In rainfed lowland rice-based systems, increasing labour scarcity due to off-farm employment is encouraging farmers to switch from transplanting to dry direct seeding (DDS). To assure stable productivity at a level comparable with or superior to transplanting, DDS management must ensure rice seedlings have access to nutrients in order to be competitive with weeds, which must also be suppressed. This paper examined farmer perceptions of DDS using a farmer survey, and used on-farm experiments to examine responses of rainfed lowland rice to integrated nutrient–weed management, based around mechanised DDS. In the survey, weeds were the biggest problem faced by farmers in using DDS (61%). In 90% of cases, farmers reported that weeds had increased under DDS, with most farmers (78%) controlling weeds by hand. All farmers said they would use DDS in the following season (100%), due to labour savings (47%), timeliness of operations, improved productivity, low investment or a combination of these (44%). In on-farm experiments, banding nutrients with the seed at sowing enhanced early dry matter of rice, while early weed dry matter was reduced. Early weed control using ducklings or hand weeding reduced weed competition and increased rice growth, with ducklings providing additional yield benefits over hand weeding. Early increases in seedling vigour of rice, and in weed suppression, carried through to greater dry matter and yield of rice at maturity. Integrated nutrient–weed management in mechanised DDS increased DDS yields, reduced DDS yield variability and contributed to sustainability of DDS rice systems.

Selenium (Se) is an essential micronutrient for humans, yet its dietary intake is low, mostly due to the low bioavailability in soils and therefore in edible plant tissues. To overcome Se deficiency, the breeding approach (i.e., genetic biofortification), namely in rice, is largely dependent on available Se pools. To ensure the success of genetic biofortification with Se, agronomic biofortification can be accomplished through foliar Se application. Considering this background, the main hypothesis of this work was centered in the foliar application of Se to attain agronomic biofortification of rice crops. This study also aimed to assess the full potential for increasing grain Se concentrations during rice filling, as well as the types of nutrients deposition. An experimental design applying two foliar fertilizers (sodium selenite and sodium selenate) was developed. As test systems, four rice genotypes (Ariete, Albatros, OP1105 and OP1109) were used and the kinetics of micro- and macro-nutrients accumulation and deposition were assessed. Biofortification was performed in field trials for two years with foliar fertilization ranging between 0 and 300 g Se ha−1. At the end of the plant cycle, selenite applications triggered 427- to 884-fold increases in grain Se concentrations among rice genotypes (Albatros > OP1105 > OP1109 > Ariete). The application of selenate also prompted 128- to 347-fold increases in grain Se concentrations in rice crops (Albatros > OP1105 > Ariete > OP1109). Regardless of the foliar fertilizer applied, Se deposition among genotypes occurred throughout the grain without relevant inhibitory effects on yields. In each genotype, micro and macronutrients varied among crop tissues.

Oil palm has become an important source of revenue for smallholders in Indonesia, but productivity of smallholder plantations is generally poor. Nutrient limitations have been suggested as an important agronomic constraint to yield. Our research aimed to quantify fertiliser use, soil and tissue nutrient status, and palm growth and yield in a sample of independent smallholder plantations. We selected 49 plantations in Indonesia in two provinces with contrasting soils. For all plantations, we obtained self-reported fertiliser use and yield data, collected soil and tissue samples, and analysed vegetative growth. More than 170 kg N ha−1 year−1 was applied in one site, and P was applied in excess of recommended quantities in both sites, but on average farmers applied less than 100 kg K ha−1 year−1. Soils in the palm circle were poor in N, P and K in 29, 40 and 82% of the plantations, and deficiencies were measured in 57, 61 and 80% of the leaflet samples, respectively. We found statistically significant correlations between tissue nutrient concentrations and vegetative growth, but a large part of the variation in the data remained unaccounted for. Single leaf area was reduced in >80% of the plantations. Average yields were estimated to be 50‒70% of the water-limited potential. Our results demonstrate that widespread nutrient imbalances and deficiencies, especially potassium and phosphorus, occur in smallholder oil palm plantations, due to inadequate and unbalanced fertiliser application practices. These deficiencies may be an important underlying cause of the overall poor productivity, which threatens the economic and environmental sustainability of the smallholder sector.

Hand plucking of tea is labour intensive, and with rising labour costs mechanical harvesting (MH) is of increasing interest. However, effects of MH on yield and quality of tea remain unclear. We harvested two tea clones for eight years with a small, wheeled machine, to investigate effects of different cutting heights on yield and quality. The harvest interval for machine plots was 40% longer than for hand plucking in the first three years and 100% longer thereafter. The yield response, relative to hand plucking, depended on cutting height. Provided that increase in bush height (table rise) was 6 cm per year or less, yields were 15–21% higher than with hand plucking and increased yield was still being maintained after eight years. The increase in yield appeared to be mainly attributable to the longer harvest interval for machine plots, so that larger shoots were harvested. There was no increase in the number of shoots harvested per year, despite more intensive plucking with the machine. In less intensively harvested plots, where table rise was 11–14 cm per year, yield was reduced compared to hand plucking, and shoot number was nearly 30% lower. Dry matter production was greatest under the least intensive harvesting, but greater intensity gave higher harvest index and yield. In plots with no table rise, but not in other plots, a large amount of die-back of plucked points was observed. This may indicate source limitation of shoot numbers. We conclude that, with an extended harvest interval and careful management of cutting height, the yield of tea can be maintained under MH. There was a reduction in green leaf quality, with coarser shoots and increased mature leaf, but a limited number of taster evaluations of quality of the black tea showed significant differences for only one clone.

Innovation platforms are fast becoming part of the mantra of agricultural research for development projects and programmes. Their basic tenet is that stakeholders depend on one another to achieve agricultural development outcomes, and hence need a space where they can learn, negotiate and coordinate to overcome challenges and capture opportunities through a facilitated innovation process. Although much has been written on how to implement and facilitate innovation platforms efficiently, few studies support ex-ante appraisal of when and for what purpose innovation platforms provide an appropriate mechanism for achieving development outcomes, and what kinds of human and financial resource investments and enabling environments are required. Without these insights, innovation platforms run the risk of being promoted as a panacea for all problems in the agricultural sector. This study makes clear that not all constraints will require innovation platforms and, if there is a simpler and cheaper alternative, that should be considered first. Based on the review of critical design principles and plausible outcomes of innovation platforms, this study provides a decision support tool for research, development and funding agencies that can enhance more critical thinking about the purposes and conditions under which innovation platforms can contribute to achieving agricultural development outcomes.

Given the importance of irrigation for rice production, this study compared the technical efficiency of irrigated and rain-fed rice (Oryza sativa) farms in the Upper Niger River Basin and Rural Development Authority (UNRBDA), Nigeria. Primary data were collected from 300 irrigators and 325 rain-fed rice producers. Applying the stochastic frontier Cobb–Douglas production function, net income analysis and Likert scale rating techniques, the study found that irrigated scheme increased marginal factor productivity and profitability. The study revealed the existence of large technical inefficiency in rain-fed farms when compared with irrigated farms. This suggests that there is room for output gains through technical efficiency improvement in the rain-fed system. The mean value of the marginal physical product of inputs (VMPPX) in the irrigated farms (₦2.32) was more than that of rain-fed farm (₦1.67). Thus, if the average producers in the rain-fed are to achieve the technical efficiency level of the average producer in the irrigated farms, they can realize 38% output gains. Similarly, the mean net farm income (NFI) of ₦62,280.00 per ha in the irrigated farm was more than double of that of rain-fed farms ₦22,391.00. The partial regression coefficients for the individual production factors (β1) and (β3) for labour input (X1) and other variable inputs (X3), respectively, were positive and significant at 1% level, suggesting that the partial elasticity of crop output with respect to labour and other costs was higher in the irrigated farms than in the rain-fed farms. The Likert scale rating techniques showed that the poor knowledge of irrigation techniques, insufficient water for irrigation during the dry season, high cost of labour and lack of access to credit were the critical constraints preventing the rain-fed rice producer from joining the irrigation scheme. In view of this, rice irrigators should be encouraged to train more rain-fed farmers on some rudiments of irrigation techniques. They should also be linked to the sources of finance. Water Users Association (WUA) should be established in communities within the scheme areas for effective communication between farmers and the officials of the UNRBDA. Decision on the allocation of resources to Fadama sites including water should be given to WUA to strengthen the membership of the organization, while the government officials serve as supervisory and advisory body.

Pea is a self-pollinated, diploid (2n = 14), annual crop produced worldwide for human consumption and animal feed. The exploitation of maximum genetic potential from available pea resources implies the knowledge of genetic parameters of yield components. Hence, the present study was conducted in a cross between two pea varieties, namely DDR14 and Explorer, its F2 progeny and F3 families to find out transgressive segregants and to determine the magnitude of narrow sense heritability and heterosis. The high narrow sense heritability values obtained indicated that rapid gain could be achieved through selection for the different traits; however, the presence of genotype x environment interaction could limit the correspondence of these estimated values with the observed ones. The selection of lines through their phenotypic values is influenced by environmental and error effects. Best linear unbiased prediction (BLUP) was used for the prediction of genotypic values using morphological data from different years, allowing the correction for environmental effects. These estimates were used for genetic analysis of the traits. Heterosis was observed for number of pods (27.1%) and number of seeds (23.3%), characters that have a direct effect on yield. The cross also showed high frequency of transgressive segregation for these characters in F3 generation (15.5% and 13.6%, respectively). There were 12.73% families transgressive for two or more characters, with genotypic values of 49.82–64.41 for number of pods and 153.75–189.59 for seed number. The crossing between Explorer and DDR14 provided a base for the selection of superior progeny.

Consider a field experiment laid out in a randomized complete block design in which you study three types of fertilizers for two winter wheat cultivars. One year, one location – the experiment is not repeated. You design it and then spend a lot of time and money to conduct it. You cultivate the soil and take care of the plants; you worry about them; you never know what can happen, so you cannot wait for the crop to be harvested. And that day finally comes. The crop is harvested, and everything is fine. And here you are, all went great, you have the data in hands, and now a simple thing to do – analyse them. Well, yes, the experiment was conducted in one year, and you are aware you cannot be sure the outcome would be the same next year or elsewhere, but whatever – suffice it to consider the conclusions as preliminary and get on with the interpretation. Why should you not? It was a properly designed experiment that took samples from the underlying infinite populations of the two winter wheat cultivars in the three water regimes studied. Statistics is here to help you out, is not it? Well, it is not. Statistics will not help you out whether the experiment was poorly designed. Agricultural science literature seldom explains what populations are studied and what types of samples are taken in designed experiments. To fill this gap, we discuss various aspects of the sampling process in designed experiments. In doing so, we look at the survey sampling methodology, a statistical framework for studying finite populations – we do this because survey sampling has developed into the advanced theory of sampling processes, and this background can help us understand the intrinsic aspects of sampling in designed experiments.

Transplanting single seedlings rather than seedlings in clumps has been increasingly attractive in hybrid rice production in China due to reduced seed requirements and higher grain yield. This study was conducted to determine grain yield and nitrogen (N) utilization in response to reductions in the N rate in hybrid rice under single-seedling transplanting. Field experiments were done in 2015 and 2016 on a moderate to high fertility soil at the Experimental Farm of Hunan Agricultural University, China. The hybrid rice cultivar Liangyoupeijiu (LYPJ) was used in 2015, and two hybrid cultivars LYPJ and Xiangliangyou 900 were used the next year. In each year, the rice plants transplanted with a single seedling per hill were grown with three N rates, including the usual N rate (150 kg ha–1) and two reduced N rates (120 and 90 kg ha–1). Grain yield, yield attributes, and N uptake and use efficiency were determined for each N rate. Significant reduction in grain yield was observed in only one of three cultivar-year combinations when N rate was reduced by 20% (from 150 to 120 kg ha–1), and the magnitude of yield reduction was only 4%. Although significant reduction in grain yield was observed in two of the three cultivar-year combinations when N rate reduced by 40% (to 90 kg ha–1), the highest yield reduction was only 7%. Yield attributes were generally changed slightly when N rate was reduced by 20%, while compensation among yield attributes and N utilization characteristics could explain why a 40% reduction in N rate did not result in substantial yield loss. Partial factor productivity of applied N (PFPN) was increased by 21–24% and 56–63% with 20% and 40% reductions in the N rate, respectively. The higher PFPN with a reduced N rate was attributed to higher recovery efficiency of applied N (REN) or to both higher REN and internal N use efficiency. Our study suggests that reducing N rate does not necessarily result in yield loss due to compensation among yield components and increased N use efficiency in hybrid rice transplanted as single seedlings under moderate to high soil fertility conditions.

A large body of evidence demonstrates the agronomic superiority of maize hybrids over open-pollinated varieties (OPVs) in intensive monoculture. However, comparisons of the performance of hybrids and OPVs in agroforestry systems are scarce. In this study, the performance of four maize hybrids and four OPVs is compared in sole crop and under mature trees. Experiments were conducted on-farm during four seasons in Bugesera, Rwanda and two seasons in Meki, Ethiopia. Two tree species were selected in Bugesera (Grevillea robusta and Senna spectabilis) and one in Meki (Acacia tortilis), and three farms were selected for each tree species, each including two plots with almost identical trees in their centre and two plots without tree. In Bugusera, grain yield was higher for hybrids (2 Mg ha−1) than for OPVs (1.5 Mg ha−1), and the presence of trees reduced the harvest index more in OPVs than in hybrids. In this region, the estimated reduction in grain yield due to the presence of trees was 0.9 and 1.1 Mg ha−1 in hybrids and OPVs, respectively, while estimated reduction in biomass was 1.5 and 1.7 Mg ha−1, respectively. In Meki, the grain yield of OPVs (2.08 Mg ha−1) and hybrids (2.04 Mg ha−1) did not differ and the presence of trees reduced their grain yields in the same manner. Our results showed that hybrids yielded more than OPVs under G. robusta and S. spectabilis in Bugesera but performed equally well under A. tortilis in Meki. We conclude that agroforestry farmers could benefit from growing hybrids in the equatorial savannahs of Rwanda, but that the choice between hybrid and OPV in equatorial savannahs of Ethiopia can simply be based on other factors such as seed costs and availability.

Due to the lack of basic information on water required by maize (Zea mays L.) in Brazil, the large amount of water applied usually exceeds crop requirements, wasting water and energy. In this study, we measured crop evapotranspiration (ETc) as evaporative heat flux from a centre pivot-irrigated maize plantation in Southern Brazil during winter and summer seasons, using the Bowen ratio method to evaluate how the degree of canopy-atmosphere coupling affects crop water needs and irrigation management. Irrigation requirements were determined by comparing ETc with reference evapotranspiration (ETo), derived from the Penman–Monteith equation and expressed as the ETc/ETo (Kc) ratio. In this study, the average Kc values obtained were 1.31 and 0.90 for the winter and summer, respectively. Using aerodynamic and canopy resistance measurements, the decoupling factor (Ω) was computed. Ω values tending to zero (0.09 and 0.20 for winter and summer, respectively) showed that strong coupling of maize plants to the atmosphere and sensitivity to high air temperatures, vapour pressure deficits and wind speed caused variations in Kc in relation to ETo ranges. During the experimental period, the Kc value ranged from 0.92 when the ETo exceeded 4 mm d−1 to 1.64 when the ETo was less than 2 mm d−1.