Use of biochar (B) and poultry manure (PM) as soil amendments can improve the productivity and sustainability of tropical agriculture. Our fieldwork is the first research on the agronomic use of B and PM for the growth of cocoyam in sandy soil of the humid tropics. In this study, the effects of B, PM and their mixture were investigated on soil properties, mineral and nutrient concentrations, growth, and corm and cormel yields of cocoyam during the 2017 and 2018 cropping seasons. The experiment consisted of 4 × 2 factorial combinations of B (0, 10, 20, and 30 Mg ha−1) and PM (0 and 7.5 Mg ha−1). In both years, the application of B and PM either alone or in combination improved soil physical and chemical properties, plant nutritional status, growth, and corm and cormel yields of cocoyam. The combination of 30 Mg ha−1 B and 7.5 Mg ha−1 PM (B30 + PM7.5) gave the highest corm and cormel yields of cocoyam. Pooled over the 2 years, application of B at 30 Mg ha−1 and PM at 7.5 Mg ha−1 (B30 + PM7.5) significantly increased corm yield of cocoyam by 47 and 66%, respectively, when compared with sole PM at 7.5 Mg ha−1 and B at 30 Mg ha−1. Lowest corm and cormel yields were obtained for the unmanure control. The combination of 30 Mg ha−1 B and 7.5 Mg ha−1 PM is recommended for soil fertility management and cocoyam production in the rainforest agroecology of SW Nigeria.

Common bean (Phaseolus vulgaris L.) is perhaps the most important grain legume in sub-Saharan Africa (SSA) smallholder systems for food security and household income. Although a wide choice of varieties is available, smallholder farmers in western Kenya realize yields that are low and variable since they operate in risky production environments. Significant seasonal variations exist in rainfall and severity of pests and diseases. This situation is worsened by the low and declining soil fertility, coupled with low capacity of farmers to purchase production inputs such as fertilizers, fungicides and insecticides, and land scarcity. The objective of this study was to investigate whether growing multiple-bean varieties instead of a single variety can enable farmers enhance yield stability over seasons and ensure food security. Five common bean varieties were evaluated in multiple farms for 11 seasons at Kapkerer in Nandi County, western Kenya. Data were collected on grain yield, days to 50% flowering and major diseases. In addition, daily rainfall was recorded throughout the growing seasons. The five varieties were combined in all possible ways to create 31 single- and multiple-bean production strategies. The strategies were evaluated for grain yield performance and yield stability over seasons to determine the risk of not attaining a particular yield target. Results indicated that cropping multiple-bean varieties can be an effective way for reducing production risks in heterogeneous smallholder systems. Yield stability can be greatly enhanced across diverse environments, leading to improved food security, especially for the resource-poor smallholder farmers operating in risk-prone environments. Although the results show that some of the single-bean variety strategies were high yielding, their yield stability was generally lower than those of multiple strategies. Resource-poor risk averse farmers can greatly increase the probability of exceeding their yield targets by cropping multiple-bean varieties with relatively low yields but high grain yield stability. Trading-off high grain yield for yield stability might be an important strategy for minimizing bean production risks.

Proximal plant sensing with active canopy sensors offers a leap in the non-destructive assessment of crop agronomic information. For managing fertilizer nitrogen (N), sensor readings must be translated using functional models or algorithms to fertilizer amounts. Six field experiments were conducted in three wheat seasons in the West Nile Delta in Egypt to develop and validate an algorithm based on GreenSeeker canopy reflectance sensor for field-specific fertilizer N management in wheat, which takes into account both spatial and temporal variability of N during the crop growth season. The proposed algorithm is based on the prediction of total N uptake and response index of N uptake determined from normalized difference vegetation index measured by the sensor from plots differing in yield potential as established by applying a range of fertilizer N levels in the four experiments conducted in the first two wheat seasons. The treatments in the two experiments conducted in the third wheat season were designed to define appropriate fertilizer N management prior to applying a sensor-based dose at Feekes 6 stage (jointing stage). The application of 40 and 60 kg N ha−1 at 10 and 30 days after sowing of wheat and a sensor-guided dose of N estimated by using the algorithm developed in this study resulted in yields similar to those obtained by following the general recommendation, but with an average of 66 kg N ha−1 less fertilizer N. These results were also reflected in a substantial increase in N recovery (21.9%) and agronomic (7.7 kg grain kg−1 N) efficiencies compared with the general recommendation, thereby proving the usefulness of the sensor-based algorithm in optimizing fertilizer N management in wheat.

In the Northern mountainous region of Vietnam, cassava–cowpea intercropping system has been widely promoted with support from the local agricultural department. However, cowpea yield is often limited because of a low Biological Nitrogen Fixation (BNF) activity due to its low natural nodulation and lack of available effective Rhizobium products. The aim of this study was to identify the most effective native rhizobia isolate nodulating cowpea with the potential to increase BNF and yield of cowpea. A greenhouse experiment was initially conducted with five treatments: three native rhizobia isolates (CMBP037, CMBP054, and CMBP065); a control (no inoculation and no N application); and N+ (no inoculation, application of N as KNO3). Field inoculations were carried out and the treatments were as follows: a control (no inoculation); CMBP (037+054) – a mixture of strains from Mau Dong; CMBP065 strain from Cat Thinh. CMBP054 and CMBP065 had the highest nodulation in the greenhouse (46.4 and 60.7 nodules plant−1, respectively) and were rated as effective with symbiotic efficiency (SEF) of 54.56 and 55.73%, respectively. In the field, CMBP (037+054) recorded significantly higher nodulation (19.4 nodules plant−1) than the control (11.7 nodules plant−1). CMBP (037+054) also increased cowpea shoot dry weight, shoot N, and yield by 28.6, 4.9, and 10.5%, respectively, compared to the uninoculated control. This effect was slope dependent (statistically significant in moderate and steep slope, not with gentle slope). Besides, the high expansion rate of intercropping with cowpea showed the high adoption level of these agroecological practices by local farmers. This study reveals the potential of native rhizobia inoculation to enhance soil fertility and sustainable agriculture in the Northern mountainous region of Vietnam and proposes enhanced efforts to promote the availability and utilization of effective inoculants for cowpea.

Rice is widely grown in rainfed lowlands during the wet season in the Mekong region. Limited nutrient availability is a common constraint on crop yield, and the optimal rate of fertilizer application depends on the soil type. The objective of our study was to evaluate rice productivity and the economic feasibility of various nutrient management regimes in Cambodia. We conducted field experiments on three soil types (Prey Khmer, Prateah Lang, and Toul Samroung, equivalent to Psamments, Plinthustalfs, and Endoaqualfs, respectively) in four provinces (Battambang, Kampong Thom, Pursat, and Siem Reap) during the 2016 and 2017 wet seasons to compare nine (2016) and seven (2017) N–P–K combinations. Grain yield ranged from 0.9 to 4.8 t ha−1 in 2016 and from 1.0 to 5.2 t ha−1 in 2017, depending on soil type and nutrient management. The Prey Khmer soil contained around 80% sand, and rice yield responded most weakly to nutrient management. The moderate fertilizer input in the current soil-specific recommendation was effective on this soil type. However, on more fertile soils with a higher clay content and a higher cation-exchange capacity (Toul Samroung and Prateah Lang), an additional 20 kg N ha−1 combined with adding 15 kg ha−1 of P2O5 or 20 kg ha−1 of K2O significantly increased yield and economic return. Although P and K use during Cambodia’s wet season is uncommon, our results demonstrate the importance of these nutrients in improving the country’s rice production.

Farmers’ access to reliable information is crucial to improving rural livelihoods, food security, and national economies in West Africa. This paper discusses the dynamics of accessing and using agricultural learning videos from commercial channels, vs project and non-project channels in Benin and Mali. Using combinations of different models to assess the effectiveness of agricultural extension programs, the findings showed that farmers were motivated to pay for videos and watch them by themselves, without facilitation. Farmers who watched the videos through project support have also continued to watch on their own if the videos are of interest to them. Nevertheless, farmers were less motivated in the learning process when they received the Digital Video Disc (DVD) free and without support to watch them. We also found that the distribution of learning videos through commercial channels reaches more serious users and increases farmers’ self-determination for learning, and farmers are more motivated to provide feedback than viewers who receive DVDs for free or via project support, Non-Governmental Organizations (NGOs), or farmer organizations. Although buying a DVD is an individual action, they like to watch the videos in groups. After buying the DVD, about 43% of respondent borrowed DVD players and one person in five bought a DVD player to watch the videos. Efforts to promote improved technologies need to expand beyond the conventional focus on research and extension services. Support to agricultural technology dissemination must go beyond assistance to smallholder farmers and NGOs (practical implication). As the private sector has a role to play, both in making technologies available and in teaching farmers how to use them, their contribution would create space for innovation (theoretical implication). Our findings suggest that successful development intervention programs can be sell audiovisual material to farmers, who will use it proactively.

To improve the national average yield of potato in Ethiopia, which is very low as compared to its potential, factors that influence technical efficiency of potato production need to be determined. Therefore, the objective of this study was to investigate the determinants of technical efficiency using a cross-sectional data collected from 368 randomly selected potato producers in Northern Ethiopia using a multi-stage sampling technique. The study employed Cobb–Douglas stochastic frontier model to get farm-level technical efficiency scores. Tobit model and principal component analysis were used to determine the factors that influence technical efficiency of farm households. The results revealed that chemical fertiliser, seed potato, plot size and labour are statistically significant factors that affect potato yield. The average technical efficiency score was estimated to be 75%; and education, experience, off-farm income, household size, membership in a farmers’ association, use of irrigation water, extension contact, use of improved seed, access to product market and weak coordination of stakeholders’ were significant factors influencing technical efficiency. The findings of the study suggest that there is a need for government intervention to create strong market linkage between producers and buyers and to give appropriate training to agricultural extension agents.

Grass pea (Lathyrus sativus L.) has a Mediterranean origin and was spread to Western Europe, Africa and South Asia. Over time, this grain legume crop has become important in South Asia, where it is often affected by waterlogging at germination. Therefore, varieties with waterlogging tolerance of seeds at germination are needed. This study evaluated waterlogging tolerance in a grass pea diversity panel. First, morpho-agronomic traits of 53 grass pea genotypes from 7 diverse countries (Afghanistan, Australia, Bangladesh, Cyprus, Ethiopia, Greece and Pakistan) were measured in a glasshouse. Seeds of the collection were then sown into waterlogged soil for 6 days and is subsequently drained for 8 days. Finally, representative genotypes from each country of origin of the three survival patterns (described below) were then tested to identify the effect of seed priming on germination and seedling growth in waterlogged soil. Canonical analysis of six traits (seed weight, pod length, pod width, flowering time, time to maturity and seedling survival) showed that genotypes from Bangladesh and Ethiopia were similar. There was a significant variation amongst genotypes in waterlogging tolerance. Genotypes from Bangladesh and Ethiopia showed the highest percent seedling survival (54% and 47%), with an ability to germinate under waterlogging and then maintain growth from the first day of draining to the final sampling (Pattern 1). In contrast, genotypes from other origins either germinated during waterlogging, but did not survive during drainage (Pattern 2) or failed to germinate and had low seedling survival during waterlogging and drainage (Pattern 3). Priming seeds reduced seedling survival in grass pea. Despite Mediterranean origin, specific ecotypes of grass pea with greater waterlogging tolerance under warm wet conditions have been favoured in Bangladesh and Ethiopia where adaptation to extreme precipitation events at germination and seedling survival upon soil drainage is critical for successful crops.

Beninese smallholders associate food crops and cash crops with immature oil palms to reduce field maintenance costs and gain income before the palms reach productive phase. Little is known about the effects of these crops on the nutritional status and growth of the palms in their immature phase even though the yield of adult palms can be affected by the management practices during this phase. The objective of this study was to evaluate the most common oil palm-based intercropping systems found in southern Benin in terms of nutritional status and growth of the palm. Within 15 oil palm farms, we compared 15 immature oil palm fields where the crop succession associated with the oil palms was dominated by maize, cassava, tomato, and pineapple. The nutrient concentrations in the soil and the palm leaves, and growth indicators were measured at the end of the immature phase. We found that the palm growth indicators were the lowest in the successions with pineapple. N and P nutrition of the immature palms was satisfactory but K was deficient in all systems, especially in those with pineapple. The K levels in the soils and palm leaves were correlated. Rough field budgets comparing the amounts of N and K applied to the crop successions with their N and K exports from non-returning products indicated that soil indigenous K supply would be particularly depleted in the systems with pineapple. We concluded that the young oil palms were affected by the competition for K exerted by the crop successions with pineapple even though they were the most fertilized in the region. The high profitable crop is therefore associated with the lowest growth rates of the immature palms. The mineral fertilizer management in these oil palm temporary intercropping systems should be improved.

Mixing of phosphate fertilizer with farmyard manure (FYM) is a simple technique for optimizing phosphorus (P) availability and then improving the productivity of wheat (Triticum aestivum) grown in alkaline calcareous soils. Diammonium phosphate (DAP) and phosphoric acid (PA) were applied to soil at 36 mg P kg−1, either as sole or after amending 1-g P fertilizer with 2-g FYM (1:2, w/w basis). After 45-day incubation, concentration of P ions in the soil solution (Cp) and exchangeable P present in soil solid (E-value) were determined to evaluate the amount of total plant-available pool. The FYM-amended fertilizers, i.e., PA+FYM and DAP+FYM, showed higher E-values, i.e., 114 and 97 mg kg−1 soil, respectively. Similarly, PA+FYM exhibited the highest proportion of P derived from fertilizer (Pdff = 51.5%) and induced the highest P uptake by wheat seedlings (L-value = 72.1 mg kg−1). Consequently, PA+FYM and DAP+FYM treatments caused higher grain yield and P-use efficiency. The regression analysis revealed strong and positive correlation between L-value and grain yield (r = 0.86), biomass production (r = 0.84) and P-use efficiency (r = 0.87) by wheat crop. Results suggested that FYM-amended inorganic P fertilizer can be a promising technique to optimize supply of P from soil, improve efficiency of inorganic P fertilizers, and improve wheat yield in alkaline calcareous soils.

Parthenium weed is an invasive species in a growing number of countries where it infests numerous crop fields, including sorghum. Two field studies were conducted to quantify the effect of parthenium weed on the performance of grain sorghum at different weed densities (0, 5, 10, 15 and 20 plants m−2) and durations of weed-crop competition (season-long weed-free, weed-free after 2, 4, 6 or 8 weeks, and season-long weedy). Our aim was to identify the density threshold and ideal duration to control parthenium weed in sorghum fields. Both field experiments were planned in a randomised complete block design each with three replications in 2016 and were repeated in 2017. Parthenium weed biomass increased significantly with increasing density and competition duration. The increasing parthenium weed density had a linear negative effect on sorghum growth, yield and yield-contributing traits. The highest yield loss, of up to 66%, was recorded at the highest parthenium weed density of 20 plants m−2 when compared to weed-free treatment. In addition, the season-long competition of this weed with sorghum caused 81% reduction in grain yield over weed-free treatment. According to our results, parthenium weed should be managed below a density of 5 plants m−2 and throughout the crop growth duration in grain sorghum fields as it can cause serious yield losses even at low densities and through strong competition at early as well as late growth stages of the crop.

High-yielding short-duration cultivars are required due to the development of mechanized large-scale double-season rice (i.e. early- and late-season rice) production in China. The objective of this study was to identify whether existing early-season rice cultivars can be used as resources to select high-yielding, short-duration (less than 115 days) cultivars of machine-transplanted late-season rice. Field experiments were conducted in Yongan, Hunan Province, China in the early and late rice-growing seasons in 2015 and 2016. Eight early-season rice cultivars (Liangyou 6, Lingliangyou 211, Lingliangyou 268, Xiangzaoxian 32, Xiangzaoxian 42, Zhongjiazao 17, Zhongzao 39, and Zhuliangyou 819) with growth durations of less than 115 days were used in 2015, and four cultivars (Lingliangyou 268, Zhongjiazao 17, Zhongzao 39, and Zhuliangyou 819) with good yield performance in the late season in 2015 were grown in 2016. All cultivars had a growth duration of less than 110 days when grown in the late season in both years. Zhongjiazao 17 produced the maximum grain yield of 9.61 Mg ha−1 with a daily grain yield of 108 kg ha−1 d−1 in the late season in 2015. Averaged across both years, Lingliangyou 268 had the highest grain yield of 8.57 Mg ha−1 with a daily grain yield of 95 kg ha−1 d−1 in the late season. The good yield performance of the early-season rice cultivars grown in the late season was mainly attributable to higher apparent radiation use efficiency. Growth duration and grain yield of early-season rice cultivars grown in the late season were not significantly related to those grown in the early season. Our study suggests that it is feasible to select high-yielding short-duration cultivars from existing early-season rice cultivars for machine-transplanted late-season rice production. Special tests by growing alternative early-season rice cultivars in the late season should be done to determine their growth duration and grain yield for such selection.

This article deals with technology transfer from science to agriculture with pearl millet (Pennisetum glaucum (L.)R.Br.) in central Tanzania as example. The major question is which validity recommendations from different types of field experiments have and how geo-information (i.e. soil and landscape position) can lead to more site-specific recommendations. Tied ridging and reduced amounts of placed fertilizer during sowing were tested to increase yields on researcher-managed plots on-station, demonstration plots in villages, and farmer-managed plots on-farm. While on-station trials provided potential yield effects, physical distance to the station and differing conditions led to a higher informational value of village plots that mirror the context of local farmers. The treatments often resulted in significant yield increase. Soil and relief information and distance to settlements (i.e. gradient of management intensity) are key factors for data variability in on-farm trials. Unexplained variability is introduced through leaving degrees of freedom with respect to management to the farmer. Apart from soil and physiographic information, the latter should be part of a detailed data collection procedure in agronomic trials in large numbers addressing Sub-Saharan smallholder farming. Balanced data sets with dispersed trials on crucial soil and relief units are essential for future research.

Relay intercropping of maize with fodder crops is a promising option for sustainable intensification of dairy small-scale farms in the Cerrado of Brazil. Twenty-six intercropping trials were conducted on farmers’ fields with the following experimental treatments: sole maize crop cropping (MS), maize-Brachiaria intercropping (MB) and maize-pigeon pea intercropping (MP). The trials were managed by the farmers, i.e. choice of conventional tillage (CT) versus no-tillage (NT), sowing dates, fertilization and weed control. Maize grain yield varied strongly across the farmer fields, from 100 to 5900 kg ha−1 in the MS treatment, 500 to 6900 kg ha−1 in MP and 300 to 5500 kg ha−1 in MB. Intercropping did not significantly affect maize grain yields under NT, but yields were reduced under CT in one out of two seasons. Maize yields in the intercropped systems were also higher under NT than CT. Total biomass productivity was significantly higher in the maize-fodder than in the sole maize system. An increased interval between sowing of maize and fodder crop significantly reduced the fodder crop biomass. Relay intercropping, especially in combination with NT, is a promising option if crop calendars and fertilization are properly managed by farmers to reduce interspecific competition between the maize and fodder crop.

Agricultural extension requires close communication with farmers, and researchers must consider farmers’ perspectives on crop management. Farmers tend to take into account the canopy appearance when they decide on fertilizer application, and this is often neglected in crop management recommendations by researchers. Our objectives were to dissect the growth characteristics that farmers implicitly account for in nutrient management of tropical rice. Farmer participatory trials were conducted in irrigated and rainfed lowlands in the Philippines during the wet seasons of 2014, 2015, and 2016. Each year, 30 participating farmers made decisions on fertilizer management for plots with different seedling ages and planting densities. These treatments greatly changed the canopy appearance, and affected farmer decisions on nitrogen (N) management, particularly in the first year. We found that plant height and leaf greenness were the major determinants of their decisions in irrigated lowlands. Under rainfed conditions, the risk of drought made farmers focus on tillering rather than plant elongation and leaf color during early growth stages, and on canopy cover and plant elongation during later stages. Across years and water regimes, farmers applied 78% more N than researchers without generally increasing grain yield. Since crop diagnosis is a key for successful management by farmers, guidelines for efficient nutrient management should include numerical targets for the traits emphasized by farmers. That will help farmers better understand their crops, and the guidelines will be more user-friendly than providing only a fertilizer application prescription.

The cover crops Mucuna pruriens var. utilis and Pueraria phaseoloides were introduced to African farmers to improve crop production on degraded soils, yet they appear not to be adopted at scale. In the humid forest zone of West and Central Africa, the dominant Acrisols and Nitisols are inherently poor even when not degraded through agriculture. In this zone, sole maize cropping and vegetable production systems are gaining importance, yet both suffer from nutrient deficiencies. Cover crops were often introduced along with a system change, requiring biomass retention, mainly for nutrient retention reasons. Farmers in the zone commonly use slash and burn systems due to added weed control and ease of operations on clean fields. This study evaluated mucuna and pueraria with and without burning the fallow biomass in an annual sole maize crop relay system against the burned and retained natural fallow. Over 14 consecutive years, biomass burning did not cause lower maize grain yields in any of the fallow types, on the contrary, the economically important marketable cob yields were higher when biomass was burned (mulched 2.10 cobs m−2 vs. 2.26 cobs m−2 when burned, p < 0.07). After cover crop fallow, maize grain yields were significantly higher than after natural fallow (1.92 Mg ha−1) over the 14 years, with maize yields in the pueraria treatment (2.63 Mg ha−1) out yielding those in the mucuna treatment (2.28 Mg ha−1). Maize produced 1.92 cobs m−2 in natural fallow, significantly less than in the mucuna (2.23 m−2, p < 0.013) and the pueraria (2.39 m−2, p < 0.001) fallow. Introducing mucuna or pueraria cover crops into slash and burn systems appears as a suitable measure to increase yields without changing the land preparation approach.

Field experiments were conducted to standardize protocols for site-specific fertilizer nitrogen (N) management in Bt cotton using Soil Plant Analysis Development (SPAD) chlorophyll meter. Performance of different SPAD-based site-specific N management scenarios was evaluated vis-à-vis blanket fertilizer N recommendation. The N treatments comprised a no-N (control), four fixed-time and fixed N doses (60, 90, 120, and 150 kg N ha-1) including the recommended dose (150 kg ha-1), and eight fixed-time and adjustable N doses based on critical SPAD readings of 45 and 41 at first flowering and boll formation stages, respectively. The results revealed that by applying 45 or 60 kg N ha-1 at thinning stage of the crop and critical SPAD value-guided dose of 45 or 30 kg N ha-1 at first flowering stage resulted in yields similar to that recorded by applying the recommended dose of 150 kg N ha-1. However, significantly higher N use efficiency as well as 30–40% less total fertilizer N use was recorded with site-specific N management. Applying 30 kg N ha-1 at thinning and SPAD meter-guided 45 kg N ha-1 at first flowering were not enough and required additional SPAD meter-guided 45 kg N ha-1 at boll formation for sustaining yield levels equivalent to those observed by following blanket recommendation but resulted in 20% less fertilizer N application. Our data revealed that SPAD meter-based site-specific N management in Bt cotton results in optimum yield with dynamic adjustment of fertilizer N doses at first flowering and boll formation stages. The total amount of N fertilizer following site-specific management strategies was substantially less than the blanket recommendation of 150 kg N ha-1, but the extent may vary in different fields.

The goal of this study was to evaluate the effects of thinning eucalyptus trees on yield and nutritive value of corn for silage and palisadegrass in a crop–livestock–forest integrated system and to evaluate the total aboveground biomass yield in systems with and without trees. Plant variables, as well as the incidence of photosynthetically active radiation (PAR) and soil moisture, were evaluated between October 2016 and March 2018 in São Carlos, Brazil, in a crop–livestock–forest and a crop–livestock system. In the crop–livestock–forest system, eucalyptus trees (Eucalyptus urograndis clone GG100) were planted in April 2011, in single rows, with 15 × 2 m spacing. In 2016, the trees were thinned, and the spacing was changed to 15 × 4 m. The treatments comprised measurements at 0.00, 3.75, 7.50, and 11.25 m from the trees of the North row in the integrated crop–livestock–forest (iCLF) system and integrated crop–livestock (iCL) system. Palisadegrass (Urochloa brizantha) was sown after harvesting the corn. Corn yields were similar between treatments, with an average of 13.6 Mg ha−1. Corn for silage presented a higher percentage of grain in total biomass in the crop–livestock–forest positions (41.4 and 42.1%) than in the crop–livestock system (35.6%). No differences in forage accumulation were observed. Crude protein content in corn for silage and palisadegrass was higher in the crop–livestock–forest treatments than in the crop–livestock system. Such results indicate that thinning was favorable to production in the crop–livestock–forest system. Total aboveground biomass yield was higher in the iCLF system, indicating better land use for this type of integrated system.

Both short- and long-term effects of fertilizers on crops and soils are often studied only in arid or paddy soils, whereas less is known about the long-term effects in paddy-upland rotations, particularly with multiple crops and frequent tillage in subtropical areas. Therefore, an 18-year field experiment was initialized to assess the effects of different types of fertilization (no fertilizer; chemical fertilizer (CF); and manure in combination with CF (MCF)) on yield and soil chemical and microbial properties in a crop rotation involving rice (Oryza sativa L., summer), rapeseed (Brassica campestris L., winter), tobacco (Nicotiana tabacum L., the following summer), and hairy vetch (Vicia villosa Roth, the following winter). MCF caused higher yields of rapeseed grains and tobacco leaves than CF after 3 or 4 years of implementing the experiment, while rice yields varied little between MCF and CF, with one exception in 2011. Compared with the initial soil properties, providing soil with MCF increased organic matter (OM), while the opposite trend was found with CF. Higher microbial biomasses, enzyme activities, bacterial operational taxonomic units, and richness and diversity indexes of bacterial communities were found in soils receiving MCF, implying the improvement of soil microbial properties in the paddy-upland rotation system with multiple crops and frequent tillage. The experimental soils under varying fertilization were dominated by four bacterial phyla (Proteobacteria, Acidobacteria, Actinobacteria, and unclassified groups), which accounted for approximately 70% of the 16S rDNA sequences. Among the top 20 predominant bacteria, 14 were commonly found in all soil samples irrespective of which fertilizer treatment was implemented. Thus, the presence of those bacteria was stable in the soil and to some extent was influenced by fertilization. Most of them were facultative anaerobic bacteria, which can adapt to both anaerobic paddy soil and aerobic drylands. The dominant bacteria at various taxonomic levels found in soils might reflect multiple soil processes such as OM turnover, nutrient cycling, physical structure formation, and xenobiotic detoxification.

Low genetic diversity acts as a major bottleneck in garden pea breeding, and diverse parents are required to generate new genetic material. The diversity of parents utilized in hybridization programme was ascertained following simple sequence repeats (SSR) markers. Thirty-six homozygous F7 progenies were isolated from three intervarietal crosses through shuttle breeding programme over a period of 6 years (2009–2014). Two experiments were conducted for two consecutive years 2014/15 and 2015/16, for evaluating the agronomic performance of progenies along with four commercial control cultivars. Analysis of variance (ANOVA) revealed that genotype, growing year and their interaction had significant effects on most of the traits. Line ‘DPP-SP-6’ recorded significantly higher pod yield/plant in comparison to all other genotypes in 2014/15, 2015/16 and for pooled over years. In addition, ‘DPP-SP-22’, ‘DPP-SP-7’ and ‘DPP-SP-17’ also performed statistically at par with best-performing check ‘Pb-89’ during both the years. These superior lines, in general, showed better pod filling, green pod colour, high shelling, sweetness and resistance to powdery mildew disease. These superior progenies could act as an alternative to the popular check varieties after their exhaustive evaluation over environments.