Nitrogen (N) fertilization affects wheat yield and grain protein concentration; however, its mismanagement can increase plant lodging. While the use of plant growth regulators such as trinexapac-ethyl (TE) can mitigate plant lodging, their effects on seed physiological quality are not well known. The aim of this study was to evaluate the effects of N fertilization and TE on wheat yield, lodging and seed quality of spring wheat varieties. It was carried out in the 2018 growing season in the environments of Londrina and Ponta Grossa, Brazil. A randomized complete block design was used with a 2 × 3 × 3 factorial arrangement to evaluate two wheat genotypes (WT 15008 and WT 15025), three top-dressing N rates (0, 40 and 120 kg ha−1), and three TE rates (0, 50 and 100 g ha−1). Agronomic characteristics related to wheat productivity (hectolitre weight, thousand-grain weight, density of fertile spikes, plant height, lodging and grain yield) and seed physiological quality (seed germination and vigour; length and dry matter of normal seedlings) were evaluated. Increasing N rates up to 120 kg ha−1 increased plant lodging up to 26.4 percentage points for WT 15025 in Londrina. TE impaired some traits of seed physiological quality. Spraying 100 g ha−1 TE on the plants reduced seedling length by 9.4% in the seeds of WT 15008 harvested in Ponta Grossa compared to the TE control (0 g ha−1). The dry matter of the seedlings from the seeds harvested in Londrina declined by 7.2% due to the application of 100 g ha−1 TE, compared to the control. However, a lower rate of TE (50 g ha−1) might be enough to minimize plant lodging without impairing the physiological quality of the seeds, depending on the rate of N fertilization. This study is the first step in providing empirical evidence for the detrimental effects of TE in combination with N on wheat seed quality, suggesting that seed producers should exercise caution in managing TE and N fertilization.

The use of fertilisers in maize production has been the focus for many years of agronomic studies on research stations in East Africa. However, information on production risks and profitability of fertiliser use on smallholder farms is generally lacking because most of the early studies have focused on mean yields and yield components on research stations. This study applied rigorous analyses to determine conditions under which (1) production risks are low; (2) the recommended nitrogen (N) and phosphorus (P) fertiliser rates achieve a yield target of ≥3 t ha−1 believed to be a necessary condition to kick start a smallholder-led ‘green revolution’ in Africa and (3) N and P fertiliser use is profitable on smallholder farms in East Africa. Analysis of data from 464 on-farm trials in Kenya, Rwanda, Tanzania and Uganda revealed significant variations in production risks and nutrient use efficiency with season and soil type. On most sites, except in Uganda, production risks were lower with the recommended N and P fertilisers than the control during both the short and long rains. Production risks were three to four times higher with N and P fertiliser relative to the control on Lixisols and Ferralsols, but such risks were much lower on Nitisols, Leptosols, Vertisols, Plinthosols and Cambisols. The probability of exceeding grain yields of 3 t ha−1 with the recommended N and P rates was over 0.60 on Nitisols and Leptosols, but less than 0.20 on Lixisols and Plinthosols. The agronomic use efficiencies of N (AEN), P (AEP) and value cost ratios (VCR) were highest on Cambisols and lowest on Plinthosols. The VCR increased linearly with increase in AEN (R2 = 0.92) and AEP (R2 = 0.87) and less so with increase in grain yields (R2 = 0.47–0.60). Net present values indicated profitably of N and P fertiliser over the long term in only 30% of the site by season combinations in Uganda compared with 69% in Kenya, 81% in Rwanda and 84% in Tanzania. Patterns of N use efficiencies were different from P use efficiencies across soil types. Therefore, we recommend that N and P fertilisers should be appropriately targeted to soils where applied nutrients are used efficiently by maize crops.

The response of wheat to the application of different rates of nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) under balanced fertilization on different soil types and agroecologies has not been well studied in Ethiopia. Therefore, the objectives of this study were to (1) determine soil-specific responses of wheat to N, P, K, and S under balanced fertilization; (2) quantify agroecology-specific N, P, K, and S response of wheat under balanced fertilization; and (3) determine nutrient use efficiency of wheat on different soil types under balanced fertilization. Trials were conducted on farmers’ fields across 24 locations covering 4 soil types and 5 agroecological zones (AEZs) from 2013 to 2017. The mean grain yields of wheat significantly varied with applied N and P fertilizer rates with soil types and AEZs. With balanced application of other nutrients, the optimum N rates for wheat were 138 kg N ha−1 on Cambisols and Luvisols, 92 kg N ha−1 on Vertisols, and 176 kg N ha−1 on Nitisols, while the optimum P rate was 20 kg P ha−1 on Cambisols and Vertisols. The nutrient dose–response curve did not reveal consistent pattern for K and S applications on all soil types. The agronomic efficiency of wheat decreased with increasing rates N and P on all soil types. The highest agronomic efficiency of N (15.8 kg grain kg−1 applied N) was recorded with application of 92 kg N ha−1 on Vertisols, while the highest agronomic efficiency of P (49 kg grain kg−1 applied P) was achieved with application of 10 kg P ha−1 on Cambisols. We conclude that applications of 92–138 kg N ha−1, 20 kg P ha−1, 18 kg K ha−1, and 10 kg S ha−1 under balanced application of zinc and boron could be recommended depending on soil type for wheat production in the study areas.

Improving grain yield and lodging resistance are two important targets for improving rice production. The aim of this study was to link grain yield and lodging resistance with growth patterns in rice. A nitrogen (N) fertilization experiment was conducted in 2020 and 2021, which consisted of two N rates (150 and 225 kg ha–1) and three N split-application ratios among the basal, early tillering, and panicle initiation stages (6:3:1, 5:3:2, and 4:3:3). The results demonstrated that increasing the N rate from 150 to 225 kg ha–1 did not affect grain yield but increased the plant lodging index by 16%. This increase in the plant lodging index was attributable to a higher plant fresh weight resulting from improved post-heading growth and a lower plant lodging load, which was partially due to a higher leaf area index. Altering the N split-application ratio from 6:3:1 to 4:3:3 increased grain yield by 4% but did not affect the plant lodging index in rice. The increase in grain yield was due to improved post-heading growth mainly resulting from increased radiation use efficiency during the post-heading period, which was partially attributable to increased specific leaf weight. An improvement in pre-heading growth in 2021 did not affect grain yield but increased the plant lodging load and decreased the plant lodging index by 36% compared to 2020. The improvement in pre-heading growth was due to a higher intercepted solar radiation resulting from higher leaf area index and incident solar radiation during the pre-heading period. The results of this study indicate that improving pre-heading growth can maintain grain yield and increase lodging resistance, while improving post-heading growth by increasing canopy radiation use efficiency (but not the leaf area index) can increase grain yield and maintain lodging resistance.

An on-farm field experiment was conducted in northeastern Thailand to assess the effects of different eucalyptus biochar (BC) application rates, in combination with mineral fertilizers, on upland rice and a succeeding crop of sugarcane on sandy soil. Soil mineral N and greenhouse gas emissions were also evaluated. The field experiment consisted of three treatments: no biochar (BC0), 3.1 Mg ha−1 of biochar (BC1), and 6.2 Mg ha−1 of biochar (BC2). All treatments received the same recommended fertilizer rate. Soil mineral N, and emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were monitored after BC application. The results revealed that the BC2 treatment caused lower soil mineral N content than that of the BC0 treatment during the upland rice period. During the sugarcane period, the BC2 treatment induced a greater soil mineral N content than the BC1 treatment but had no significant difference from the BC0 treatment. The BC2 treatment resulted in significantly lower cumulative CH4 and N2O emissions than the BC0 treatment during the upland rice period. In conclusion, we found that the BC2 treatment alleviated the global warming potential from CH4 and N2O emissions throughout the experiment, causing slight changes in soil N availability in the upland rice–sugarcane cropping system.

Numerous technologies have contributed to the recent development of agriculture, especially the advancement in hyperspectral remote sensing (HRS) constituted a revolution in crop monitoring. The widespread use of HRS to obtain crop parameters suggests the need for a review of research advances in this area. HRS offers new theories and methods for studying crop parameters, but much work needs to be done both experimentally and theoretically before we can truly understand the physical and chemical processes that predict these crop parameters. The study focuses on the following elements: 1) The article provides a relatively comprehensive introduction to HRS and how it can be applied to crop monitoring; 2) Current state-of-the-art techniques are summarized and analyzed to inform further advances in crop monitoring; 3) Opportunities and challenges for crop monitoring applications using HRS are discussed, and future research is summarized. Finally, through a comprehensive discussion and analysis, the article proposes new directions for using HRS to study crop characteristics, such as new data mining techniques including deep learning provide opportunities for efficient processing of large amounts of HRS data; combining the temporal and dynamic characteristics of crop parameters and vegetation growth processes will greatly improve the accuracy of crop parameter detection and monitoring; multidata fusion and multiscale data assimilation will become HRS monitoring. Multidata fusion and multiscale data assimilation will become another research hotspot for HRS monitoring of crop parameters.

Ethiopia has heterogeneous topographic, climatic and socio-ecological systems. Recommendations of agricultural inputs and management practices based on coarse domains such as agro-ecological zones (AEZ) may not lead to accurate targeting, mainly due to large intra-zone variations. The lack of well-targeted recommendations may contribute to the underperformance of promising technologies. Therefore, there is a need to define units where similar environmental and biophysical features prevail, based on which specific recommendations can be made for similar response units (SRUs). We used unsupervised machine learning algorithms to identify areas of high similarity or homogeneous zones called ‘SRUs’ that can guide the targeting of agricultural technologies. SRUs are landscape entities defined by integrating relevant environmental covariates with the intention to identify areas of similar responses. Using environmental spatial data layers such as edaphic and ecological variables for delineation of the SRUs, we applied K- and X-means clustering techniques to generate various granular levels of zonation and define areas of high similarity. The results of the clustering were validated through expert consultation and by comparison with an existing operational AEZ map of Ethiopia. We also augmented validation of the heterogeneity of the SRUs by using field-based crop response to fertiliser application experimental data. The expert consultation highlighted that the SRUs can provide improved clustering of areas of high similarity for targeting interventions. Comparison with the AEZ map indicated that SRUs with the same number of AEZ units captured heterogeneity better with less within-cluster variability of the former. In addition, SRUs show lower within-cluster variability to optimal crop response to fertiliser application compared with AEZs with the same number of classes. This implies that the SRUs can be used for refined agricultural input and technology targeting. The work in this study also developed an operational framework that users can deploy to fetch data from the cloud and generate SRUs for their areas of interest.

In intensive livestock production systems, estimating forage production and its nutritive value can assist farmers in optimizing pasture management, stocking rate, and feed supplementation to animals. In this study, we aimed to use vegetation indices, determined using a proximal canopy reflectance sensor, to estimate the forage mass, crude protein content, and nitrogen in live forage of Marandu palisadegrass (Urochloa brizantha). Pasture canopy reflectance was measured at three wavelengths (670, 720, and 760 nm) using a Crop Circle device equipped with an ACS-430 sensor. Total forage mass, plant-part composition, leaf area index (LAI), and crude protein content were assessed during 14 growth cycles in a pasture under four management regimes, comprising different combinations of two N fertilization rates and two irrigation schedules. For each forage assessment, pasture canopy reflectance data were used to calculate the following vegetation indices: normalized difference vegetation index, normalized difference red edge, simple ratio index (SRI), modified simple ratio, and chlorophyll index. In addition, we also performed analyses of the linear and exponential regressions between vegetation indices and total forage mass, leaf + stem mass, leaf mass, LAI, crude protein content, and nitrogen in live forage. The best estimates were achieved for total forage mass, leaf + stem mass, leaf mass, and nitrogen in live forage using SRI (R2 values between 0.72 and 0.79). When estimating pasture productive variables (total forage mass, leaf + stem mass, leaf mass, and LAI) from SRI, the equations showed R2 values between 0.69 (leaf mass) and 0.74 (LAI) and relative errors ranging from 19% to 21%. For each of the water and nitrogen supply conditions evaluated, this index facilitated the monitoring of forage mass time series and nitrogen in live forage and the extraction of this nutrient by the pasture.

In sub-Saharan Africa (SSA), farmers intercrop common beans with maize but apply inorganic or organic fertilisers targeting only maize. Effects of this practice on bush bean yield have not been fully evaluated with respect to input use and compatibility when intercropped with maize. An on-farm trial managed by smallholder community members was conducted to assess the influence of various soil fertility management options and cropping systems on the yield of two bush bean genotypes (SER45 and SER83) in two agro-ecological zones of Malawi. The farmer-managed trials were laid out in split-plot design, with the bean genotypes as main plots and a combination of the soil fertility management options (i.e., no input, manure, fertiliser and fertiliser + manure) and cropping systems (i.e., sole crop and intercrop) as subplots. The trials were affected by terminal drought and dry spells, but results show that manure and fertiliser application enhanced the resilience of the drought-tolerant bean genotypes. The genotype SER45 was responsive to manure application in the sole crop, giving a 44.4% yield increase over no-manure application. In sole cropping with fertiliser plus manure, bean yields improved by 40.1% for SER45 and 78.3% for SER83 relative to the no-input control. Although sole cropping had higher bean yields, the treatment with manure and fertiliser had a higher land equivalence ratio for intercrop of 1.54 for SER45 and 1.32 for SER83 over sole cropping. These results show that, under smallholder farmer management, the climate adaptability of bush bean genotypes could be enhanced by the combined application of organic and inorganic fertilisers in maize–bean intercrop. The combined application also enhances whole-farm productivity of the common maize–bean intercrop practice than monocrop, hence is of benefit to most low-input smallholder farmers of SSA.

Drought is considered as the major environmental stress affecting coffee production, and high phosphorus (P) supply may alleviate the drought effects on crop metabolism. Here, we hypothesized that high P supply would mitigate the impacts of drought on Arabica coffee physiology, morphology, and biomass accumulation. Potted Arabica coffee plants were grown under two P levels: the recommended P fertilization (P), and twice the recommended fertilization (+P), and two water regimes: well-watered and water withholding for 32 days. Leaf, stem, and root P concentrations were increased under +P, with plants showing higher photosynthesis and growth than the ones receiving the recommended P dose. Higher plant growth under high P supply seems to upregulate leaf photosynthesis through the source–sink relationship. Under the water deficit, the reduction of leaf photosynthesis, stomatal conductance, transpiration, water use efficiency, carboxylation efficiency, chlorophyll content, number of plagiotropic branches, plant leaf area, and vegetative biomass production was similar comparing plants fertilized with the recommended P to those supplied with +P. However, Arabica coffee trees under high P supply and water deficit presented morphological and physiological traits similar to plants under well-watered and recommended P fertilization.

Single-cross pearl millet hybrids are widely grown in India, but this cultivar type has not been adopted in Africa. Hybrids from India have proven to be highly susceptible to downy mildew disease in Africa, the continent where the disease originated. We investigated an alternative strategy of growing topcross hybrids where both the parents are of African origin and both are only partially inbred. We investigated root characteristics – length, diameter, area, volume and dry weight – under drought stress and well-watered controlled conditions in genotypes that included potential parents of topcross hybrids. Several, including population Civarex 06_05, had better developed roots under drought while also having good roots under more favourable conditions. Some of these genotypes were backrossed to a male-sterile line based on the A4 cytoplasm to produce male-sterile populations with stable male sterility. Civarex 06_05 had good combining ability when used as a female parent and produced high-yielding topcross hybrids. Two of the topcross hybrids were on restorer populations Toroniou, originating from Mali, and Maiwa from Nigeria. On the experimental station and in farmers’ fields, one was much superior in yield to the best local alternatives and both had superior downy mildew resistance. Current efforts on the seed production of these topcross hybrids are described, and the constraints to the commercialisation in Mali of promising topcross hybrids are discussed.

Ammonium has been reported as a ‘preferred’ nitrogen (N) source for sugarcane (Saccharum spp.), which can improve N use efficiency (NUE) in this crop. We aimed to evaluate the preferential uptake of ammonium and nitrate in sugarcane genotypes contrasting with NUE under controlled conditions. Four sugarcane genotypes previously selected by another experiment (ER: efficient and responsive; ENR: efficient and nonresponsive; IR: inefficient and responsive; INR: inefficient and nonresponsive) were grown in a growth chamber and fertilized with two 15N-labeled forms [(NH4)2SO4 (15N-NH4+) or KNO3 (15N-NO3−)]; soil was used as substrate. Plants were evaluated at three time points: 0, 24, and 72 h after 15N-fertilization. For the efficient genotypes (ER and ENR), the soil NH4+ levels were about 20% lower than those found for the inefficient genotypes (IR and INR) indicating greater N extraction by the plant. Nitrogen derived from fertilizer (NDFF) and 15N recovery from fertilizer (15N RFF) in roots were influenced by the genotypes, in which responsive genotypes (ER and IR) presented a mean value 40% higher than the genotype INR, showing that greater absorption is more related to response than efficiency. Three days after N application, NDFF and 15N RFF from 15N-NH4+ were greater than 15N-NO3− in 40% and 65% for the roots and aerial part, respectively. The results of this study confirmed that sugarcane presents preferential uptake of NH4+ N form 3 days after fertilization. The use of nitrification inhibitors can be considered for providing a longer NH4+ residence time in the soil, also contributing to augmenting the NUE in sugarcane.

Sustaining productivity of the rice-based cropping systems in the Eastern Indo-Gangetic Plain (EIGP) requires practices to reverse declining soil fertility resulting from excessive tillage and crop residue removal, while decreasing production costs and increasing farm profits. We hypothesize that the adoption of conservation agriculture (CA), involving minimum tillage, crop residue retention and crop rotation, can address most of these challenges. Therefore, the effects of crop establishment methods – strip planting (SP), bed planting (BP) and conventional tillage (CT); and levels of crop residue retention – high residue (HR) and low residue (LR) on individual crop yield, system yield and profitability were evaluated in a split-plot design over three cropping seasons in two field experiments (Alipur and Digram sites) with contrasting crops and soil types in the EIGP. The SP and BP of non-rice crops were rotated with non-puddled rice establishment; CT of non-rice crops was rotated with puddled transplanted rice. In the legume-dominated system (rice-lentil-mung bean), lentil yields were similar in SP and CT, while lower in BP in crop season 1. A positive effect of high residue over low residue was apparent by crop season 2 and persisted in crop season 3. In crop season 3, the lentil yield increased by 18–23% in SP and BP compared to CT. In the cereal-dominated system (rice-wheat-mung bean), significant yield increases of wheat in SP and BP (7–10%) over CT, and of HR (1–3%) over LR, were detected by crop season 3 but not before. Rice yields under CA practices (non-puddled and HR) were comparable with CT (puddled and LR) in both systems. Improved yield of lentil and wheat with CA was correlated with higher soil water content. The net income of SP increased by 25–28% for dry season crops as compared to CT and was equal with CT for rice cropping systems. Conservation agriculture practices provide opportunities for enhancing crop yield and profitability in intensive rice-based systems of the EIGP of Bangladesh.

Field experiments were conducted in 2015 and 2016 to study the effect of tillage frequency, seed rate, and glyphosate on teff and weeds. The experiments were arranged in a split plot design with three replications consisting of tillage frequency (conventional, minimum, and zero tillage) as the main plot and the combination of seed rate (5, 15, and 25 kg ha−1) and glyphosate (with and without) as subplots. Results showed that zero tillage reduced teff biomass yield by 15% compared to minimum tillage and by 26% compared to conventional tillage. Zero tillage and minimum tillage also diminished grain yield by 21% and 13%, respectively, compared to conventional tillage. Lowering the seed rate to 5 kg ha−1 reduced biomass yield by 22% and 26% compared to 15 and 25 kg ha−1, respectively. It also reduced the grain yield by around 21% compared to 15 and 25 kg ha−1 seed rates. Conventional tillage significantly diminished weed density, dry weight, and cover by 19%, 29%, and 33%, respectively, compared to zero tillage. The highest seed rate significantly reduced total weed density, dry weight, and cover by 18%, 19%, and 15%, respectively, compared to the lowest seed rate. Glyphosate did not affect weed density but reduced weed dry weight by 14% and cover by 15%. Generally, sowing teff using minimum tillage combined with glyphosate application and seed rate of 15 kg ha−1 enhanced its productivity and minimized weed effects.

The OxG hybrid bunches contain more parthenocarpic fruits (PF) than normal fruits (NF) and present problems of development and ripening due to either an asynchronous opening of flowers or insufficient pollination. The objective of this study was to compare the effect of α-naphthaleneacetic acid (NAA) and gibberellic acid (GA3) in the induction and development of PF and NF, the fatty acid profile (FAP), and the oil potential in the ‘Coari x La Mé’ oil palm hybrid. NAA and GA3 induced parthenocarpy in the fruits and did not alter the FAP of the mesocarp oil. The commercial dose of pollen (0.9 g talc + 0.1 g pollen) resulted in increased bunch weight (BW) (20.8 kg) and lower percentage of PF in the bunch (65.4%). The most effective hormonal doses to induce the formation of PF in the bunch were NAA 300 and 600 mg L-1. GA3 alone or in mixture with NAA increased the percentage of PF but did not increase the BW, indicating that GA3 had no synergistic effect on BW. The NAA applications represent alternatives to complement assisted pollination of OxG hybrids to increase bunch production and oil yield.

Phosphorus (P) is a limiting resource for agricultural production in the tropics. Urochloa spp. is commonly used as a cover crop and has mechanisms to mobilize partially the nonavailable P forms from the soil. The use of Urochloa intercropped with Arabica coffee (Coffea arabica L.) is increasing in Brazil, but P cycling has been overlooked in this system. Here, we proposed two experiments to test the hypothesis that Urochloa decumbens could mobilize and absorb P from deep soil layers and increase overall P cycling of the intercrop system. We measured U. decumbens root and shoot dry mass (SDM), root morphology and activity, nutrient uptake, soil nutrient availability, and soil P fractionation in both experiments. To better understand P cycling by Urochloa alone, in the first experiment, U. decumbens was cultivated in rhizotrons where adequate P was supplied in distinct soil layers – 0.0 to 0.3 m, 0.3 to 0.8 m, 0.8 to 1.3 m, and 1.3 to 2 m. Root dry mass (RDM) and morphology were not affected by P availability. Moreover, total biomass production (root plus shoot) and P uptake were higher when P was available in the superficial top soil layer compared to P availability in more than one layer or only in the bottom layer. Nevertheless, U. decumbens was able to reach and acquire P from depth. Correlation analysis showed that P cycling was strongly dependent on SDM, labile, and moderately labile fractions of soil P and was not significantly correlated with RDM. The second experiment aimed at verifying P uptake and mobilization from different soil depths in field conditions. P was supplied in different depths of the soil profile – 0.3 m, 0.6 m, and 0.9 m – in the field with preestablished U. decumbens intercropped with Arabica coffee plants. Shoot P content was higher at the first sample date when P was supplied at 0.3 m, compared to 0.6 m, 0.9 m, and control with no P. Soil P fractionation showed that there was no P mobilization of less labile forms by U. decumbens during the evaluated time. Our results showed that P fertilization in the top layer rather than suppling P trough the soil profile can maximize U. decumbens growth. Also, Urochloa P accumulation was enough to support coffee demand even in high yields and can be an alternative to increase P use efficiency in coffee production systems, being an effective recycler of P.

The genotype × environment (GE) interaction analysis is fundamental in crop breeding programs to guide selection and for recommendation of high performing and stable genotypes for breeding objectives. This study aimed at quantifying the GE interaction effects and determines grain yield stability among winter bread wheat genotypes under rainfed conditions of Iran. Twenty-four winter wheat genotypes were evaluated under nine test locations using a randomized complete blocks design with four replications during three cropping seasons (2019–21). The additive main effects and multiplicative interaction (AMMI) model and several parametric and nonparametric stability statistics were applied for analysis of grain yield data collected from the experiments. AMMI analysis of variance for grain yield revealed significant effects (p < 0.01) for genotype, environment, and GE interaction. The environment was the main source of variation and accounted for 83.5% of the total yield variation, followed by GE (6.5%) and genotype (1.0%) effects. The AMMI biplot analysis indicated the genotypes G3, G23, G22, G10, and G19 as high yielding with stability performance across environments. Genotypes G14, G13, G20, and G9 showed large positive interaction with the environments featuring the highest rainfall during growing season, while genotypes G7, G6, and G21 had a large positive interaction with environments with low rainfall. Spearman’s rank correlation analysis revealed that the AMMI stability value, Shukla’s stability variance (σ2i), Wricke’s ecovalence (W2i), coefficient of determination (R2i), variance in regression deviations (S2di), and nonparametric statistic of S2(i) were not correlated with mean yield in tested genotypes, showing they are related to static/biological concept of stability. In contrast, the genotypic superiority index (Pi) and regression coefficient (bi) were significantly correlated (p < 0.01) with mean yield and corresponded to dynamic/agronomic concept of stability. These findings suggest that selection of genotypes should be considered based on selection objectives of using the various stability parameters described here. In conclusion, the selected genotypes in this study should be recommended as new cultivars or parental lines for grain yield and stability improvement under rainfed conditions of Iran or similar agro-ecologies.

Cassava flour is the main source of carbohydrates for family farmers in the Amazon region of Brazil. Cassava is mainly grown under shifting cultivation, in recurrent cultivation periods initiated through slash-and-burn. Its sustainability is, however, questioned due to the associated deforestation and often rapidly decreasing crop productivity. There is an urgent need to make these cassava systems more sustainable and more profitable, but we currently lack a deep understanding of the key factors governing their productivity. We conducted an on-farm study on 37 cassava fields of smallholder farmers at three locations that spanned a range of crop-fallow frequencies, some of which were initiated through slash-and-burn while others through fire-free land clearance. First, we analysed how cassava plant density at harvest was related with pedoclimatic and management factors in slash-and-burn systems. Second, we assessed the relationship between plant density and cassava root yield at harvest and conducted a yield gap analysis to better understand which factors govern cassava productivity beyond plant density in slash-and-burn systems. Finally, we compared cassava productivity between slash-and-burn and the fire-free land clearing techniques that some farmers started to adopt in the study region. Cassava yields averaged 7.2 ± 5.4 Mg ha–1 (50% of the average yield of 14.2 Mg ha–1 in the Pará State), and ranged from 0 (in case of root rot diseases) to 24 Mg ha–1. Cassava yield was associated with plant density at harvest (ranging from 0 to 10 000 plants ha–1), suggesting that managing plant density is a key determinant of the attainable yield levels. In addition, differences in cassava root yields could be largely explained by differences in labour inputs for weeding and fallow clearing, the effect of the latter depending on soil texture. Therefore, our results suggest that labour is a key production factor for cassava in the shifting cultivation systems of the Eastern Amazon in which the use of external inputs, such as chemical fertilizers and herbicides, is limited. Further, root yields were influenced by the method of field preparation, whereby yields were about 50% lower (and more variable) when fields were prepared by slash-and-burn than by mechanical ploughing or herbicide application. Despite the significantly higher yields, these alternatives to burning the vegetation are, however, still hardly adopted in Paragominas. Hence, there is a need for supporting more sustainable production systems through local and national public policies. These new systems should not only focus on soil fertility management but also on weed control and, more generally, on labour productivity.

This study analyses the experience and response of farmers within a multi-year collaborative research trial focused on the development of forage-based fallows in eight communities in the central Peruvian Andes. Quantitative data from a rural household survey were used to characterize farming household socioeconomic factors, livelihood strategies and soil and crop management practices of community members belonging to four participation groups with respect to the trials: 1) current participants near the end of the trial; 2.) those who participated early on, but dropped the trials after the first year; 3) those who participated in meetings but not directly in experiments; and 4) those who never participated meaningfully in the process. Furthermore, qualitative interviews of farmers in the four groups were used to examine trends and questions arising from the quantitative survey findings. Analysis of this mixed-methods dataset showed that better resource-endowed households (in terms of human and social capital, more livestock assets, higher levels of farm value production and income, and farm inputs) tended to be more likely to participate compared to households with lower levels of these variables. Our findings suggest that the differences in resource endowment among participation group households may be related to household life cycles, where access to resources change over time, reflecting the changing demography of a household. It was established that farm households with intermediate-age children, that is near the middle of a farm life cycle trajectory, are those with the most wherewithal to participate in trials and likely serve as examples and test cases for other farms with younger parents or older farmers with children moved away. Follow-up interviews indicated that farming households at either end of the farm life cycle trajectory may be using a ‘wait-and-see’ approach to the trials carried out by their neighbours who have more labour and other resources to deploy. In light of these findings, we suggest that participatory research should aim to ensure that the voices, challenges and opportunities of Non-participants are represented in the research process and experimental design. Additionally, greater consideration should be placed on understanding management by context issues in order to better target potential farming innovations such as improved fallows, at multiple levels, from the field to the household and to the community and beyond.

The aim of the study was to analyze the role of small-scale dairy farms in central Mexico in combating rural poverty from a gender perspective. Specifically, it was determined whether these production systems generated sufficient income for alleviating poverty and purchasing the basic food basket. Two hundred and twelve farmers were selected through snowball sampling. To maintain a gender perspective, female-headed farms were considered as an independent group, and male-headed farms were grouped according to multivariate statistics. Two official indicators of poverty were considered in the economic analysis: income and the extreme poverty line. Factor analysis identified four factors that explained 66.10% of accumulated variance. The cluster analysis identified five groups of farms headed by males. Then, a comparative analysis was carried out for the six groups, including the female-headed group (FG). The economic analysis revealed that, if 52% of income are production costs, groups 1, 2, 3, and 4 generated sufficient gross income to purchase the basic food basket to the household of the area. However, the FG and group 5 did not generate sufficient gross income to purchase the food basket. In contrast, if 70% of income are productions costs, only groups 1 and 4 generated sufficient gross income. It can be concluded that small-scale dairy farms generate sufficient daily income under certain conditions for the purchase of the basic food basket and, therefore, help to fight poverty in rural families, especially in groups 1 and 4. In the case of the FG and groups 2, 3, and 5, dairy production along with the diversification of productive activities and backyard activities supports the livelihoods of rural families. It is recommended that existing gender norms be further explored because these could directly influence the motivation of farmers, particularly female producers, to adopt or reject agricultural and livestock technologies.