Spanish Focus Group with farmers
On June 3rd Spanish team held its Focus Group after postponed it several times due to COVID lockdown. This meeting was moderated by Ana Sanchez Montero (SHui Project Manager) because of travel restriction for the Göttingen University due to the pandemic.
Despite the difficulties, the discussion on “Water management in Agriculture” was successful in a region where water is a scarce commodity. Farmers were focused on woody crops: olive trees, vines, almond and other nuts, stone fruit trees.
In-Season Interactions between Vine Vigor, Water Status and Wine Quality in Terrain-Based Management-Zones in a ‘Cabernet Sauvignon’ Vineyard
SHui exchanging experiences with Spanish Operational Groups
On April the 7th, SHui partners at IAS-CSIC participated in the MAPA conference on “Exchange of experiences between Operational Groups and Projects focus on soils. MAPA is Ministry of Agriculture, Fisheries and Food from Spain.
During the webinar, SHui offered collaboration opportunities with Operational Groups and showed its current experience with one of them.
Bio-fertilizers issued from anaerobic digestion for growing tomatoes under irrigation by treated wastewater: targeting circular economy concept
A. Tallou 1, F. Aziz 2,A. J. Garcia 3, F. P. Salcedo 3, F. E. El Minaoui 1 & S. Amir 1
1 Polydisciplinary Laboratory of Research and development, Faculty of Sciences and Techniques, Sultan Moulay Slimane University of Beni Mellal, Beni Mellal, Morocco
2 Laboratory of Water, Biodiversity & Climate Change, Semlalia Faculty of Sciences, University Cadi Ayyad, B.P. 2390, 40000, Marrakech, Morocco
3 Department of Irrigation, CEBAS-CSIC, Campus Universitario de Espinardo, 30100, Murcia, Spain
Tomatoes (Solanum lycopersicum) plant were provided with bio-fertilizers issued from anaerobic digestion of olive mill wastewater without and with 1%, 5% of phosphate residues in mesophilic conditions for 25 days. 1% of raw substrates (OMW raw; OMW + 1%PR raw; olive mill wastewater + 5%phosphate residues raw; and phosphate residues) and digestates (olive mill wastewater digestate, olive mill wastewater + 1%phosphate residues digestate and olive mill wastewater + 5%phosphate residues digestate) was provided fortnightly to the plants. Reclaimed water from a wastewater treatment plant located in the study site was used for automatically controlled irrigation. It contained a low level of chemical fertilizers to compare tomato plant growth, leaf analysis, steam water potential, production yield and fruit quality results to plants fed with bio-fertilizers. Generally, parameters and results were progressively increased during the growing and harvesting stage, which refer to the essential elements that cover the plant’s needs. Plants fed with bio-fertilizers showed the most extended plant height (olive mill wastewater + 5% phosphate residues raw), and the best accumulation of essential elements in leaves (olive mill wastewater + 1% phosphate residues digestate and olive mill wastewater + 5%phosphate residues digestate). The maximum average fruit weight per treatment (35.5 g) was obtained when applying the digestates mixture of olive mill wastewater raw and olive mill wastewater + 5% phosphate residues. The maximum yield production per plant was obtained when applying phosphates residues. Bio-fertilizers (digestates) showed good performances, high fruit quality and perfect tomato yield production compared to the control plants. Results obtained during this study are considered promising regarding environmental framework. However, this study was done in a laboratory scale and needs to be applied in a large scale to provide more data on the effectiveness of the digestates application. It is also recommended to apply these bio-fertilizers on different crops and various soils for a better evaluation.
Soil damage that might a-maize you ? Time to cover up !
Cristina McBride-Serrano, SHui Research Technician at Lancaster University.
Forage maize production is rapidly expanding in the UK to provide animal feed and biofuel. In North-West England (Cumbria), planting such row crops is extremely damaging to soils. Bare soil between rows, wet conditions and late harvests using heavy machinery provide a “perfect storm” that compacts and erodes soil. Winters here are predicted to become even wetter with more frequent rainfall events. Therefore, improved soil and water management is needed to hold the soil in place to avoid environmental damage off-farm.
As a research technician at Lancaster University, last growing season we assessed whether undersowing cover crop mixtures in maize would affect soil water retention and movement. We hoped that cover crops might protect the soils from erosion during the winter months. Last October, when the crop was harvested, was the wettest since 2014. The contractors had to wait over two weeks for the soils to be dry enough to avoid getting their heavy machinery stuck.
I was unprepared for the spectacle post-harvest, as the entire field looked like it had been used as a motorway. Since our trial area was the driest patch of the field, it was used as an access point during harvesting and was particularly badly damaged. There were hardly any cover crops to be seen. A month later, the field started showing signs of waterlogging due to the compaction caused by the traffic. By Christmas, the conditions had rapidly deteriorated, with runoff stripping the topsoil, transporting sediment to the end of the field and down the road. The winter months have left clear signs of erosion behind.
The farmer is aware of the damage and doesn’t want a repeat. We are continuing to work with cover crops together. This year, he is interested in interseeding rye grass in all his maize fields. We hope that earlier (cover) crop establishment will better protect the soil from harvesting operations later this year.
Since working with SHui, and after this experience, I’ve become increasingly interested in working with farmers to reduce soil degradation, manage the excess water, and improve ecosystem services, helping farmers build resilience to a changing climate. With the support of the Perry Foundation and the James Hutton Institute, I will soon start a PhD project to research the potential benefits of increased plant diversity to enhance soil-associated ecosystem services in agroecosystems. I want to support farmers by increasing crop resilience to abiotic stress and minimise environmental degradation of the sort I’ve described here.
SHui has opened my eyes to the challenges of arable cropping in Cumbria, and similar challenges faced by farmers in other countries across our project. I’m greatly looking forward to contributing to solving these challenges through my PhD research, which will continue beyond SHui.
Estimating stomatal conductance and evapotranspiration of winter wheat using a soil-plant water relations-based stress index
Received 20 October 2020, Revised 4 March 2021, Accepted 7 March 2021, Available online 18 March 2021.
Stomatal conductance, closely related to water flow in the soil-plant-atmosphere continuum, is an important parameter in the Penman-Monteith (P-M) model for estimating evapotranspiration (ET). In this study, a novel soil water stress index ω, considering intrinsic soil-plant water relations, was introduced into the Jarvis empirical estimation model of stomatal conductance to improve the representation of the effect of soil water stress on stomatal conductance. The index ω accounted not only for current water availability by combing the effects of relative distribution of soil water to roots and nonlinear stomatal response, but also for the hysteresis effect of water stress by means of the inclusion of a recovery coefficient. Combined plant and soil-based measurements from a greenhouse experiment provided the basis for investigating the relationship between leaf stomatal conductance gs and root zone soil water stress represented by ω. The response of gs to root-weighted soil matric potential was found to be nonlinear. The relationship between gs and the extent of previous water stress (i.e. the water stress recovery coefficient curve) was generalized by a power function and was verified and confirmed using results obtained from the literature. The reliability of ω was tested by coupling it into the Jarvis model to estimate leaf (gs) and canopy (gc) stomatal conductance, and thereupon into the P-M model to estimate cumulative ET (CET) in the greenhouse experiment and two field experiments. The estimated gs, gc and CET agreed well with the measurements, with root mean squared error not more than 0.0006 m s−1, 0.0020 m s−1 and 8.2 mm, respectively, and determination coefficient (Nash-Sutcliffe efficiency coefficient) consistently greater than 65% (0.14). Therefore, ω should be feasible and reliable to delineate the response of stomatal physiological reaction to water stress, and hence helpful for accurate estimation of ET using Jarvis-based P-M models.
In-depth analysis of soil management and farmers’ perceptions of related risks in two olive grove areas in southern Spain
Received 15 December 2020, Revised 15 January 2021, Accepted 19 January 2021, Available online 25 January 2021.
This manuscript presents a questionnaire-based study aimed to provide a detailed analysis on the different soil management carried out by olive farmers in two representative olive-growing areas in southern Spain (Cordoba and Estepa), their perceptions on cover crop use and the possible influence of the different types of farms and farmers’ typologies on these perceptions. Our results show a relatively large variability of soil management, with fourteen options, as a result of a combination of different alternatives for bare soil and cover crops with the use or not of pruning residues, but with a great similarity between both areas. The results indicate a high adoption of soil conservation measures in the two study areas, with 63% of farmers using cover crops and 80% a mulch of pruning residues, higher than that reported in previous studies in Southern Spain, and a trend of lower use of these techniques by less experienced and younger farmers. This high penetration of soil conservation measures resulted in a significant reduction of soil erosion risk, as indicated by the relatively low values for the cover and management factor (C) of RUSLE, also calculated and presented in this study, but also the possibility of focusing further efforts on farmers with less experience. Our results indicate the persistence of a minor, but relevant, percentage of farmers using bare soil management (37%) and no mulching (20%), with a moderate concern on the impact of soil erosion on soil degradation and provision of ecosystem services. This suggests the need to concentrate efforts also on this cluster of farmers to enhance the success of what seems to be a remarkable expansion of the use of soil conservation measures in recent decades in Southern Spain, but also in similar areas in the Mediterranean basin.