RESPONS BIBIT KAKAO (Theobroma cacao L.) ASAL SOMATIC EMBRYOGENESIS TERHADAP KOMPOSISI MEDIA TANAM YANG BERBEDA

One of the critical success cocoa cultivation is the use of quality plant materials. Cocoa plant material obtained through propagation techniques Somatic Embryogenesis (SE) is the latest method that can produce planlet that are the same with source, have a taproot and a branched structure similar with plant from seeds. Another advantage of this SE technique can be mass-produced seedlings, pest-disease free, growth is more uniform, more vigor, high yield and drought resistant. The objective of the experiment is to know the growth media composition which give the best effect on growth cacao seedling (Theobroma cacao L.) from Somatic Embryogenesis (SE). The experiment was conducted at The Agricultural Experiment Station of Agriculture Faculty, Padjadjaran University, Jatinangor, altitude ±700 m above sea level with soil type is Inceptisols. The experiment was conducted from June until October 2013, used Randomized Block Design (RBD), consisted of nine treatments combinations and replicated three times. The treatments were topsoil : casting (2 : 1) + urea 0,5 g application-1, topsoil : cattle dung (2 : 1) + urea 0,5 g application-1, topsoil : cacao pods compost (2 : 1) + urea 0,5 g application-1, topsoil : casting (2 : 1) + urea 0,75 g application-1, topsoil : cattle dung (2 : 1) + urea 0,75 g application-1, topsoil : cacao pods compost (2 : 1) + urea 0,75 g application-1, topsoil : casting (2 : 1) + urea 1 g application-1, topsoil : cattle dung (2 : 1) + urea 1 g application-1, topsoil : cacao pods compost (2 : 1) + urea 1 g application-1. The result of the experiment showed that the growth media composition consist of topsoil : casting (2 : 1) + urea 0,75 g application- 1 give better effect on vegetative growth of cacao seedling from SE compared to other treatment combinations, increased stem diameter, leaves number, shoot dry weight and total plant dry weight at 16 MST is 17,54g

Simulated soil erosion and crop productivity

Non-Peer ReviewedSeveral different soil types were employed to study the effects of simulated soil erosion on wheat and canola productivity. Varying amounts of topsoil were scraped from the surface of experimental fields and crops were grown using three levels of fertilizer applications. Topsoil removal treatments included 0 cm removed, (a basis for comparison) , 5, 10, and 20 cm of topsoil removed. Fertilizer application treatments consisted of no fertilizer applied, recommended rate of fertilizer applied and approximately double the recommended rate. Crops utilized for this study were Columbus wheat and Westar canola. It was found that yields generally decreased as the amount of topsoil removed increased. Data indicated yields to be severely depressed on all topsoil removal treatments where no fertilizer was applied. Soil texture played a role in determining the outcome of yields in that on the coarse textured soils, even twice the recommended rate of fertilizer was not able to bring the yields back to that of the control. The recommended rate of fertilizer application was able, on the other hand, to mitigate topsoil losses on the fine textured soils and in some cases yields exceeded the control at twice the recommended rate of fertilizer

Jurusan Budidaya Tanaman Perkebunan Politeknik Negeri Lampung

The efforts to achieve optimal results in the development of oil palm cultivation one of which is the use of the planting medium. Palm oil seedlings require planting medium that has the chemical and physical properties are good. Media palm nurseries generally consist of topsoil are mixed with sand and organic matter which is expected to obtain a good medium fertility premises. Top soil needs more difficult, so we need to look for alternative media to growing media prenursery palm oil. This study used randomized complete design and experiment arranged in seven media with four replications. The applications method of media: 100 % topsoil (A), topsoil and salvinia compost (1:1) (B), topsoil and coir palm oil (1:1) (C), topsoil and salvinia compost (1:2) (D) , topsoil and coir palm oil (1:2) (E), coir palm oil and salvinia compost (1:2) (F) , topsoil , salvinia compost, and coir palm oil (1:1:1) (G). All data were analyzed for variance. Data analysis followed by separation of means using LSD test with significance level of 5%. The resulted showed that both time and applications method of topsoil have affect on growth component. The best application method was topsoil, salvinia compost, and coir palm oil increased dry weight and root dry weight

Evaluation of the NDICEA model

Within the N-Toolbox project the NDICEA nitrogen model, one of the key tools in the virtual Toolbox, has been improved and tested in England, Denmark and Spain. The model performance was evaluated on datasets from these three countries by means of visual observation, RMSE and RSR from the soil nitrogen dynamics. In England the scenarios with organic fertilizer performed better than those with artificial fertilizer, leading to the suggestion that the calculated nitrogen release out of fertilizer could be improved. Timing of the soil sampling on soil inorganic nitrogen is important to realize a good model evaluation; two samples only, before sowing and after harvest, is not enough. When soil mineral nitrogen samples were taken during crop growth, model calculation and measured values showed sometimes big differences. It is suggested to improve the plant nitrogen uptake sub-model. In the Danish dataset the soil mineral N of the topsoil was well described, but that of the subsoil was not. This might be caused by the depth of the subsoil, which was up to 2.5 meters. The model performance could be improved by introducing a multi-layer soil sub-model instead of the actual two-layer soil sub-model. Spain, with its different climatic and soil conditions, needed an adaptation of the evapotranspiration calculation and a calibration of the scenarios to reach an acceptable model performance. If more Spanish datasets were studied, the NDICEA model could be enriched with standard Spanish soils and evapotranspiration data. For the improvement of the model, equations from the EU-ROTATE_N model are used to describe root growth and nitrogen uptake in more detail

Thirty years of growing cereal without P and K fertilization

Over thirty years a significant depletion of P and K in soil occured when the were not given in fertilizers. This caused a reduction in crop yield. An abundant P application exceeding the crop uptake very clearly prevented the yield reduction but did not raise the extractable P concentration in the soil. Severe K deficiency did not start to appear until 20 years of growing cereal without fertilizer K. K application compensating for the uptake by the crop did not prevent the decrease of its extractable concentration in this soil, but this decrease did not affect crop yield

Long-term fate of sewage-sludge derived cadmium in arable soils

The focus of this work was to improve knowledge of the long-term fate of cadmium supplied to arable soils by sewage sludge. Emphasis was placed on measured and modelled changes in the solubility and mobility of cadmium, resulting from long-term turnover of both sludge-derived and inherent organic matter of the soil. Measurements were conducted in a long-term sludge supplied field experiment, situated at Ultuna (60°N, 17°E), started in 1956. Furthermore, batch studies on soil samples and modelling exercises in WHAM were performed in order to study the speciation of cadmium in the soil-solution system. A comprehensive model -the SLAM model- was developed to increase the understanding of the influence of soil and sludge adsorption characteristics on cadmium solubility and bioavailability, and the migration rate of cadmium in soil profiles. The long-term sludge supplies had increased the solubility of cadmium, measured in crop cadmium concentration, as an effect of enhanced acidification and increased Cd concentration in the soil. A low Cd migration was measured, attributed to non-equilibrium Cd concentration in percolating water, a high cadmium sorption capacity in the subsoil and root driven Cd circulation in the soil profile. No increased Cd sorption capacity was measured in the sludge supplied soil, despite the almost doubled soil organic matter content. This might be partly attributed to the higher iron oxide and hydroxide concentration measured in the sludge, forming more stable complexes with soil humic compounds compared to cadmium complexes with soil humic compounds. A Monte-Carlo analysis of the SLAM model suggested that the major parameters affecting leaching and crop uptake of cadmium were the cadmium loading and the partitioning coefficient for sludge-derived inorganic material and parameters controlling the effect of pH on sorption. Long-term scenario simulations in SLAM identified critical factors influencing plant cadmium uptake: the cadmium concentration in the sludge, the adsorption capacity of the sludge in relation to the adsorption capacity of native soil and the proportion of the sludge adsorption capacity contributed by the inorganic fraction

P-equilibrium fertilization in an intensive dairy farming system: effects on soil-P status, crop yield and P leaching

In the coming decade, European dairy farms are obliged to realize a balance between phosphor (P) inputs to their farmland (in inorganic fertilizers and manure) and outputs (in crop products), the so-called P-equilibrium fertilization. The objective of the present study is to analyze the long-term effects of P-equilibrium fertilization on soil-P status (total soil-P and available soil-P), crop yield and P leaching on dry sandy soil, using data from experimental dairy farm ‘De Marke’, where P-equilibrium fertilization has been applied since 1989. For grassland, P availability is expressed in P-Al and for arable land in Pw. Total and available P status were monitored in the upper topsoil (layer 0–0.2 m). Total soil-P was also monitored in the lower topsoil (layer 0.2–0.4 m) and in the subsoil (0.4–0.6 m). From 1989 to 2006, Pw and P-Al (means of all farmland) decreased by 26 and 25%, respectively. In the same period, mean total-P content of the farmland decreased by 16%. There was a large variation in initial P status (1989) of the various plots. The rate of decline in all soil-P indicators was positively correlated to their initial values. In plots with the lowest initial values, P status did not change, while in plots with high initial values it tended to stabilize at lower levels. At equilibrium-P fertilization, Pw is estimated to stabilize at 20. This is lower than the recommended P status of Dutch soils used for maize cropping. P-Al is estimated to stabilize at 30–40, which corresponds to the current recommendations for grassland. The data show that at P-equilibrium fertilization, soil available-P status is higher in a maize-ley rotation than in permanent grassland. The decline in total P and available P did not affect crop yield, nor did it affect the P concentration in groundwater, but at ‘De Marke’, P emission to groundwater is generally low. The results obtained suggest that P-equilibrium fertilization can be compatible with efficient crop productio

Sources of nitrogen for winter wheat in organic cropping systems

In organic cropping systems, legumes, cover crops, residue incorporation, and manure application are used to maintain soil fertility, but the contributions of these management practices to soil nitrogen (N) supply remain obscure. We examined potential sources of N for winter wheat (Triticum aestivum L.) in four experimental cropping systems established in 1997 on three soil types. Three of the four systems were under organic management. Topsoil N, depth of the A horizon, and cumulated inputs of N since 1997 were determined at plot level. Labile soil N pools (mineral N, potentially mineralizable N [PMN], microbial biomass N [MBN]) were monitored during two growth periods; at one site, biomass C/N ratios were also determined. Soil for labile N analysis was shielded from N inputs during spring application to isolate cumulated system effects. PMN and MBN were correlated across all sites and rotations (r2=0.72). The MBN corresponded to 46-85, 85-145 and 74-172 kg N ha-1 at the three sites and differed significantly between cropping systems, but MBN could not explain differences in wheat grain N yields. Instead, a multiple linear regression model explained 76 and 82% of the variation in grain N yields in organic cropping systems in 2007 and 2008, showing significant effects of, respectively, topsoil N, depth of A horizon, cumulated inputs of N, and N applied to winter wheat in manure. Thus, soil properties, and past and current management all contributed to winter wheat N supply

A pilot study to assess soil spectroscopic methods for mapping key topsoil properties in the Blackwater sub-catchments (Wensum DTC)

This report describes findings from sampling and analyses of soils across the Blackwater drain catchments, part of the Wensum demonstration test catchment (DTC) project funded by Defra. Recent studies have shown how spectroscopic techniques can be used to estimate soil properties and airborne spectroscopy could be an effective means to aid continuous mapping of soil properties across the landscape. Before an airborne survey is undertaken it is important to assess whether the relationships between infra red (IR) spectra and soil properties are sufficiently strong for the cost of the airborne survey to be justified. A secondary objective was to determine the concentrations of soil organic carbon (SOC) in soils across the cultivated parts of the catchment to determine whether there is any evidence that low SOC concentrations might indicate that the topsoil may exhibit poor structural stability contributing to enhanced sediment in stream and drainage channels