Nutrient stock in the forest component in a crop-livestock-forest integration system in Central Brazil

Integrated systems are sustainable alternatives, where agricultural, forestry, and/or livestock components occupy a given area through consortium, rotation, or succession. Considering this importance, this work had as objective to quantify the stock of above-ground biomass (wood, leaves, bark, and branches) of 6 years Eucalyptus urograndis in a crop-livestock-forest integration system (CLFS). It also involved calculation of the nutrient utilization in biomass conversion through the Biological Utilization Coefficient (BUC) and design of different export scenarios of these nutrients through the harvest in order to calculate the reduction in the demand for inputs. Nutrient stock was determined from the biomass sampled in the field and from the plant tissue analysis. It is verified that the highest concentrations of macronutrients are present in wood component, except for Ca. The concentration gradient of micronutrients was: Leaves> Fe> Mn> B> Cu> Zn; Branches and Bark: Fe> Mn > B> Zn> Cu; and wood: Mn > Fe > Zn > Cu > B. Considering BUC conversion rate decline, it presented the following order: S> P> Mg> Ca> N> K for macronutrients and B> Cu> Zn> Fe> Mn for micronutrients. The most appropriate export scenario was to harvest only timber component to minimize the nutritional export. The nutritional dynamics within the eucalyptus are altered according to the diametric structure of the trees. The nutritional elements are concentrated in different compartments according to the availability and need of the plants.

Land-use changes and slope positions impact on the degradation of soil functions in nutrient stock within the Kalikungkuk micro watershed, East Java, Indonesia

Degradation of soil functions in storing and cycling nutrients may be related to topography and land-use change. The research aimed to analyze the impact of land-use changes and slope positions on soil function in nutrient stock within Kalikungkuk micro watershed of East Java, Indonesia. Four different land-uses such as vegetable crops, agroforestry, shrub and forest were selected with three slope positions (e.g. ridge, slope, and valley), and three replications of each. Soil samples were collected at 0-10, 10-30, 30-50, and 50-100 cm depth of soil. Variables measured included soil properties (e.g. bulk density, soil texture, pH, CEC, soil nutrients). Slope positions impact on differences in soil physical (i.e. soil bulk density, soil texture) and chemical (i.e. total N, exchangeable K) properties. In addition, forest conversion to other land-uses (i.e. agroforestry, shrub, vegetable crops) decreased soil nutrient concentration (i.e. total C, total N, Ca, Mg, Na), and consequently resulted in degradation of soil nutrient stocks of especially C and N. The strong positive correlation between soil nutrient stock (e.g. C and N) and vegetation cover such as canopy cover, basal area, and litter (r = 0.63 – 0.78, r table 1% = 0.39) showed the benefit of biodiversity in maintaining soil function on the nutrient stock.

Nutrient Stocks and Distribution in Ghanaian Cocoa Ecosystems

There is a paucity of information on nutrient stocks and distribution in the cocoa ecosystem for the management of production sites to improve its productivity. Apart, sites with long histories of cocoa production could differ in nutrient stocks and distribution relative to recent production regions. Therefore, some existing cocoa farms in Ghana were sampled on the basis of shade management (shaded and unshaded) and production site longevity (Eastern region > Western North region) to determine the nutrient stock and distributions in them. Over 93% of the total ecosystems’ elementary nutrients were stored in the soil. Higher nutrient stocks occurred under shaded cocoa ecosystem. Nutrient element concentrations in cocoa tree biomasses followed the order: N > Ca > K > Mg > P > S > Al = Fe > Zn = Mn, and mostly concentrated in leaf > root = husk > branch > stem. On average, region as a main factor affected nutrient distributions. There was a sharp distinction between macronutrient and micronutrient accumulations in favour of Eastern region and Western North region, respectively. Therefore, the regional distinction with respect to macro- and micronutrients could be used as a guide to fertilizer recommendation for cocoa systems in the two regions.

Effect of Altitude on Nutrient Concentration, Nutrient Stock and Uptake in Fine Root of Sal (Shorea Robusta Gaertn.) Forest in Terai and Hill Areas of Eastern Nepal

The present study was conducted to understand the effect of altitude on the nutrient concentration, nutrient stock, and uptake in the fine root of the Terai Sal forest (TSF) and Hill Sal forest (HSF) in eastern Nepal. Annual mean fine root biomass in 0-30 cm soil depth was found higher in HSF (6.27 Mg ha-1) than TSF (5.05 Mg ha-1). Conversely, fine root production was higher in TSF (4.8 Mg ha-1 y-1) than HSF (4.12 Mg ha-1 y-1). Nitrogen, phosphorus, and potassium content in fine roots were slightly higher in TSF than HSF. Nutrient concentration in fine roots of smaller size (<2 mm diameter) was nearly 1.2 times greater than that of larger size (2–5 mm diameter) in both forests. In HSF total stock of different nutrients (kg ha-1) in fine root was 55.62 N, 4.99 P, and 20.15 K whereas, these values were 49.49 N, 4.14 P, and 19.27 K only in TSF. However, total nutrient uptake (kg ha-1y-1) by fine root (both size classes) was greater in TSF (48.5 N, 4.3 P, and 18.6 K) than HSF (36.9 N, 3.3 P, and 13.5 K). The variability in fine root nutrient dynamics between these two forests was explained by the differences in fine root biomass and production which were influenced by the combined effect of varied altitude and season. The fine root, as being a greater source of organic matter, the information on its nutrient dynamics is inevitable for the management of soil nutrients in the forest ecosystem.