On-farm Plots Research Articles

Improving the prediction of potato productivity: APSIM-Potato model parameterization and evaluation in Tasmania, Australia

Crop growth models are required to be extensively evaluated against actual data from field grown plants in order to have confidence in their prediction of crop productivity under various management options or a future changed climate. We evaluated the ability of the APSIM-potato model to predict production, phenology, and Nuptake of potato (Solanum tuberosum L.) under Tasmanian conditions. On-farm monitoring plots were established in north-west Tasmania within four different well-managed potato fields grown during the 2012/13 cropping season. Detailed soil and crop data sets measured in the on-farm plots planted with two potato cultivars, 'Russet Burbank' and 'Moonlight' were used to parameterise and evaluate the model. The model ealistically reproduced the observed tuber yield with high precision (a mean N-RMSE of 15.4% and modelling efficiency of 1.0 for both cultivars). Measured mean tuber yield was 17 t ha-1 for 'Russet Burbank' with a simulated yield of 20 t ha-1. For 'Moonlight' simulated tuber yield was 16.0 t ha-1 compared to measured yield of 15.1 t ha-1. The simulation results provide insight on the model performance under Tasmanian conditions. The results suggest that the model has potential to be used for purposes such as simulating productivity under various management options and climate change impact studies. Additional experiments are however required to improve cultivar specific input parameters such as phenology, leaf area and leaf duration and other functions that needs further refinement to improve model ability to simulate plant organs beside the tuber

Arbuscular mycorrhizal fungi with different soil fertility amendment practices in agricultural landscapes of Kenyan highlands

Several interrelated and site-specific agronomic factors ranging from agroecological conditions to systems management practices have been shown to variably affect arbuscular mycorrhizal fungi (AMF) diversity in the soil. Also, there have been various attempts in the past to evaluate the potential of AMF field inoculation but a majority focussed on the use of exotic strains, disregarding the potential of the existing naturally occurring strains. In an attempt to address these problems, our study aimed to develop ‘best-bet practice’ based on soil fertility amendment practice (SFAP) that encourages occurrence and diversity of AMF in the soil. Control treatment (no application) was compared with three (3) SFAP used singly or in combination with AMF or two other soil nutrients enhancing organisms (Bacillus and Trichoderma) which included the following: (1) Mavuno (macro- and micronutrients and secondary nutrients) fertilizer, (2) calcium ammonium nitrate (CAN) plus triple super phosphate (TSP) and (3) cattle manure. Maize (Zea mays L.) and common bean (Phaseoli vulgaris L.) were planted at on-station and on-farm plots for two consecutive cropping seasons with the experiment replicated in two benchmark sites of Embu and Taita-Taveta Districts. Embu site recorded a lower soil pH and also very low phosphorus levels compared to Taita site. The number of AMF spores per kg of soil was very low, ranging from 30 to 100, at Embu in the first season and application of SFAP resulted in no significant difference. However, in the second season, use of Trichoderma + CAN plus TSP was shown to significantly stimulate AMF species in the soil, with a 250 % increase in species density compared to use of Bacillus + Manure. At Taita, after the first cropping season, significant change in spore density was only recorded from AMF applied singly with a 66.1 % increase in spore density compared to Control treatment. In comparison, after the second cropping season, use of AMF applied singly, AMF + CAN plus TSP and AMF + Manure increased spore density by 135.4, 109.6 and 100 % respectively compared to Control treatment. Use of AMF applied singly increased species density in the soil by 100 and 81.1 % compared to CAN plus TSP and Trichoderma treatments respectively after first season at Taita site: while after the second cropping season, application of AMF + CAN plus TSP, AMF + Manure and AMF + Mavuno increased AMF species density in the soil by 60.3, 51.5 and 55.9 % respectively compared to Control treatment. These findings provide evidence that it is possible to increase the number of AMF spores in the soil through inoculation with native species and also possibly stimulate dormant species through other SFAP treatments.

English

Adoption of some indigenous vegetables that are grown and consumed by local farmers along with arable crops, to serve as means of nutrient sufficiency, especially small holder farmers in Nigeria was carried out using extension approaches with the aim of increasing food security, farm income and conserving vegetables. Multi-stage participatory extension approach was used first to purposefully select five states in the southwestern Nigeria. Data were collected through the use of structured interview scheduled consisting of open and close ended questions on personal socio-economic characteristics, the cropping system, available vegetables and other factors. In addition, Focus Group Discussion (FGD) guide was used to elicit qualitative data such as socio-cultural status, effect of community norms on the vegetables and factors influencing the production. Interview schedule and Focus Group Discussion guide were subjected to content validity. Simple descriptive statistical techniques such as frequency, percentages, means and standard deviation were used to analyze and summarize the data. The project revealed a high level of adoption due to the increase knowledge of the nutritional potentials of some of the vegetables. Agronomic performances of the vegetables in on-farm plots significantly showed the economic potentials of the vegetables and led to significant increase in the farmers’ income as more of the vegetables were produced and sold and the on-farm sites served as ex-situ means of conservation. Improved handling of the vegetables and thus reduced genetic disappearance.   Key words: On-farm, adoption, under-utilized vegetables, conservation, smallholder farmers.

Implications of Conservation Agriculture for Men's and Women's Workloads Among Marginalized Farmers in the Central Middle Hills of Nepal

Measures of gender-based labor distribution can contribute to understanding the feasibility of agricultural development in mountainous subsistence farming communities. Conservation agriculture (CA) can provide sustained crop yield and improved soil and water conservation in mountain areas prone to degradation and where few inputs are available. This study sought to measure the gendered labor impacts of CA practices and to assess their feasibility in remote farming communities. We surveyed farmers in 3 tribal villages in the Middle Hills of Nepal, where communities consist of smallholder (<2 ha) farmers cultivating highly sloping, marginal lands. Face-to-face interviews and time allocation surveys were used to quantify distribution of labor and to identify engagement in agricultural decision-making in 87% of the households. On-farm plots were used to measure differences between the gender-based labor demands of conventional and CA practices. Results show that women bear a disproportionate burden (53–55%) of on-farm labor. Field trials showed that women would predominantly manage increases in labor demands from CA, particularly where more labor for plowing, sowing, and harvesting is required, yet 51.3% indicated that they have limited control over adoption of new practices. In situations where women are already overburdened, technologies that require additional labor may prove unsustainable. It is crucial to adapt technologies to provide gender-sensitive solutions and meet the needs of the local community. Identifying the gendered constraints of CA is vital to improving understanding of agricultural livelihoods.

Analysis of conservation agriculture preferences for researchers, extension agents, and tribal farmers in Nepal using Analytic Hierarchy Process

Many smallholders in Nepal rely on marginal lands that are subject to declining fertility due in part to traditional farming practices. The adoption of conservation agriculture practices has the potential to improve livelihoods and food security but depends on knowledge sharing among farmers, extension agents, and researchers. This study uses Analytic Hierarchy Process (AHP) to determine farmer, extension professional, and researcher preferences for selected conservation agriculture production systems (CAPS) and a widely-practiced traditional production system. This data is then used to determine which CAPS have the highest likelihood of adoption and identify misunderstandings or knowledge gaps among farmers, extension personnel and scientists. AHP was conducted in three tribal villages and at two NGOs that provide research and extension services to smallholders in the central Middle Hills region of Nepal. Overall, soil quality was identified as the most important factor affecting long-term household income, the primary motivator of adoption in study villages. Farmers generally preferred full tillage followed by cowpea solo crop in the second growing season while extension agents and researchers preferred strip tillage followed by cowpea and millet intercrop in the second season. Results indicate that (1) stakeholders prefer CAPS over traditional systems, (2) farmers prefer full tillage over minimum tillage and (3) the farmers in the village of Khola Gaun may be more prepared to adopt minimum tillage and intercropping than the other villages. Communication among all stakeholders should be improved and the results of on-farm plots should be used to reinforce understanding of CAPS benefits. It should be kept in mind that labor savings is not a main motivator of adoption among village farmers and further research should be conducted in Khola Gaun to learn why farmer preferences there differ significantly from farmer preferences in other villages.

Exotic tree species displace indigenous ones on farms at intermediate altitudes around Mount Kenya

Agroforestry systems are potentially suitable for conservation of tree genetic resources. Farmers around Mt. Kenya usually integrate trees into their farm. Large parts of these trees seem to be of exotic origin, whereas indigenous species have priority for conservation. This study aimed at determining on-farm richness, composition and frequency of indigenous and exotic woody species around Mount Kenya to assess the suitability of farms for the conservation of indigenous tree species. 265 on-farm plots of 0.5 ha size each were selected in 18 different agro-ecological zones by using a stratified sampling scheme. All woody species within the plot were recorded with their local and scientific names. Total species richness was 424 (including 306 indigenous ones), mean richness per plot 16.5 species (including 8.8 indigenous ones). Eight out of the 10 most frequent species were exotic ones with Grevillea robusta from Australia ranking first (found on almost 76% of the surveyed farms). The proportion of indigenous species increased with increasing aridity and temperature. Dominance of exotic species was found at farms of humid mid- and highlands. Ordination analysis revealed that mostly exotic species contributed to separation of farms in the highlands and upper midlands, whereas indigenous species in the lower midlands and lowlands. As the frequencies of most indigenous trees were low, only parts of the surveyed farms can contribute to conservation of tree genetic resources, particularly the less intensively managed farms of the more arid lands. Farmers’ access to knowledge on valuable indigenous tree species and to quality seedlings of these trees need to be improved to increase indigenous species’ frequencies on farms and possibly to replace some of the exotic species in the future.

Interaction between Grain Yields of Rice and Environment (Soil) in Four Agroecological Zones in Nigeria

Rice grows in all agroecological zones (AEZs) of Nigeria as the weather (rainfall, solar radiation, relative humidity) is optimum. Investigation was conducted in four AEZs to evaluate the effect of environment (soil) on the grain yields (GYs) of four new rice cultivars for Africa (NERICA) compared with farmers cultivars (i.e., Ofada and ITA 150). The experimental design was a randomized complete block design (RCBD) replicated 10 times. The treatments were four AEZs [the northern Guinea savanna (NGS), derived savanna (DS), southern Guinea savanna (SGS), and Sudan savanna (SS)], four NERICA rice cultivars [WAB 189-B-B-B-HB (or WAB 189), WbAB 450-1-P-38-HB (or P-38), WAB-450-11-1-P31-1-HB (or P-31), WAB-450-24-3-2-P18-HB (or P-18)], Ofada, and a control (ITA 150). Ten on-farm plots were used as replicates. All trials were farmer managed. Data were collected on the soil physicochemical characteristics before the experiment, while GYs were collected at harvest. Results of the GYs were analyzed using analysis of variance (ANOVA). Soil properties that significantly related to the GYs of rice were isolated using stepwise multiple regression analysis (SMRA). The most stable rice cultivar across all AEZs was obtained from the slope of a regression equation from the cultivar means versus environmental means. Results of the soil chemical properties showed that across all AEZs, soil fertility status varied between low and medium. Furthermore, the GYs of rice cultivars ranged between 2.55 and 3.44 t ha−1 and were of the order ITA 150 > P 18 > P 31 > Ofada > P 38 > WAB 1, though not significantly different. However, across AEZs, the GYs of rice were of the order SS > SGS > NGS > DS. The SMRA showed that the only three soil properties (pH, available P, and clay) significantly related to the GY of three of the rice cultivars (Ofada, P31, and WAB 189) with R2 values of 36, 53, and 63% respectively. The slopes of regression equations were 0.50, 0.65, 0.69, 0.85, 0.89, and 0.98 respectively for rice cultivars P31, P38, P18, ITA 150, Ofada, and WAB 189. This suggested that the most stable rice cultivars were P31 and P38. However, observations across sites showed that majority of farmers still prefer to grow Ofada on their farms, suggesting most local farmers are not yet aware of these rice cultivars. Results further showed that with proper management of the soil pH and available P and soil moisture (i.e., clay content), the GYs of these rice varieties could be improved. Critical organic carbon, available phosphorus, exchangeable potassium, and clay contents required for a sustained and continuous cultivation of these rice cultivars were 7.0 g kg−1, 8 mg kg−1, 0.13 cmol kg−1, and 198 g clay kg−1, respectively.

Field Evaluation of Two Nitrogen Testing Methods in Maine

Although the pre-sidedress soil nitrate test (PSNT) can identify corn (Zea mays L.) fields that may respond to supplemental N fertilizer, the test has not been widely adopted by producers. Additional N-testing methods are needed. Studies were conducted to evaluate the (i) accuracy of a leaf chlorophyll nitrate test for N (LCNT), (ii) influence of hybrid and planting date on chlorophyll readings, (iii) accuracy of normalizing chlorophyll measurements against a high-N reference plot, and (iv) use of early-dent stage earleaf chlorophyll measurements to identify N-deficient or N-excessive sites. Fifty nonreplicated onfarm trials and two replicated experiments were conducted from 1993 through 1995 in central Maine. Following planting, we established high-N subplots (720 sq ft) where we applied 200 lb N/acre. At the V-6 stage, PSNT samples were collected and analyzed using the Penn State quick-test method. A Minolta 502 chlorophyll meter was used to measure V-6 and early-dent stage leaf chlorophyll (SPAD units). SPAD and yield ratios were calculated by dividing whole field and high-N subplot averages. Using the PSNT, we identified sites that would respond to sidedress N 82% of the time. The V-6 stage LCNT was accurate 80% of the time. However, V-6 stage chlorophyll values were influenced by hybrid and planting date. V-6 SPAD ratios may reduce variation, although they did not improve test accuracy on the on-farm trials. Using early-dent stage SPAD ratios, we could identify sites that responded to supplemental N 83% of the time, but we were unable to identify sites with excessive N.

Surveying farmers' agroforestry plots: experiences in evaluating alley-cropping and tree border technologies in Western Kenya

Evaluation of existing on-farm agroforestry plots should provide useful supplementary information for the design of improved agroforestry systems, in both research and development projects. Such evaluation has been little used, however, largely due to the methodological difficulties of surveying highly variable on-farm plots, and difficulties in identifying key variables for measurement. This paper describes a set of methods and tools used in evaluating plots of alley-cropping and tree borders around crop fields established by farmers working with the CARE Agroforestry Extension Project in western Kenya. Details of survey design, sampling, and implementation are discussed, and suggestions made for carrying out agroforestry surveys in other projects. A condensed version of the questionnaire is appended.