Five-year Field Trial Research Articles

Rotary Tillage Plus Mechanical Transplanting Practices Increased Rice Yields with Lower CH4 Emission in a Single Cropping Rice System

As the main contributor to greenhouse gas (GHG) in paddy soil, information on methane (CH4) emission characteristics under different tillage and cultivation practices are limited. A five-year field trial was conducted from 2019 in a single-cropping rice system in Taihu Lake region, east of China. The experiment had a completely randomized block design, and the treatments included rotary tillage plus rice dry direct seeding (RD), rotary tillage plus rice mechanical transplanting (RT), and plowing tillage plus rice mechanical transplanting (PT). We determined the rice yield, GHG emission, soil traits, and methanogens and methanotrophs in 2022 and 2023. The results revealed that PT and RT significantly increased rice yield compared to RD, whereas PT simultaneously increased CH4 emissions. The year-averaged cumulative CH4 emissions in PT were increased by 38.5% and 61.4% higher than RT and RD, respectively. Meanwhile, yield-scaled global warming potentials (GWPs) in RT and RD were lower than those in PT. Tillage and cultivation practices shifted mcrA and pmoA abundances, and PT significantly decreased pmoA abundance. The community structure and diversity of the methanogens and methanotrophs were not significantly affected. Structural equation model analyses illustrated that CH4 emissions were regulated by mcrA and pmoA directly, which in turn, regulated by soil carbon and nitrogen. Overall, rotary tillage plus mechanism transplanting was a feasible agronomic technology in a single-cropping rice system in Taihu Lake region, exhibiting higher and more stable rice productivity, accompanied with lower CH4 emissions and yield-scaled GWP.

Issue Information

Plant Biotechnology JournalVolume 21, Issue 5 p. 885-886 Issue InformationOpen Access Issue Information First published: 16 April 2023 https://doi.org/10.1111/pbi.13849AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Front cover image: The cover picture shows the five-year field trial with genetically modified hybrid aspen. Blind screening of transgenic lines in the field identified an unknown function member of 2-oxoglutarate-dependent digoxygenases which suppression increased growth and saccharification yields after a pilot-scale industrial-like pretreatment. Cover illustration refers to the article published in this issue (Donev et al., pp. 1005–1021). Volume21, Issue5May 2023Pages 885-886 RelatedInformation

Winter cover crops to reduce herbicide inputs into spring-planted maize pastoral systems in New Zealand

ABSTRACT The use of cover crops can improve the environmental sustainability of intensive cropping systems. A five-year field trial was undertaken to evaluate the effect of multi-season cover cropping on weed suppression within a no-till spring-planted maize system in the Waikato region in New Zealand. Five cover crop treatments were compared: gland clover (Trifolium glanduliferum Boiss.); faba bean (Vicia faba L); oats (Avena sativa L.); and Italian ryegrass (Lolium multiflorum Lam.), and winter fallow. The results demonstrated that in this system, herbicide treatments can be reduced to one application to terminate the winter cover crop and a single maize post-emergence application, thus reducing selection pressure for herbicide-resistance, without any loss in silage or grain production. Furthermore, a legume-based cover crop gave higher yields than the grass cover-crops and reduced the damage by the maize and grass pest cosmopolitan armyworm (Mythimna separata Walker). The build-up of crop residue over time was detrimental to the establishment of the small-seeded clover and ryegrass cover crops but good weed suppression and grain yields were achieved in the final season by replacing them respectively with the larger seeded woolly pod vetch (Vicia eriocarpa (Hausskn.) Halácsy) and a blue lupin (Lupinus angustifolius L.)/ mustard (Sinapis alba L.) mix.

Satureja montana L. Cultivated under Polypropylene Woven Fabric on Clay-Textured Soil in Dry Farming Conditions

During a five-year field trial established with Satureja montana L. under polypropylene woven fabric (PPWF) on clay-textured soil in dry farming conditions in South Banat, Serbia, the influence of a single basal application of compost and mineral fertilizers at different planting densities (3.6 and 5 plants m−2) on the yield was investigated. Single-dose fertilization positively influenced the yields of S. montana in both applied fertilization models. In the third production year, the dry herb yield achieved by applying organic fertilizers in dense cultivation (1016 g m−1) was comparable with that obtained in the mineral plot (961 g m−1). Furthermore, the plants were optimally supplied with N, P, and K macronutrients, with equal amounts removed by yield, in both tested fertilization plots. The use of PPWF proved beneficial to cultivated plants in terms of water-use efficiency and weed suppression. However, severe yield loss was observed in the fourth and fifth production years as a result of the extreme rainfall conditions; the excess moisture retained by PPWF applied to heavy clay soil favored the development of soil-borne pathogens. Other mulch materials should be further investigated for the production of S. montana on heavy clay soil.

Comprehensive effects of integrated management on reducing nitrogen and phosphorus loss under legume-rice rotations

Paddy fields-based cropping systems are usually located in areas with dense water networks, so nitrogen (N) and phosphorus (P) losses from rice paddy fields caused by runoff might pose a serious pollution risk to their surrounding water bodies. However, current research over establishing a low fertilizer input paddy-based cropping system with comprehensive management for reducing runoff losses of N and P is insufficient. A five-year field trial was carried out with a rice-fava planting system in the Erhai Lake watershed from 2015 to 2019. Three treatments were designed namely chemical fertilizer plus manure (CMF), reduced chemical fertilizer combined with manure at the same application rate under CMF treatment (RF), and returning straw plus chemical and organic fertilizers at the same rate with RF treatment (RFS). The mean annual runoff losses of total N (TN) and total P (TP) range from 0.99 to 1.39 kg ha −1 yr −1 and 0.09–0.12 kg ha −1 yr −1 . Compared with CMF treatment, RF had lower runoff losses of TN and TP by 20.86% and 23.05%, respectively, but the yields and soil fertility were also reduced. After returning straw, soil organic carbon (SOC), TN, and crop yields were maintained or even increased, and runoff losses of TN and TP were further reduced by 9.48% and 7.41%, respectively, compared with RF. Therefore, the runoff losses of N and P decreased by selecting the rice-fava rotation system and reducing chemical fertilizer input through manure application and straw returning, which greatly reduced the surplus N and P in this system. Moreover, the temporal variation in the concentration of TN and TP, along with the N:P ratio approved the existence of potential risk caused by TN and TP losses to the watershed in the early stage of rice growth. Overall, in addition to taking field measures to reduce the N and P runoff losses from paddy fields, the runoff water with high N and P concentrations in early rice growth stage cannot be ignored. • Rice-fava system with low fertilizer maintained yield and had low environment risk. • Straw returning ensured crop yields under substituting chemical fertilizer by manure. • Combined of straw returning and manure substitution reduced nutrient runoff loss. • Runoff N/P concentration and N:P ratio in early stage of rice may need interception.

Responses of Seed Yield Components to the Field Practices for Regulating Seed Yield of Smooth Bromegrass (Bromus inermis Leyss.)

Agronomic practices improve seed yield by regulating seed yield components, and the relationship between seed yield and seed yield components is still unclear in smooth bromegrass (Bromus inermis). To optimize seed production and yield in smooth bromegrass, a five-year field trial was designed with split-split-plot to study the combined effects of row spacing (30, 45, 60, and 75 cm), phosphorus (0, 60, 90, and 120 kg P ha−1) and nitrogen (0 and 100 kg N ha−1) on seed yield and seed yield components including fertile tillers m−2 (FTs), spikelets per fertile tiller (SFT), florets per spikelet (FS), and seeds per spikelet (SS). The results showed that FTs as a key factor had a positive effect to seed yield with the biggest pathway coefficient, while SS had a negative effect. Meanwhile, an interaction effect between FTs and SS was observed. FS and SS were increased with phosphorus application under the condition of sufficient nitrogen. In addition, sufficient precipitation at the non-growing season resulted in more FTs in the next year in rain-fed regions. Therefore, the optimum seed yield of smooth bromegrass can be obtained with row spacing (45 cm), nitrogen (100 kg N ha−1), and phosphorus application (60 kg P ha−1).

Saccharification Potential of Transgenic Greenhouse- and Field-Grown Aspen Engineered for Reduced Xylan Acetylation.

High acetylation of xylan in hardwoods decreases their value as biorefinery feedstocks. To counter this problem, we have constitutively suppressed RWA genes encoding acetyl-CoA transporters using the 35S promoter, or constitutively and wood-specifically (using the WP promoter) expressed fungal acetyl xylan esterases of families CE1 (AnAXE1) and CE5 (HjAXE), to reduce acetylation in hybrid aspen. All these transformations improved the saccharification of wood from greenhouse-grown trees. Here, we describe the chemical properties and saccharification potential of the resulting lines grown in a five-year field trial, and one type of them (WP:AnAXE1) in greenhouse conditions. Chemically, the lignocellulose of the field- and greenhouse-field-grown plants slightly differed, but the reductions in acetylation and saccharification improvement of engineered trees were largely maintained in the field. The main novel phenotypic observation in the field was higher lignification in lines with the WP promoter than those with the 35S promoter. Following growth in the field, saccharification glucose yields were higher from most transformed lines than from wild-type (WT) plants with no pretreatment, but there was no improvement in saccharification with acid pretreatment. Thus, acid pretreatment removes most recalcitrance caused by acetylation. We found a complex relationship between acetylation and glucose yields in saccharification without pretreatment, suggesting that other variables, for example, the acetylation pattern, affect recalcitrance. Bigger gains in glucose yields were observed in lines with the 35S promoter than in those with the WP promoter, possibly due to their lower lignin content. However, better lignocellulose saccharification of these lines was offset by a growth penalty and their glucose yield per tree was lower. In a comparison of the best lines with each construct, WP:AnAXE1 provided the highest glucose yield per tree from saccharification, with and without pretreatment, WP:HjAXE yields were similar to those of WT plants, and yields of lines with other constructs were lower. These results show that lignocellulose properties of field-grown trees can be improved by reducing cell wall acetylation using various approaches, but some affect productivity in the field. Thus, better understanding of molecular and physiological consequences of deacetylation is needed to obtain quantitatively better results.

Including chicory and selecting white clover varieties as strategies to improve temporal stability of forage yield and quality in white-clover-based temporary grassland

Clover-based crop stands are gaining importance in temporary grasslands for intensive livestock production. However, knowledge of their optimal composition to achieve high temporal stability of forage provision is insufficient, particularly so for long cultivation periods. A five-year field trial was conducted to study the effect of adding a non-leguminous forb to clover-based crop stands and to evaluate the impact of the clover variety on inter- and intra-annual stability of forage yield and quality. At two contrasting sites, we cultivated eight white clover (Trifolium repens) populations in pure stands and in mixtures with perennial ryegrass (Lolium perenne) and/or chicory (Cichorium intybus) under a four-cut system without fertilization and determined the seasonal and annual forage yield and quality. Temporal stability of forage provision differed between crop stand types, with marked differences between years and cropping sites. In the study years with lower than long-term precipitation, adding chicory enhanced temporal stability of forage yield as compared to white clover pure stands or clover-grass mixtures at least at the site with deep soil, and maintained or enhanced that of forage quality as compared to clover-grass mixtures. This was often reversed in the study years with higher than long-term precipitation. The white clover populations only slightly varied in temporal stability of forage provision, and did so independently of the crop stand type. Our findings highlight the potential but also constraints of including a non-leguminous forb in unfertilized mown clover-based crop stands, as well as of decisions on the clover variety, to improve temporal stability of forage provision.

Five-Year Field Trial of Eight Camelina sativa Cultivars for Biomass to be Used in Biofuel under Irrigated Conditions in a Semi-Arid Climate

Camelina sativa is a promising oilseed crop used for dietary oil and as a biofuel feedstock. C. sativa is a highly adaptable, cool season crop that can be grown on marginal lands with minimal inputs, making it potentially suitable for growth in Northern Nevada and other cooler and drier semi-arid regions of North America. A five-year (2011 to 2015) field trial was conducted to evaluate the seed yield, oil content, and oil and biodiesel production potential of eight C. sativa cultivars in semi-arid regions of Northern Nevada. Columbia, Cheyenne, Calena, and Blaine Creek were ranked as the top four varieties based on the five-year study of mean seed yield, oil content, and estimated oil and biodiesel production values, although none of the cultivars were significant (p > 0.05). Overall, Columbia displayed the highest seed yield, harvest index, oil yield and potential biodiesel production of 910 kg ha−1, 0.147, 273.4 kg ha−1, and 86.4 L ha−1, respectively, across five growing seasons. For each individual year across the eight cultivars, seed yield, oil content, oil and potential biodiesel production was highest in 2015, and lowest in 2012 and 2013 (the drier years). The seed yields of this study fall within the ranges of yields reported in both the irrigated and rainfed locations of the Western United States. Based on the seed yield, oil, and the estimated oil and biodiesel productivity reported in this study, C. sativa can be grown successfully with supplemental irrigation in semi-arid environments like Nevada.

Inter-annual variation in P speciation and availability in the drought-rewetting cycle in paddy soils

Successive application of phosphorus (P) fertilizer under different cropping systems could result in remarkable changes in soil P fractions, accompanied by inducing soil P accumulation and increasing eutrophication risks. However, relatively little attention has been paid to annual changes in soil P fractions and P losses via runoff in drought-rewetting paddy fields. In the present study, we explored inter-annual variations in soil P speciation, availability and runoff P in a five-year field trial in a winter wheat and summer rice rotations system, and in different rice-growth stages. Four P fertilization treatments were applied, including P fertilization in both farming seasons (wheat and rice) (PR + W), application of P fertilizer only in rice-growing seasons (PR), application of P fertilizer only in wheat-growing seasons (PW), and no P fertilization (Pzero). Our results showed that P fertilization treatments (PW, PR, and PR + W) significantly altered the proportions of inorganic P (Pi) fractions, while no P fertilization in the wheat-growing seasons (Pzero, PR) significantly decreased NaHCO3-Pi contents in the wheat-growing seasons and decreased NaHCO3-Pi and NaOH-Pi concentrations in the rice-growing seasons (p < 0.05). Application of P fertilizer in the wheat-growing seasons treatments (PW, PR+W) maintained the stability of soil P fractions both in the wheat- and rice-growing seasons. Moreover, compared to the PR+W treatment, the PW treatment reduced total P (TP) losses from runoff. For inter-annual drought-rewetting variation in P speciation and availability, there was a significant correlation between Olsen-P and NaHCO3-Pi and NaOH-Pi contents in the wheat-growing seasons, and Olsen-P was significantly correlated with NaHCO3-Pi, NaOH-Pi, and HCl-P in the rice-growing seasons. Furthermore, we focused on the change in detailed rice-growth stages, and found aeration significantly increased NaHCO3-Pi, NaOH-Pi, NaOH-Po and HCl-P contents, and there was a significant correlation between soil Olsen-P and the P fractions in the A-aeration growth stage in rice, which could be attributed to the short-term drought-rewetting cycle facilitating the release of soil P. The present study revealed changes in soil P speciation and availability in a drought-rewetting cycle in paddy soils, and indicated the optimized agricultural P management strategies had the potential to reduce environmental risks.

Soil acidity, available phosphorus content, and optimal biochar and nitrogen fertilizer application rates: A five-year field trial in upland red soil, China

Biochar has been used as an amendment to reduce soil acidity and increase soil nutrients content and crop yields. While many laboratory studies have focused on the short-term effects of single application of biochar on soil properties, little is known about the long-term effects of biochar combined with nitrogen fertilizer on soil pH, available P content, and crop yields. Additionally, few studies have investigated the optimal biochar and nitrogen fertilizer application proportions in worldwide. A five-year field trial was conducted to study the effects of biochar (0, 5, 20 and 40 t ha−1) combined with nitrogen fertilizer (0, 60, 90, 120 kg ha−1) on soil pH, available P, rapeseed, and sweet potato yield. Multi-dimensional nonlinear regression models were built to predict the highest crop yields and the optimal economical biochar and nitrogen fertilizer application rate. The results were as follows: high dose of biochar (20 and 40 t ha−1) combined with nitrogen fertilizer can significantly increase soil pH, available P content, rapeseed and sweet potato yields in the first year; however, the effectiveness on these metrics weakened over time, biochar needed to be applied approximately every three years in the rapeseed-sweet potato rotation system in order to maintain the positive effects on crop yields. The multi-dimensional regression models showed that the highest yields of rapeseed and sweet potato are 3.34 t ha−1 and 39.7 t ha-1 when the application rates of biochar were 80.8 t ha-1 and 59.4 t ha-1 respectively. However, high dosages of biochar can increase crop yields without increasing net income. The highest net income was $29,206 ha−1 5y−1 ($5841 ha−1 y−1) when the application rates of biochar and nitrogen fertilizer are 11.4 t ha-1 and 102 kg ha-1, respectively. The integrated use of biochar and nitrogen fertilizer was a promising strategy to obtain higher and sustained productivity of the rapeseed-sweet potato cropping system in upland red soil. From the point of view of crop yields and economic benefits, 11.4 t ha−1 biochar was the optimal biochar application rates for the local farmers.

Grain yield and grain protein of old and modern durum wheat cultivars grown under different cropping systems

A five-year field trial was performed in a typical Mediterranean environment to compare grain yield (GY) and GY stability, grain protein percentage (GP) and GP stability resulting from different cropping systems: two based on 14 old durum wheat landraces/cultivars grown in low-fertility soils; and one based on 14 modern cultivars grown in high-fertility soils. Cropping systems were also differentiated in terms of sowing date, sowing rate (250 vs. 350 viable seeds m−2 for the modern cultivars only) and nitrogen rate (36, 76 and 112 kg N ha-1 on average for the ‘OLDlow’, ‘OLDmedium’ and ‘MODERN’ cropping systems, respectively). Depending on the year, the GY of the OLDlow system ranged from 22% (2017) to 74% (2016) of that obtained in the MODERN system. The maximum GY obtained in the OLDlow system was 4.18 t ha-1. The average GY obtained with modern cultivars varied from 5.6 to 6.6 t ha-1; with the exception of that obtained in 2016 (only 3.37 t ha-1). The higher GY of the modern cultivars was the main cause of higher rainfall productivity, reaching a maximum value of 23 kg ha-1 mm-1. In all the systems, the between-year variation in GY was associated with the corresponding variation in grain number m−2 (GNO), but anthesis date was only negatively associated with GY for the old cultivars, while GP was negatively associated with GY and GNO only in the modern cultivars. GP was always higher in the OLDlow (11.9–14.0 %) and OLDmedium (13.4–15.7%) systems compared with the MODERN one (10.5–12.1 %) in spite of the lower nitrogen fertilization rate, which also assured a higher nitrogen fertilizer recovery efficiency.The three systems were comparable in terms of GY stability, in spite of the later anthesis of old cultivars, which was expected to exacerbate the impact of the terminal drought typical of Mediterranean environments. With regard to GP stability, the old cultivars were less stable than the modern ones. The greatest GxY interaction was generated by the more favourable years, whereas the least interaction occurred in the year with the most severe drought stress. Rainfall, during post-anthesis in particular, but also after sowing, was the main driver of GxY interaction for GY and GP, either directly or via its interaction with nitrogen availability.

The crucial factors of soil fertility and rapeseed yield - A five year field trial with biochar addition in upland red soil, China

Biochar has been used as an amendment to improve soil fertility and increase crop yield. However, the effects of biochar on soil properties and rapeseed yield in upland red soil have not been thoroughly investigated, and the factors crucial for rapeseed yield are not yet clear. A five-year field trial was conducted to investigate the effects the of biochar (biochar application rates of 0, 2.5, 5, 10, 20, 30, and 40 t ha−1, respectively) on soil physicochemical and microbial properties as well as rapeseed yield in upland red soil in Jiangxi Province, China. Results showed that biochar can significantly increase soil pH, available phosphorus, organic carbon, Ks, and water retention, however, the influences of biochar on these indexes declined over time. Soil total nitrogen increased significantly when the dose of biochar exceeded 5 t ha−1, and the content of total nitrogen in the 40 t ha−1 biochar treatment increased each year. While the application of biochar gradually increased the contents of NH4+-N, NO3−-N and enhanced the soil microorganism and enzymatic activities during the first three years, they had returned nearly to their starting values by the end of this study. Rapeseed yield and yield components were significantly improved relative to the control for all biochar amendments in the first year, but the rapeseed yield in all biochar treatments decreased steadily after 2012. According to the principal components analysis and path analysis, the most responsive parameters in the upland red soil were soil acidity and hydraulic properties, meanwhile, soil acidity and hydraulic properties had greater impacts on rapeseed yield than did other indexes. Taken together, these results suggest that biochar can significantly improve soil fertility and rapeseed yield, but the improvements are not permanent. Soil acidity and hydraulic properties were the crucial factors that determined soil fertility and rapeseed yield in upland red soil.

Properties of a sandy clay loam Haplic Ferralsol and soybean grain yield in a five-year field trial as affected by biochar amendment

Biochar may increase soil fertility and crop yield by enhancing soil organic carbon (SOC), nutrient availability and water retention. However, the mechanisms through which biochar effects crop yield at field scale and the time span over which biochar can affect soil properties and crop yield are still little known. The aim of this study was to evaluate the effect of wood biochar as soil amendment, combined with the application of synthetic fertilizer in a zero-tillage system, on soil physical-chemical properties and soybean grain yield in a 5-year field trial settled on a sandy clay loam Haplic Ferralsol of the Brazilian savannah. Immediately after biochar application (year 0), soil pH and plant available water (PAW) increased and Al3+ and bulk density (BD) decreased linearly with biochar application rate. Later, in year 5, biochar had no effect for PAW and BD increased with biochar rates. The SOC was not affected until the third year after application, but increased linearly with biochar rates at 4 and 5years after its application. Macro-porosity (MAC) was affected in a quadratic manner reaching a maximum at 8Mgha−1 biochar rate in years 0 and 2, however in year 5 it decreased with increasing biochar rates. Soybean grain yield increased with biochar rates until the third year after its application. There was almost no interaction effect of biochar and synthetic fertilizer; except for potassium (K+) availability and grain yield in year 3. Possible control mechanisms of biochar effect on soybean grain yield through its effect on soil fertility and physical-hydraulic properties are discussed. The effect of biochar on soybean yield depended on multiple independent factors that included soil and environmental variables. Because of this its effect on yield was variable through the years, which makes it rather unpredictable. Biochar, however, may have an important contribution to sustainable production through enhancing the effect of conservation soil management, like the use of green manure or mulching, on SOC accumulation.

The combination of subsoil and the incorporation of corn stover affect physicochemical properties of soil and corn yield in semi-arid China

ABSTRACTThe main objective of this study was to investigate the effects of combining subsoil and incorporation of corn stover on soil profile, soil physicochemical properties, and corn yield. A five-year field trial was conducted that consisted of two treatments arranged in a completely random design and replicated three times. Two soil management operations were tested: subsoil + corn stover incorporation (plow construction [PC] treatment) and conventional rotary tillage (control check [CK] treatment). Compared with rotary tillage, it was found that combining subsoil and corn stover incorporation significantly affected corn grain yield in all seasons. Further, combining subsoil and corn stover incorporation significantly increased the thickness of the plow layer, quantity of plow layer soil, thickness of the plow pan and soil bulk density, as well as soil organic matter, available nitrogen, available phosphorus, and available potassium. Evidence indicates that reconstructing the soil plow layer through combination of subsoil and corn stover incorporation improved soil structure, nutrient content, and corn yield. It is of interest that farmers are now applying subsoil and returning crop straw instead of solely relying on rotary tillage.

Suitability of Untreated and Composted Olive Mill By-Products as Amendments in Organic Olive Orchards

ABSTRACT.In the Mediterranean area, the proper soil application of olive pomace compost (OPC) and olive mill wastewater (OWW) could play a crucial role in replacing the annual losses of organic matter, thus sustaining agriculture. Therefore, the objectives of this five-year field trial were: (i) to investigate the effects of OWW and OPC, applied at different doses, on soil fertility in an organic Mediterranean olive grove; (ii) to assess the influence of treatments on production and quality responses of olive trees. In a randomized block experimental design, the following experimental treatments were compared: (i) OWW; (ii) OPC; (iii) the same olive pomace compost used in treatment (ii) distributed to supply a double rate of N per plant (OPCx2). These treatments were compared to: (a) commercial NPK organic-mineral fertilizer (Org-min); and (b) green manure of broad bean (GM). Soil parameters were analyzed to assess soil fertility at the beginning of the field trial and in the medium and longer term. At harvest, agronomical performance of treatments was also evaluated. At the end of the field trial, olive pomace compost (mean of OPC and OPCx2) significantly increased total organic carbon by 47.5% compared to Org-min, and the humified organic carbon values were significantly higher for OWW, OPC, and OPCx2, as compared to GM. The values for olive yield components in GM were lower than in OPC and OWW. Therefore, results showed that OWW and OPC application could be a suitable substitute of traditional methods (GM) to improve overall soil fertility and sustain yield in organic olive grove.

PERFORMANCE OF ITALIAN STRAWBERRY GENOTYPES ON FUMIGATED, NON-FUMIGATED SOILS AND ORGANIC CULTURE

The performance of 10 strawberry (Fragaria × ananassa) genotypes from Italian breeding programs was tested on cold-stored plants and fresh plug plants in a five-year field trial at Cesena in Italy's Po Valley with and without pre-plant soil fumigation. The same genotypes were evaluated in the last 2 years under organic culture at the same farm. The plants in fumigated soil had 15% more brunch crowns, 30% higher yield and 6% bigger fruit than those grown in non-fumigated soil. Significant genotype × fumigation interactions were detected. Cultivars 'Record', 'Roxana' and the advanced selections '97.70.3', '97.129.11', '98.78.7' and '00.92.4' showed the highest yields both in fumigated (more than 900 g/plant) and non-fumigated soils (more than 700 g/plant). Selection '97.129.11' is well suited to the plug-plant technique and had higher yield, more than 800 g/plant, than that recorded on cold-stored plants grown in non-fumigated soil. Organic plug plants produced the same yield as cold-stored plants, with cultivars 'Record' and 'Roxana' and selections '97.129.11' and '00.92.4' showed good adaptability to this system. Our results confirm that plant productivity is increased by fumigation, although some genotypes showed high yield in non-fumigated and organic culture. This appears to be a good opportunity for developing cultivars specifically adapted to the sub-lethal effects of organisms in non-fumigated and organic soils.

The INS model system

The construction of a pilot for “Information Network System” (INS), started recently, is a milestone in INS development. The pilot plant, called a Model System, started its five-year field trial in September, 1982. Through the test, studies will be made on technical feasibility and service requirements. Further, an intensive assessment for the formation of INS will be made from the viewpoints of the social and cultural sciences. With the results obtained from the Model System, comprehension of what INS can be gained, and problems relating to establishment of INS can be solved.

The effects of topdressing and overs owing hill pastures

Summary The results of a five-year field trial to nleasure the effects of superphosphate and surface sowing with clovers on hill pastures are presented. Clover establishment from surface sowing was recorded in permanent quadrats, and changes in botanical composition of the pasture were measured by the point analysis method. Herbage yields and composition were determined by frame cuts. By the end of the five-year period, oversowing alone had increased yield by 22 %, fertiliser alone by 36 % and seed and fertiliser together had doubled yield.