Questions as to which crop to grow, where, when and with what management, will be increasingly challenging for farmers in the face of a changing climate. The objective of this study was to evaluate emergence, yield and financial benefits of maize, finger millet and sorghum, planted at different dates and managed with variable soil nutrient inputs in order to develop adaptation options for stabilizing food production and income for smallholder households in the face of climate change and variability. Field experiments with maize, finger millet and sorghum were conducted in farmers’ fields in Makoni and Hwedza districts in eastern Zimbabwe for three seasons: 2009/10, 2010/11 and 2011/12. Three fertilization rates: high (90kgNha-1, 26kgPha-1, 7tha-1 manure), low (35kgNha-1, 14kgPha-1, 3tha-1 manure) and a control (zero fertilization); and three planting dates: early, normal and late, were compared. Crop emergence for the unfertilized finger millet and sorghum was 70% for the fertilized treatments. In contrast, the emergence for maize (a medium-maturity hybrid cultivar, SC635), was >80% regardless of the amount of fertilizer applied. Maize yield was greater than that of finger millet and sorghum, also in the season (2010/11) which had poor rainfall distribution. Maize yielded 5.4tha-1 compared with 3.1tha-1 for finger millet and 3.3tha-1 for sorghum for the early plantings in the 2009/10 rainfall season in Makoni, a site with relatively fertile soils. In the poorer 2010/11 season, early planted maize yielded 2.4tha-1, against 1.6tha-1 for finger millet and 0.4tha-1 for sorghum in Makoni. Similar yield trends were observed on the nutrient-depleted soils in Hwedza, although yields were less than those observed in Makoni. All crops yielded significantly more with increasing rates of fertilization when planting was done early or in what farmers considered the ‘normal window’. Crops planted early or during the normal planting window gave comparable yields that were greater than yields of late-planted crops. Water productivity for each crop planted early or during the normal window increased with increase in the amount of fertilizer applied, but differed between crop type. Maize had the highest water productivity (8.0kgdrymattermm-1ha-1) followed by sorghum (4.9kgmm-1ha-1) and then finger millet (4.6kgmm-1ha-1) when a high fertilizer rate was applied to the early-planted crop. Marginal rates of return for maize production were greater for the high fertilization rate (>50%) than for the low rate (100%) than for the high rate (<100%). Although maize yield was greater compared with finger millet, the latter had a higher content of calcium and can be stored for up to five years. The superiority of maize, in terms of yields, over finger millet and sorghum, suggests that the recommendation to substitute maize with small grains may not be a robust option for adaptation to increased temperatures and more frequent droughts likely to be experienced in Zimbabwe and other parts of southern Africa.
Tag: crop yield
Effect of spatial variability of Nitrogen supply on environmentally acceptable Nitrogen fertilizer application rates to arrable crops
Current N recommendation schemes are based on the Maximum Economic Yield (MEY), as obtained at “economic optimum’ fertilizer application rates. Environmental standards for the amount of mineral N left in the soil at harvest time will soon restrict fertilizer rates to obtain an Environmentally Acceptable Production (EAP). For MEY, but especially for EAP, spatial variability of N supply in a field which is managed as if it were a homogeneous unit should be taken into account. Degree of spatial variability in N supply should be explicitly taken into account in future discussions of the conflict between environmental and production targets.
Water consumption of tree wind break systems in Central Asia
Trees for Food Security- 2 Project in Rwanda
Rejoinder to comments on Minasny et al., 2017 soil carbon 4 per mille
Interaction Tree crop and agroforestry parkland Intermediate tree cover can maximize groundwater recharge in dry tropics
Institutional Perspectives of Climate-Smart Agriculture: A Systematic Literature Review
Climate-smart agriculture (CSA) is increasingly seen as a promising approach to feed the growing world population under climate change. The review explored how institutional perspectives are reflected in the CSA literature. In total, 137 publications were analyzed using institutional analysis framework, of which 55.5% make specific reference to institutional dimensions. While the CSA concept encompasses three pillars (productivity, adaptation, and mitigation), the literature has hardly addressed them in an integrated way. The development status of study sites also seems to influence which pillars are promoted. Mitigation was predominantly addressed in high-income countries, while productivity and adaptation were priorities for middle and low-income countries. Interest in institutional aspects has been gradual in the CSA literature. It has largely focused on knowledge infrastructure, market structure, and hard institutional aspects. There has been less attention to understand whether investments in physical infrastructure and actors’ interaction, or how historical, political, and social context may influence the uptake of CSA options. Rethinking the approach to promoting CSA technologies by integrating technology packages and institutional enabling factors can provide potential opportunities for effective scaling of CSA options.
Potential economic benefits of modifications to urea that increase yield through reduction in nitrogen losses
Many modifications to urea such as inhibitors, algicides, soluble salts, and acidifying agents have been proposed to overcome losses of urea-N, but little is known about the potential economic benefits and acceptable farm-level prices for modified urea. The objective of this study was to develop and use a method for estimating the potential economic benefits of modifications to urea that reduce N losses and enhance crop yields. The method is applicable for crops with a response to N that is well represented by a quadratic model, and for modifications to urea that do not alter the maximum attainable yield with added N. The increment in profit of farmers with the use of modified urea is determined by the difference in net benefit between modified urea and conventional urea when these fertilizers are used at rates that maximize profit. The increment in profit with modified urea increased linearly with increasing saving of N from loss, decreased with the increasing cost of modifying urea, and increased as the price of conventional urea-N increased. The increased price of N for modified urea, expressed as a percentage increase over the price of conventional urea-N, must be <20% when N saving = 17% of applied N, <40% when N saving = 29% of applied N, and <80% when N saving = 44% of applied N to obtain a positive increment in profit. The results suggest that modified urea would be most economical in environments with high response of the crop to urea-N, high price of conventional urea, and high losses of urea-N that can be prevented by the urea modification
Selection for reproductive stage drought avoidance in rice using infrared thermometry
Water deficits cause major yield reductions on the world’s rainfed riceland. The most severe water deficits occur during the reproductive phase. Differences in canopy temperature among crop cultivars are known to be related to drought avoidance characters. In developing a practical field screening system for reproductive phase drought resistance in rice (Oryza sativa L.), we assessed the canopy temperature response of a range of germplasm, and related the results to other plant characters related to drought resistance. Field experiments were conducted on a silty clay loam Typic Hapludoll at the International Rice Research Institute. Planting of the test cultivars was staggered, to synchronize flowering during the water-deficit period. Canopy temperature measurements were made on 12 dates in Trial 1 and 8 dates in Trial 2. Mean canopy temperatures (Tc) increased from 28 to 37 degrees C during the stress period. Grain yield (r2 = -0.63**) and spikelet fertility (r2 = 051**) were related to midday Tc on the day of flowering. Highly significant differences were observed in canopy temperature among entries, with low coefficients of variation (2.0-2.7%). Entries with a history of outstanding vegetative stage drought screening scores consistently remained coolest under stress. Visual drought tolerance scores (r = 0.72**) and leaf rolling scores (r = 0.68**) were correlated with mean canopy temperatures under moderate water stress, but not under severe stress (r =
Sesbania tree fallows on phosphorus-deficient sites: Maize yield and financial benefit
Rotation of Sesbania sesban (L.) Merr., a fast-growing N2-fixing tree, with maize (Zea mays L.) has potential for increasing fertility of tropical soils, where fertilizer use by resource-poor farmers is limited. At two sites in Kenya (Ochinga, with a Kandiudalfic Eutrudox soil, and Muange, with a Kandic Paleustalf), we compared maize yields and financial returns for (i) sesbania grown for three or four seasons followed by three maize crops (sesbania fallow), (ii) one maize crop followed by natural regrowth of vegetation for three seasons and then three maize crops (natural fallow), and (iii) maize monoculture for seven seasons. After the fallows, plots were split with and without added P. Maize responded to P at both sites. Cumulative grain yields for seven seasons of maize monoculture were 8.4 Mg ha1 at Ochinga and 5.6 Mg ha1 at Muange. They were comparable to cumulative maize yields for sesbania fallow (Ochinga, 10.6 Mg ha1 Muange, 4.5 Mg ha1) and natural fallow (Ochinga, 7.7 Mg ha1; Muange, 4.2 Mg ha1), even though maize was grown for only three or four seasons in the fallow treatments. Sesbania fallow was financially attractive at Ochinga (500 mm rain in each season) but not at Muange, where low rainfall (<300 mm in each posffallow season) limited maize yield. Phosphorus fertilization of maize at Ochinga increased (P < 0.2) net benefit for sesbania fallow. Improved fallows have potential to supply nutrients to crops, but they are unlikely to eliminate the need for P fertilizers on P-deficient soils.