Agronomic Inputs Research Articles

Resource use efficiencies, environmental footprints and net ecosystem economic benefit of direct-seeded double-season rice in central China

Intensive cropping systems with two or three harvests per year are vital to produce sufficient food for the growing population. Improvements in the sustainability of these systems are critical for global food security. Transplanted double-season rice (TPD), an important cropping system in China, is seriously threatened by various challenges such as labor shortage, poor resource use efficiency, high environmental footprint, and low profitability. These challenges could be potentially alleviated by shifting TPD to direct-seeded double-season rice (DSD). Due to the limited thermal energy, ultrashort-duration cultivars matured within 95 days have to be used in DSD in central China. However, it is unknown whether DSD with ultrashort-duration cultivars (DSDS) can improve resource use efficiency and reduce environmental costs compared with TPD in this region. This study aimed to compare the resource use efficiency (energy, water, labor, and fertilizer), carbon and nitrogen footprints, and net ecosystem economic benefit of DSDS and TPD with ultrashort-duration (TPDS) and medium-duration cultivars (TPDM). Results showed that total energy output was 222.0 GJ ha−1 in DSDS, which was comparable to that of TPDM but was significantly increased by 9.5% compared with TPDS. Compared with TPD (i.e. both TPDS and TPDM), the total energy input, labor input, water input, and nitrogen surplus in DSDS reduced by 16.9%, 53.2%, 36.8%, and 31.4%, respectively, leading to significant increases in energy use efficiency, labor productivity, water use efficiency, and nitrogen use efficiency. Furthermore, DSDS decreased direct CH4 and NH3 emissions and indirect carbon emission and reactive nitrogen losses from agronomic inputs, and consequently reduced carbon footprint by 28.6–42.7% and nitrogen footprint by 12.9–14.8% compared with TPD. As a result, the net ecosystem economic benefit in DSDS was significantly increased by 65.9–188.2% relative to TPD. These findings suggest that DSDS is a highly promising strategy to maintain high productivity with less resource inputs and environmental pressures but high economic benefits in central China.

Remote Sensing in Field Crop Monitoring: A Comprehensive Review of Sensor Systems, Data Analyses and Recent Advances

The key elements that underpin food security require the adaptation of agricultural systems to support productivity increases while minimizing inputs and the adverse effects of climate change. The advances in precision agriculture over the past few years have substantially enhanced the efficiency of applying spatially variable agronomic inputs for irrigation, such as fertilizers, pesticides, seeds, and water, and we can attribute them to the increasing number of innovations that utilize new technologies that are capable of monitoring field crops for varying spatial and temporal changes. Remote sensing technology is the primary driver of success in precision agriculture, along with other technologies, such as the Internet of Things (IoT), robotic systems, weather forecasting technology, and global positioning systems (GPSs). More specifically, multispectral imaging (MSI) and hyperspectral imaging (HSI) have made the monitoring of the field crop health to aid decision making and the application of spatially and temporally variable agronomic inputs possible. Furthermore, the fusion of remotely sensed multisource data—for instance, HSI and LiDAR (light detection and ranging) data fusion—has even made it possible to monitor the changes in different parts of an individual plant. To the best of our knowledge, in most reviews on this topic, the authors focus on specific methods and/or technologies, with few or no comprehensive reviews that expose researchers, and especially students, to the vast possible range of remote sensing technologies used in agriculture. In this article, we describe/evaluate the remote sensing (RS) technologies for field crop monitoring using spectral imaging, and we provide a thorough and discipline-specific starting point for researchers of different levels by supplying sufficient details and references. We also high light strengths and drawbacks of each technology, which will help readers select the most appropriate method for their intended uses.

The greenhouse gas rebound effect from increased energy efficiency across China's staple crops

A thorough examination of the uneven greenhouse gas rebound effect (GHG-RE) from increased energy efficiency at crop-specific level can contribute to GHG emissions reduction. This study first evaluated the embodied energy intensities (EEIs) and embodied GHG intensities (EGHGIs) of China's 32 staple crops from 1997 to 2017. Then, a rebound quantization model was introduced to assess crop-specific GHG-REs. The decisive agronomic inputs for uneven crop-specific GHG-REs were further examined. Finally, a structural path analysis (SPA), combined with a structural path betweenness analysis was adopted to identify the high-priority energy paths involved in producing decisive agronomic inputs, in order to improve energy efficiency while curbing uneven crop-specific GHG-REs. The results show that: (1) grain crops generate larger GHG-REs than cash crops. (2) To prevent rapid growth in GHG-REs, six key and six potentially key staple crops must be paid adequate attention. (3) The energy efficiency of plastic film is the primary contributor to crop-specific GHG-REs; agricultural machinery, synthetic fertilizers, and seeds also play important roles. (4) Emphasis should be placed on energy-saving in the production of decisive agronomic inputs. (5) According to the characteristics of high-priority energy paths, different energy-saving measures can be adopted when producing various decisive agronomic inputs.

Models of mycorrhizal colonization patterns and strategies induced by biostimulator treatments in Zea mays roots.

Agronomic inputs and technologies, especially fertilizers, act on the evolution of the symbiotic partnership between arbuscular mycorrhizal fungi and cultivated plants. The use of the MycoPatt method for the assessment of mycorrhizas in maize roots leads to the extraction of large parameter databases with an increased resolution over the colonization mechanism. The application of a biostimulator treatment on plants acted toward a reduction of root permissiveness for mycorrhizas. The phenomenon was noticeable through an increased colonization variability that overlapped with plant nutritional needs. The annual characteristic of the plant was highlighted by the simultaneous presence of arbuscules and vesicles, with a high share of arbuscules in the advanced phenophases. Colonized root parts presented numerous arbuscule-dominated areas in all phenophases, which indicated a continuous formation of these structures and an intense nutrient transfer between partners. Mycorrhizal maps showed the slowing effect of the biostimulators on colonization, with one phenophase delay in the case of biostimulated plants compared to the ones without biostimulators. The forecast models presented gradual colonization in plants without biostimulators, with the expansion of new hyphal networks. The use of biostimulators on plants exhibited a lower permissiveness for new colonization areas, and the mechanism relies on hyphae developed in the former phenophases.

Successful approaches for on-farm experimentation

On-farm experiments are used increasingly in agronomic research because they are commercially relevant, but they can carry greater risks of failure than traditional small plot experiments conducted by scientists. Experimental failures can result from farmer withdrawal, errors in treatment application or harvest, or non-provision of yield data by farmers. This paper describes the development and testing of approaches for on-farm experimentation and concludes which approaches should be adopted to maximise success. The programme of work included the largest on-farm research network in the UK, with farmers conducting around 50 on-farm experiments per year from 2017 to 2019 to compare fungicide programmes in winter wheat. The project developed management approaches to mitigate the risks of experimental failure such that in 2019, 96 % of experiments were completed and returned a yield result; a greater success rate than is commonly achieved in on-farm experiments. Statistical analysis of yield maps resulted in an average site SED (standard error of the difference between means) of 0.26 t/ha, which is comparable to that achieved in randomised, replicated small plot experiments. The large number of experimental sites enabled a greater level of precision in the cross-site analysis (SED 0.06 t/ha), showing the potential of on-farm experiments for detection of small yield effects if the appropriate yield analysis is undertaken. The project results received substantial publicity within the UK arable farming community, demonstrating the value of effective on-farm research for engaging and informing farmers. • On-farm experiments risk failure from treatment or harvesting errors, or non-provision of yield data by host farmers. • Risks can be mitigated by good farmer liaison, marking test tramlines, and providing instructions for yield data transfer. • Large series of on-farm experiments deliver precise comparisons of agronomic inputs in commercial situations. • The results of on-farm experiments are relevant and persuasive for the farming community.

Potential application of pre-harvest LED interlighting to improve tomato quality and storability

Growing conditions and agronomical inputs play a key role in determining fruit qualitative and nutraceutical traits at harvest and post-harvest. The hereby presented research investigated the effects of pre-harvest supplemental LED interlighting on post-harvest quality of hydroponically grown tomatoes (Solanum lycopersicum “Siranzo”). Three LED treatments, applied for 16 h d-1 (h 8.00–00.00), were added to natural sunlight and consisted of Red and Blue (RB), Red and Blue + Far-Red (FR), and Red and Blue + Far-Red at the end-of-day for 30 min (EOD), with an intensity of 180 µmol m-2 s-1 for Red and Blue, plus 44 µmol m-2 s-1 for Far-Red. A control treatment (CK), where plants were grown only with sunlight, was also considered. Fruits at red stage were selected and placed in a storage room at 13 °C in darkness. Fruit quality assessment was performed at harvest time and after one week of storage. RB and FR increased fruit firmness compared to CK, opening possible benefits toward reducing fruit losses during post-harvest handling. RB treated fruits also maintained a higher content of lycopene and β-carotene after the first week of storage. The study demonstrates that supplementary LED interlighting during greenhouse tomato cultivation may enhance storability and help preserve fruit nutritional properties during post-harvest.

Distribution of trace metals and radionuclides contamination in two sections of sediment cores from the Nyong estuary, Cameroon, southern Atlantic coast

This study investigated the spatial distribution of trace metals (Fe, Mn, Ni, Cr, Co, Sc and V) and radionuclides (Th and U) contamination in surface and bottom sediments from the Nyong estuary, Cameroon southern Atlantic coast, to provide informations on the pollution status of these sediments and the possible sources of pollutants. Salinity were measured in situ in interstitial water and dried sediment were analyzed for grain size parameters and geochemical composition. Salinity decreases from downstream to upstream, with 19.88 PSU as the highest value and sand is the main constituent (79.25 %). The concentrations of these elements varied significantly among depth (surface and bottom section), with a preferential contribution from the surface. In this surface section, several elements (Fe, Mn, Co, Sc and V) contributed about 80 % to the distribution of each of them in the estuary. Enrichment Factor (EF), Geo-accumulation Index (Igeo) and Contamination Factor (CF) of Nyong estuary surface sediments revealed a moderate pollution, while bottom sediment were unpolluted to moderate polluted. The pollution load index (PLI) show that surface sediments (3.86) and bottom sediments (1.19) are polluted. Pearson correlation and component principal analysis confirmed the natural origin of selected elements (Fe, Mn, Ni, Cr, Co, Sc, V, Th and U) through the weathering and the erosion of sources rocks. However, Pearson correlation analysis and the high Ni (3.91) and Cr (3.54) EF values in bottom sediments suggest a reception of other contaminants from the same emission sources or similar sources, may be agronomic inputs.

Effects of Cricket Frass Biofertilizer on Growth of Spring Onion (Allium Fistulosum L.) and Physicochemical Properties of Soil

Objective: This study aims to assess the effects of cricket frass biofertilizer on the growth and yield potential of spring onion (Allium fistulosum L.) and its residual effects on physicochemical properties of the soil in greenhouse and field conditions. Methods: 7 treatments namely cricket frass (0t/Ha, 5t/Ha, 10t/Ha, 15t/Ha, and 20t/Ha), poultry manure (15t/Ha) and cattle manure (15t/Ha) were used and replicated 3 and 4 times in field and greenhouse conditions respectively. Plots of 1m2 arranged in a randomized complete block design for field experiment and pots with 5kg of soil laid out in a completely randomized design for the controlled experiment were used. Spring onion transplants were maintained in both trials for 16 weeks with uniform agronomic inputs. Growth and yield were assessed based on plant height, crop growth rate, number of leaves per plant, plant fresh weight, plant dry weight and root to shoot ratio. The effect of frass on soil was scored based on the percentage of organic carbon, nitrogen, phosphorus, and potassium at the start and end of the experiment. The data was assessed for normality (Shapiro-Wilks test) and subjected to analysis of variance at P<0.05 using R-statistical software. Treatment means were separated using fishers-protected least significant different. Results: Frass application increased growth and yield traits in both trials with the exception of the number of leaves per plant, regardless of the dosage. Frass at 15t/ha outperformed all other treatments and competed favorably against conventional manures obtained from poultry and cattle. Frass bio-fertilizer significantly increased the organic carbon, phosphorus, potassium, calcium and magnesium content of the soils. Frass contained adequate nutrients in labile forms that contributed to growth and yields. This significance can also be linked to the presence of growth promoters and stimulation of microbial population in soils, which is characteristic of insect manures. The high levels of nutrients in the soil after planting confirms frass as an amicable soil amendment that buffers and supports soil properties. Conclusion: Cricket frass biofertilizer is a valuable bio-fertilizer that has the potential to improve the quality of soils and support the growth and yields of notable kitchen vegetables such as onions.

Bittersweet cocoa: Certification programmes in Ghana as battlegrounds for power, authority and legitimacy

Critical studies on the interlinkages of access, power and sustainability in high value tropical commodity systems are gaining traction in the academic literature. This article draws on access theory to examine how the distributional effects of a private sector certification programme on rural cocoa growing communities are bound up in the power relations between the state, private sector actors and smallholders in Ghana. The article is based on a qualitative case study approach involving 40 semi-structured interviews, 20 in-depth interviews and field observations conducted between 2018 and 2021. We found that the private sector firm certification incentives such as premiums, agronomic inputs and technical services are distributed unevenly, and also contribute to increased production costs, theft, unjust gender relations, and labour exploitation. We argue that the certification programmes obfuscate the deteriorating relations between the state and the farmers and enable the private firms to gain foothold and affirm their operational legitimacy and market links with smallholders. We conclude that revising the certification programmes would require market and institutional reform. The revision also needs to take into account the existing structural differences among farmers, and between the state and the market for better sustainable transitions.

Sweet basil can be grown hydroponically at low phosphorus and high sodium chloride concentration: Effect on plant and nutrient solution management

Agronomic inputs in agriculture easily exceed crop needs causing environment pollution. Phosphorus (P) is a macronutrient largely used in agriculture as a mineral fertilizer that requires an accurate management because it is a finite and non-renewable resource. Growing plants hydroponically can optimize plant nutrition achieving high crop nutrient use efficiency. However, irrigation water of poor quality (saline) interferes with crop performance. In this study, the effects of different P and NaCl levels in the root zone were evaluated on basil plants grown in a deep liquid culture system in a growth chamber. Two experiments with different P (from 0.1 to 1.0 mol m−3) and NaCl (from 0 to 60 mol m−3) concentrations in the nutrient solution were carried out. Plant growth, leaf gas exchanges and fluorescence, uptake of minerals and water, and leaf quality (content of minerals and pigments, and antioxidant capacity) were analysed. The most relevant morphological plant response to the low P (i.e., roughly 0.1 x of a standard nutrient solution) concentration consisted in a greater root/shoot ratio. However, plants growing at low P concentration did not show any reduction in yield and quality. Sodium chloride did not significantly affect plants yield and quality up to a concentration of 30 mol m−3 confirming the tolerance of basil to moderate saline stress. Significant reduction in the total biomass, water uptake and photosynthesis instead occurred at NaCl 60 mol m−3. These results confirmed the hypotheses that basil can be grown hydroponically at low P and high NaCl concentration with proper management of the nutrient solution. The absence of significant interactions between P and NaCl suggests that these two factors can be managed independently with potential benefits for crop economic and environmental sustainability.

Precision land leveling for sustainable rice production: case studies in Cambodia, Thailand, Philippines, Vietnam, and India

Laser-controlled land leveling (LLL) can help improve rice production's spatial and temporal management, leading to optimized water and crop management. This research resulted in sustainable performance indicators to illustrate that LLL is a sustainable technology for rice production. The assessment was conducted in Cambodia, the Philippines, Thailand, Vietnam, and India. Benefits of LLL include saving land use, water, and agronomic inputs, increasing yield, and decreasing postharvest losses resulting in saving energy of 3.0–6.9 GJ ha−1 and decreasing emissions by 1151–1486 kg CO2-eq ha−1. Additionally, LLL application can obtain a net profit of USD 52–84 ha−1 per rice production season in the countries studied. The result demonstrated that LLL is a sustainable technology as well as strongly supports sustainable rice production. The study would lead to better adoption of this technology through its evidence-based promotion.

What drives management decisions and grain yield variability in Mesoamerican maize cropping systems? Evidence from small-scale farmers in southern Mexico

CONTEXTSmall-scale cropping systems face enormous challenges in obtaining efficient, stable and predictable responses to grain yields due to their great biophysical, management and socioeconomic complexity. In Mesoamerica, traditional managements have incorporated modern agricultural practices; however, the efficacy of these tools on grain yield and systems´ sustainability is unknown. We explored biophysical, agronomic and socioeconomic drivers determining the maize cropping system and grain yield in Southern Mexico. OBJECTIVESThe specific objectives were i) to investigate the effects of geopedologic soil characteristics on maize grain yield, ii) characterise tropical maize cropping systems and model how agronomic factors determine grain yield variability and iii) identify underlying socioeconomic drivers, which determine the agronomic ones and, consequently, the maize cropping systems. METHODSOn-field interviews and soil data from geopedologic unit maps from maize cropping systems in a Mesoamerican region, Chiapas, Mexico, were used. Structural equation modelling (SEM) and quantitative and qualitative analyses were used to explore the data set. RESULTS AND CONCLUSIONSWe found that cropping systems are differentiated into conventional (CS) and traditional (TS). Soils determined grain yield variability independently from the cropping systems. The most common agronomic inputs expected to positively impact grain yield were not effective in any cropping system. In CS, neither pesticides nor fertilisation determined the crop grain yield; plant density explained 72% of crop grain yield variation. In TS, grain yield was negatively related to plant density, while the fallow period slightly explained grain yield. We identified that cultural practices acquired by the farmers in their birthplace determine the type of the current maize cropping system. SIGNIFICANCEWe highlight inconsistent modern agronomic management of the studied maize cropping systems where agrochemical inputs (fertilisers and pesticides) do not translate into higher grain yields or systems' sustainability. New theoretical models for small-scale maize cropping systems incorporating socioeconomic and cultural drivers might be necessary to predict better maize grain yield.

Spatial and Seasonal Structure of Bacterial Communities Within Alpine Vineyards: Trentino as a Case Study

Bacteria have a fundamental role in determining the fitness of grapevine, the composition of grapes and the features of wines but at present, little information is available. In this work, the bacteria colonizing the different portions of grapevine (bark, leaves and grapes) were explored in the vineyards of the Alpine region of Trentino, considering the impact of different environmental and agronomical variables. The vineyards included in the work were selected based on their different geographical positions (altitude) and grapevine training systems in order to explore the whole variability of the grapevine ecosystem. Moreover, the surface amount of copper was measured on grapes and leaves during the vegetative growth. Bacterial analysis, performed using plate counts and Illumina MiSeq, revealed an increase in the concentration of grape bacteria proportional to the progress of the ripening stage. Conversely, the peak of bacterial concentration onto leaf and bark samples occurred in August, probably due to the more favourable environmental conditions. In bark samples, the bacterial microbiota reached the 7 log CFU/cm2, while 6 log UFC/g were measured in grape samples. A remarkable biodiversity was observed, with 13 phyla, 35 classes, 55 orders, 78 families and 95 genera of bacteria present. The presence of some taxa (Alphaproteobacteria, Desulfovibrionaceae, Clostriadiales, Oscillospira, Lachnospiraceae and Bacteroidales) was ubiquitous in all vineyards, but differences in terms of relative abundance were observed according to the vegetative stage, altitude of the vineyard and training system. Bacteria having oenological implication (Lactobacillus, Pediococcus and Oenococcus) were detected in grape samples collected in August, in low abundance. The data revealed a complex bacterial ecosystem inside the vineyard that, while maintaining common traits, evolves according to environmental and agronomical inputs. This study contributes to define the role of bacteria in the complex balance established in each vineyard between human actions and agricultural environment, known as terroir.

Managing Density Stress to Close the Maize Yield Gap.

Continued yield increases of maize (Zea mays L.) will require higher planting populations, and enhancement of other agronomic inputs could alleviate density-induced stress. Row spacing, plant population, P-S-Zn fertility, K-B fertility, N fertility, and foliar protection were evaluated for their individual and cumulative impacts on the productivity of maize in a maize-soybean [Glycine max (L.) Merr.] rotation. An incomplete factorial design with these agronomic factors in both 0.76 and 0.51 m row widths was implemented for 13 trials in Illinois, United States, from 2014 to 2018. The agronomic treatments were compared to two controls: enhanced and standard, comprising all the factors applied at the enhanced or standard level, respectively. The 0.51 m enhanced management control yielded 3.3 Mg ha–1 (1.8–4.6 Mg ha–1 across the environments) more grain (25%) than the 0.76 m standard management control, demonstrating the apparent yield gap between traditional farm practices and attainable yield through enhanced agronomic management. Narrow rows and the combination of P-S-Zn and K-B fertility were the factors that provided the most significant yield increases over the standard control. Increasing plant population from 79,000 to 109,000 plants ha–1 reduced the yield gap when all other inputs were applied at the enhanced level. However, increasing plant population alone did not increase yield when no other factors were enhanced. Some agronomic factors, such as narrow rows and availability of plant nutrition, become more critical with increasing plant population when density-induced stress is more significant. Changes in yield were dependent upon changes in kernel number. Kernel weight was the heaviest when all the management factors were applied at the enhanced level while only planting 79,000 plants ha–1. Conversely, kernel weight was the lightest when increasing population to 109,000 plants ha–1 while all other factors were applied at the standard level. The yield contribution of each factor was generally greater when applied in combination with all other enhanced factors than when added individually to the standard input system. Additionally, the full value of high-input agronomic management was only realized when matched with greater plant density.

Exploring the potential of moringa leaf extract as bio stimulant for improving yield and quality of black cumin oil

The history of plants to be utilized as medicines is thousands of years old. Black cumin is one of the most widely examined plant possessing naturally occurring compounds with antimicrobial potential. Foliar application of growth stimulators is a successful strategy to enhance yield and quality in many crops. A field study was planned to apply growth stimulator like moringa leaf extract on black cumin crop grown under field conditions using RCB design with three replications. All other agronomic inputs and practices were uniform. The treatments were moringa leaf extract concentrations (10%, 20%), growth stages (40 days after sowing, 80 DAS, 120 DAS, 40 + 80 DAS, 40 + 120 DAS, 80 + 120 DAS, 40 + 80 + 120 days after sowing) and two controls unsprayed check (i.e. no moringa leaf extract, no water) and sprayed check (no moringa leaf extract + water). Application of 20% moringa leaf extract at stage-7 (40 + 80 + 120 days after sowing) had significantly increased plant height, branches plant−1, essential oil content, fixed oil content, peroxidase value and iodine value of black cumin oil over unsprayed control. Application of moringa leaf extract showed maximum results and improves growth and yield of black cumin when applied at 40 + 80 + 120 days after sowing. As this study was only conducted using moringa leaf extract, it is advisable to conduct an experiment with various bio stimulants along with fertilizer combinations and growth regulators to check their synergistic effects for more reliable and acceptable recommendations in future.

Integrating multiple inputs for soft red and white winter wheat

AbstractMichigan winter wheat (Triticum aestivum L.) growers continue to adopt intensive management strategies. However, instead of broadscale implementation of an entire collection of inputs simultaneously, practitioners question which inputs may better contribute to improved production. Studies evaluated soft winter wheat plant growth, grain yield, and expected economic net return for multiple agronomic and nutrient inputsacross varying production intensities. Field trials established in Richville and Lansing, MI, during 2017 and 2018 evaluated six agronomic inputs including: seeding rate, fungicide, plant growth regulator (PGR), autumn starter fertilizer, weekly nitrogen (N) applications, and a high N rate. Autumn‐applied starter fertilizer was the only individual input resulting in a consistent grain yield response. Removal of autumn starter fertilizer from high‐input (HI) management decreased grain yield an average of 1.6 Mg ha–1 while increasing grain yield 1.1 Mg ha–1 on average when added to low‐input (LI) management. Autumn starter fertilizer accounted for 71% of the grain yield difference between HI and LI. Although greater management intensity increased grain yield compared to LI management in 3 of 4 site‐years, expected net return was greater when utilizing LI management. Results suggest producers consider current soil, plant, and climate conditions at the time of application and across variabilities through the field as weather factors may control much of the uncertainty growers encounter when deliberating between individual or multiple input adoption.

Comparisons between main and ratoon crops in resource use efficiencies, environmental impacts, and economic profits of rice ratooning system in central China

Rice production in China is constrained by excessive water consumption, labor shortage, large environmental footprint, and low economic profit. Rice ratooning is a promising practice to increase famers' profit with higher resource use efficiency and less environmental impact compared with other rice cropping systems. However, there is limited information on the differences in energy use efficiency, water and labor productivity, environmental footprint, and economic return between main crop (MC) and ratoon crop (RC) in this cropping system. This study was conducted to compare the system performance between the two crops of ratoon rice using on-farm survey data. Average grain yield was 8.40 and 4.55 t ha−1 for MC and RC, respectively. Although RC produced 45.9% lower grain yield, it had 57.3% less total energy input and 71.0% lower total production cost than MC, which resulted in a significantly higher energy use efficiency, net energy ratio, net economic return and benefit-to-cost ratio. Lower total energy input and production cost of RC was mainly attributed to the reduction in fertilizer application and labor input, respectively compared with MC. In addition, both labor and water productivity of RC was significantly higher than those of MC. Furthermore, the global warming potential (GWP) and yield-scaled GWP of RC was 59.3% and 23.4% lower than those of MC, respectively, due to lower agronomic inputs and GHGs emissions. Overall, our results suggested that RC had higher resource use efficiency, better economic performance, and less environment impact compared with MC.

Influence of Cultivars and Nitrogen Fertilizer Rates and Application Mode on Yields and Quality Parameters of Ratoon Sugarcane in Western Kenya

Productivity of sugarcane in Kenya has declined despite use of recommended production practices including introduction of elite high yielding and early maturing sugarcane varieties. Farmers continue to use recommended agronomic inputs for the old low yielding and late maturing varieties on these elite varieties. Nitrogen fertilizer rates in single or split doses for old varieties are still in use yet their appropriateness on new varieties remains untested culminating to decline in sugarcane productivity in Kenya. Currently, cane payment is based on delivered milling cane weight. The industry plans to change payment to a combination of quality and yields. Influence of agronomic inputs and timing of harvesting period on proposed mode of payment is unknown. Harvesting age in western Kenya remains 18-20 months after ratooning (MAR). However, optimal age that combines quality and yields is not documented. Influence of these agronomic practices on quality, yields and optimal harvesting age of ratoon crop of new (D8484) and old (CO421) varieties were evaluated in a 2x4x3 split-split-plot design replicated three times. Four rates of nitrogen as urea, all applied at 3 MAR, split once (50-50%) and applied at 3 and 6 MAR or split three times (40-30-30%) and applied at 3, 6 and 9 MAR were evaluated. Yields and quality parameters were monitored from 10th-24th MAR. Variety D8484 out-yielded (p≤0.05) CO421 throughout demonstrating its superiority. Yields reached maximum at 20 and 19 MAR for CO421 and D8484, respectively. Maximum pol and brix were attained at 18 and 15 MAR for CO421 and D8484, respectively, while commercial cane sugar (CCS) was maximum at 18 and 17 MAR for CO421 and D8484, respectively. Results demonstrated that for high returns, D8484 should be harvested between 15-18 MAR while CO421 between 17-19 MAR. The 60 kg N/ha, that produced higher (p≤0.05) output in both varieties, from 16th MAR is recommended for both varieties. Split fertilizer application did not affect productivity.

Zucchini squash production in conventional and organic cultivation systems

Organic production must be carried out following the EU regulations and their protocols. On the contrary, conventional cultivation instead can be carried out using the best agronomic approaches available and using the latest innovative resources. Organic cultivation is more widespread in permanent crops (olive and grape crops) than vegetable ones, and even less in protected cultivation systems, due to the high intensity production processes which render the application of organic growing protocols more complex. The comparison between the two systems of cultivation, organic and conventional, is difficult because the two cultivation methods are often carried out in different farms and hence in different environmental conditions. Cultivation using the two methods was conducted in a greenhouse from November to March 2017/2018. Results demonstrated that the total fruit yield zucchini squash in organic cultivation was not significantly different to the conventional one (43.2 Mg ha-1 and 46.4 Mg ha-1, respectively). The agronomic inputs (fertilizers, fungicides, and insecticides) were higher in the organic cultivation system than conventional one. The water use efficiency was higher in the conventional cultivation system (150.6 kg m-3 ha-1) compared to the organic one (147.6 kg m-3 ha-1). No statistically significant differences were found for the fruit number per plant and for the marketable fruit at the end of the growing period. Significant differences for the harvest period were only detected for fresh weight, shape index, firmness, and titratable acidity. In conclusion, this work demonstrated that the organic system required higher inputs compared to the conventional cultivation. The extensive experience of the grower allowed for comparable yields between the two systems.

The Use of Crop Yield Autocorrelation Data as a Sustainable Approach to Adjust Agronomic Inputs

Agricultural fields have natural within-field soil variations that can be extensive, are usually contiguous, and are not always traceable. As a result, in many cases, site-specific attention is required to adjust inputs and optimize crop performance. Researchers, such as agronomists, agricultural engineers, or economists and other scientists, have shown increased interest in performing yield monitor data analysis to improve farmers’ decision-making concerning the better management of the agronomic inputs in the fields, while following a much more sustainable approach. In this case, spatial analysis of crop yield data with the form of spatial autocorrelation analysis can be used as a practical sustainable approach to locate statistically significant low-production areas. The resulted insights can be used as prescription maps on the tractors to reduce overall inputs and farming costs. This aim of this work is to present the benefits of conducting spatial analysis of yield crop data as a sustainable approach. Current work proves that the implementation of this process is costless, easy to perform and provides a better understanding of the current agronomic needs for better decision-making within a short time, adopting a sustainable approach.