The environmental conditions and test duration in rainfall simulators have been major constraints to find reliable differences in preharvest sprouting (PHS) among wheat cultivars. This study aimed to elucidate the temperature conditions and degree-days (DD) that enable higher discrimination of genotypes in a PHS test. Thirteen genotypes with different degrees of PHS (BR 18, BRS 220, CD 104, CD 105, CD 108, CD 114, CD 116, Frontana, IPR 085, IPR 128, IPR 136, OR1 and Safira) were evaluated in a rainfall simulator, during four years, conducting two trials per year. The tests were carried on 20 spikes per cultivar, kept in a vertical position on Styrofoam plates, spaced 10 cm between rows and 5 cm within the row. The air temperature data were recorded on a thermograph and the DD were calculated from the mean daily air temperature assuming a base temperature of 4 °C. The Falling Number (FN) parameter and germination percentage (GP) data were averaged for each test. The temperatures (minimum, mean and maximum) and the DD were regressed and correlated with FN and GP. Any increase in the minimum and mean air temperature and accumulated DD decreased FN values and increased GP. Higher genotypic discrimination was achieved at an average air temperature of 21.5 °C and 35 DD. These values can be used as reference to set simulated rain testing condition for screening genotype for PHS based on FN or pericarp rupture of grains.

This paper describes the results of 3 year's data from farmers using the Adaptive Yam Minisett Technique (AYMT) to produce seed yams in Nigeria. A total of 30 sites were established each year between 2013 and 2015 in the Idah area (Kogi State) of Nigeria and 58 plots in the Amoke area (Benue State) in 2015. Each site had yam setts (80 to 100 g) untreated and treated with a pesticide ‘dip’ prior to planting and farmers (male and female) were free to select the variety and manage the sites as they wished. In line with previous research, the results suggest that treatment does increase the weight of tubers produced by a sett but not necessarily the number of tubers. Varietal differences were also observed. For the first time, the results suggest that the time of planting does have a significant impact on seed tuber weight, with later planting leading to small tubers. Also, the gender of the farmer had an impact on some of the agronomic variables, with male owners of the site generally producing more and larger tubers per sett planted and sprouted than female owners. Various mechanisms for the latter are discussed in the paper.

Despite tremendous efforts made in agricultural sectors in sub-Saharan Africa in the last two decades, fruits production and consumption to reduce malnutrition and chronic diseases remain low and have received less attention. Moreover, our knowledge of the current production situation and options for improvement are still limited. In this study, we investigated citrus farming systems and production bottlenecks to identify leverage points for intensification of smallholder citrus farming systems in Benin. We provided a typology of citrus orchards based on 17 quantitative and qualitative variables using Factor Analysis of Mixed Data combined with Hierarchical Cluster Analysis. The typology revealed four categories of citrus farms based on biophysical resources, socioeconomic resources and system management practices. Categories 1 and 2 included farms characterised by less diversified cropping systems with non-recommended management practices. Orchard categories 3 and 4 included farms with high varietal diversity and improved management practices. However, farmers of category 4 neglected staking and digging practices. The inadequate farming practices explained some of the production bottlenecks, which were orchard-type dependent. We discussed the implications of our findings and suggested a number of policy and strategic decisions as well as research and development actions for improving citrus production in Benin.

Maize (Zea mays L.) is the most important staple crop in West and Central Africa (WCA), but its production is severely constrained by low soil nitrogen (low N). Fifty-six extra-early open-pollinated maize cultivars developed during three breeding eras, 1995–2000, 2001–2006 and 2007–2012, were evaluated under low N and high soil nitrogen (high N) at two locations in Nigeria in 2013 and 2014, to investigate the genetic gains in grain yield and identify outstanding cultivars. During the first breeding era, the emphasis of the programme was on breeding for resistance to the maize streak virus (MSV) and high yield potential, while the major breeding emphasis during the second era was on recurrent selection for improved grain yield and Striga resistance in two extra-early-maturing source populations, TZEE-W Pop STR (white) and TZEE-Y Pop STR (yellow). Starting from the third era, the source populations were subjected to improvement for tolerance to drought, low N and resistance to Striga. A randomized incomplete block design with two replications was used for the field evaluations. Results revealed genetic gains in grain yield of 0.314 Mg ha−1 (13.29%) and 0.493 Mg ha−1 (16.84%) per era under low N and high N, respectively. The annual genetic gains in grain yield was 0.054 Mg ha–1 (2.14%) under low N and 0.081 Mg ha–1 (2.56%) under high N environments. The cultivar 2009 TZEE-OR2 STR of era 3 was the most stable, with competitive yield across environments, while 2004 TZEE-W Pop STR C4 from era 2, and TZEE-W STR 104, TZEE-W STR 108 and 2012 TZEE-W DT STR C5 from era 3 were high yielding but less stable. These cultivars should be further tested on-farm and commercialized in WCA. Substantial progress has been made in breeding for high grain yield and low-N tolerance in the sub-region.

Rubber is usually cultivated for lifespan of 30 years based on the technical feasibility of managing tapping panels. For obtaining early financial benefits, there is a demand for shorter lifespan with intensified tapping. With no research conducted on this line, the present study was focussed to investigate the financial feasibility of shortening the lifespan of rubber trees through lifecycle analyses with three principal scenarios of intensified harvesting, i.e. Intensified Harvesting throughout the Total harvesting Period to obtain a part or full amount of yield lost due to shortening the lifespan (IHTP), Intensified Harvesting only during last 6 Years (IH6Y) and Intensified Harvesting at last ¼ of harvesting Period (IH¼P). In IHTP, intensified tapping to achieve 10–15% of yield loss due to shortening the lifespan was found to be effective to reduce the lifespan even up to 21 years. Market price of rubber and tree stand per hectare were found to be the critical factors determining the best lifespan particularly in IHTP. The best lifespan under IH6Y and IH¼P scenarios was in the range of 19–22 years. Agronomic, environmental and social implications in shortening lifespan of rubber are discussed.

A 2-year field study was conducted in central Greece (Larissa) and was repeated simultaneously in northern Greece (Thessaloniki) to determine the productivity and the competitive ability against corn poppy (Papaver rhoeas L.) of six faba bean (Vicia faba L.)-barley (Hordeum vulgare L.) intercrops grown at three seeding ratios (75:25, 50:50 or 25:75% of the recommended seeding rates) and two crop arrangements (alternate or mixed rows). Faba bean and barley sole crops were also included. Corn poppy dry weights in barley sole crop or faba bean-barley intercrops were 83 to 85% or 50 to 99%, respectively, lower than that in faba bean sole crop. Total dry matter (DM) and total crude protein (CP) yields of faba bean-barley intercrops were, in most cases, not significantly affected by corn poppy competition. The results obtained in both locations indicated that intercropping faba bean with barley could be an alternative practice to that of faba bean sole crop in sustainable production systems, because of its greater productivity, balanced nutritive value and competitiveness against aggressive weeds such as corn poppy.

Applying stochastic frontier Cobb–Douglas production function, the study assessed the efficiency of sweet potato (Ipomoea batatas) producers in the Southern region of Ethiopia. The study revealed the existence of fairly large technical inefficiency in sweet potato production. The technical efficiency ranged from 12.6 to 93.7%, with more than half of the producers above the mean efficiency level (66.1%). This suggests that there is room for output gains through technical efficiency improvement. If the average producers in the study region are to achieve the technical efficiency level of the most efficient producer in the sample (93.7%), they can realize nearly 30% output gains. The analysis of allocative efficiency also revealed that sweet potato producers were producing sweet potato with sub-optimal utilization of production inputs, suggesting that potential for output gains remains to be exploited through reconfiguration of the existing resource use. They can make more value out of their sweet potato production by reconfiguring their current utilization of production inputs in favour of more land and manure but less seed rate. Furthermore, age and education are important determinants of the efficiency of sweet potato production. In view of these findings, it is advisable to put in place appropriate extension intervention programmes that enable sweet potato producers to exploit the potential gains in sweet potato output through technical and allocative efficiency improvement.

Bud removal of the cuttings at underground level has been claimed by cassava growers in Thailand as a method to increase cassava yield. This practise should be tested experimentally to explain the reason for yield increase. The objective of this study was to investigate the effects of bud removal and cutting length on storage root yield and starch content of three cassava varieties. Field experiment was conducted in a split–split plot design with four replications in 2010 and 2011, under rainfed conditions. Three cassava varieties (KU50, RY9 and HB60) were assigned as main plot. Two cutting lengths (15 cm and 30 cm) were assigned as sub plots, and two treatments of buds (buds cut and not cut) were assigned as sub–sub plots. The buds on the cuttings that were inserted into the soil were removed. In 2010, the plants from 15-cm long cuttings subjected to bud removal had higher fresh storage root yield (88.4 Mg ha−1) than did plants from 30-cm long cuttings subjected to bud removal (75.8 Mg ha−1). Cutting of buds also had higher fresh storage root yield (89.1 Mg ha−1) than did non bud-cutting (75.0 Mg ha−1). KU50 had the highest fresh storage root yield (91.4 Mg ha−1), dry root yield (48.4 Mg ha−1) and starch yield (20.1 Mg ha−1). Cutting length of 15 cm had higher starch concentration in storage roots (25.6%) than did cutting length of 30 cm (24.2%). HB60 had the highest starch concentration (27.0%) among cassava varieties tested. The data in 2011 were similar to the data in 2010. The responses of varieties to bud removal and cutting length are discussed.

The effects of sole and intercropping of rainfed maize (Zea mays L.) were evaluated with soybean (Glycine max L.) and groundnut (Arachis hypogea L.) on crop yield, weed smothering efficiency (WSE) and nutrient (NPK) balance at Eastern Himalayan Region (EHR), India. Grain yield of maize was highest (3886 to 4110 kg ha−1) in the solitary system followed by maize-soybean intercrops at 1:2 rows. However, system productivity as well as production efficiency was higher by 47.3-63.3% and 39.5-58.4%, respectively in intercropping with groundnut at 1:5 rows compared to solitary maize. WSE was relatively higher to solitary soybean and was comparable to maize-groundnut intercropping at 1:5 row proportions. Similarly, NPK uptake was higher in intercropping of maize-soybean systems at 1:5 row proportions. Inclusion of legumes as intercrops in predominantly solitary rainfed maize may improve the system productivity while sustaining the nutrient availability in the vast uplands of the EHR and other similar rainfed hilly ecosystems.

Two field experiments were conducted during the rainy seasons of 2013 and 2014 to evaluate the effects of biological nitrogen fixation (BNF) and/or sowing N fertilization on the growth and yield of Phaseolus vulgaris L. In addition, leaf soluble protein content (LSPC) was measured at four growth stages in both seasons. Plants were subjected to the following treatments: only fertilized with 20 kg N ha−1 at sowing and with 40 kg N ha−1 at 25 days after emergence (DAE) (F); only inoculated with Rhizobium tropici strain SEMIA 4080 at sowing and fertilized with 40 kg N ha−1 at 25 DAE (I+N); and inoculated and fertilized with 20 kg N ha−1 at sowing and with 40 kg N ha−1 at 25 DAE (IF). An additional treatment was done only in the second season and plants were inoculated with no N fertilization at any phase (I−N). Crop growth rate and leaf area index were enhanced by IF and F treatments as compared to I+N treatment, however, net assimilation rate did not differ among the treatments. At the pollination and flowering stages for seasons, LSPC was significantly increased by IF treatment, which also caused the highest final yield compared with the remaining treatments in both seasons. Therefore, the fertilization with 20 kg N ha−1 at sowing together with inoculation and 40 kg N ha−1 at 25 DAE is recommended for obtaining high yield in bean cultivation with high technology. As the inoculation with Rhizobium at sowing and fertilization with 40 kg N ha−1 at 25 DAE (I+N) had the same crop yield as plants fertilized at sowing and at 25 DAE (F), it can be recommended for a low-cost technology cultivation employed by small farmers.

Fertilization of rubber plantations has been poorly documented despite the huge economic and ecological impact of this tropical perennial crop, especially in Southeast Asia. The main objective of this paper is to provide information on the fertilization practices of rubber smallholders in Thailand and to investigate the drivers of these practices. Data were sourced from individual interviews conducted with 414 rubber smallholders. The results showed that 99.4% of the mature rubber plantations were fertilized with either chemical or organic fertilizers, or both. The average dose of chemical fertilizers was 105/53/92 kg ha−1 of N/P/K that is consistent with the national recommendations. We estimated that almost two-thirds of the plantations had intensive or very intensive fertilization practices. Geographical location, especially the distinction between historical and new rubber-producing areas, appeared as a major factor explaining differences in fertilization practices. Several drivers commonly found in the literature did not affect the fertilization practices of the rubber farmers, highlighting some specificity of perennial crops and a context where access to fertilizer was not an issue. The high economic and environmental costs of intensive fertilization practices, while their benefit to the yield of rubber plantations continues to be debated, show the need to conduct research on sustainable fertilization practices in rubber smallholdings.

Quality of animal manure as a nutrient source for crops and as a soil conditioner depends on how fast the organic matter is decomposed, releasing plant nutrients or building up the soil organic matter (SOM) pool. This turnover process is governed by manure composition, soil temperature, soil moisture and secondary metabolites in the manure such as tannins. To investigate the turnover and nutrient release from tannin-containing manure, a litterbag experiment was conducted in an irrigated lowland soil of northern Oman. A standardized quebracho tannin extract (QT) was either added to the goats’ diet and defecated with manure (QTf), or added to manure in a QT water suspension (QTc) prior to field application. Litterbags were installed within a two-year field experiment at 10-cm depth at the beginning of a consecutive sweet corn and radish cultivation, followed by their recovery every 2-–6 weeks until crop harvests. The litterbags contained pure goat manure (control) and the two types of QT-amended goat manure. Generally, QT increased OM remaining in litterbags at sampling by up to 22% compared with the control. QT reduced relative C, N, P and K release by 10% to 63% compared with the control, but effects were contradictory under sweet corn and radish. While under radish, both QT treatments reduced or tended to reduce C, N, P and K release from manure, QTc even increased N and P release under sweet corn. QTf, on the other hand, did not affect C, P and K release under sweet corn, whereas N release was reduced by 36–63% under both crops. As quebracho tannins in goat manure slowed down organic matter decomposition and reduced nutrient release, they may be useful agents in manure application to increase SOM pools and soil nutrient pools. However, the immobilization particularly of N by tannins can reduce the availability of this nutrient to crops.

This paper aims to determine the influence of family farming features on efficient use of water. The analysis focusses on a random sample of family farms in the province of Almería, southeast Spain. A hierarchical regression model was conducted to determine how the water efficiency is related to environmental awareness and certain characteristics of farmers, decision-makers and the family farm itself. The results show that these family farms strive to be more efficient in their use of water when they are going to be inherited, when there are younger decision-makers who have received a better education, and also when women are involved. Moreover, this efficiency is positively related to more ecological production and to the farmer's habitual behaviour with respect to water economy. The study provides evidence regarding the influences of socio-economic and environmental features of family farming on water use efficiency that may prove useful for other analyses and policy makers on water management in agriculture.

Rice is the main food for most of the human population, so sustainable rice production is very important for food security. The fertility of the soil in paddy fields is the key factor controlling rice growth and production. Steel slag amendment is becoming an effective method to increase the soil fertility, stabilize rice production and reduce greenhouse-gas emissions in Asiatic paddy fields (i.e. Korea, Japan, Bangladesh and China). We studied the relationships of steel slag amendment with plant–soil nutrient allocation, stoichiometry and rice yield in a paddy field in subtropical China. Amendment was associated with higher soil N and P availability, lower available-N:available-P ratio and higher available Ca and Si concentrations. Increases in P, Ca and Mg availability were correlated with high yields. High yields under steel slag amendment were also associated with high foliar and stem N and P concentrations and lower N:P ratios and with high shoot/root N and P concentration ratios, traits that are typically associated with productive ecosystems able to support species with high growth rates. The positive correlation between steel slag application and yield was partially due to an indirect effect (35% of the total effect) of enhancement of soil Ca, Si and P availability, which were positively correlated with yield. Steel slag amendment in this paddy field increased plant growth and yield by enhancing nutrient availability, altering soil and plant stoichiometry and shifting stem:root nutrient allocation.

Biochar application appears to be a promising method to improve soil physicochemical and biological properties by increasing soil carbon. Along with the influence of hardwood biochar on wheat growth, yield and soil quality for a period of two years, this study also evaluates the major soil parameters to be taken as minimum data set while assessing the impact of hardwood biochar in an acidic sandy loam soil. Five fertilizer treatments combining inorganic fertilizers and biochar were applied: unfertilized control (T1); 100% NPK (T2); 5 Mg ha−1 biochar (T3); 100% NPK + 5 Mg ha−1 biochar (T4); and 50% N + 100% PK + 5 Mg ha−1 biochar (T5). Biochar application (T3 vs. T1; T4 and T5 vs. T2) significantly increased leaf chlorophyll content, net photosynthesis rate, leaf N concentration and above and below-ground biomass, with improved wheat yield and grain quality (total grain protein and carbohydrate). Soil pH, water-holding capacity, available nutrients (N, P and K), organic carbon and its fractions also enhanced in biochar applied plots with reduced bulk density. Increased activities of soil enzymes urease, phosphatase, dehydrogenase, fluorescein di-acetate and arylsulphatase were recorded in biochar treatment along with significant increase in N recovery index (22%) and agronomic efficiency (40%). Multivariate analysis identified activity of phosphatase, pH and humic acid to fulvic acid ratio as the indicators to explain the total variance from biochar addition in acidic sandy loam soil under wheat cultivation. Soil quality index showed a significant improvement when biochar was added with reduced N doses (T5). This study confirms the efficacy of biochar as a soil conditioner when applied with reduced N fertilizer and would be a sustainable option to improve wheat production and soil quality in acidic sandy loam soils of northeast India.

Durum wheat (Triticum durum) is one of the most important cereal crops in the Mediterranean region; however, its cultivation suffers from low yield due to environmental constrains. The main objectives of this study were to (i) assess genotype × environment (GE) interaction for grain yield in rainfed durum wheat and to (ii) analyse the relationships of GE interaction with genotypic/meteorological variables by the additive main effects and multiplicative interaction (AMMI) model. Grain yield and some related traits were evaluated in 25 durum wheat genotypes (landrace, breeding line, old and new varieties) in 12 rainfed environments differing in winter air temperature. The AMMI analysis of variance indicated that the environment had highest contribution (84.3% of total variation) to the variation in grain yield. The first interaction principal component axis (IPCA1) explained 77.5% of GE interaction sum of squares (SS), and its effect was 5.5 times greater than the genotype effect, indicating that the IPCA1 contributed remarkably to the total GE interaction. Large GE interaction for grain yield was detected, indicating specific adaptation of genotypes. While the postdictive success method indicated AMMI-4 as the best model, the predictive success one suggested AMMI-1. The AMMI biplot analysis confirmed a rank change interaction among the locations, indicating the presence of strong and unpredictable rank-change location-by-year interactions for locations. In contrast to landraces and old varieties, the breeding lines with high yield performance had high phenotypic plasticity under varying environmental conditions. Results indicated that the GE interaction was associated with the interaction of heading date, plant height, rainfall, air temperature and freezing days.

This paper evaluates 30-year (2013–2042) projections of the selected climatic parameters in cotton/wheat agro-climatic zone of Pakistan. A statistical bias correction procedure was adopted to eliminate the systematic errors in output of three selected general circulation models (GCM) under A2 emission scenario. A transfer function was developed between the GCM outputs and the observed time series of the climatic parameters (base period: 1980–2004) and applied to GCM future projections. The predictions detected seasonal shifts in rainfall and increasing temperature trend which in combination can affect the crop water requirements (CWR) at different phonological stages of the two major crops (i.e. wheat and cotton). CROPWAT model is used to optimize the shifts in sowing dates as a climate change adaptation option. The results depict that with reference to the existing sowing patterns, early sowing of wheat and late sowing of cotton will favour decreased CWR of these crops.

Topdressing of N fertilizer, whenever leaf greenness, as measured by Chlorophyllmeter (SPAD), falls below the threshold value can be used for site-specific N management in wheat cultivation. Herein, a field experiment was conducted to analyse the effect of SPAD-based N management on wheat productivity and N use efficiency during the dry season of 2010/11 and 2011/12 on acid lateritic soil of eastern India. The experiment had 12 treatments, with nine treatments combining three SPAD thresholds (38, 40 and 42) and three N levels (15, 25 and 35 kg N ha−1) as real time N management (RTNM), one fixed time N management (FTNM), one farmers’ fertilizer practise (FFP) and control (Zero N), with three replications. The grain yield of RTNM ranged from 90 to 113% as that of FTNM, but using considerably less N. Maintaining SPAD threshold of 40 up to heading stage by topdressing 25 kg N ha−1 at each time (N25S40) caused the highest grain yield (4483 kg ha−1). While saving 22.5 kg N ha−1 (18.8%), N25S40 increased agronomic N use efficiency by 58.5%, nitrogen recovery efficiency by 15.1% and partial factor productivity of applied N by 26.4% when compared with conventional fertilizer recommendations (i.e. FTNM). The SPAD-based N management strategy was found very promising in efficiently managing N fertilizer in wheat for improving wheat productivity and N use efficiency.

Weed management is the major challenge to the success of boro rice (rice grown during Dec–Jan to May–Jun, also known as summer rice) in Southern Asia. Herbicide seems to be a cost effective and strategic tool from an agronomic view point to control weeds; however, herbicide application can potentially interfere with soil enzyme activity and microbial biomass carbon (MBC). A field study was conducted in 2012/13 and 2013/14 to evaluate the performance of sole and combined application of different pre-emergence herbicides in comparison to manual weeding in boro rice. Lowest weed density, biomass and highest weed control efficiency (~83%) were recorded with the pyrazosulfuron ethyl, causing higher grain yield (6.7 Mg ha−1 in 2012/13 and 4.5 Mg ha−1 in 2013/14) than treatments with chlorimuron + metsulfuron-methyl, bensulfuron methyl + pretilachlor, butachlor fb 2,4D, butachlor and cono-weeder. Among, the herbicidal treatments butachlor caused lower grain yield and higher weed density and biomass when compared to the others. Although grain yield was highest in weed-free treatments but net returns and (B:C) benefit cost ratio was highest for pyrazosulfuron ethyl due to high cost of hand weeding. After 15 days of herbicide application, lowest microbial biomass carbon was recorded with bensulfuron methyl + pretilachlor, whereas lower values of dehydrogenase and fluorescein diacetate activities were observed with the application of chlorimuron + metsulfuron-methyl at 15 days after herbicide application. Our results suggest that pyrazosulfuron ethyl is one broad-spectrum and economically effective herbicide for controlling weeds as an alternative to labour consuming hand weeding in boro rice cultivation.

The objectives were to assess the following: (1) the relationship between sward height and chemical composition of four pasture types in association with grazing behaviour and body condition score (BCS) of dairy cows, and (2) the possibility of developing predictive equations of the nutrient intake and grazing behaviour within a continued grazing system. Pasture type had a significant (p < 0.01) effect on nutrient supply from January to June for all pastures investigated. Ryegrass–white clover pasture (RW) had the highest metabolizable protein and metabolizable energy, followed by kikuyu pasture (KP), which was significantly (p < 0.001) higher than native pastures 1 and 2 (NP1 and NP2). The highest values for effective grazing time, bite rate and BCS were found when dairy cows grazed RW followed by KP, NP2 and NP1. The results suggested that pasture type and sward height influenced grazing behaviour and BCS of dairy cows during the dry season. In the same vein, RW showed higher effective grazing time, bite rate, nutrient intake and BCS than the other three pastures suggesting that RW pastures that appear to be more expensive than native pastures could result in superior cow performance.