On the basis of a preliminary experiment with 20-day-old Cicer seedlings, wherein the values obtained by integrating the in vivo nitrate reductase (NR) activity with the duration closely approximated the actual reduced N, a field experiment was conducted with cv BG 203 (indeterminate type) to ascertain the extent to which the nitrate assimilated via the enzyme NR contributed to the total reduced N. Soil-derived N accounted for 15.1, 8.3 and 7.2% of the total reduced N at pre-flowering (I), profuse flowering (II) and seed filling (III) stages respectively. Out of the total soil-derived N, 10.1, 59.3 and 30.6% was reduced during stages I, II and III respectively.

The production of lentil (Lens culinaris) was examined in 24 on-farm trials conducted over three seasons (1985/86 to 1987/88) in northwest Syria to examine the main effects and interaction of sowing date, weed control, Sitona weevil control, and fertilizer application (phosphorus and nitrogen). Advancing the date of sowing from late winter (mid January) to early winter (mid-November) resulted in an increased yield of grain and straw in all years across locations. Responses to phosphorus application were also significant in all years. Controlling Sitona weevil increased grain yield by 20% in early sown crops and by 14% in those that were sown late. Weed control by the pre-emergence application of cyanazine and pronamide increased grain yield by 59% in early sowings and by 20% in late sowings. Economic analysis of the improved production practices showed that early sowing combined with the control of Sitona and weeds, and phosphorus application, gave the highest probability of an increase in net revenue with virtually no risk of economic loss to the farmer.

Water depth at or shortly after planting is critical for the establishment and subsequent tolerance of excess water in rice. A crop transplanted early in the season produced twice as much grain as a later planted crop. A semi-dwarf variety (CR 1018) and a taller variety (CR 1030) performed similarly after early transplanting, but the tall variety performed better when planted late under excess water. Seedling age did not greatly alter the yields when crops were transplanted early, but after late planting 45-day-old seedlings were best.

Land degradation and declining productivity in the Ethiopian Highlands are primarily caused by soil fertility decline due to erosion, nutrient depletion, and soil acidity. An integrated soil fertility management (ISFM) project operating over a six-year period aimed to combat this and boost yields through participatory demonstrations. Despite high levels of yield variability expected from a farmer-managed observational study over a wide area, results show that crop yields increased with increased use of ISFM. Detailed statistical analysis using multiple linear regression models explained the contribution of individual practices. Use of improved varieties and line-seeding rather than broadcasting were consistently and highly significant. The contribution of inorganic blended fertiliser was less clear, probably due to low soil organic matter and use on acidic soils, although response to nitrogen was highly significant. The contribution of organic fertilisers was less than expected, possibly due to soil disturbance from farmer practices of multiple ploughing. Responses to crop residue management and agroforestry practices were significant on most crops reflecting their importance in improving soil water management, soil organic matter and recycling nutrients. Response to lime application on acid soils was highly significant confirming the importance of correcting acidity. Unexplained differences are attributed to the additive effects of using several ISFM treatments as well as unrecorded beneficial farmer management practices. It can be concluded that ISFM can play an essential role in improving productivity, addressing food insecurity and the challenges of climate change. Further expansion will require advocacy, awareness-raising, field-level extension and involvement of the private sector.

The aim of this work was to determine the importance of the genotype-by-environment interaction in true potato seed breeding. In order to establish the importance of this type of interaction, experiments were sited across three Peruvian locations, San Ramon (warm mid-altitude slopes), Huancayo (cool Andean highlands), and La Molina (coastal desert). The genotype by environment interaction significantly affected tuber yield in all breeding materials (4x-4x from random or selected parents, and 4x-2x crosses). For example, the 10 most outstanding 4x-2x crosses for tuber yield were different when tested in warm and cool locations. Similarly, two clones derived from 4x-4x crosses were among the best 15 hybrids assessed in the two lower altitude locations. These two offspring provide examples of crossover genotype-by-environment interaction for tuber set, non-cross order genotype-by-environment interaction for tuber yield and lack of genotype-by-environment interaction for days to flowering. Because top yielding true potato seed offspring for each location were locally adapted, cultivars or advanced selections from the target area should be the parental sources of true potato seed offspring.

Uptake of P32 from labelled KH2PO4 solutions, injected in the top-soil at points distributed over 4000 cm.2 in the zone of high root activity, was measurable soon after application with accumulation of P32 in leaves increasing thereafter with time. The recently-acquired P32 was distributed uniformly in the tree canopies. Uptake of P32 reached a maximum when the number of injection points was increased from 15 to 30 per tree, with 45 and 60 injection points leading to little further change in P32 content of leaves. In the zone of high root activity, strip application of P32 was as efficient as application in a circle around each tree. The practical implications of these observations in relation to P-fertilization of coffee are discussed.

The response to sulphur (S) and irrigation of mustard although site-specific, is less studied across sites. Economics and greenhouse gases (GHGs) emissions are other important considerations for developing resource-efficient technologies, but hardly studied in mustard. The objectives of this study were to appraise productivity, economics and GHGs emissions under three irrigation regimes combined with four levels of S, laid out in a split plot design with three replications. Results showed that two irrigations at 30 and 60 DAS combined with 60 kg S ha−1 resulted in highest gross and net returns, which were 30.9 and 37.2% higher than that in single irrigation at 30 DAS, and 47.2 and 68.0% higher than that in single irrigation at 60 DAS without S application, respectively. Estimated GHGs emissions from common inputs (machinery, diesel, fertilizer and insecticides) of mustard were 1486.2 kg CO2 eq ha−1 with greater share (95%) of fertilizer. Econometric analysis predicts that 1% increase in irrigation and S use will lead to 10.29 and 9.98% increase in mustard yield, respectively.

A pot experiment was carried out to study various aspects of growing peanuts in highly calcareous soil, with special reference to iron chlorosis. There was good agreement among the criteria used to evaluate the need for iron and the effectiveness of different chelates or methods of application (i.e. visual symptoms, chemical diagnosis and yield response). Of the iron chelates tested, Sequestrene 138 proved the most effective. Promising results were also obtained by coating seeds with chelate as an iron starter, followed by an additional top dressing. The results indicate the possibility of growing peanut economically in the highly calcareous soil tested using iron chelate —Fe EDDHA (Sequestrene 138).

Intensification of maize production is imperative to improve food security for the rising population in the central rift valley (CRV) of Ethiopia, whose livelihood is principally based on rainfed maize that operates under shrinking landholding and high seasonal rainfall variability. This study examined different levels of intensification options in maize production by sequentially introducing minimum tillage and seed priming, phosphorus (P) fertilizer microdosing, surface mulching and nitrogen (N) fertilizer microdosing. Field experiments were conducted with five treatments, steps or levels consisting of conventional tillage (farmers practice as a control); minimum tillage + seed priming, unfertilized (step 1); step 1 + microdosing 53 kg ha−1 P (step 2); step 2 + 4 ton ha−1 maize stover as surface mulch (step 3) and step 3 + 53 kg ha−1 N (step 4). These steps represented increasing levels of intensification. Except at the lowest level (step 1), agronomic and economic responses improved with increasing levels of inputs. Relative to the very high and increasing gross margin, production costs were low but slowly increased with increasing levels of inputs. Except at the lowest level, the value cost ratio was above 4 even at the highest levels of inputs, demonstrating that such kind of intensification can be achieved with low risk. Likewise, the fertilizer use efficiency was quite high even at the highest of levels of inputs signifying the efficiency of the pocket application of fertilizer through the microdosing method. The improvement in maize establishment and yield and the reduction in the days to maturity could contribute to make maize production more adaptive to the existing seasonal rainfall variability. Depending on the affordability to the external inputs and their feasibilities, the different technology packages in the intensification ladder may give different choices for the farmers to improve maize production in the CRV of Ethiopia.

The objectives and management policy of an experimental farm for studies on the sugar beet crop are described. Farm yields of sugar beet and cereals are discussed in relation to yields in experiments and on a national scale. Some aspects of experimental accuracy and design are considered.

Cowpea is an important supplement to the staple diet of maize in Zimbabwe, but its productivity is poor beacuse of pest infestations. This paper reports the results of experiments conducted over two crop seasons on the feasibility of producing a grain crop of cowpea intercropped with cotton to take advantage of cotton's slow initial growth and of drift from insecticides applied to it. Intercropping reduced the yield of cotton by between 11.5 and 73% depending on the type of season and the treatments applied, but the reduction was compensated by the yield of cowpea. The yield reduction was greater in the drier first season and with simultaneous planting of the two crops. Cowpea consistently performed better as an intercrop than as a sole crop, mainly because of the protection it received from the insecticides applied to the cotton.

Remote sensors permit forecasting the nutrient status and yields in crops of economic importance in Colombia. The objective of this study was to determine the relationships between normalized difference vegetation index (NDVI) and yield as well as concentrations of ${\rm {N - NO}}_3^ - $ and K+ in stem sap of potato cultivars Diacol Capiro and Pastusa Suprema (Solanum tuberosum L., Group Andigenum) in relation to different fertilizer rates. Increasing doses (0, 1450, 1900 and 2375 kg ha–1) of macro- and micronutrient fertilizers were applied to determine NDVI behavior at 55, 75, 100, 125 and 150 days after planting. For Capiro, significant differences in NDVI readings (0.84–0.88) were found between phenological stages. In both cultivars, NDVI correlated positively with yield and K+ concentrations in stem sap during tuber filling and maturation, while in Capiro no correlation was established between NDVI values and ${\rm {N - NO}}_3^ - $ concentrations in stem sap. The NDVI readings could be used to forecast productivity and K status in potato Group Andigenum.

In a 3-year field study with mustard (Brassica juncea L.) on deep well-drained sandy loam and loamy sand soils, 11 post-sowing irrigation schedules based on pan evaporation and growth stages were compared. One irrigation three weeks after sowing gave maximum grain yield and water use efficiency, increasing yield 40% in 1973–74 and 30% in 1976–77 compared with no irrigation. The total water use in this treatment averaged 31·2 cm, of which 15·8 cm was extracted from the 0–180 cm soil profile. Use of soil water by the crop decreased with the amount of post-sowing irrigation. More than one post-sowing irrigation tended to decrease yield and water use efficiency.

Hybrids made for the first time on six experimental photosensitive sorghum seed parents (whose breeding is described) were tested with their pollen parents, which included good dwarf varieties, in replicated small plot trials at Samaru in 1972. Grain yields of up to 5000 kg./ha. were recorded from hybrids with acceptable plant types and grain qualities, which was 40 per cent more than from the best varieties. Some hybrids, though giving over 6000 kg./ha., were unacceptable due to excessive plant height or poor grain appearance. Seed parent yields, determined in an adjacent trial, ranged from 1700 to 2900 kg./ha.

The effect of fungicides on the development of powdery mildews on cucumber and okra was studied. Most of the chemicals tested controlled the disease and significantly increased yields, though a dimethirimol-resistant Oidium sp. appeared on okra. Seed dressing with the systemic fungicides thiophanate and benomyl conferred resistance to the disease for a few days whereas soil application gave protection for more than eleven weeks.

The choice of an appropriate cropping system is critical to maintaining or enhancing agricultural sustainability. Yield, profitability and water use efficiency are important factors for determining suitability of cropping systems in hot arid region. In a two-year field experiment (2009/10–2010/11) on loam sandy soils of Bikaner, India, the production potential, profitability and water use efficiency (WUE) of five cropping systems (groundnut–wheat, groundnut–isabgol, groundnut–chickpea, cluster bean–wheat and mung bean–wheat) each at six nutrient application rate (NAR) i.e. 0, 25, 50, 75, 100% recommended dose of N and P (NP) and 100% NP + S were evaluated. The cropping systems varied significantly in terms of productivity, profitability and WUEs. Averaged across nutrient application regimes, groundnut–wheat rotation gave 300–1620 kg ha−1 and 957–3365 kg ha−1 higher grain and biomass yields, respectively, than other cropping systems. The mean annual net returns were highest for the mung bean–wheat system, which returned 32–57% higher net return than other cropping systems. The mung bean–wheat and cluster bean–wheat systems had higher WUE in terms of yields than other cropping systems. The mung bean–wheat system recorded 35–63% higher WUE in monetary terms compared with other systems. Nutrients application improved yields, profit and WUEs of cropping systems. Averaged across years and cropping systems, the application of 100% NP improved grain yields, returns and WUE by 1.7, 3.9 and 1.6 times than no application of nutrients. The results suggest that the profitability and WUEs of crop production in this hot arid environment can be improved, compared with groundnut–wheat cropping, by substituting groundnut by mung bean and nutrients application.

Food security under smallholder farming can be improved through innovative intensification of cropping systems. Maize (Zea mays L.) – mungbean (Vigna radiata (L.) Wilczek) – common bean (Phaseolus vulgaris L.) sequential intercropping was studied to evaluate the patterns of radiation capture and radiation use efficiency and to determine the effects of leaf removal and row orientation on performance and intercropping efficiency. Sequential intercropping captured 1039 MJ m−2 photosynthetically active radiation (PAR) accounting for 70% of incident seasonal PAR. The corresponding sole stands for maize captured 41%, mungbean 29%, common bean 34% and mungbean–common bean 63%. Intercropped components had interception ratios of 0.98, 0.31 and 0.61 for maize, mungbean and common bean, respectively. Associated maize used intercepted light with similar efficiency, mungbean with greater efficiency and common bean with lesser efficiency compared to sole crops. Maize leaf removal and row orientation had no significant effect on performance and partial land equivalent ratio (LER) of maize. Leaf removal under East–West (EW) orientation increased grain yield by 96%, total biomass by 63%, partial LER by 92%, in common bean and total LER by 7%. Leaf removal also improved grain yield, biomass yield, partial LER, in common bean and total LER during the wetter year of 2013. Similarly, EW orientation was advantageous in 2013 raising total LER by 8%. Maize leaf removal and EW row orientation had synergistic effects on intercropping efficiency and economic benefit and both have exerted positive influence under favourable weather. Total LER values of 1.47 in 2013 and 1.29 in 2015 had revealed greater biological efficiency for intercropping during both years though it was more profitable in 2013. Thus, the cropping system can be adopted under timely onset of the rainy season using EW row orientation while leaf removal can also be practiced depending on weather conditions and convenience.

Phenotypic correlation coefficients of flag leaf blade length, breadth and sheath length with plant height, grain yield and its components were computed in four wheat varieties and their ten F2 crosses. Flag leaf sheath length was positively related to plant height, grain yield and its components in almost all the populations, but little or no such relation occurred with flag leaf blade length and breadth in most cases. The data suggested the possibility of selecting plants with longer flag leaf sheaths, with obvious yield advantage.

Mean yields and average trends with time are given for cotton, finger millet and groundnuts grown in a rotational experiment during the period 1936–64. The experiment, which ran for five cycles, involved a five-year rotation with three different resting periods, five types of resting cover, and farmyard manure at three levels. Yield trends differed from crop to crop, and a critical level of total soil nitrogen is suggested in partial explanation. Responses to farmyard manure in most crops increased over die years, with increasingly marked negative curvature in a pattern that showed most strongly in cotton crops immediately following the application of manure.