the compost C:N ratio was 11. Table 1. Hairy vetch and compost biomass, carbon and nitrogen applied to the soil in 2016 and 2017. Soil inorganic N, and nitrate concentration in leaf petiole sap. The effect of hairy vetch and compost on soil inorganic N
Rafael A. Muchanga, Toshiyuki Hirata and Hajime Araki
Matthew J. Leavitt, Craig C. Sheaffer, Donald L. Wyse and Deborah L. Allan
-market operation. Appropriate cover crops for northern climates can depend on rotations, machinery, and desired cash crops, but much research has been focused on the use of winter rye ( Secale cereale L.) ( Singer, 2008 ; Snapp et al., 2005 ) and hairy vetch
Aref A. Abdul-Baki, John R. Stommel, Alley E. Watada, John R. Teasdale and Ronald D. Morse
Ten cultivars of processing tomatoes (Lycopersicon esculentum Mill.) grown in bare soil or on black polyethylene and hairy vetch (Vicia villosa Roth.) mulches were evaluated for yield, fruit processing quality, and leaf necrosis. Yields were higher, fruit was heavier, and leaf necrosis less in hairy vetch than in bare soil or black polyethylene mulch. With the exception of pH, yield and fruit quality component responses to mulch treatments were not cultivar-dependent. Fruit pH, soluble solids concentration, and color equaled values obtained using bare soil production practices. Percent solids was highest with black polyethylene and lowest in hairy vetch. The hairy vetch mulch delayed fruit maturity compared to the bare soil and black polyethylene. The hairy vetch cultural system has the potential to increase yield of processing tomatoes.
John R. Teasdale and Aref A. Abdul-Baki
Growth analysis was used to document growth responses of staked, fresh-market tomatoes (Lycopersicon esculentum Mill.) to black polyethylene or hairy vetch (Vicia villosa Roth) mulches. Leaf area and dry mass of vegetation and fruit were measured weekly during two growing seasons. Growth was better early in the season but worse later in the season for plants grown with black polyethylene than with hairy vetch mulch. Unit leaf rate (rate of growth per unit leaf area) of fruit was higher with black polyethylene than with hairy vetch, whereas the reverse was true of vegetation. This relationship led to a higher leaf area ratio and leaf area duration of plants grown with hairy vetch than with black polyethylene. Consequently, tomatoes grown with black polyethylene produced higher early yield because of increased partitioning to fruit. However, tomatoes grown with hairy vetch eventually outgrew and outyielded those grown with black polyethylene because of increased partitioning to leaf area.
Aref A. Abdul-Baki, John R. Teasdale and Ronald F. Korcak
A 3-year experiment was conducted to determine the optimum fertilizer N requirements of fresh-market tomato (Lycopersicon esculentum Mill.) `Sunbeam' grown on a hairy vetch (Vicia villosa Roth.) or black polyethylene mulch. In 1993 and 1994, four rates of fertilizer N (0, 56, 112, and 168 kg·ha-1) as water-soluble NH4NO3 were applied in 14 equal applications through the trickle irrigation system starting 1 week after planting. Four additional rates (224, 280, 336, and 392 kg·ha-1) were applied in 1995 to assess the plant response to supra-optimal levels of N. Hairy vetch produced 3.3–4.5 t·ha-1 of above-ground biomass and a total N content of 126–169 kg·ha-1 in the above-ground biomass. Leaf N content at 7 weeks after transplanting of tomatoes correlated positively with yield from black polyethylene but did not correlate with yield from the hairy vetch plots where leaf N content was optimal at all N rates. Predicted tomato yields were higher for the hairy vetch than for the black polyethylene treatment at all applied N rates in all years. Tomatoes grown in black polyethylene required N at 130 to 144 kg·ha-1 to achieve yields equivalent to those grown following unfertilized hairy vetch. Tomato yield increased in response to applied N in both mulches in all 3 years; optimum N rates of 89 and 190 kg·ha-1 in hairy vetch and black polyethylene, respectively, were predicted by a linear plateau model, and 124 and 295 kg·ha-1 by a quadratic plateau model. The linear plateau model is recommended because it would allow less N to become available for runoff and leaching.
John R. Teasdale and Aref A. Abdul-Baki
Temperature and root length at selected locations within a raised bed under black polyethylene, hairy vetch (Vicia villosa Roth) residue, or bare soil were measured and correlated with tomato (Lycopersicon esculentum Mill.) growth. Early in the season, before the tomato leaf canopy closed, soil temperature was influenced more by vertical depth in the bed than by horizontal position across the bed. Maximum soil temperatures under black polyethylene averaged 5.7 and 3.4C greater than those under hairy vetch at 5 and 15 cm deep, respectively. More hours at optimum temperatures for root growth (20 to 30C) during the first 4 weeks of the season probably accounted for greater early root and shoot growth and greater early yield of tomatoes grown with black polyethylene than hairy vetch residue or bare soil. After canopy closure, soil temperatures under tomato foliage within the row were reduced by an average of 5.2 and 2.2C at 5 and 15 cm deep, respectively, compared to those on the outer edge of the beds. Most tomato roots were in areas of the bed covered by the tomato canopy where temperatures in all treatments remained in the optimum 20 to 30C range almost continuously. Soil temperature, therefore, did not explain why tomato plants in the hairy vetch treatment had equal or higher total yields than the black polyethylene or unmulched treatments.
Aref A. Abdul-Baki and John R. Teasdale
Nitrogen requirements by fresh-market field tomatoes (Lycopersicon esculentum Mill.) were determined on plants grown in a hairy vetch mulch (HVM) or in black polyethylene mulch (BPM). Nitrogen treatments were 0, 56, 112, and 168 kg/ha delivered weekly through the trickle system. Yields in BPM increased significantly with higher applications of nitrogen from 54 to 91 tons/ha and chlorophyll content of fully expanded leaves increased from 7.8 to 11.3 OD664 per 100 mg fresh weight. In contrast, neither yield nor chlorophyll content of leaves increased significantly by adding nitrogen. The 0 nitrogen treatment in HVM yielded 89 ton/ha and chlorophyll content was 13.5 OD664 making it equivalent to those in BPM that had received 168 kg nitrogen/ha. The results suggest that hairy vetch can provide all the nitrogen required by the subsequent tomato crop and produces high yields and vigorous plants.
Aref A. Abdul-Baki and John R. Teasdale
A 3-year study was conducted at the Beltsville Agricultural Research Center, Beltsville, Md., to evaluate plant stand, growth, and yield of snap bean (Phaseolus vulgaris L.) cultivars Carlo and Matador grown with conventional tillage (CT) or with no-tillage hairy vetch (Vicia villosa Roth) (HV) mulch. Plant stand and dry mass of both cultivars in CT were similar to those in no-till HV. However, leaf area and yield with no-till HV were significantly higher than those with CT.
Erin C. Hill, Mathieu Ngouajio and Muraleedharan G. Nair
Laboratory experiments were conducted to study the effect of aqueous extracts of hairy vetch (Vicia villosa Roth) and cowpea (Vigna unguiculata (L.) Walp) cover crops on germination and radicle elongation in seven vegetable and six weed species. Lyophilized aqueous extracts of the cover crops were dissolved in reverse osmosis (RO) water to produce seven concentrations: 0.00, 0.25, 0.50, 1.00, 2.00, 4.00, and 8.00 g·L–1. Each treatment had 4 replications and the full experiment was repeated. Experiment 1 (E1) and Experiment (E2) were conducted under similar conditions. In general, seed germination was not affected by extracts of both cover crops. However, radicle growth of all species tested (except common milkweed exposed to cowpea extract) was affected by the cover crop residue extracts. Low concentrations of hairy vetch extract stimulated the radicle growth of carrot, pepper, barnyardgrass, common milkweed, and velvetleaf. Likewise, low concentrations of cowpea extract stimulated the growth of corn, barnyardgrass, and velvetleaf. At higher concentrations all species tested were negatively affected. The order of species sensitivity to the hairy vetch extract, as determined by the IC50 (concentration required to produce 50% radicle inhibition) values, was common chickweed > redroot pigweed> barnyardgrass E1 > carrot E1 > wild carrot > corn > carrot E2 > lettuce > common milkweed > tomato > onion > barnyardgrass E2 > velvetleaf > pepper > cucumber (most sensitive to least sensitive). For cowpea the order was common chickweed > redroot pigweed > corn > tomato > lettuce > wild carrot > pepper > carrot > cucumber > onion> barnyardgrass and velvetleaf. Results suggest that the susceptibility of weeds and vegetable crops to aqueous extracts of hairy vetch and cowpea is dependent on both species and extract concentration.
Pumpkin is usually grown on bare ground. Weeds are controlled by pre-emergence herbicides and cultivation early in the season before pumpkin vines cover the ground. The pumpkin fruit lie on bare ground and covered with soil. In pick-your-own pumpkin operation it is impossible to walk on muddy fields to pick pumpkin fruits. Experiment was carried out using three treatments (Control-bare ground, Rye only mulch, and rye/hairy vetch mulch) replicated four times in complete randomized block design with plot sizes of 30 ft (9 m) by 30 ft (9 m). In each plot, two pumpkin rows were planted 8 ft (2.4 m) a part and 2 ft (0.6 m) a part within rows. In rye only, and rye/hairy vetch plots, two 2-ft wide strips 8-ft a part were mowed and rototilled in each plot. Cover crop in between the rows were rolled using a multi-culchler roller, and emergence of eastern black night shade (Solanum phytanthum Dun.), red root pig weed (Amaranthus retroflexus L.), and common lambsquarters (Chenopodium album L.) on cover crop plots between the rows were evaluated 4-10 weeks after transplanting. The effect of cover mulches on pumpkin fruit number, yield, fruit size, and fruit rots were assessed as well. Emergence of red root pigweed, black nightshade, and common lambsquarters was less than 2, 1, and 1/2 seedlings per 12-ft-2 (1-m-2) area respectively. There was no significant difference in marketable fruit number between control and strip tilled plots. Control plots had higher pumpkin fruit weight than rye/hairy vetch plots, and no significant difference between rye only and rye/hairy vetch plots. Control plots had significantly larger fruits and higher fruit rot incidence than strip tilled plots.