Ideotyping integrated aquaculture systems to balance soil nutrients.

Due to growing land scarcity and lack of nutrient inputs, African farmers switched from shifting cultivation to continuous cropping and extended crop area by bringing fragile lands such as river banks and hill slopes into production. This accelerated soil fertility decline caused by erosion, harvesting and insufficient nutrient replenishment. We explored the feasibility to reduce nutrient depletion by increasing nutrient utilization efficiencies, while diversifying and increasing food production through the development of integrated aquaculture – agriculture (IAA). Considering the climatic conditions prevailing in Kenyan highlands, aquaculture production scenarios were ideotyped per agro-ecological zone. These aquaculture production scenarios were integrated into existing NUTrient MONitoring (NUTMON) farm surveydata for the area. The nutrient balances and flows of the resulting IAA-systems were compared to present land use.The effects of IAA development on nutrient depletion and total food production were evaluated. With the development of IAA systems, nutrient depletion rates dropped by 23–35%, agricultural production increased by 2–26% and overall farm food production increased by 22–70%. The study demonstrates that from a bio-physical point of view, the development of IAA-systems in Africa is technically possible and could raise soil fertility and total farm production. Further studies that evaluate the economic feasibility and impacts on the livelihood of farming households are recommended

Immediate effects of microclimate modification enhance native shrub encroachment

Shrubs have become more dense and expanded beyond their range all over the world for a variety of reasons including increased temperatures, overgrazing, and alteration of historical fire regime. Native shrubs have been encroaching on Virginia barrier island grasslands for over half a century for unknown reasons. Species composition, soil nutrients, leaf area index (LAI), and ground and air temperature were recorded across the shrub to grass transition and at free-standing shrubs in a coastal grassland in order to determine the effect of shrub encroachment on plant community and microclimate. Species richness was significantly lower inside shrub thickets. Soil water content, organic matter, nitrogen (N), carbon (C), and LAI were higher in shrub thickets and free-standing shrubs compared to grasslands. Summer and fall maximum temperatures were lower and more moderate where shrubs were present. Fall and winter minimum temperatures were highest inside shrub thickets. Native shrubs impact microclimate and species composition immediately upon encroachment. These shrubs lower overall species composition, increase soil nutrients and moisture, moderate summer temperature, and increase winter temperature, which has consequences on a larger scale. As barrier islands are critical for protecting marsh and mainland habitats, understanding this mechanism for shrub expansion is important to predict future encroachment of shrubs and displacement of grassland habitat

Dairy farming in Uganda. Production Efficiency and Soil Nutrients under Different Farming Systems

Prior to the 1980s, milk production in Uganda occurred largely in two contrasting production systems. In the wetter parts of the country, especially in the southwest, there were a few large, mostly government-owned commercial dairy farms on which exotic and cross-bred dairy cattle were kept in paddocks and grazed on improved or natural pastures. In the drier eastern and northeastern parts of the country, pastoralists kept large numbers of local cattle breeds, notably the Small East African Zebu (SEAZ), under traditional extensive management systems. Although the pastoralists marketed some milk, most was consumed by the household. Cattle were also valued as an expression of cultural prestige and a means of accumulating capital and meeting planned and emergency expenses. Smallholders, who tended to keep a few low yielding indigenous cattle as well as growing crops, made little contribution to the nation’s marketed milk and were primarily subsistence-oriented

Soil & Nutrients

Soil and Nutrients In the session "Soil and Nutrients" at the Organic Innovayion Days 2021, arranged by TP Organics in Brussel as a webininar event, alternative soil nutrients as well as peat and plastic were presented and discussed by the experts Jakob Magid from Copenhagen University (H2020 project RELACS), Anne-Kristin Løes from Norwegian Centre for Organic Agriculture (NORSØK, H2020 project Organic-PLUS) and Francis Rayns from Coventry University (Organic-PLUS). The Nitrogen use efficiency is highly variable between countries and farms​ and in the case of many farms below 60 kg N/ha. To ensure nutrient supply and avoid soil nutrient depletion, recycling of societal waste streams needs to be further developed and researched. Anne-Kristin Løes stressed that the demand for nutrients and organic matter to be applied in organic agriculture will increase significantly due to the EU Farm to Fork target of 25% organic land target by 2030. On the use of plastic and biodegradable mulch films, Francis Rayns remarked that many types of alternative materials are available, but more knowledge about treatment technologies and applications is needed. Loose mulch films also require further investigation, especially for small and medium growers. Organic farming should lead the way in phasing out the use of peat

Spatial Variability of Soil Nutrients Content Related to Rice Yield

Spatial Variability of Soil Nutrients Content Related to Rice Yield (T Syam): Soil nutrients content and its spatial distribution are very important data for site specific fertilizer management to supply sufficient crop nutrition.  The study was carried out  at the farmer paddy field in Rejomulyo Village, Metro Town District of Lampung Province. The aim of this study was to evaluate the relationship between soil nutrients content (N, P, K) and rice yield. Soil samples were collected before fertilizers treatment by the grid sampling method and GPS was used as a tool for precisely determine sample site location.  Rice yield data were collected by small plot method on the each-of soil sample location. Spatial analysis using GS + software and statistical analysis using SPSS software. The result indicated that total nitrogen in the soil had a significantly correlation with the rice yield   (r = 0.95**) and their spatial distribution was relatively similar each others.  Spatial maps of soil nutrients content could be used for the variable rate fertilizers treatment, especially for nitrogen

Analysis of Soil Nutrients and Organic Matter in organic and conventional Marine Shrimp ponds at Guaraíra Lagoon, Rio Grande do Norte State, Brazil

This study compares the soil nutrients from an intensive and semi-intensive and an organic marine shrimp farm located in Guaraíra Lagoon, Rio Grande do Norte State, Brazil. The organic system showed significant lower levels of organic matter and phosphorus when compared to the two conventional systems. The results indicate that the conventional systems release large amount of nutrients into the environment and the organic system is a sink of nutrients from the Guaraira Lagoon ecosystem

Derivation of a dual porosity model for the uptake of nutrients by root hairs

Root hairs are thought to play an important role in mediating nutrient uptake by plants. We develop a mathematical model for the nutrient transport and uptake in the root hair zone of a single root in the soil. Nutrients are assumed to diffuse both in the soil fluid phase and within the soil particles. Nutrients can also be bound to the soil particle surfaces by reversible reactions. Using homogenization techniques we derive a macroscopic dual porosity model for nutrient diffusion and reaction in the soil which includes the effect of all root hair surfaces

Marker assisted breeding and mass selection of wheat composite cross populations

Utilising diverse populations instead of single line varieties is expected to lead to a number of advantages in cereal production. These include reduced epidemics of plant diseases, improved weed competition and better exploitation of soil nutrients, resulting in improved yield stability. However, a number of challenges must be met before diverse wheat populations can be introduced into commercial wheat production: one of these is the development of breeding technologies based on mass selection which enable breeders and farmers to improve specific traits in populations and maintain diversity at the same time

Divergent behaviour of soil nutrients imprinted by different land management practices in the Three Gorges Reservoir Area, China

Soil nutrients are essentially regulated by land management practices via modulating biotic element input and metabolism. The Three Gorges Reservoir Area in China was dominated by a farming landscape, but land management has become diversified over recent decades. How these restorative management practices may have affected soil nutrients is not completely understood. In this study, a space-time substitution approach was applied to evaluate soil nutrients and their stoichiometric changes in response to post-farming land management practices. Soil samples(0–10 cm, 10–20 cm, and 20–40 cm) were collected from present-day croplands, cypress plantations, eucalyptus plantations, abandoned croplands, and citrus plantations. Soil organic matter, soil organic carbon, total nitrogen, alkaline hydrolyzed nitrogen, total phosphorus, and available phosphorus were determined. The results showed that soil organic matter and total nitrogen in abandoned croplands, cypress plantations, eucalyptus plantations and citrus plantations were increased by 186% and 190%, 184% and 107%, 45% and 33%, and 45% and 54%, respectively, in comparison with present-day croplands. Soil nutrients except for total phosphorus decreased more with soil depth by exclusion of tillage mixing. The analysis of the comprehensive soil nutrient index showed that abandoned croplands (0.90) and cypress plantations(0.72) exhibited better nutrient recovery capacity. Soil C:P and N:P ratios increase in abandoned croplands, cypress plantations, and eucalyptus plantations. Phosphorus may become a limiting factor for plant growth with prolonged recovery in abandoned croplands, cypress plantations, and eucalyptus plantations, while soil organic matter and total nitrogen deficiencies are exacerbated in citrus plantations and present-day croplands. Therefore, cropland abandonment and reforestation (particularly cypress trees plantation) are recommended practices for restoring soil nutrients in the Three Gorges Reservoir Area