• Authors:
    • Mukhwana, E. J.
    • Norton, U.
    • Norton, J. B.
  • Source: Soil Science Society of America Journal
  • Volume: 76
  • Issue: 2
  • Year: 2012
  • Summary: Soils typically show 20 to 40% decline in soil organic carbon (SOC) due to cultivation, most of it in the first 10 yr, but studies on SOC depletion may actually underestimate losses of the original SOC. Starting 40 to 50 yr ago, expanding use of non-inversion tillage, fertilizers, and herbicides lead to reduced disturbance and increased residue production that undoubtedly began recovery of SOC depleted during previous decades when farmers used only intensive tillage to control weeds and stimulate release of nutrients from crop residues. We measured SOC and total N stocks, density fractions, and labile C and N at 10 study sites in two rain-fed production areas in southeastern Wyoming. Systems evaluated include historic inversion-tillage-based winter wheat ( Triticum aestivum L.)-fallow with no inputs, conventional winter wheat-fallow, minimum- and no-till continuous rotations and permanent grass cover. Results were then compared to SOC under nearby native grasslands. Soils beneath historic wheat-fallow were the most depleted in SOC, with 13.8 and 17.6 Mg C ha -1 in the upper 30 cm at the two study areas, or 37% of the SOC under the two native sites. Soil OC contents were statistically similar across conventional, minimum-till, and no-till systems, ranging from 64 to 78% of native SOC levels, and significantly higher under permanent grass, with both sites having 90% of native SOC levels. Free light fraction organic carbon (LFOC) contents were lowest beneath the historic system, but increased in systems with fewer disturbances. When normalized by SOC and total N, the labile C and N pools generally increased with increasing disturbance, especially microbial biomass carbon (MBC) and dissolved organic carbon (DOC). Soil OC contents under the historic, inversion tillage system were much lower relative to native grasslands than found in other studies, which, together with other findings, suggest that SOC levels have begun to recover under the modern conventional system. Free LFOC and labile pool C and N contents indicate that conservation tillage systems in place for a relatively short time are facilitating further recovery of SOC.
  • Authors:
    • Moriasi, D.
    • Steiner, J. L.
    • Starks, P. J.
    • Saleh, A.
    • Osei, E.
  • Source: Journal of Soil and Water Conservation
  • Volume: 67
  • Issue: 2
  • Year: 2012
  • Summary: No-till farming has been identified as an important conservation practice with potential to improve soil quality and protect water quality. However, adoption of new tillage and production practices is determined by numerous economic and noneconomic factors in addition to land stewardship. The objective of this study was to assess the effects of fuel costs and crop yield on farm-level economics in no-till systems in comparison with other tillage systems for wheat production in southwestern Oklahoma. The Farm-level Economic Model, an annual economic simulation model, was used in conjunction with survey data from the Fort Cobb Reservoir Watershed in southwestern Oklahoma to determine impacts of alternative tillage practices on farm profits. Sensitivity analysis was performed using plausible ranges in diesel prices, winter wheat grain yields, herbicide costs, labor wages, and farm size. The results indicate that if winter wheat grain yields are not significantly impacted by tillage systems, no-till would be more profitable than conventional tillage or the current mix of tillage practices in the watershed. Only when there is a significant wheat yield penalty associated with no-till (10% or greater) might no-till be less profitable than conventional tillage or the status quo at reasonably high fuel prices. In general, for each 1% improvement in wheat yields under no-till relative to conventional tillage, no-till farm profits improve by US$7 ha -1 (US$3 ac -1) on farms that produce only winter wheat and an average of US$2.50 ha -1 (US$1 ac -1) if averaged across all farms in the Fort Cobb Reservoir Watershed, including those that do not produce winter wheat. The study also finds that higher diesel prices, higher labor wages, lower herbicide costs, and smaller farm sizes are all relatively advantageous to no-till.
  • Authors:
    • Ge, Y.
    • Morgan, C. L. S.
    • Sarkhot, D. V.
    • Grunwald, S.
  • Source: Biomass and Bioenergy
  • Volume: 41
  • Year: 2012
  • Summary: Understanding and quantifying the impact of bioenergy crops on soil carbon (C) storage is an essential component of crop management. Our objectives were to (i) compare total (TC), organic (OC), and inorganic carbon (IC) storage under Cynodon dactylon (L.) Pers and the energy crop Arundo donax L. along the soil profile, and (ii) determine the effect of these crops on available soil C (measured as hot water extractable C, HC) as an indirect indicator of soil C changes. The study site was within the Rio Grande floodplain in Quemado, Texas covered by A. donax and C. dactylon. Soil samples were taken from five soil depths: 0-10, 10-20, 20-30, 30-40, and 40-50 cm at 125 locations in a 34.5 ha field; TC, IC, and HC were measured and OC was derived. In all four C pools, soils under A. donax had higher C content (volumetric C or Cv, kg m -2) than soils under C. dactylon, except for IC at the top two depths. Larger soil C storage under A. donax as compared to C. dactylon was consistent throughout the profile. The effect was most pronounced for volumetric HC content (HCv) with 43% higher amount under A. donax than C. dactylon at 0-10 cm depth. In areas, where A. donax is considered an invasive species, the available biomass can be used for bioenergy production and the higher soil carbon under A. donax can provide additional economic return in a C economy.
  • Authors:
    • Hoogmoed, W. B.
    • Oenema, O.
    • Cai D.
    • Jin, K.
    • Wu, X.
    • Zhao, Q.
    • Feng, Z.
    • Zhang, D.
    • Dai, K.
    • Wu, H.
    • Wang, X.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: Dryland farming in the dry semi-humid regions of northern China is dominated by mono-cropping systems with mainly maize ( Zea mays L.) or wheat ( Triticum aestivum), constrained by low and variable rainfall, and by improper management practices. Addressing these problems, field studies on tillage and residue management for winter wheat and spring maize were conducted at 4 sites in Linfen, Tunliu and Shouyang (Shanxi province) and Luoyang (Henan province). These studies (a.o.) explored the impacts of different tillage and residue application methods on soil physical conditions, water storage, water use, water use efficiency (WUE) and crop yields of wheat and maize. An analysis of the results of these studies is presented. Conservation tillage, comprising no-till as well as reduced tillage practices (subsoiling, deep ploughing) showed benefits which were more prominent in combination with residue application. Benefits compared to conventional tillage were found in the form of improved soil physical conditions, such as higher topsoil bulk densities but lower subsoil bulk densities. This resulted in a better water storage during the summer fallow or rainy season in winter wheat fields, and a better water conservation and soil protection in spring maize fields. Compared to conventional methods, reduced tillage gave yields around 13-16% higher in spring maize and round 9-37% higher in winter wheat. Yields under no-till were very close to those from conventional methods. Surface application of crop residue for maize was found to increase the risk for delayed seedling emergence, because of low temperatures, leading to a recommendation for incorporation of residue in combination with reduced tillage. For winter wheat, subsoiling in combination with straw mulching after harvest in summer every other two or three year, and no-till seeding is a promising practice for sandier soils and low rainfall conditions. For heavier clay loam soils, deep ploughing with straw mulching after wheat harvest in summer every other two or three year, and no-till seeding practice is recommended. For spring maize, deep ploughing with straw and fertilizers incorporation after harvest in fall, and no-till seeding practices are recommended. Subsoiling or no-till with residue mulching after harvest in fall, and no-till seeding practices in spring are also promising practices, the latter only in situations where low spring temperatures are not a problem. Continuous no-till is not recommended.
  • Authors:
    • Wei, T.
    • Cui, R.
    • Ding, R.
    • Yang, B.
    • Han, Q.
    • Liang, L.
    • Jia, Z.
    • Wang, X.
  • Source: Transactions of the Chinese Society of Agricultural Engineering
  • Volume: 28
  • Issue: 6
  • Year: 2012
  • Summary: A field experiment (2007-2010) was conducted at Weibei Dryland to determine the effects of different organic fertilizer rates on soil moisture and economic returns of maize (Zea mays L.). Organic fertilizer at rates of 0 (CK), 7500, 15 000 and 22 500 kg.hm -2 combined with the same rate of chemical fertilizer was applied into field plots. The results showed that manure treatments significantly increased soil moisture storage by 11.49%-21.63% compared with CK; high rate of manure treatment increased soil moisture storage by 9.09% than low rate of manure treatment during maize big trumpet period in the fourth year of fertilization (2010). High rate of manure treatment significantly increased the average soil moisture storage in 200 cm soil layer by 4.79%-7.65% compared with control. Medium rate of manure treatment had significantly higher average soil moisture storage in 200 cm soil layer by 6.50% than control in the fourth year of fertilization. Manure treatments significantly increased water use efficiency by 12.37%-37.55% compared with control. High and medium rates of manure treatments significantly increased water use efficiency in contrast with low rate of manure treatment. Soil conditions were no longer the major limiting factors for increasing water use efficiency with the manure application years increased. It is suggested that medium rate of manure treatment had an obvious effect on conserving moisture and increasing income of maize.
  • Authors:
    • Alldredge, J. R.
    • Long, D. S.
    • Young, F. L.
  • Source: Crop Management
  • Issue: March
  • Year: 2012
  • Summary: Growers are becoming interested in producing canola ( Brassica napus or B. rapa) in the dryland, wheat-fallow region of the Pacific Northwest. Currently, agronomic research for spring canola in this region has not been initiated. This study evaluated the effect of no-till planting methods on stand establishment, crop yield, and seed oil quantity of spring canola in Washington and Oregon in 2009 and 2010. The treatments included: double disk opener; broadcast; broadcast plus rolled; Kile opener; Cross-Slot opener; and hoe opener (at Washington only). In this study, canola establishment was generally greatest with the double disk opener and least in the broadcast or broadcast plus rolled treatments at all four site-years. Yield was least in the broadcast treatment and rolling broadcast seed increased yield only 50% of the time. In three out of four site-years, canola planted with the various no-till openers yielded higher than broadcast seed. The adoption of spring canola in the wheat-fallow region of the Pacific Northwest would improve pest management strategies, diversify markets, and increase sustainability.
  • Authors:
    • Li, F.
    • Gan, Y.
    • Li, X.
    • Si, J.
    • Xiong, Y.
    • Liu, C.
    • Jin, S.
    • Zhou, L.
  • Source: Field Crops Research
  • Volume: 126
  • Year: 2012
  • Summary: Understanding plant-soil relationships may help maximize crop productivity while maintaining and improving soil quality. Field experiments were conducted in 2006 and 2007 at the Dryland Agricultural Experimental Station of the Loess Plateau, Lanzhou University, China, to determine the effects of various ridge-furrow and plastic-mulching techniques on the growth and yield of maize ( Zea mays L.) and soil biochemical properties. Five treatments were designed: (1) flat-plot sowing without ridge-furrow mulching (CK), (2) large (80 cm) and small (40 cm) ridges alternated and fully mulched with plastic (DRM), (3) on-furrow sowing with plastic mulch applied only on the ridge at a row spacing of 60 cm and 40 cm alternatively (RM), (4) flat-plot sowing with plastic mulch at a row spacing of 60 cm and 40 cm alternatively (NM), and (5) flat-plot sowing with plastic mulch at a row spacing of 80 cm and 40 cm alternatively (WM). The results showed that film mulching enhanced soil microbial biomass; where microbial biomass carbon (MBC) in the DRM treatment reached 633 mg kg -1 at harvest in 2007, three times the MBC of the CK. The MBC:SOC ratios were 8.8%, 7.1%, 5.7% and 5.4% in DRM, RM, NM and WM, respectively. The ridge-furrow with plastic-mulching increased soil light fraction carbon (LFOC) in both years, averaging up to 1.04 g kg -1 at harvest. Underground plant biomass increased substantially in the mulching treatments, especially in DRM. Positive correlations were found between total biomass and LFOC, between MBC and LFOC, and between MBC and available phosphorus (AP), but a negative correlation between SOC and soil mineral nitrogen (MN). The carbon to phosphorus (C/P) ratio was highest in DRM among treatments, but the content of SOC, MN, and C/N ratio in DRM was lowest, suggesting that the DRM treatment strengthened the interactions between maize and soil, and that the increased content of LFOC with time provides a basis for increasing productivity in future years. In conclusion, the ridge-furrow and plastic-mulching technique brought about a challenge in maintaining soil fertility, but this technology provides a potential opportunity of substantially increasing crop yields in semiarid rainfed regions.
  • Authors:
    • Tortosa, F.
    • Villafuerte, R.
    • Barrio, I.
  • Source: Wildlife Biology
  • Volume: 18
  • Issue: 1
  • Year: 2012
  • Summary: Damage caused by wildlife foraging can lead to significant agricultural losses and the problem can be further complicated if the damage-inducing animal is a valuable resource in its own right. Provision of alternative food sources such as cover crops might be a means of reducing the damage which appears to be linked to scarcity of alternative foods in intensively-managed agroecosystems. Cover crops may provide other benefits to agroecosystems, i.e. preventing soil erosion but can potentially have some undesired consequences, i.e. water competition with the cash crop. In our study, we tested the effectiveness of cover crops in reducing the damage caused by foraging European rabbit Oryctolagus cuniculus to vineyards in a semi-arid agroecosystem in southern Spain. Experimental treatments consisted of a combination of the presence/absence of sown cover crops (70% oat Avena sativa and 30% garden vetch Vicia sativa) with/without rabbit exclusion. In the 2009 growing season, we assessed rabbit-induced damage using a browsing index on vine shoots, rabbit use of plots was estimated based on faecal pellet counts and grapevine yield was measured at harvest. Rabbits ate the cover crops, and rabbit use was highest in the plots sown with the oat and vetch cover crop. However, the effect of the presence of the cover crop on the amount of damage caused by rabbits was limited and, moreover, the presence of the cover crop had a negative effect on grapevine yield. Exclosure fences effectively reduced rabbit damage by keeping rabbit densities close to zero, but even a low rabbit number (~1 rabbit/ha) can cause significant damage. Although cover crops provided rabbitswith an alternative food source, they acted as attractants for rabbits and were not effective in reducing the damage caused to vineyards by higher rabbit numbers. Therefore, adding cover crops might not be an effective measure in controlling rabbit-induced damage in semi-arid wine-growing regions.
  • Authors:
    • Khan, M.
    • Said, G.
    • Khan, M.
    • Khan, S.
    • Inayat, U.
    • Khalid, U.
  • Source: Journal of Integrative Agriculture
  • Volume: 11
  • Issue: 6
  • Year: 2012
  • Summary: Conservational tillage (CT) in combination with broad spectrum herbicide may be more efficient and economical in controlling weeds, reducing cost of cultivation, and enhancing wheat yield. Field experiments were carried out to evaluate the effect of tillage and herbicides on weeds and wheat yield under rice-wheat cropping system (RWCS). The results indicated that broad spectrum herbicides particularly, carfentrazone ethyl ester+isoproturon (Affinity 50 WDG) reduced weeds density by 93 and 95% compared to control and also produced the maximum grain yield (6818 and 6996 kg ha -1) and HI (harvest index, 44.7 and 44.6%) in 2007-2008 and 2008-2009 growing seasons, respectively. The maximum weeds infestation and the lowest yield were recorded in control. Tillage methods significantly influenced grain yield and HI, while no significant effect on all other parameters. The overall mean yield was significantly higher in zero tillage (5575 kg ha -1) and reduced tillage (5584 kg ha -1) compared to CT (5479 kg ha -1). Besides increasing wheat yield, Affinity 50 WDG and zero tillage are important weed management practices that can be integrated into wheat production in RWCS. However, in case of perennial weeds or insect pests' infestation, CT in combination with Affinity 50 WDG would be more productive than conservation tillage.
  • Authors:
    • Khan, M.
    • Said, G.
    • Inayatullah, A.
    • Khan, S.
    • Khalid, U.
    • Aziz-ur-Rehman
    • Khan, M.
  • Source: Philippine Agricultural Scientist
  • Volume: 95
  • Issue: 2
  • Year: 2012
  • Summary: Conservation tillage practices with an appropriate seed rate recover the declining wheat ( Triticum aestivum L.) yield and soil quality using conventional tillage in poorly drained silty clay soil (calcareous, hyperthermic and Typic Torrifluvents) in rice-wheat cropping system. Field experiments were conducted for 2 consecutive yr to study the impact of three tillage techniques [zero (ZT), reduced (RT) and conventional tillage (CT)] and four seed rates viz. 70, 100, 130 and 160 kg ha -1 on wheat yield, soil organic matter and total soil nitrogen in rice-wheat cropping system in northwestern Pakistan. Mean values for tillage revealed that conservation tillage (ZT and RT) resulted in higher spikes per m 2, biological yield, grain yield, soil organic matter and total soil nitrogen compared with CT. Mean values for seed rates displayed the highest yield and yield components at 130 kg ha -1 and showed the lowest values at 70 kg ha -1 seed rate. The results revealed that ZT/RT in combination with 130 kg ha -1 seed rate produced higher grain yield compared with CT in the first growing season. In contrast, CT in combination with 130 kg ha -1 seed rate gave the highest grain yield in the second growing season. The results emphasized the necessity of using 130 kg ha -1 seed rate in ZT for improving soil organic matter and total soil nitrogen, and sustaining wheat yield in poorly drained silty clay soil. However, in case of severe infestation with weeds or insect pests, CT in combination with 130 kg ha -1seed rate may be the best alternative.