High-input Systems Research Articles

Long-term weed dynamics and crop yields under diverse crop rotations in organic and conventional cropping systems in the Canadian prairies

Alternative cropping systems are gaining attention throughout the world in order to increase the sustainability of agro-ecosystems. On the Canadian prairies, the tillage-based crop-fallow system has been replaced by no-till reduced input systems or tillage-based organic systems with more diversity in crop rotations but with no external inputs. However, the long-term effects of these alternative systems on weed and yield parameters have not been assessed. A study to examine weed and crop yield dynamics under diverse cropping systems was conducted within a 18-year cropping systems study near Scott, Saskatchewan. The trial was laid out in a split-split-plot design with four replicates. The main plots were three levels of inputs; a high input system (HIGH) that used tillage and inputs to maximize yield, a reduced system (RED) that used no-till practices and minimal inputs, and a tillage-based organic system (ORG) with no external inputs. The subplots were cropping diversity (rotations); fallow-annual grains (LOW), diversified annual grains (DAG), and diversified annuals and perennial forage (DAP). The sub-sub plots were the six phases of each rotation. There was an input by rotation interaction for weed biomass but not for weed density and crop yields. ORG systems had 7× and 4× greater weed density (107 plants m−2), 4× higher weed biomass (154kgha−1), and 32% and 35% lower yields (1052kgha−1) than RED and HIGH systems respectively. RED and HIGH input systems had similar crop yields and lower weed density than ORG. The LOW rotation had the lowest weed density. LOW and DAG rotations had similar yields, which were higher than in DAP. All systems showed an increase in weed density and biomass over time but did not impact on crop yields which was increasing over time likely influenced by a concurrent increase in rainfall. This study concludes that eliminating tillage and reducing agrochemicals is possible but eliminating agrochemicals requires better crop rotations for weed management as well as for nutrient management.

Single marker assisted selection in Brazilian Morada Nova hair sheep community-based breeding program

Morada Nova hair sheep show traits desirable for lamb production especially in extensive production systems in Northeastern Brazil, representing an important genetic resource for producing lamb in semi-arid climates in Brazil and elsewhere. Performance testing has been carried out annually with this breed since 2008. In the present study, Morada Nova sheep from two Brazilian states: Ceará (140 animals) and São Paulo (112 animals) were genotyped for a SNP associated with litter size, which is almost only found in Brazilian locally adapted sheep breeds (FecGE). The total observed frequency of FecGE was 0.65, while an increased number of observed heterozygotes was also observed (χ2=7.274, p<0.01). No significant FecGE allele frequency differences were observed (p=0.3708) in 139 performance-tested rams classified as Elite/Superior or Regular/Inferior in the states of Ceará and São Paulo. Considering that litter size has been shown to positively affect farm profitability in medium to high input systems, we suggest that inclusion of FecGE genotyping information in future selection indexes estimated with basis on performance test data, fine-tuned to regional production systems may contribute to increase profitability gains observed in the Morada Nova community-based breeding program.

Safflower Growth as Affected by Cropping Intensity and Micronutrient Foliar Spray

ABSTRACTPlant growth analysis is a useful set of quantitative methods that describe the performance of whole plant systems. To evaluate growth changes in safflower (Carthamus tinctorius L.), an experiment was conducted as a split-plot arrangement with three replications at the Urmia University farm in 2011. Cropping systems (main plots) included conventional (high-, medium-, and low-input) and ecological (eco-friendly) systems. Micronutrient treatments [separate and combined use of Zn (2 g/l) and Mn (3 g/l), water spray and control] were the subplots. Leaf area index (LAI), total dry matter (TDM), crop growth rate (CGR), and relative growth rate (RGR) were evaluated and subjected to variance and regression analyses. Leaf area index showed an early increasing trend up to 900 growing degree days (GDDs); afterwards, LAI declined in both cropping systems and micronutrient treatments. In the two sets of treatments, a linear response for TDM and RGR was observed. The trend for CGR in response to treatments was different; except for high-input system, the trend was linear for Zn+Mn and quadratic for other treatments. The LAI and TDM were less in ecological and low-input systems than in medium and high-input systems. Application of micronutrients increased growth parameters, particularly during the early growth stages. Because decreased chemical inputs did not adversely affect safflower growth, farmers should be able to reduce chemical inputs to obtain an acceptable level of safflower production.

Morphological diversity in a barley composite cross-derived population evolved under low-input conditions and its relationship with molecular diversity: indications for breeding

SUMMARYIn order to reduce the environmental impact of agriculture and improve the resilience and sustainability of our food systems, there is an increasing interest in shifting from the present agricultural systems, which are characterized by high external inputs, to low-input productive systems characterized by high resilience and sustainability. Purposely developed varieties are needed for the latter. With the rapid disappearance of landraces, heterogeneous populations such as composite cross populations (CCPs) or line mixtures, developed through evolutionary plant breeding, could be the ideal source of breeding material for the development of new cultivars for low-input productive systems. Parental lines of CCPs should be selected among old breeding lines, varieties or landraces because the specific characteristics required for low-input or organic farming systems might have been lost during selection of modern varieties. In the current scenario of renewed interest in evolutionary plant breeding, the evolution of diversity in heterogeneous populations needs to be better investigated to maximize the advantages that can be obtained by their utilization.The present paper reports on the analysis of 88 barley plants chosen randomly from a CCP, namely AUT DBA (where AUT indicates autumn sowing and DBA is the acronym of the former Department) that was multiplied for 13 years under a low-input management system without any conscious human selection, aiming to investigate the morphological diversity still existing in the population and its potential value as source of breeding material for low-input/organic agriculture and understanding the traits that contributed to the adaptive success of certain groups of individuals.Eighteen plant and spike morphological traits were analysed using bi-dimensional spatial analysis, cluster analysis, non-parametric tests and multivariate approaches. Low lodging and loose smut damage were observed in the CCP where several individuals were superior to the best control for at least one of the four yield-related traits, namely spike weight, number of seeds per spike, weight of seeds in a spike and grain weight. Three morphological clusters were identified using cluster analysis. Clusters 2 and 3 grouped the largest number of CCP individuals which, compared with those in cluster 1, were characterized mainly by heavier spikes with higher seed number, taller culms and early flowering. Interestingly, the plant architecture of all the controls was different from that of the most frequent genotypes in the CCP, showing that low-input systems may require a plant architecture different from the one usually considered as the most suitable for high-input systems. Taking advantage of results from Raggiet al. (2015), phenotypic data were also analysed according to individual genetic group assignment. Results suggest that plant height at the beginning of stem elongation, and days to heading, together with traits related to culm and leaf morphology, could have played a significant role in determining the success of plants from genetic group D, which is the group most represented in the CCP.According to the wide range of morphological diversity existing in the AUT DBA and the high percentage of lines that show favourable combinations of different traits, this population could be a useful gene-pool from which to select lines for breeding activities. Even though further use of the CCP for breeding purposes may be limited by its possible evolution, there are different ways of manipulating the CCP to counteract the undesirable changes without great economic and/or technical efforts. The high number of multi-locus genotypes and the evolutionary responses observed in AUT DBA show that the prediction that phenotypic micro-evolution in natural systems may be limited by low genetic variances in harsh environments and low selection pressure in good environments is not necessarily true for low-input systems.

Comparison greenhouse gas (GHG) emissions and global warming potential (GWP) effect of energy use in different wheat agroecosystems in Iran.

The aims of this study were to determine energy requirement and global warming potential (GWP) in low and high input wheat production systems in western of Iran. For this purpose, data were collected from 120 wheat farms applying questionnaires via face-to-face interviews. Results showed that total energy input and output were 60,000 and 180,000 MJha(-1) in high input systems and 14,000 and 56,000MJha(-1) in low input wheat production systems, respectively. The highest share of total input energy in high input systems recorded for electricity power, N fertilizer, and diesel fuel with 36, 18, and 13%, respectively, while the highest share of input energy in low input systems observed for N fertilizer, diesel fuel, and seed with 32, 31, and 27%. Energy use efficiency in high input systems (3.03) was lower than of low input systems (3.94). Total CO2, N2O, and CH4 emissions in high input systems were 1981.25, 31.18, and 1.87kgha(-1), respectively. These amounts were 699.88, 0.02, and 0.96kgha(-1) in low input systems. In high input wheat production systems, total GWP was 11686.63kg CO2eq ha(-1) wheat. This amount was 725.89kg CO2eq ha(-1) in low input systems. The results show that 1ha of high input system will produce greenhouse effect 17 times of low input systems. So, high input production systems need to have an efficient and sustainable management for reducing environmental crises such as change climate.

Effects of diet forage proportion on maintenance energy requirement and the efficiency of metabolizable energy use for lactation by lactating dairy cows

The objective of the present study was to examine the effect of dietary forage proportion (FP) on metabolizable energy (ME) requirement for maintenance (MEm) and the efficiency of ME use for lactation (kl) in lactating dairy cows. Data used were derived from 32 calorimetric chamber experiments undertaken at our institute between 1992 and 2010, including data from 818 Holstein-Friesian cows (HF), 50 Norwegian Red cows, and 62 crossbred cows (Jersey × HF or Norwegian Red × HF). Animals were offered forage-only rations (n=66) or forage and concentrate rations (n=864) with FP ranging from 18 to 100% (dry matter basis). The effect of FP was evaluated by dividing the whole data set into 4 groups according to the FP ranges, categorized as FP <30%, FP=30 to 59%, FP=60 to 99%, and FP=100%. The MEm for individual cows was calculated from heat production minus energy losses from inefficiencies of ME use for lactation, energy retention and pregnancy, and kl was obtained from milk energy output adjusted to zero energy balance (El(0)) divided by ME available for production. Increasing FP significantly reduced ME intake and milk energy output, although the differences between the 2 low FP groups were not significant. However, increasing FP significantly increased the ratio of heat production over ME intake and MEm (MJ/kg0.75), with the exception that the increases did not reach significance in heat production/ME intake between FP <30% and FP=30 to 59%, or in MEm between FP=60 to 99% and FP=100%. However, the FP had no significant effect on the kl values, which were similar among the 4 groups of cows. The effect of FP was also evaluated using the linear mixed regression technique relating El(0) to ME intake. The results demonstrated that with a common regression coefficient (slope), the regression constants (intercepts) taken as net energy requirement for maintenance significantly increased with increasing FP. However, the increase between the 2 high FP groups did not research significance. It is concluded that increasing diet FP had no effects on kl but significantly increased maintenance energy requirement (MJ/kg0.75). These results indicate that using the current energy feeding systems to ration dairy cows managed under low input systems may underestimate their nutrient requirements, because the majority of feeding systems adopted globally do not differentiate the maintenance energy requirements between low and high forage input systems.

Influence of liquid-volume and airflow rates on spray application quality and homogeneity in super-intensive olive tree canopies

Olive is a key crop in Europe, especially in countries around the Mediterranean Basin. Optimising the parameters of a spray is essential for sustainable pesticide use, especially in high-input systems, such as the super-intensive hedgerow system. Parameters may be optimised by adjusting the applied volume and airflow rate of sprays, in addition to the liquid to air proportion and the relationship between air velocity and airflow rate. Two spray experiments using a commercial airblast sprayer were conducted in a super-intensive orchard to study how varying the liquid volume rate (testing volumes of 182, 619, and 1603lha−1) and volumetric airflow rate (with flow rates of 11.93, 8.90, and 6.15m3s−1) influences the coverage parameters and the amount and distribution of deposits in different zones of the canopy.. Our results showed that an increase in the application volume raised the mean deposit and percentage coverage, but decreased the application efficiency, spray penetration, and deposit homogeneity. Furthermore, we found that the volumetric airflow rate had a lower influence on the studied parameters than the liquid volume; however, an increase in the airflow rate improved the application efficiency and homogeneity to a certain threshold, after which the spray quality decreased. This decrease was observed in the high-flow treatment. Our results demonstrate that intermediate liquid volume rates and volumetric airflow rates are required for the optimal spraying of pesticides on super-intensive olive crops, and would reduce current pollution levels.

An analysis of the energy efficiency of winter rapeseed biomass under different farming technologies. A case study of a large-scale farm in Poland

The article presents the results of a three-year study investigating the impact of production technology on the energy efficiency of winter rapeseed produced in large-scale farms. Rapeseed biomass produced in a high-input system was characterized by the highest energy demand (30.00 GJ ha−1). The energy demand associated with medium-input and low-input systems was 20% and 34% lower, respectively. The highest energy value of oil, oil cake and straw was noted in winter rapeseed produced in the high-input system. In the total energy output (268.5 GJ ha−1), approximately 17% of energy was accumulated in oil, 20% in oil cake, and 63% in straw. In lower input systems, the energy output of oil decreased by 13–23%, the energy output of oil cake – by 6–16%, and the energy output of straw – by 29–37% without visible changes in the structure of energy accumulated in different components of rapeseed biomass. The highest energy gain was observed in the high-input system. The low-input system was characterized by the highest energy efficiency ratio, at 4.22 for seeds and 9.43 for seeds and straw. The increase in production intensity reduced the energy efficiency of rapeseed biomass production by 8–18% (seeds) and 5–9% (seeds and straw).

Environmental assessment of tropical perennial crops: the case of the Brazilian cashew

This study is an original environmental assessment of the Brazilian cashew, a perennial tree cultivated in 30 tropical countries that yields four products: nuts, apples, gum and wood. While economic and agronomic data regarding cashew are available worldwide, the environmental issues related to the main production systems and products commercialized by Brazilian farms have not been discussed consistently. This environmental assessment is important to guide the efforts of researchers and farmers for improving the environmental performance of cashew cropping systems and products. Life cycle assessment is applied to assess the environmental impacts of cashew systems and products, considering multi-cropping systems, agriculture functions and allocation procedures. Two cashew cropping systems are compared: (i) a high-input system, or reference system, developed through 20 years of research, and (ii) a low input system, as defined by a sample of farms practicing multi-cropping systems. Aspects and impacts of these systems are reported via the following production stages: nursery, establishment, and low and full production. Two agriculture functions are adopted to analyze the cropping systems: land management (impacts per hectare) and financial (impact per US$ from total sales receipts). The impacts of cashew products are evaluated using the crop production function (per kilogram of product). The impacts of products are measured using both mass and economic allocation. This study shows that the low and full production stages account for the majority of impact in both cropping systems, but land transformation for the establishment of cashew orchards is the main contributor of climate change. The analysis of multiple agriculture function shows different results for the study of cashew production systems and products. Considering the land management function (impacts per hectare), the low-input system causes less significant environmental impact, when compared to the high-input system, in all categories but toxicity. When the financial function is analyzed (impacts per US$ from total sales receipts from one ha), the low-input system achieves better performance for only eutrophication and water depletion impact categories. The analysis of the crop production function (impacts per kilogram of product) shows that the choice of allocation procedure also affects the results when comparing the impact values of products from different cropping systems. If the choice is for mass allocation, products from the low-input system achieve better environmental performance, but if economic allocation is chosen, products from the high-input system perform equal or better than when produced in the low-input system. From the joint analysis of agriculture functions, the conclusion is that the best option to improve the environmental performance of the Brazilian cashew production is to adjust the high-input system with modifications regarding fertilization and pest management. From this case study, the benefits of considering multi-agriculture functions and accounting for all production stages in the study of perennial crops are highlighted. The importance of developing emission and characterization factors to reduce uncertainty when estimating pollutant loads and evaluating impacts of perennial crops cultivated in tropical regions is also discussed. This study advances the knowledge base on the environmental assessment of perennial crops in general, and on cashew crops specifically.

Contraction force versus action potential duration of cardiomyocytes: which methodology is more informative for selection of effective 1,4-dihydropyridine compounds in experimental research?

Background. Identification of activity properties of new synthesized compounds is important to help choose the adequate research methodology. The goal of this experimental research was to determine the relationship between the chemical structure of 25 compounds of 1,4-dihydropyridine derivatives and their effects on the contraction force of guinea pig papillary muscles and the action potential (AP) duration. Methods. AP recordings were obtained with standard microelectrodes that were made from borosilicate glass capillaries, filled with 2.5 M KCl and connected to the high-input impedance amplification system. 1.0 Hz stimulation frequency was used. The contraction of papillary muscles was recorded by using a force transducer. Both signals (inotropic response and AP) were digitised by an A/D converter and registered by a computer specialised program. Results. The results have shown that most of 1,4-dihydropyridine derivatives possessed the negative inotropic action and had the negligible impact on the AP duration. It was identified that 1,4-dihydropyridine compound OSI 9719 (2-propoxyethyl-4-difloemethoxyphenyl-2-methyl-5-nitro-1,4-dihydro­pyridine-3carbo­xylate) had a prolonged duration of AP and simultaneously increased the force of contraction (p

Impacts of eucalypt plantation management on soil faunal communities and nutrient bioavailability: trading function for dependence?

Short-rotation forestry systems provide a range of ecosystem goods and services, yet the effects of intensive management on soil invertebrate community composition and ecosystem functioning are relatively unknown. Using an established eucalypt plantation study system, we investigated the effects of irrigation and inorganic fertilisation, and a dual fertilisation and irrigation treatment, on soil invertebrate abundance and community composition. Additionally, plant root simulator probes were used to estimate the effect of these interactions on nutrient bioavailability as a proxy for ecosystem functioning. Fertilisation reduced soil mite and nematode abundance when applied with irrigation, likely due to the increased solubilisation of inorganic fertilisers in water-limited soils. However, differences in soil invertebrate abundances were not associated with changes in plant nutrient bioavailability. Our findings suggest that high input systems can maintain productivity at the expense of shifts in the soil faunal community, which creates a “lock-in”, whereby there is a continuous need for artificial inputs in order to maintain productivity. Reliance on artificial inputs may reduce the soil’s intrinsic capacity to maintain natural ecosystem function in the longer term and should therefore be considered in plantation planning and management.

Economics of Utilizing Alternative Containers in Ornamental Crop Production Systems

As high-input systems, plant production facilities for liner and container plants use large quantities of water, fertilizers, chemical pesticides, plastics, and labor. The use of renewable and biodegradable inputs for growing aesthetically pleasing and healthy plants could potentially improve the economic, environmental, and social sustainability of current production systems. However, costs for production components to integrate sustainable practices into established systems have not been fully explored to date. Our objectives were to determine the economic costs of commercial production systems using alternative containers in aboveground nursery systems. We determined the cost of production (COP) budgets for two woody plant species grown in several locations across the United States. Plants were grown in plastic pots and various alternative pots made from wood pulp (WP), fabric (FB), keratin (KT), and coconut fiber (coir). Cost of production inputs for aboveground nursery systems included the plant itself (liner), liner shipping costs, pot, pot shipping costs, substrate, substrate shipping costs, municipal water, and labor. Our results show that the main difference in the COP is the price of the pot. Although alternative containers could potentially increase water demands, water is currently an insignificant cost in relation to the entire production process. Use of alternative containers could reduce the carbon, water, and chemical footprints of nurseries and greenhouses; however, the cost of alternative containers must become more competitive with plastic to make them an acceptable routine choice for commercial growers.

Energy use and economical analysis of seedy watermelon production for different irrigation systems in Iran

Abstract Resource and energy use efficiency is one of the principal requirements of eco-efficient and sustainable agriculture. Seedy watermelon (Citrullus vulgaris; Joboni population) is irrigated by two methods including full and reduced irrigation systems in Iran. The objective of the present study was to compare seedy watermelon production in full (high input) and reduced (low input) irrigation systems in terms of irrigation water energy use efficiency (IWEUE), energy budget and economic analysis. Data were collected from 116 full irrigated and 93 reduced irrigated farms in northeast of Iran by using a face-to-face questionnaire in 2011–2012. The results showed that the total energy consumed under high input systems was 25625.94 MJ ha − 1 , whereas under low input was 3129.3 MJ ha − 1 . IWEUE and all of the energy indexes were improved in the reduced irrigation system compared to the full condition. The direct and renewable energies in the reduced irrigation system were higher than full irrigation. The economical analysis indicated that higher return was gained by the full irrigation system due to higher yield compared to the reduced irrigation system. Human labor had the highest impact on seedy watermelon among the other inputs based on the Cobb–Douglas production function.

Morphological Characterization and Agronomic Evaluation of Yellow Vein Mosaic Virus Resistant Single Cross Hybrids for Yield and Quality Traits in Okra (Abelmoschus esculentus L. Moench)

Okra (Abelmoschus esculentus L. Moench) is a traditional pod vegetable widely grown in low, medium and high-input systems for domestic and export markets. The economic and ecological sustainability of okra in these systems is under question because of the low-yielding potential, sub-optimal pod quality and susceptibility to biotic and biotic stresses especially the yellow vein mosaic virus (YVMV) of the traditionally cultivated open-pollinated varieties (OPVs) and landraces. Development and use of improved varieties with high yield potential, superior pod quality and resistance to YVMV play an important role in bringing sustainability of okra in these systems. Fifteen single cross hybrids developed by crossing six newly developed inbred lines (RNOYR-14, RNOYR-15, RNOYR-16, RNOYR-17, RNOYR-18 and RNOYR-24), in half-diallel fashion during rainy season 2012, were evaluated along with three local hybrid checks [No. 64 (Mahyco), Avantika (228) (Bioseed) and Shakti (Nunhems)], one OPV check (Arka Anamika) and one OPV cross check for YVMV susceptibility (Pusa Sawani) in a randomized complete block design with three replications during summer 2013 at the Vegetable Research Station, Hyderabad for studying their yield potential, pod quality and resistance to YVMV. All of the 15 single cross hybrids were resistant to YVMV with 0% incidence as against 100% incidence in OPV checks Arka Anamika and Pusa Sawani. On the basis of mean performance, three crosses RNOYR-15 × RNOYR-16, RNOYR-16 × RNOYR-17 and RNOYR-17 × RNOYR-18 were of significantly higher yield potential than the standard check “No. 64”, but of comparable yield potential with other checks “Avantika” and “Shakti”. In addition, these three crosses also of superior pod quality could be exploited for development of commercial hybrid okra. These hybrids would be advantageous for production and quality improvement, trade facilitation and environmental protection.

Managing greenhouse gas emissions in two major dairy regions of New Zealand: A system-level evaluation

New Zealand dairy farms are responsible for a large proportion of this nation's greenhouse gas emissions (GHG-e), arising mainly from enteric methane and urinary nitrogen deposition on pasture. De-intensification and the use of specific mitigation strategies can reduce GHG-e from dairy farms, but are generally costly. In this study, a farm-level model is used to analyse the cost of GHG-e mitigation strategies in medium- (10–20% imported feed) and high-input (20–40% imported feed) systems in the two major dairy regions of New Zealand (Waikato and Canterbury). Production intensity is measured solely in terms of feed importation, in accordance with standard practice in this nation. The focus of the study is to assess the cost-effectiveness of a variety of de-intensification and mitigation strategies aimed at reducing the negative impact of emissions constraints (reductions of 10, 20, and 30%) on farm profit. De-intensification options include changes in stocking rate, nitrogen fertiliser application, and supplement quantity. Mitigation options include feeding crops, improved reproductive management, use of feed pads, use of stand-off pads, and use of nitrification inhibitors. The model showed that a combination of reduced N fertiliser application and lower stocking rates were the larger changes experienced in the systems studied when GHG-e reductions were introduced. Nitrification inhibitors were only useful for mitigation once the GHG-e reductions required were so stringent that their cost was warranted to offset the significant costs associated with de-intensification in the high-input systems. Stand-off and feed pads were too expensive to warrant their use when not already available. Overall, de-intensification of the farming system proved to be more profitable than the use of specific mitigation practices when reduction of GHG-e was required. Maintaining a given intake of imported feed reduces the degree to which de-intensification may be used for abatement, thus inflating the cost of mitigation strategies on high-input farms.

Carbon and nutrient fluxes and balances in Nuba Mountains homegardens, Sudan

Management intensification has raised concerns about the sustainability of homegardens in the Nuba Mountains, Sudan. This study aimed at assessing the sustainability of these agroecosystems following the approach of carbon (C) and nutrient balances. Three traditional (low input) and three intensified (high input) homegardens were selected for monitoring of relevant input and output fluxes of C, nitrogen (N), phosphorus (P) and potassium (K). The fluxes comprised those related to management activities (soil amendments, irrigation, and biomass removal) as well as estimates of biological N2 fixation, C fixation by photosynthesis, wet and dry deposition, gaseous emission, and leaching. Annual balances for C and nutrients amounted to −21 kg C ha−1, −70 kg N ha−1, 9 kg P ha−1 and −117 kg K ha−1 in high input homegardens and to −1,722 kg C ha−1, −167 kg N ha−1, −9 kg P ha−1 and −74 kg K ha−1 in low input homegardens. Photosynthesis C was the main C input flux with averaged of 7,047 and 5,610 kg C ha−1 a−1 in high and low input systems, respectively. Biological N2 fixation (17 kg N ha−1 a−1) was relevant only in low input systems. In both systems, the annual input of 77 kg K ha−1 through dust was highly significant and annual gaseous C losses of about 5,900 kg C ha−1 were the main C loss. In both garden types, the removal of biomass accounted for more than half of total nutrient exports of which one-third resulted from weeding and removal of plant residues and two-third from harvest. The observed negative nutrient balances may lead to a long-term decline of crop yields. Among other measures the reuse of C and nutrients in biomass removals during the cleaning of homegardens may allow to partially close C and nutrient cycles.

Bread wheat performance, fusarium head blight incidence and weed infestation response to low-input conservation tillage systems in eastern Canada

Munger, H., Vanasse, A., Rioux, S. and Légère, A. 2014. Bread wheat performance, fusarium head blight incidence and weed infestation response to low-input conservation tillage systems in eastern Canada. Can. J. Plant Sci. 94: 193–201. Bread wheat performance, the incidence of diseases like fusarium head blight (FHB) and weed infestations may be affected by low-input systems and conservation tillage practices. This 2-yr study assessed the effects of three 24-yr-old tillage treatments (MP: moldboard plow; CP: chisel plow; NT: no-till) and two cropping systems (high-input: herbicide and mineral fertilizer; low-input: mechanical weed control and organic fertilizer) on wheat productivity, deoxynivalenol (DON) content, Fusarium graminearum inoculum production, and weed infestation in hard red spring wheat. In 2009, low-input CP and NT yields were 13 and 31% lower, respectively, than low-input MP yield, which was comparable with all of the high-input treatment yields. In 2010, yields were 23% lower in CP and NT compared with MP, and 32% lower in low-input than in high-input systems. Optimum wheat yield in low-input systems appeared conditional to adequate weed control, which was achieved with MP and CP tillage. Protein content, test weight, and 1000-kernel weight were higher in the high-input system than in the low-input system, except for test weight in 2009. DON content was not affected by tillage in either year, and was lower in low-input system than in high-input system in 2009. Fusarium graminearum inoculum measured in 2009 was similar across tillage treatments in the high-input system, whereas in the low-input system, the inoculum was lower in NT than in MP. In 2010, DON content was not affected by any treatment. Hot and dry conditions were not conducive to pathogen development, and may explain the low level of DON and the lack of treatment effect.

Performance of tissue-cultured versus sucker-derived East African highland banana (Musa AAA-EA) under high and low input systems in Uganda

Banana (Musa spp.) is a vegatatively propagated crop and the type of planting material is of great importance for the productivity of banana plantations. Traditionally, sucker derived planting materials have been used to establish banana plantations but there is a risk of transmitting pests such as plant-parasitic nematodes with untreated suckers. Tissue cultured banana plants are pest-free and widely grown in commercial dessert banana plantations but are not common agricultural practice under East African conditions. This study aimed at evaluating the agronomic performance and nematode infestation levels of sucker-derived and tissue cultured planting material of the East African highland cooking banana cultivar Nabusa (Musa spp., genome group AAA-EA) over five crop cycles. A field trial was conducted in Central Uganda using tissue culture plants, untreated suckers, pared suckers or pared and hot water treated suckers.All plants were cultivated under mulched or non-mulched conditions to represent high or low input systems, respectively. Mulch in general improved agronomic performance of banana. Type of planting material also influenced plant growth and yield. Tissue culture plants developed faster and yielded higher during the first crop cycle than sucker-derived material but not thereafter. Plant height and bunch weight of untreated suckers was inferior to all other planting material from the third crop cycle onwards. All mulched plants flowered earlier in all crop cycles. Duration from planting to the first harvest was less for tissue-cultured plants, but planting material had no influence on days to harvest from the third crop cycle onwards. Nematode densities were higher in roots from plants grown from untreated suckers than all other planting material, with Radopholus similis consistently recovered in greater densities than Helicotylenchus multicinctus across treatments. Mulching had no influence on nematode densities, root necrosis, number of root base lesions or number of dead roots. Nematode associated damage was higher in plants from untreated suckers but did not differ among tissue-cultured and pared and hot water treated or pared sucker plants. This study demonstrates the benefits of using clean planting material for cooking banana over five consecutive crop cycles and confirms the beneficial effects of mulching. In order to achieve high banana yields over several crop cycles, clean planting material needs to be supported by the application of mulch. However, this study shows that the application of mulch will not offset the detrimental effects of plant parasitic nematode-infected sucker planting material.

Sustainability and climate variability in low-input peasant maize systems in the central Mexican highlands

One of the most important challenges for agriculture is addressing high climatic variability by creating productive, resilient and adaptable systems that are highly efficient in terms of water and energy use and having the aims of neither degrading nor contaminating the environment. In Mexico, these characteristics are fulfilled by many seasonal peasant agricultural systems. Systems utilizing native seeds produce an important portion of white maize for human consumption in addition to safeguarding key agricultural genetic resources. This article evaluates the sustainability of such systems and describes the current challenges and opportunities in a representative peasant community in the watershed of Lago de Pátzcuaro in Mexico. Community farming and livestock management practices were analyzed, and ecological, economic and social indicators were measured over a two-year period. During the first year, low-input systems, which are based on the use of organic fertilizers and crop rotation, provided better results in terms of ecological indicators and equal results in terms of economic and social indicators than those achieved using a high chemical input system. In the second year, which featured early frosts and a winter drought, productivity declined in all systems; however, the most diversified systems (in terms of the maize varieties grown and the sowing of other crops) more successfully resisted these climatic adversities.

Pedigree analysis of the Nilagiri sheep of South India

The Nilagiri sheep is a dual utility (fine wool and meat), native to the Nilagiri hills of Tamil Nadu. It is known for its adaptability to high altitude and low input system of rearing. At present, this breed is endangered with less than a thousand numbers existing, of which about 50 percent is maintained at Sheep Breeding Research Station, Sandynallah. Efforts are on to conserve the breed in-situ. Generation interval (GI), pedigree completeness level, inbreeding coefficient (F), average relatedness (AR), effective population size (Ne), and effective number of founders (fe) and ancestors (fa) were studied for the breed. Pedigree analysis was carried out using data available at the research station on 5 051 animals from 1965 onwards using ENDOG ver. 4.8. Higher values of pedigree completeness (more than 80 percent for 5th generation), balance in percent of ancestors between sire and dam pathways and higher equivalent complete generations (7.12) for the reference population were indicative of the depth in pedigree. The GI, F, and AR were 3.36 years, 2.17 and 3.45 percent, respectively. Ne based on maximum number of generations and individual increase in inbreeding was 298.83 and 97.25, respectively. fe and fa were 59 and 41, respectively, for the reference population. F was far from critical values of inbreeding and fe/fa ratio indicated absence of stringent bottlenecks. The effective population size was on the higher end of the range reported for endangered sheep breeds. The knowledge on genetic diversity and effective population size coefficients would support the cause of conservation.