Good Soil Fertility Research Articles

Can Nitrogen Fertilizer Management Improve Grain Iron Concentration of Agro-Biofortified Crops in Zimbabwe?

Improving iron (Fe) concentration in staple grain crops could help reduce Fe-deficiency anaemia in communities dependent on plant-based diets. Co-application of nitrogen (N) and zinc (Zn) fertilizers has been reported to improve both yield and grain Zn concentration of crops in smallholder farming systems. This study was conducted to determine if similar effects are observed for grain Fe concentration. Field experiments were conducted in two years, in two contrasting agro-ecologies in Zimbabwe, on maize (Zea mays L.), cowpea (Vigna unguiculata [L.] Walp) and two finger millet (Eleusine coracana (L.) Gaertn.) “seed pools”. The two finger millet “seed pools” were collected during previous farmer surveys to represent “high” and “low” Fe concentrations. All plots received foliar Fe-ethylene diamine tetra-acetic acid (EDTA) fertilizer and one of seven N treatments, representing mineral or organic N sources, and combinations thereof. Higher grain yields were observed in larger N treatments. Grain Fe concentration increased according to species: maize < finger millet < cowpea but varied widely according to treatment. Significant effects of N-form on grain Fe concentration were observed in the low finger millet “seed pool”, for which mineral N fertilizer application increased grain Fe concentration to a greater extent than other N forms, but not for the other species. Whilst good soil fertility management is essential for yield and grain quality, effects on grain Fe concentration are less consistent than reported previously for Zn.

Effects of cow dung and wood biochars and green manure on soil fertility and tiger nut (Cyperus esculentus L.) performance on a savanna Alfisol

Two field experiments were conducted concurrently in 2019. The study investigated the effects of single and combined application of wood biochar (WB) and cow dung biochar (CDB) with green manure (GM) on soil properties, performance, and tuber qualities of tiger nut. The treatments consisted of: CDB at 10 t ha−1, WB at 10 t ha−1, GM—Tithonia diversifolia at 10 t ha−1, CDB + GM, WB + GM, control. The six treatments were arranged in RCBD with three replications. CDB, WB, and GM either sole or combined increased moisture content, SOC, nutrient contents, culturable microorganisms, performance, moisture, ash, fiber, and protein contents of the tiger nut compared with the control. CDB has a higher N, C: N ratio, P, K, Ca, Mg, CEC, and pH relative to. CDB alone and CDB + GM increased growth and yield compared with WB alone and WB + GM. CDB + GM has the highest value of growth and yield of tiger nut. GM alone improved growth and yield of tiger nut compared with the two sole biochar treatments. CDB + GM and WB + GM increased growth and yield of tiger nut compared with their sole forms. This was adduced to biochar allowing the retention of nutrients from rapidly decomposing Tithonia within the rooting zone, thereby promoting better effectiveness of nutrient uptake and increase in yield. Therefore, for good soil fertility and tiger nut yield, it is important that the addition of a fast releasing nutrient source to biochar be sought.

Coffee agroforestry systems capable of reducing disease-induced yield and economic losses while providing multiple ecosystem services

Crop losses caused by pests and diseases decrease the incomes and threaten the livelihoods of thousands of families worldwide. A good example of the magnitude of these impacts are the massive crop losses experienced by coffee farmers in Central America due to coffee leaf rust. Coffee farmers need agroecosystems that are capable of regulating the negative impacts of pests and diseases while providing other ecosystem services on which their households and society depend. In this study, we aimed to identify the most promising coffee agroforestry systems for regulating diseases and ensuring the provision of other ecosystem services. During two years, in a research network of 61 coffee plots under a wide variety of shade and management conditions in Turrialba, Costa Rica, we quantified primary and secondary coffee losses (yield and economic losses) and indicators of three other ecosystem services: provisioning of agroforestry products (bananas, plantains, other fruits, and timber), maintenance of soil fertility and carbon sequestration. We then performed an analysis of the relationships between losses and ecosystem service indicators. Based on the results of relationships and on three criteria, we identified the coffee agroforestry systems that had the lowest losses due to diseases and that provided desirable levels of agroforestry products, soil fertility and carbon sequestration. We found multiple significant relationships between losses and ecosystem services (including both tradeoffs and synergies) which allowed us to derive recommendations for better management strategies to reduce yield losses. We identified six coffee agroforestry systems (CAFs) as the most promising ones for reducing losses while simultaneously providing other ecosystem services. One of these CAFs was a simple agroforestry system (dominated by service trees), three were medium diversified CAFs and two were highly diversified CAFs (systems including service trees, timber trees, fruit trees and musaceas). The six CAFS differed in their cropping practices and farmer profitability objectives. The six CAFs offer several options for the design of new coffee plantations or for the transformation of existing plantations. Several of this promising CAFs use little fungicides, which is an indicator that the reduction of chemical inputs could be possible. Our results suggest that the regulation of diseases and associated losses in agroforestry systems should be based on, and take advantage of, the positive effects of plant biodiversity, adequate shade cover, good soil fertility, and minimal use of fungicides.

Biochar, poultry manure and NPK fertilizer: sole and combine application effects on soil properties and ginger (Zingiber officinale Roscoe) performance in a tropical Alfisol

Abstract Biochar has a low chemical composition and is recalcitrant to degradation. For good soil fertility and nutrient use efficiency of crops it becomes imperative that addition of a fast releasing nutrient source to biochar be sought. Therefore, studies were conducted in 2017 and 2018 to evaluate the effects of biochar with poultry manure (PM) and NPK fertilizer on soil properties, growth and yield of ginger. Treatments evaluated were: biochar applied alone at 15 t ha-1 , PM applied alone at 15 t ha-1, NPK fertilizer applied alone at 200 kg ha-1, biochar applied at 15 t ha-1 with poultry manure applied at 15 t ha-1 (B+PM), biochar applied at 15 t ha-1 with NPK fertilizer applied at 200 kg ha-1 (B+NPK) and a control with no amendment whatsoever. The experimental design was a randomized complete block design with three replications. Biochar, PM, NPK fertilizer alone or B+PM and B+NPK improved soil physical and chemical properties, growth and yield of ginger compared to no amendment (control). NPK fertilizer did not improve soil physical properties nor increased pH, OM, Ca and Mg significantly. B+PM and B+NPK improved soil physical and chemical properties, growth and ginger yield compared to their sole forms. Although B+PM had better soil physical properties, B+NPK increased yield and growth of ginger compared to B+PM. B+NPK increased the yield of ginger by 12.2% and 10.6% in 2017 and 2018, respectively compared with B+PM. B+NPK also increased the yield of ginger by 49.2% and 50.3% in 2017 and 2018, respectively compared to biochar alone. This was related to high presence of nutrients in B+NPK especially N and K which are important for ginger rhizome formation.

Genotype-Environment Interaction: Trade-Offs between the Agronomic Performance and Stability of Dual-Purpose Sorghum (Sorghum bicolor L. Moench) Genotypes in Senegal

Introducing sorghum (Sorghum bicolor L. Moench) genotypes into new environments is necessary for expanding the production of food and fuel, but these efforts are complicated by significant genotype × environment interactions that can reduce their effectiveness. This study set out to thoroughly analyze genotype × environment interactions and assess trade-offs between the agronomic performance and the stability of grain and biomass yields of ten contrasting genotypes under Sudano-Sahelian conditions. Experiments were carried out in a randomized complete block design with four replicates. They were conducted from 2013 to 2016 in Bambey, Sinthiou Malem and Nioro du Rip in Senegal. The joint analysis of variance revealed a highly significant effect (p < 0.0001) of genotypes (G), environments (E) and G × E interaction. Most genotypes showed specific adaptations. The best grain yields were obtained by the Nieleni and Fadda hybrids, while the improved varieties IS15401 and SK5912 were best for biomass production. An Additive Main effect and Multiplicative Interaction (AMMI) analysis showed that good grain yields were associated with environments having good soil fertility and good rainfall, while biomass yields were more influenced by the sowing date and rainfall. Similarly, we were able to confirm for our 10 sorghum genotypes that yield stability was generally associated with low performance, except for the Nieleni and Fadda hybrids, which performed well for grain and biomass production regardless of the environment. The Senegalese control genotype, 621B, showed particular susceptibility to growing conditions (soil), but remained very productive (more than 3 tons per hectare) under good agro-pedological conditions. These results lead us to recommend the Fadda and Nieleni hybrids for the entire study region, while 621B can also be recommended, but only for highly specific environments with good soils.

Comparing farmers' qualitative evaluation of soil fertility with quantitative soil fertility indicators in Kitui County, Kenya

Soil fertility is vital for agricultural productivity, yet poor soils and erosion remain a management challenge in many parts of sub-Saharan Africa. One challenge is that soil scientists and farmers often evaluate soil fertility using different knowledge systems and the implications have not been clearly reconciled within the literature. In particular, whether farmers are observing similar aspects of structure and function as classified in soil science. If so, what can we learn about how soil fertility is evaluated and communicated in terms of developing a hybrid approach that improves communication of ideas between different stakeholders. This paper addresses this challenge by examining the similarities and differences between farmers' qualitative evaluation and soil science quantitative analysis for soil fertility classification, and how location of soils influence farmers' evaluation of soil fertility. Empirical fieldwork was carried out in two villages in Kitui County, Kenya with 60 farmers using semi-structured interviews and focus group discussion. Based on farmer perception, 116 soil samples of the best and worst soil fertility taken and analysed for physiochemical factors. Farmers had a consistent classification system and primarily relied on texture and colour as indicators for good soil fertility and texture alone for poor soils.Soils with fine texture under the local semi-arid climate were associated with higher pH, TOC and WHC and fertile black and red soils were associated with pH, TOC, WHC and AP based on differences in bed rock. Poor soil fertility was associated with sandy soils and soils with no colour in their local name. Spatial location is an important consideration in farmers' evaluations, reflecting awareness of local diversity in soil and historical social or environmental factors. Local historical narratives reveal the importance in changes to humus, consistent with technical knowledge about the role of soil organic matter for soil fertility. The paper provides a better understanding of farmers' soil classification, evaluation processes and perspectives that help to inform scientists working with alternative frameworks for assessment and, in doing so, supports the development of local tailor-made soil assessment systems.

Connecting microbial capabilities with the soil and plant health: Options for agricultural sustainability

Abstract Microorganisms are the key players in every agro-ecosystem. They are the natural inhabitants of all the soil and plant systems, in which they represent dominant presence in terms of their vast diversity and multipronged functional capabilities. Multifarious physical, chemical and biological factors usually represent good soil fertility status as a guaranty of sustainable agro-ecology, plant health and crop productivity. Since healthy soils are largely characterized by their profound biological and chemical behavior, microbial functionalities related to nutrient fixation, recycling, acquisition, sequestration, solubilization, mobilization, decomposition, degradation and remediation may act as definitive indicators. Functional capabilities of microbial communities associated with soils and plant parts have been critically identified and characterized in the past few decades. Application of individual microbes or their consortia in many crops established their role in finding out a supplement and/or substitute in the existing agricultural practices which are largely dependent on synthetic chemical inputs in present time. We are presenting here a detailed account of microbial community functions, their relation with the soil and plant health and the potential indicative roles they play to establish a sustainable soil ecological environment for supporting crop growth, development and yield in long term.

Land use and biochar effect on nitrate leaching in a Typic Haplustert of central India

Studies on the effect of biochar on nitrate leaching are few. Hence, a laboratory column experiment was conducted using surface (0–20 cm) soil from three different land uses of a Vertisol, to investigate the effect of biochar amendment on leaching behaviour of nitrate and salts. The three selected land uses were: thick forest, agriculture land use with good soil fertility and good crop production history and agriculture land use with low soil fertility and poor crop production history. Biochar was added at 0, 0.5, 1.0 and 2.0% (w/w) to the soil in the upper half of the columns. The treatments were taken with three replications in a factorial completely randomized design. The PVC made columns (40 cm height and 11 cm internal diameter) filled with soil to a bulk density of 1.2 Mg m−3 were leached with deionized water once a week for 15 consecutive weeks. Nitrate in form of KNO3 was added at the rate equivalent to 100 mg N kg−1 soil (220 kg ha−1) at each application in the 1st, 8th and 11th week. The forest soil showed significantly higher salt and NO3−-N leaching. Biochar amendment @ 0.5% or at higher level showed a significant reduction in NO3−-N leaching in the forest and good agriculture soil, whereas, in the poor agriculture soil, no significant effect was observed even at 2.0% biochar amendment level. With the highest level of biochar amendment (2%, w/w), reduction in NO3−-N leaching to the extent of 27% and 23% was observed in the forest and good agriculture soil, respectively. Biochar application significantly reduced salt leaching in the forest soil at 0.5% amendment level, and in the good agriculture soil at 1.0% level. At 2.0% biochar amendment, reduction in salt leaching to the extent of 18% and 16% was observed in the forest and good agriculture soil, respectively.

Nanopowders of cuprum, cobalt and their oxides used in the intensive technology for growing cucumbers

The paper covers the development of an intensive technology for growing vegetables using some nanodrugs. Each farm growing cucumbers is intended to increase its production of vegetables by means of multiplying their yield, which can be achieved by combining a number of vegetables grown both in the open and on protected ground. Since the cucumber enters its fruiting period early, it requires very good soil fertility and mineral nutrition conditions. This research aims to study effects of biologically active nanopowders of cuprum, cobalt and their oxides on the vital, metric and weight parameters of cucumber seeds, their antioxidant system, the metabolism regulation during the ontogeny of cucumber plantlets and the content of pigments in cucumber sprouts under the influence of nanopowders. Cobalt and cuprum nanoparticles at the concentration range of 0.1-10 g/ha are regarded as regulators of the cucumber sprouts growth and development and are considered to be environmentally sound. The maximum concentration of copper oxide nanoparticles is 1.0 g/ha. Changes occurring in plant cells affect all the centres of metabolic activity, including mitochondria, plastids, ribosomes and a nuclear apparatus. Both in organelles and the cytoplasm, enzymes are subject to changes, especially superoxide dismutase, peroxidase and catalase, whose activity and spectrum change under the action of nanoparticles. The discovered ability of nanoparticles to activate physiological and biochemical processes during seeds germination is of a special interest from a practical viewpoint.

Effects of planting pattern on growth and yield and economic benefits of cotton in a wheat-cotton double cropping system versus monoculture cotton

The double-cropping system of wheat and cotton is widely adopted in the Yellow River Valley of China, but it remains unclear if and how planting patterns impact cotton yield and economic benefits in this system. Using monoculture cotton (CM) as the control, we conducted a 2-year field experiment to investigate the effects of three planting patterns, cotton intercropped with wheat (CIW), cotton transplanted after wheat (CTW), and cotton direct-seeded after wheat (CDW) under the wheat-cotton double cropping system on cotton growth, yield and economic benefits in two fields differing in soil fertility. The results indicated that double cropping significantly decreased cotton yield relative to monoculture irrespective of planting pattern and fields, but the decrements were considerably reduced in the high soil fertility field. Averaged across two years, cotton yields of CIW, CTW and CDW were reduced by 16.2, 30.0 and 38.8% in the low fertility field relative to that of CM, while they were reduced by 7.5, 22.4 and 22.7% in the high fertility field. The yield difference among planting patterns was attributed to the variation in both the number of bolls and boll weight, while the yield difference between two fields was largely due to the number of bolls. Similar differences in biomass accumulation were observed among planting patterns. Accelerated early development of cotton, extended duration of the fast biomass accumulation and the enhanced total biomass and accumulation rate were observed in the high fertility relative to those in the low fertility field. Economic analysis showed that, based on total costs and output values of two crops, the net revenue of CIW, CTW and CDW was increased by 28.5, 10.9 and 36.5% in the low fertility field; and by 56.3, 31.8 and 74.4% in the high fertility field, compared to CM averaged by two years. CDW might be a new alternative for cotton production in Yellow River Valley when taking both profitability and management simplification into consideration. Our results also support that good soil fertility is a prerequisite for high yield and net return in wheat-cotton double cropping, especially for CDW.

STRATEGI PENGEMBANGAN KAWASAN AGROWISATA RURUKAN

The purpose of this research is to identify the right strategy in developing Rurukan agro tourism area. The research location was conducted in two urban villages: Rurukan and Rurukan 1, East Tomohon Subdistrict, Tomohon City. This research was conducted for 3 (three) months from November 2016 to January 2017. The data used in this study are primary data and secondary data. Primary data are data taken through direct observation on site, interview with respondents who selected 10 people to fill out the research questionnaire as follows: Government (3 people), namely Lurah Rurukan, Lurah Rurukan One, and Officials of Tomohon City Tourism Office, Community Shop (2 persons) and Tour Manager (5 persons). Secondary data is data obtained from the offices of two urban villages and Tourism Office. The analytical method used SWOT Analysis. Based on the results of research and discussion, it can be concluded that the development strategy of Rurukan agro tourism area is Rapid growth strategy. This development strategy is in accordance with the position of Rurukan area that needs a progeny strategy to support growth, through several strategies that can be implemented, namely: (1) Utilizing some existing tourism object to attract investors so that it can become a growing tourism sector and interest in Tomohon ; (2) utilizing the famous agro tourism with its trademark to become a cultural development area, especially in Tomohon City; (3) utilizing a good soil fertility level in the Rurukan area to be planted with fruits such as strawberries, which are highland fruit trees to be enjoyed by tourists.

Mineral Fertilization with UAN on Natural Grassland Festuca rubra L. with Agrostis capillaries L.

An important part of efficient livestock production is ensuring the sufficient grass for hay and pasture. However, low soil nutrient levels often limit forage production. With good fertilizer management and soil fertility, the productivity of many hay and pasture fields can be greatly improved. Through good fertilizer management, the productivity of many hay and pasture fields can be significantly improved by Ross H. McKenzie (2005). The aim of this paper was the effect of fertilization with liquid fertilizer (UAN) the harvest of dry and floristic composition changing on natural grassland. The experiment whose results we present was placed in 2014 in the place in Baisoara Mountain village, Cluj County. Experience has been placed on the Festuca rubra and Agrostis capillaries - of grassland type. The natural grassland of Festuca rubra with Agrostis capillaries responded very well to mineral fertilizers with liquid fertilizer UAN. The floristic composition of natural grassland fertilized with liquid fertilizers based on nitrogen, it can be seen an increase the Gramineae families and an evidence downward trend from Fabaceae families.

Organic weed management in perennial fruits

Weed management is key component of establishing and sustaining a profitable organic orchard. Good site preparation is a critical part of an orchard establishment plan. Pre-plant weed control coupled with addressing soil fertility issues before planting can dramatically increase the options available to producer for weed management, while reducing the time to commercially viable levels of fruiting and harvest. Tillage may be the best option on sites with perennial rhizomatous weeds and low soil fertility, or where there is high risk of rodent damage to the crop. Dead organic mulches are best suited to sites with low presence of perennial rhizomatous weeds and sites where at least moderate levels of soil fertility are present. While living mulches tend to provide a desirable habitat in the orchard understory, they are competitive with the crop for water and nutrients, regardless of whether they are mowed or not. They should only be used on sites with good background soil fertility, with frequent mowing, and where climate or irrigation minimize risk of moisture stress. Most manufactured mulches can provide effective weed control for a longer period of time but reduce soil fertility management options. The use of biodegradable mulches under dead organic mulches poses interesting possibilities and should be studied further. Organic herbicides are presently not effective enough or too costly to be used as the primary means of weed control but would be a useful tool for spot and edge control of weeds in mulches.

It is not worthwhile to fertilize sweet sorghum (Sorghum bicolor L. Moench) with cattle slurry: Productivity and nitrogen-use efficiency

Sweet sorghum (Sorghum bicolor L. Moench) is a viable alternative to maize when irrigation water is unavailable or too expensive. In areas with intensive livestock activities animal slurries are predominantly applied to maize. Although sweet sorghum is fairly investigated species, little is know about the efficiency with which the crop can use nitrogen (N) applied in the form of cattle slurry. Then, a field experiment was devised to explore the following research questions: (i) what is the effect of cattle slurry and industrial fertilizers on sweet sorghum productivity? (ii) which is the N-use efficiency for cattle slurry and industrial fertilizers applied to sweet sorghum? The study was conducted in the years from 2008 to 2012 (five years) in the alluvial plain of the Po Valley, Northern Italy. The fertilization treatments applied annually were: (i) no fertilization (control); (ii) industrial fertilizers 120kgNha−1, applied in the form of urea, +52kgP ha−1, applied in the form of superphosphate, (IF); (iii) cattle slurry 10mm, i.e. 10Lm−2 (CS10); and (iv) cattle slurry 20mm, i.e. 20Lm−2 (CS20). The indigenous soil N supply varied from 112 to 243kgNha−1. The experiment was not irrigated. The observed average annual yields were, in decreasing order: 34.6MgDMha−1 in 2008, 31.7 in 2011, 29.5 in 2009, 27.9 in 2010 and 27.2 in 2012. Physiological efficiency applied N (PEN, kg yield increase per kgN uptake), recovery efficiency applied N (REN, kgN uptake increase per kgN applied) and agronomic efficiency of applied N (AEN, kg yield increase per kgN applied) were evaluated in this study. In the range of observed values the PEN was 63kg DM yield per kgN uptake, the REN varied from 0 to 0.33 and the AEN was zero in all the years of experiment. Fertilization tends to increase N uptake but not yield nor stem juice sugar content. Our findings indicate that under conditions of good soil fertility, sweet sorghum should be considered poorly suited to receive cattle slurry application, due to the absence of yield gain and to the low N-use efficiency. Moreover, the high N uptake achieved by the crop with no fertilization, combined with the modest REN suggest the animal slurry should rather be applied to crops possessing higher efficiency in utilizing N applied with fertilizers. Nevertheless, the frugality of sweet sorghum should be considered a virtue in the light of the increasing interest in reducing the input for energy crop production.

Soil and vegetation seasonal changes in the grazing Andean Mountain grasslands

Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna (Vicugna vicugna) and alpaca (Lama pacos). The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined: total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. The good soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.

Application limestone forms and doses for alfalfa in no-tillage system

Alfalfa (Medicago sativa L.) requires good soil fertility. Brazil is characterized by acidic soils which reduce the potential of the crop. Generally, liming is incorporated into the soil, but in tillage systems it is inadvisable. This study aimed to evaluate the effects of the lime application method and dose on pH, Al+3, V % and Ca+Mg in the soil and on dry matter yield of alfalfa cultivated under a consolidated no-tillage system. The experiment was conducted at the Experimental Station of Parana Agronomic Institute, located in Pato Branco city, in Parana state. The plots consisted of the types of lime application (plowing+harrowing, subsoil and surface), the sub-plots was the lime dose (0, 2, 4, 6 and 8 Mg ha-1) and the sub-sub-plots were the sampled soil depth (0-5; 5-10; 10-20 and 20-30 cm). The results show the application of lime, even superficially, caused increases in pH, concentration of Ca and Mg and base saturation of the soil, while also reducing the concentration of Al, especially in the surface layers of the soil. The practice of plowing and harrowing or of subsoiling, with the aim of lime incorporation in a consolidated no-tillage system is unnecessary. If it is required, the application of lime to the soil should be done superficially for alfalfa cultivated in this system.

Ecological characteristics influence farmer selection of on-farm plant density and bunch mass of low input East African highland banana (Musa spp.) cropping systems

East African highland bananas (Musa spp., AAA-EA group) are a primary food and cash crop for smallholders in Rwanda and much of the East African highlands. Their production generally declines over time due to poor farm management and declining soil fertility. Farmers believe that among the bunch mass maintaining factors, plant density management offers some prospect. They often decrease banana mat (i.e. a single mother plant with interconnected suckers) density in an effort to increase bunch size, but the effectiveness and profitability of this practice has not been studied. In addition, not much research has been executed on the influence of climatic and edaphic factors on variations in on-farm plant density. An on-farm survey was conducted in contrasting agro-ecological sites of Rwanda (Ruhengeri, Rusizi, Karongi, Butare, Ruhango, Kibungo and Bugesera) to determine existing densities and their relationship to bunch mass. A plant density assessment method was used that measures the average distance of five mats to their respective nearest four mats to calculate average mat spacing. Plant density positively correlated with surplus/deficit water supply (i.e. difference between rainfall and water demand by bananas) (r2=0.62), with highest plant densities (>1500matsha−1) found in high rainfall areas (>1200mmyr−1) with water surplus (218–508mmyr−1) and lowest plant densities (1000–1400matsha−1) found in lower rainfall areas (1000–1200mmyr−1) with water deficit (from −223 to −119mmyr−1). Heaviest bunches (18.1–20.8kgfreshmassplant−1) were found at lowest plant densities and medium sized bunches (14.7–15.5kg) at highest plant densities. Lower soil and banana leaf nutrient contents (especially N, K, Ca and Mg) were observed on weathered soils (Acrisols) and were associated with smaller bunch mass in comparison to fertile soils (Andosols, Nitisols). Farmers tended to reduce mat densities (i) if they wanted to intercrop bearing in mind site characteristics, and (ii) to increase bunch mass to adapt to market preferences. The plant densities generally recommended by extension bodies (3m×3m or 2m×3m; i.e. 1111 and 1666matsha−1, respectively) are seldom practiced by farmers, nor do they seem to be very appropriate, as higher densities seem productive in areas with high rainfall and relatively good soil fertility.

Comparison of planting stock for establishing black walnut in central Kansas

Abstract Reliability and cost of different types of planting stock under various climatic and site conditions are important. We tested three types of planting stock for survival and growth: bare-root seedlings, nuts, and container stock of black walnut. In this study, in which we had good soil fertility, weed control, and moisture, we found no difference in the success between the three types of plantings. If seed predation problems may exist, using bare-root, dormant seedlings in the spring for establishing typical forestry plantings is encouraged; otherwise seeds may be used if in an open field site.

Resource flows and nutrient balances for crop and animal production in smallholder farming systems in eastern Uganda

Resource flow models are useful tools that assist farmers in analysing their soil fertility management strategies and in planning, experimenting and adapting ways to improve the use of scarce local resources. Resource flows and farm nutrient balance studies were carried out in eastern Uganda to ascertain the movement of organic resources and nutrients in and out of the farm system during a participatory learning and action research (PLAR) process. The resource flows were transformed into nutrient flows and partial nutrient balances were calculated using the Resource Kit computer package. Results of a farmers’ soil fertility management classification at the start of the PLAR intervention in 1999 revealed that 3% of the farmers were good soil fertility managers (class I), 10% were average soil fertility managers (class II) and 87% were poor soil fertility managers (class III). The results indicate that the net farm nutrient balances in kg ha 1 per season for all the nutrients [nitrogen (N), phosphorus (P), and potassium (K)] were negative for both the good and the poor soil fertility managers. Class 1 farm balances irrespective of the season, were however more negative than those of class 3 farms. For the long rains seasons (LR 2000, 2001 and 2002), the average net farm nutrient balances for N, P, and K for class I farms were5.0,0.6 and8.0 kg ha 1 year 1 , while for the short rains seasons (SR 2000 and 2001), the nutrient balances were 3.5, 0.5 and 6.0 kg ha 1 year 1 , respectively. For the class III farms, the average net farm nutrient balances for N, P, and K in the long rain seasons (LR 2000, 2001 and 2002) were 3.3, 0.3 and 4.0 kg ha 1 year 1 while for the short rains seasons (SR 2000 and 2001), the nutrient balances were 3.5, 0.5 and 5.0 kg ha 1 year 1 , respectively. Soil management interventions for these small-scale farmers should aim at reversing nutrient depletion with a focus on profitable management of the crop production system, which is the major cause of nutrient depletion.

The efficiency of nitrogen fertiliser for rice in Bangladeshi farmers’ fields

Bangladesh is currently self sufficient in rice ( Oryza sativa L.), which accounts for approximately 80% of the total cropped area, and 70% of the cost of crop production. However, farmers are increasingly concerned about the perceived decline in productivity, expressed as the return on fertiliser inputs. Agronomic efficiency is a measure of the increase in grain yield achieved per unit of fertiliser input that can provide a way to quantify the observation of farmers. This study indicates that the yields achieved where only P and K fertiliser were applied ranged from 3–5 t ha −1, indicating good soil fertility, particular in terms of soil N supply (37–112 kg N ha −1). However, at recommended rates and at rates used by farmers, the yield response to application of fertiliser N was low. Data shows that grain yields were significantly correlated in both years ( R 2 = 0.77 and R 2 = 0.67) with plant uptake in nitrogen. The internal nitrogen use efficiency seems to confirm that sink formation was limited by factors other than nitrogen. Low agronomic efficiency (5–19 kg grain kg −1 N) was caused by poor internal efficiency (45–73 kg grain kg −1 N), rather than low supply of soil N or loss of fertiliser N. Thus, often the applications of large amounts of N fertiliser (39–175 kg N ha −1) by farmers to increase yields of high yielding variety Boro rice were not justified agronomically and ecologically. A rate of 39 kg N ha −1 is very low, hardly an environmental threat. No one single factor could be identified to explain the low internal efficiency. Therefore, it is concluded that the data presented tend to confirm the indication that yields are limited by a factor other than nitrogen, which could be crop establishment, plant density, water or pest management, micro-nutrients deficiency, poor seed and transplanted seedling quality, varieties and low radiation.