive phosphate), with 6 replicates, consisting by pots with 2 dm3 of capacity. To the Oxisol used to fill the plots was incorporated dolomitic limestone to increase base saturation to60%. Safflower cultivar used was IMA 0213 with a final population of three plants per plot. Plant height, number of leaves and chlorophyll index were evaluated at 15, 30, 45 and 55 days after emergence. In the last evaluation plants were cut and the number and diameter of the chapters, shoot and chapters dry mass, volume and root dry mass were also evaluated. The results were submitted to analysis of variance and regression up to 10% probability. In general, safflower crop shows a positive response to application of reactive natural phosphate. Doses between 389 and 600 mg dm-3 promoted best results for development and safflower production in an Oxisol.

APLIKASI KOMPOS TANDAN KOSONG KELAPA SAWIT DAN PUPUK NPKMg TERHADAP SIFAT KIMIA TANAH ULTISOL DAN KADAR HARA DAUN KELAPA SAWIT (Elaeis guineensis Jacq)

Low productivity of oil palm in Ultisol need to resolve by utilizing appropriate input and efficient soil management. Utilization of organic waste materials such as oil palm empty bunches (OPEB) is one of way for that. This research was conducted in Kuantan Singingi, Riau from September 2017 to February 2018. The aim of this research is to having dose of OPEB compost and NPKMg fertilizer that can optimize the value of soil chemical characters and nutrient content in leaves. The study determined the effect of composite oil palm empty bunches with cow manure (2:1(w/w)) and NPKMg (13:6:27:4) fertilizer. The study used a completely randomized design consisting of 6 levels :{(2,25 kg NPKMg), (10 kg OPEB compost + 1,75 kg NPKMg), (20 kg OPEBcompost + 1,5 kg NPKMg), (30 kg OPEBcompost+ 1,25 kg NPKMg), (40 kg OPEBcompost + 1,00 kg NPKMg), (50 kg OPEB compost) per tree}, each treatment was repeated 3 times. Parameters measured include soil chemical characters and nutrient content in leaves. The results of study showed, aplication 50 kg per tree TKKS compost was able to increase soil pH. Aplications (2.25 kg NPKMg, 50 kg TKKS compost, 20 kg compost TKKS + 1.50 kg NPKMg and 30 kg compost TKKS + 1.25 kg NPKMg) per tree can increase base saturation. Each treatment application for fertilization has been tested, given the same effect in all soil chemical characters tested beside pH and KB, and same effect in all leaf nutrient contents tested beside Zn.Key words : Palm Oil, Compost, OilPalmEmptyBunches, NPKMg

Calcium and Magnesium Ratio in Alfalfa Cultivation

The Alfalfa is an important forage for animal feeding, used in breeding of specialized herds due to its high protein content, besides having high palatability and energy value. In this context, the objective of this study was to evaluate the effect of calcium and magnesium ratio in the correction of Oxisol for the cultivation of alfalfa (Medicago sativa L.) cv. Creole. The experiment was conducted in the greenhouse at Federal University of Mato Grosso, Campus Rondonopolis-MT. The experimental design was completely randomized with nine treatments relating about calcium/magnesium nutrients: 0/0; 1/0; 0/1; 3/1; 6/1; 9/1; 12/1; 15/1 and 18/1, with 5 repetitions. The evaluated variables were plant height, number of leaves, number of basal shoots, SPAD index, stem diameter, fresh and shoot dry mass, root dry mass and root volume, soil pHCaCl2 and water use efficiency. The results were submitted to analysis of variance and Scott-knott test (p ? 0.05). Both the first and second cut, plant height was lower (24.76 ± 2.57 and 32.82 ± 13.01 cm, respectively) in absence of fertilizers (0/0) in relation to the other ratios. However, the treatments with Ca and/or Mg did not vary significantly, with a mean of 38.07 ± 2.94 and 51.73 ± 7.43 cm, in the first and second cut, respectively. The shoot dry mass showed similar behavior. Lower mass was observed in absence of Ca/Mg in the first cut (1.12 g DM pot-1) and second cut (1.84 g DM pot-1). In the other relations, it was observed a mean of 2.90 and 4.79 g DM pot-1 between the cuts. Likewise, the production of root was lower in absence of fertilizers (1.66 ± 1.05 g DM pot-1) and the others Ca/Mg ratios did not differ from each other (6.14 ± 1.98 g DM pot-1). The SPAD index there was significant effect only in the first cut between the ratio 0/0 and the others, with a mean of 43.48 ± 2.83 and 48.85 ± 2.19, respectively. In the second cut, SPAD index was 38.47 ± 5.82. Soil pH ranged from 5.87 to 5.31 between the cuts. Alfalfa was low sensitive to calcium and magnesium ratios in soil correction, but responded positively to the plant development with increased base saturation.

Forage production in a natural grassland with limestone and phosphorus dosages

The objective of this study was to assess forage production in a natural grassland by applying different doses of limestone and phosphorus, and the influence of these applications on soil profile. The treatments consisted of the application of limestone doses of 0.0, 7.2, and 14.4 t ha-1 and phosphorus doses of 0,35, 70, and 140 kg of P2O5 ha-1 on the soil surface. The experiment was conducted in a randomized complete block design with split-plots and three replications. The limestone doses were distributed in the main plot and applied only at the beginning of the experiment, whereas the phosphorus doses were distributed in the subplots with subsequent annual maintenance applications. Was used a ruler (cm) for monitoring the growth of pastures and, when grasses reached an average height of 20 cm, forage samples were collected in each subplot and botanical and morphological components were separated and dried until a constant weight was achieved. In the third and fourth assessment years, soil samples were collected in the 0-5, 5-10, 10-15, and 15-20-cm layers to evaluate the influence of treatments on the chemical properties of the soil. The variables analyzed were related to the production of several components, including fodder, native grasses, leguminous plants, unwanted plants, and dead material, in addition to soil properties such as pH, exchangeable aluminum concentration, and base saturation. There was no interaction between the limestone and phosphorus treatments. The effect of limestone doses on forage production was assessed in the third year, and, in the following year, the intermediate dose of limestone (7.2 t ha-1) produced the highest yield (2,316.1 kg of dry matter [DM] of forage ha-1). The increase in phosphorus doses increased forage production in the second year, and reached yields of up to 2,232 Kg DM ha-1 in the fourth year. In summary, the production of natural pastures was enhanced by the application of 25% of the recommended dose of limestone (7.2 t ha-1), and by the application of 50% of the recommended dose of phosphorus (70 kg P2O5 ha-1). The increase in limestone doses directly affected the chemical properties of the soil by decreasing acidity and exchangeable aluminum, and increasing base saturation, even in deeper layers (0-20 cm). The increase in phosphorus doses did not increase the mobility of this nutrient in the deeper layers of the soil (10-20 cm), and the effects were restricted to a depth of up to 10 cm.

Land use effects on subtropical, sandy soil under sandyzation/desertification processes

Very fragile sandy soils have high erosion susceptibility, low water retention, and low nutrient and carbon storage. In southern Brazil, substitution of native grassland by grain production in conventional tillage has caused severe degradation, even reaching an extreme state of “sandyzation” or non-vegetated sand. We measured indicators to assess soil quality in a Quartzipsamment (“Neossolo Quartzarênico”) under different uses and also in extreme state of “sandyzation” or non-vegetated sand, where annual average rainfall is 1511mm with regular distribution throughout the year. Four land uses/conditions were evaluated: (i) native grassland (NG) (4% clay); (ii) nine years-old eucalyptus forest (EF) (4% clay); (iii) corn production in conventional tillage (CT) (3% clay); and (iv) extreme state of “sandyzation” or non-vegetated sand (NVS) (2% clay). Measured soil chemical properties were soil organic carbon (SOC) in 0–2.5, 2.5–5, 5–7.5, 7.5–10 and 10–20cm soil layers, Ca, Mg, K, Al saturation, and effective cation exchange capacity (CEC) in 0–2.5cm layer. Measured soil physical properties were soil bulk density (BD), total porosity (TP), macroporosity (Macro), microporosity (Micro), water retention, and saturated hydraulic conductivity (Ks) in 0–3, 5–8, and 10–13cm soil layers, whereas aggregate stability in water was measured in 0–5cm soil layer. Soil chemical and physical properties indicate an extreme state of degradation of NVS, which had significantly lowest SOC and thus low CEC, associated to leaching of exchangeable bases and high aluminum saturation. CT also provided a significant decrease in SOC in all soil layers, and other in chemical properties in the 0–2.5cm layer, whilst EF was the most efficient system to build up SOC compared to NG in surface layers (0–2.5 and 2.5–5cm) and presented better chemical conditions. In general, soil physical quality was degraded in NVS and improved in EF, whilst there were no significant differences in CT compared to NG for most soil physical properties. Soil physical properties were closely related to surface SOC of the different land uses. NVS provided a significant decrease in Micro, whilst EF provided a significant increase in TP and Macro in 0–3 and 5–8cm soil layers. High TP and Macro, low Micro, and very high Ks were observed in NVS. The CT provided significant decrease in water aggregate stability compared to NG and the water aggregate stability rank was EF>NG>CT, whereas NVS soil was completely devoid of aggregation. NVS restricts plant growth, root development, plant nutrient uptake and soil cover, thus creating an environment prone to wind erosion and soil degradation. Management practices that include permanent soil cover, restore SOC, improve soil aggregation and create pores for water retention and availability, increase base saturation and promote nutrient cycling are necessary to preserve these fragile lands.

Determinación de atributos en genotipos de algodón (Gossypium hirsutum L.) en la rotación maíz-soya asociados a suelos ácidos mejorados de la altillanura colombiana

En Colombia, en los últimos 15 años, se ha desarrollado un proceso de investigación para la ampliación de la frontera agrícola focalizado en la altillanura plana, con énfasis en la construcción de capa arable asociado a la saturación de bases, mediante el encalamiento, la labranza vertical y la rotación arroz, maíz y soya, con la posibilidad de otras especies como el algodón que podrían ingresar al modelo. Para ello, se realizó una investigación pionera en Colombia para determinar la adaptación del algodón en las condiciones de las sabanas ácidas mejoradas de la altillanura. Se desarrolló una prueba de evaluación agronómica con cinco genotipos élites de algodón en un diseño de bloques completos al azar en cuatro localidades en suelos con una saturación de bases superior al 80 %. Los resultados permitieron identificar un genotipo (LC-156), que presentó una adaptación a la altillanura, asociado a un rendimiento promedio de 2,2 t/ha de algodón semilla, 1,5 t/ha de algodón tipo fibra media a larga y un porcentaje de extracción de fibra superior al 36,0 %. La ventaja comparativa de esta región para una producción sostenible de algodón está dado por el rendimiento de algodón fibra superior al promedio nacional, reducción del 33,2 % en los costos de producción, calidad de fibra media larga con destino para la exportación y la ausencia del insecto plaga de mayor importancia económica en Colombia, el picudo (Anthonomus grandis Boheman).

Linnebjer—A South Swedish Oak Forest and Meadow Area—Revisited after Half a Century

An oak forest and three wet meadows/fens were reinvestigated after 50 years concerning tree vitality, biomass and productivity, and soil chemistry. Sulphur and nitrogen deposition has changed dramatically during these years, and the aim was to analyse the differences in both the oak forest and the open field ecosystems. Trees were re-measured and soil profiles were resampled. Important visible changes in the oak forest were stated concerning the vitality of oaks. Aboveground there was a decrease in tree biomass, production and litter fall, but a huge increase in standing dead logs. During the years, the deposition of sulphur had decreased drastically, but nitrogen deposition was still high. Soil acidification in the forest had decreased, reflected in an increased base saturation in the forest, in spite of slightly lowered pH-values. Strongly increased amounts of exchangeable Ca and Mg now appeared in the forest soil, and a substantial transport of calcium and magnesium had obviously taken place from the forest soil to the meadow and fens during the years. However, the most important soil change was the accumulation of organic matter. The increased accumulation of organic matter in turn meant increased amounts of colloid particles and microsites for ion exchange in the soil. This favoured 2-valence base cations, and especially Ca and Mg that increased very much in all the studied ecosystems. Carbon as well as nitrogen had strongly increased in the forest, meadow and fen soils. This was interpreted as a natural result of increased vegetation growth due to high nitrogen deposition, increased global annual temperature and increased carbon dioxide concentration in air. It was concluded that the decreased deposition of sulphur had had a positive effect on soil chemistry, and that the deposition of nitrogen probably had stimulated vegetation growth in general, and contributed to increased amount of organic matter in the soils. However, in this studied oak forest, the decreased vitality and many killed trees were also suspected to be a result of high nitrogen deposition. Obviously increased tree growth was counteracted by decreased stress resistance, and increased appearance of pathogens in the oak trees.