• Authors:
    • Xue, X.
    • Chen, G.
    • Hu, Y.
    • Ren, C.
    • Eneji, A.
    • Islam, M.
  • Source: Journal of Agriculture, Biotechnology and Ecology
  • Volume: 3
  • Issue: 3
  • Year: 2010
  • Summary: Oat is an important grain and forage crop and is now being cultivated as a promising forage crop in northern China. Increased land degradation and shortage of forage resources for animal production over-winter have accentuated the need for alternative cropping systems in arid regions of northern China (
  • Authors:
    • Fernandez-Quintanilla, C.
    • Izquierdo, J.
  • Source: Agrociencia
  • Volume: 44
  • Issue: 1
  • Year: 2010
  • Summary: Lolium rigidum is a major grass weed of winter cereals in the Mediterranean area, in spite of the continuous use of herbicides in these crops. New management approaches focus on the reduction of the seed banks by enhancing crop competitiveness and, consequently, minimizing weed seed rain. However, the spatial heterogeneity that exists within fields results in differences in the growth and the competitiveness of crops and weeds. In order to determine if the competitive interactions between barley and L. rigidum are site-specific biomass and seed production of this weed, growing in monoculture (plots with L. rigidum) and in mixed culture (plots with L. rigidum+barley), were studied at three sites (in upland, mid-slope and lowland positions) within barley fields. In each site were determined weed populations, and in soil separates, nutrient content, organic matter, slope and orientation were determined for each site. Crop presence significantly reduced weed biomass between 5 and 79% and seeds per spike between 10 and 48%, depending on the site. The competitive effect of the crop was greater in the more fertile sites (with higher N, P and organic matter content). In these sites, differences in plant biomass accumulation between the weed in monoculture and the weed in mixed culture started to be significant after stem elongation. Regardless the reduction in the number of seeds per spike observed in the most fertile sites, seed rain (measured as seeds m -2) could still be very important if weed density of the site is high. The differences in the competitive interactions between barley and L. rigidum observed within the fields suggest that adequate crop husbandry practices addressed site-specifically to enhance crop competitiveness can play an important role as a mechanism to reduce L. rigidum populations over the long term.
  • Authors:
    • Chianu, J.
    • Kimetu, J.
    • Waswa, B.
    • Vanlauwe, B.
    • Kihara, J.
    • Bationo, A.
  • Source: Experimental Agriculture
  • Volume: 46
  • Issue: 1
  • Year: 2010
  • Summary: Many food production systems in sub-Saharan Africa are constrained by phosphorus (P).We hypothesized that within legume-cereal rotation systems: targeting P to the legume phase leads to higher system productivity, and that use of grain legumes leads to better economic returns than use of herbaceous legumes. Four P application regimes: (i) no P, (ii) P applied every season, (iii) P applied in season 1 only and (iv) P applied in season 2 only were tested for four seasons in three cropping systems (continuous maize, mucuna-maize rotation and soybean-maize rotation) in a split plot experiment set up in Nyabeda, western Kenya. Treatments where P was applied were better than no P treatments.While continuous cereal systems showed the need for application of P every second season, rotation systems involvingmucuna and soyabean indicated that application in one out of three seasons could be sufficient. Nitrogen fertilizer equivalence was 52 to >90 kg N ha -1 for soyabean and 37 to >90 kg N ha -1 for mucuna, depending on P fertilization and season. Analysis of marginal rates of return (MRR) showed that soybean-maize rotation with one application of P was the most economically viable option, with an MRR of at least 147% compared to other non-dominated options.
  • Authors:
    • Tittonell, P.
    • Leveque, J.
    • Sogbedji, J.
    • Guibert, H.
    • Kintche, K.
  • Source: Plant and Soil
  • Volume: 336
  • Issue: 1/2
  • Year: 2010
  • Summary: Soil degradation in the savannah-derived agroecosystems of West Africa is often associated with rapid depletion of organic carbon stocks in soils of coarse texture. Field experiments were conducted over a period of more than 30 years at two sites in semiarid Togo to test the impact of agricultural management practices on soil C stocks and crop productivity. The resulting datasets were analysed using dynamic simulation models of varying complexity, to study the impact of crop rotation, fertiliser use and crop residue management on soil C dynamics. The models were then used to calculate the size of the annual C inputs necessary to restore C stocks to thresholds that would allow positive crop responses to fertilisers under continuous cultivation. Yields of all crops declined over the 30 years irrespective of crop rotation, fertiliser use or crop residue management. Both seed-cotton and cereal grain yields with fertiliser fluctuated around 1 t ha -1 after 20 years. Rotations that included early maturing sorghum varieties provided larger C inputs to the soil through residue biomass; around 2.5 t C ha -1year -1. Soil C stocks, originally of 15 t ha -1 after woodland clearance, decreased by around 3 t ha -1 at both sites and for virtually all treatments, reaching lower equilibrium levels after 5-10 years of cultivation. Soil C dynamics were well described with a two-pool SOM model running on an annual time step, with parameter values of 0.25 for the fraction of resistant plant material (K 1), 0.15-0.20 for the decomposition rate of labile soil C (K 2) and 8-10 t C ha -1 for the fraction of stable C in the soil. Simulated addition of organic matter to the soil 30 years after woodland clearance indicated that additions of 3 t C ha -1year -1 for 15-20 years would be necessary to build 'threshold' soil C stocks of around 13 t ha -1, compatible with positive crop response to fertiliser. The simulated soil C increases of 0.5 to 1.6% per year are comparable with results from long-term experiments in the region. However, the amounts of organic matter necessary to build these soil C stocks are not readily available to resource-poor farmers. These experimental results question the assumption that crop residue removal and lack of fertiliser input are responsible for soil C decline in these soils. Even when residues were incorporated and fertilisers used at high rates, crop C inputs were insufficient to compensate for C losses from these sandy soils under continuous cultivation.
  • Authors:
    • Zombre, P.
    • Dakuo, D.
    • Traore, O.
    • Koulibaly, B.
    • Bonde, D.
  • Source: Tropicultura
  • Volume: 28
  • Issue: 3
  • Year: 2010
  • Summary: The effect of crop residues management on crops yields and nutrients balances in a cotton-cereals cropping system was studied in a long-term experiment carried out from 1982 to 2006. The experimental design was a simple nonrandomized blocks comparing extensive management of crops residues (T1), semiintensive management of crops residues (T2) and intensive management of crops residues (T3). Crops yields, soil chemical properties and mineral balances were measured. Results showed that after 25 years, soil carbon contents decrease was respectively 44%, 15% and 13%, with an extensive, semi-intensive and intensive management of crops residues. Total phosphorus decrease was 25% in all the treatments. Exchangeable Ca and Mg declined from 2.43 to 1.37 cmol+ kg -1 and 0.9 to 0.29 cmol+ kg -1 respectively while the Sum of Exchangeable Bases declined from 3.79 to 1.79 cmol+ kg -1. Recycling crops residues to compost and manure increased cotton yields from 13 to 22%, maize yields from 45 to 60%, and sorghum yields from 19 to 44%. Mineral balance in N, P, K and S was improved after 25 years of continuous cultivation while using compost or manure. At the same time, the decline of soil properties was due to nutrients losses which need to be evaluated. This study recommends integrated crops residues management and the use of rock phosphate to improve sustainability in cottoncereals cropping systems.
  • Authors:
    • Li, L.
    • Du, F.
    • Zhang, F.
    • Zhang, W.
    • Li, H.
  • Source: Plant Nutrition and Fertilizer Science
  • Volume: 16
  • Issue: 5
  • Year: 2010
  • Summary: Since 2004, China has significantly increased its grain production due to the impetus of strong policy support from the government, including soil testing and fertilizer recommendation. This paper analyzes the changes in fertilizer efficiency in China's grain production systems by comparing the farmers' practice in 2008 and 2001. In the period investigated, chemical fertilizer application rate increased by 5.4% and 29.0% in wheat and maize production, respectively, and decreased by 4.3% in rice cultivation. Total fertilizer consumption increased by 1.3 * 10 6 t on grain crops, but its proportion decreased from 68% to 50% in the total chemical fertilizer consumption of the country. PFP (partial factor productivity, i.e. grain yield divided by the amount fertilizer), used to represent the fertilizer use efficiency of rice, was higher than that of wheat and maize. The PFP of wheat and rice increased from 10.6 kg/kg to 11.9 kg/kg and from 13.9 kg/kg to 15.7 kg/kg, respectively, and that of maize decreased from 13.8 kg/kg to 11.5 kg/kg. The change of planting structure had a strong impact on fertilizer application. The concentration of the production of main cereal crops to the areas with advantageous conditions is believed to be good to the improvement of fertilizer efficiency of cereal crops. On the other hand,the continuous increase in the cultivation area of economic crops will bring additional variables to the changing trend of fertilizer efficiency in China.
  • Authors:
    • Gamzatov, I.
    • Muslimov, M.
  • Source: Kormoproizvodstvo
  • Issue: 12
  • Year: 2010
  • Summary: Continuous green fodder conveyor production system allows quality fodder supply during the grazing season. Field trials were conducted in Dagestan, the North Caucasus, Russia, with Red Steppe cattle. Data are tabulated on sowing dates and period of use of fodder crops, i.e. natural pastures, winter rape, winter rye + winter vetch, pea-oat + vetch-oat, regrowth of perennial grasses after hay cutting, Sudan grass, maize and maize + Sudan grass, sorghum, regrowth of Sudan grass and sorghum, maize sown after winter cereals grown for green fodder, maize and sorghum grown for silage for additional feed rations, winter rye after pea + oat, squash, pumpkin, fodder watermelon and fodder beet, and regrowth of natural pastures and meadows. The importance of natural pastures and drought resistant plants, such as sorghum crops, for production of high yield of fodder in dry conditions of Dagestan is considered.
  • Authors:
    • Armstrong, R.
    • Nuttall, J.
  • Source: Australian Journal of Soil Research
  • Volume: 48
  • Issue: 2
  • Year: 2010
  • Summary: Subsoil physicochemical constraints can limit crop production on alkaline soils of south-eastern Australia. Fifteen farmer paddocks sown to a range of crops including canola, lentil, wheat, and barley in the Wimmera and Mallee of Victoria and the mid-north and Eyre Peninsula of South Australia were monitored from 2003 to 2006 to define the relationship between key abiotic/edaphic factors and crop growth. The soils were a combination of Calcarosol and Vertosol profiles, most of which had saline and sodic subsoils. There were significant correlations between EC e and Cl - ( r=0.90), ESP and B ( r=0.82), ESP and EC e ( r=0.79), and ESP and Cl - ( r=0.73). The seasons monitored had dry pre-cropping conditions and large variations in spring rainfall in the period around flowering. At sowing, the available soil water to a depth of 1.2 m (theta a) averaged 3 mm for paddocks sown to lentils, 28 mm for barley, 44 mm for wheat, and 92 mm for canola. Subsoil constraints affected canola and lentil crops but not wheat or barley. For lentil crops, yield variation was largely explained by growing season rainfall (GSR) and theta a in the shallow subsoil (0.10-0.60 m). Salinity in this soil layer affected lentil crops through reduced water extraction and decreased yields where EC e exceeded 2.2 dS/m. For canola crops, GSR and theta a in the shallow (0.10-0.60 m) and deep (0.60-1.20 m) layers were important factors explaining yield variation. Sodicity (measured as ESP) in the deep subsoil (0.80-1.00 m) reduced canola growth where ESP exceeded 16%, corresponding to a 500 kg/ha yield penalty. For cereal crops, rainfall in the month around anthesis was the most important factor explaining grain yield, due to the large variation in rainfall during October combined with the determinant nature of these crops. For wheat, theta a in the shallow subsoil (0.10-0.60 m) at sowing was also an important factor explaining yield variation. Subsoil constraints had no impact on cereal yield in this study, which is attributed to the lack of available soil water at depth, and the crops' tolerance of the physicochemical conditions encountered in the shallow subsoil, where plant-available water was more likely to occur. Continuing dry seasonal conditions may mean that the opportunity to recharge soil water in the deeper subsoil, under continuous cropping systems, is increasingly remote. Constraints in the deep subsoil are therefore likely to have reduced impact on cereals under these conditions, and it is the management of water supply, from GSR and accrued soil water, in the shallow subsoil that will be increasingly critical in determining crop yields in the future.
  • Authors:
    • Obi, M.
    • Obalum, S.
  • Source: Soil & Tillage Research
  • Volume: 108
  • Issue: 1/2
  • Year: 2010
  • Summary: Evaluation of the impact of tillage-mulch practices under different cropping systems on soil physical properties is needed in southeastern Nigeria to identify those combinations with the potential of alleviating the physical constraints of the Ultisols predominant in the area. An investigation was carried out on a sandy loam soil at Nsukka to determine the effects of no-till (NT) and conventional tillage (CT) each with bare fallow (B) and mulch cover (M) on soil physical properties under three cropping systems [sole sorghum ( Sorghum bicolor L. Moench), sole soybean ( Glycine max L. Merrill), and sorghum-soybean intercrop]. The layout was a split-plot in randomized complete block design, with the tillage systems as the main plots and the mulch practices as the sub-plots. The treatments [no-till and bare (NTB), no-till with mulch (NTM), conventional tillage and bare (CTB) and conventional tillage with mulch (CTM)] were replicated four times. The selected key parameters evaluated after two years were density of earthworm casts, soil organic matter (SOM), bulk density (BD), total porosity (TP), pore size distribution (PSD), mean weight diameter (MWD), and saturated hydraulic conductivity (K sat). Earthworm activity was significantly ( P≤0.001) higher with NT under the intercrop system. Values were generally very low for SOM (1.06-1.48%), moderate for BD (1.34-1.51 Mg m -3) and TP (46-52%), and low to moderate for MWD (1.1-2.9 mm). The K sat was within the slow to rapid range (8.1-57.0 cm h -1). Neither the tillage nor the mulch factors influenced SOM, BD, PSD, and MWD in the cropping systems. The TP was significantly ( P≤0.05) higher in the CT compared to the NT under the sole sorghum, where interaction showed higher value in the CTM compared to the rest. There was significant ( P≤0.05) enhancement of K sat in the CT under the sole sorghum and the intercrop systems; whereas the value was significantly ( P≤0.01) higher in the bare fallow under the sole soybean. The cropping systems had more pronounced effect on the physical properties than the tillage-mulch management practices. All the measured parameters indicated significant ( P≤0.05) improvements under the sole soybean, except BD and MWD which were significantly ( P≤0.05) improved under the intercrop. Intercropping cereals and legumes on NT may be ideal for alleviating the soil's structural constraints.
  • Authors:
    • Odoemenem, I.
  • Source: African Journal of Agricultural Research
  • Volume: 5
  • Issue: 9
  • Year: 2010
  • Summary: Lack of evidence on allocation and use of capital resource among small-scale cereal crop farmers of Benue state has led to a continuous depression of capital resource flow in the sub-sector. In providing this evidence, a singular, convenient and sufficient criteria for appraising the use of credit by the small-scale farmers was explored. Using 370 respondents drawn from 6 local government areas of Benue State which is acclaimed the "Food Basket of the Nation", the sources and uses of capital resources were explored. Field data were collected using structured questionnaire. The data were analyzed using simple descriptive statistics comprising frequency distribution, percentages and means, as well as multiple regression analysis. The findings of the study indicated that the cultivated farm size of the surveyed cereal crop farmers ranged between 0.5-10 ha with a mean of 3.01 ha. 84% of the surveyed farmers utilized their agricultural credits for the purchase of improved seeds, agro-chemicals and hiring of farm labour, while 16% used part of their agricultural credit for family health services and the payment of school fees. These are forms of capital accumulation for future agricultural services.