In experiments conducted with three rice varieties at different plant populations and N levels, the non-lodging varieties responded to 150 kg N/ha. The highest yield in non-lodging varieties were at the highest transplanted density, but at the lowest density in the lodging variety. The percentage of total milled rice of all varieties was not significantly affected by N application, which improved head-rice recovery in chalky IR-8, but had no significant effect on non-chalky varieties. Competition for nutrients could be a major factor limiting head rice return at high densities.

Many farmers are intensifying production systems by applying greater amounts of inorganic fertilizers, irrigation and pesticides, especially to cash crops. Such intensified systems, even though economically profitable in the short run, may not be sustainable. This paper analyses the economics and sustainability of an intensified rainfed rice-based system in Ilocos Norte, Philippines. Farmers use high levels of inorganic fertilizers for cash crops such as sweet pepper, garlic and tomato. Although these crops generate high levels of income, the high input systems may not be sustainable in the long run due to adverse on-site and off-site effects. Preliminary estimates of total factor productivity that include on-site effects only, display no clear time trend. However, negative externalities created by high nitrate contamination of groundwater and high rates of pesticide usage could make the system unsustainable by adversely affecting human health and the environment.

The pattern of yield and productivity of a typical Raphia swamp is described and suggestions are made for improving the crop by selection

Dormancy in seeds of Sesbania sesban is caused by a water-impermeable seed coat (hard seeds or hardseededness). A two-phase pretreatment technique was developed for breaking seed dormancy and was validated using different accessions and seed lots. Seeds were first soaked in water at 80 °C for 8 min and prepared for the germination test. Ungerminated hard seeds at the first count (after four days incubation) during the germination test were then subjected to a second treatment by mechanically scarifying the seed coat. The effects of water temperature and variation in initial hardseededness and viability among and within accessions were also investigated. The optimum water temperature, allowing maximum seed germination without increasing the percentage of abnormal seedling/dead seeds was 80 °C. The mean percentage of hard seeds across 30 seed lots of six accessions was reduced to 26% after phase 1 and to 0% after phase 2. In addition, full germination occurred within only 10 days for treated seeds while germination in untreated seeds had reached only 48% after 14 days. Significant differences existed among the seed lots within the accessions (p > 0.05) for the percentage of initial hard seed and for the effects of treatments on breaking seed dormancy. The two-phase technique developed was validated using over 1000 seed lots of S. sesban, and it was found to be a rapid and cost-effective method for breaking hard seed dormancy with potential for wider use for hard-seeded legumes.

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.

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 aim of this study was to compare the effects of cowpea green manure and inorganic nitrogen (N) fertilizers on yields of winter wheat and soil emissions of nitrous oxide (N2O). The comparisons included cowpea grown solely as green manure where all biomass was terminated at maturity by tillage, summer fallow treatments with 90 kg N ha−1 as urea (90-N), and no fertilization (control) at planting of winter wheat. Fluxes of N2O were measured by closed chamber methods after soil incorporation of cowpea in autumn (October–November) and harvesting of winter wheat in summer (June–August). Growth and yields of winter wheat and N concentrations in grain and straw were also measured. Cowpea produced 9.5 Mg ha−1 shoot biomass with 253 kg N ha−1 at termination. Although soil moisture was favorable for denitrification after soil incorporation of cowpea biomass, low concentrations of soil mineral N restricted emissions of N2O from cowpea treatment. However, increased concentrations of soil mineral N and large rainfall-induced emissions were recorded from the cowpea treatment during summer. Growth of winter wheat, yield, and grain N concentrations were lowest in response to cowpea treatment and highest in 90-N treatment. In conclusion, late terminated cowpea may reduce yield of winter wheat and increase emissions of N2O outside of wheat growing seasons due to poor synchronization of N mineralization from cowpea biomass with N-demand of winter wheat.

Taichung (Native) No. 1 rice was grown under controlled conditions with a basic temperature regime of 30°C by day and 20°C by night. Periods of 2, 4 and 12 hours at 15°C (59°F) were imposed during darkness for the first or second 40 days, or for the first 80 days after sowing. Floral initiation was delayed by cool periods of 2 hours at night or longer, and delay from this cause was always accompanied by reduced grain yields, resulting from fewer spikelets per panicle or increased tiller sterility. This effect was not overcome when the cool periods ceased after floral initiation. Cool periods longer than 4 hours had a greater effect when they were given in the first 40 days.

At Pantnagar, India, linear response in maize to nitrogen application was observed up to 150 kg. of N/ha. with some of the most promising hybrids and composites released by the All India Co-ordinated Maize Improvement Programme. Increase in grain yield, and total nitrogen accumulation in grain, were substantially more in Ganga 2 than in the local cultivar or the composites, at higher rates of N application. In absolute terms, the local cultivar accumulated more nitrogen in its grain, but the relative amounts declined at higher rates of N application. Among the yield components influencing ultimate grain yield, barrenness exerted a negative influence on grain yield through the number of cobs per plot. Among cob characters, such as thousand grain weight and number of grains per cob, the former exerted a substantial influence on grain yield.

Understanding the genetic variability, heritability and genetic advance (GA) of traits in any plant population is an important pre-requisite for variety development. The objectives of the study were to assess the level of genetic variability among vegetative growth traits and yield, assess the relationship among the growth traits and yield and predict GA for the most heritable traits among Robusta coffee full-sib families. The trial was established in June 2009 at the experimental fields of the Cocoa Research Institute of Ghana with 62 full-sib families planted in a randomized complete block design with six replications. Significant (p < 0.05) variation was observed among the full-sib families evaluated for all traits, except for span (canopy diameter). Span and number of laterals were genetically correlated (p < 0.001) with cumulative yield (2013–2017), with span being the vegetative growth trait most strongly related to cumulative yield (rg = 0.60, p < 0.001). The most heritable vegetative growth and yield traits were, respectively, number of laterals (H2 = 0.59) and cumulative yield (H2 = 0.41). The top 10 families (BP40, BP41, BP9, BP36, BP34, BP28, BP37, BP14, BP4 and BP10) in terms of cumulative yield are proposed for multi-location evaluation and possible release as hybrids for coffee farmers in Ghana.

Since 1970 the University College of North Wales, in co-operation with the Saudi Arabian Ministry of Agriculture and Water, has been investigating the potential for forage production in all-year-round irrigated conditions in Saudi Arabia, and the principal results of the first 4 years of field experiments are discussed. Both temperate and tropical annual forages as well as perennial species were tested, and generally produced high yields with high nutritional value. Fertilizer responses and different management practices were evaluated and their relevance to the development of systems of forage production are discussed.

Ecoregional research has the potential to help address some of the huge challenges facing agriculture in developing countries by developing technologies that work under different agro-ecological conditions, and the processes by which these technologies can be adapted to work in other areas with similar conditions. The CGIAR system has been developing ecoregional research as a new paradigm for over a decade. In this paper we evaluate one of the most ambitious of these initiatives called the Benchmark Area Approach (BAA) pioneered by the International Institute of Tropical Agriculture. We evaluate the BAA against nine good practice criteria for ecoregional research and finding that the approach is delivering, or has the potential to deliver, on all nine. Many of the lessons learnt from this evaluation will be relevant to current and future attempts to undertake co-ordinated multi-locational research for development.

The leaching of boron, studied after high rates of application under different management practices, indicated that leaching was rapid and that the presence of cover crops was likely to reduce the immediate availability of boron to the main crops.

Responses in yield of dry bean genotypes of different growth habits [determinate (Type I), indeterminate small vine (Type II), indeterminate large vine (Type III), and indeterminate climbing (Type IV)] were evaluated over two growing seasons. Types II and III gave higher yields than Type I, with Type II the highest. Narrow between-row spacings (50 cm) tended to give higher yields than 75 cm spacings for all habits, though Type I seemed less responsive than the indeterminate habits, Types II and III. Close within-row spacing (5 versus 10 cm) was not beneficial for beans of any growth habit. Yields of beans with climbing habit grown on different support systems and at different spacings are also reported.

A series of trials investigated the response of a range of groundnut genotypes to varied levels of competition from millet in intercrop situations in both the Sahelian and Sudanian agro-climatic zones. No genotype interactions were observed in response to different millet population levels. Introducing millet into groundnut cultivation provided considerable benefits to the farmer, particularly at the less dense millet populations, but the introduction of groundnut into millet cropping consistently reduced the yield of millet, with little gain in groundnut yields.

The cotton-wheat double-cropping system is widely used in the Yellow River Valley of China, but whether and how different planting patterns within cotton-wheat double-cropping systems impact heat and light use efficiency have not been well documented. A field experiment investigated the effects of the cropping system on crop productivity and the capture and use efficiency of heat and light in two fields differing in soil fertility. Three planting patterns, namely cotton intercropped with wheat (CIW), cotton directly seeded after wheat (CDW), and cotton transplanted after wheat (CTW), as well as one cotton monoculture (CM) system were used. Cotton-wheat double cropping significantly increased crop productivity and land equivalent ratios relative to the CM system in both fields. As a result of increased growing degree days (GDD), intercepted photosynthetically active radiation (IPAR), and photothermal product (PTP), the capture of light and heat in the double-cropping systems was compared with that in the CM system in both fields. With improved resource capture, the double-cropping systems exhibited a higher light and heat use efficiency according to thermal product efficiency, solar energy use efficiency (Eu), radiation use efficiency (RUE), and PTP use efficiency (PTPU). The cotton lint yield and biomass were not significantly correlated with RUE across cropping patterns, indicating that RUE does not limit cotton production. Among the double-cropping treatments, CDW had the lowest GDD, IPAR, and PTP values but the highest heat and light resource use efficiency and highest overall resource use efficiency. This good performance was even more obvious in the high-fertility field. Therefore, we encourage the expanded use of CDW in the Yellow River Valley, especially in fields with high fertility, given the high productivity and resource use efficiency of this system. Moreover, the use of agronomic practices involving a reasonably close planting density, optimized irrigation and nutrient supply, and the application of new short-season varieties of cotton or wheat can potentially enhance CDW crop yields and productivity.

The conservation of genetic resources is discussed in relation to the stages in the evolution of crop plants. Strategies for the collection and conservation of wild species, landraces and advanced cultivars are considered in relation to the pratical needs of plant breeders and other users.

Four isolates of Azolla pinnata collected from Bangkok, Bangladesh, Vietnam and India grew well when used in paddy fields both before and after transplanting with rice varieties of different heights and times to maturity. Azolla increased plant height, tillering, 1000-grain weight, grain and straw yields, nitrogen concentration and uptake, and soil fertility.

The response of rice to Azolla was similar to that obtained by applying 60 kg N ha−1 as urea in three split applications. The different Azolla isolates differed in their growth, N2-fixation and response to rice crops and soil fertility. All these characteristics were better in the isolates from Bangkok and Vietnam than in those from Bangladesh and India. Azolla growth and N2-fixation were better with short rice varieties (IR-36, Ratna and Kalinga-II) than with Mahsuri, a tall rice variety, but Mahsuri, having a longer growing season, showed a better response to Azolla.