between different crops are considered to be the major safe and effective measures for alleviating soil sickness. In particular, appropriate crop rotations and intercropping, mixed intercropping, and relay intercropping are the most simple and effective
Lantian Du, Baojian Huang, Nanshan Du, Shirong Guo, Sheng Shu, and Jin Sun
W.J. Lamont, D.L. Hensley, S. Wiest, and R.E. Gaussoin
Two systems of relay-intercropping muskmelons (Cucumis melo L.) with Scotch pine (Pinus sylvestris L.) Christmas trees using black plastic mulch and drip irrigation were evaluated for their potential to improve cash return. Returns ranged from a high of $26,200/ha for plastic mulch-drip irrigation and a selling price of $l.00/melon to a low of $6900/ha for bare ground-drip irrigation and a selling price of $0.40/melon. The benefit-cost index ranged from 24 to 3.4, depending on the system evaluated. Pine growth apparently was impeded by plastic mulch; however, increased yields of melons grown under plastic mulch may offset the slight decrease in pine growth.
Steven J. Guldan, Charles A. Martin, and Constance L. Falk
`Sugar Snap' snap peas (Pisum sativum L.) were interseeded into a stand of `Española Improved' chile pepper (Capsicum annuum L.) in July or Aug. in 1995, 1996, and 1997. Peas were interseeded as one or two rows per bed, giving planting rates of about 92 or 184 kg·ha-1, respectively. Our objectives were to determine: 1) if intercropped pea would reduce chile yield and vice versa; 2) the effects of pea planting rates and dates on pea yield. Intercropped peas reduced chile yield by about 22% in 1995, but had no significant effects in other years. Pea plants from the August intercrops reached the flowering stage but did not produce pods in 1995 or 1996; some small pods were produced from August intercrops in 1997. Final plant densities were lower and less uniform in 1996 than in 1995 or 1997. Intercropped peas yielded less than monocropped peas in all years. Pea yields ranged from 1370 to 3960 kg·ha-1 when monocropped, 31 kg·ha-1 (1996 single-row) to 646 kg·ha-1 (1995 double-row) when intercropped. In 1995 only, the double-row intercrop yielded more peas than the single-row intercrop. Pod yield/plant was reduced 80%, 98%, and 96% in 1995, 1996, and 1997, respectively, by intercropping. Estimated gross revenues for the treatments indicate that, under the price assumptions used in the study, interseeding snap peas into stands of chile in north-central New Mexico is not economically advantageous compared with monocropped chile.
Steven J. Guldan, Charles A. Martin, Jose Cueto-Wong, and Robert L. Steiner
Three legumes [hairy vetch (Vicia villosa Roth.), barrel medic (Medicago truncatula Gaerth.), and black lentil (Lens culinaris Medik.)] were interseeded into `New Mexico 6-4' chile pepper (Capsicum annuum L.) when plants were 20–30 cm tall (3 Aug., “early” interseeding) or when plants were 30–40 cm tall (16–17 Aug., “late” interseeding) in 1993 and 1994. Our objectives were to determine the effect of legume interseeding on cumulative chile yield, and late-season dry-matter and nitrogen yields of aboveground portions of the legumes. Legumes were harvested on 8 Nov. 1993 and 15 Nov. 1994. Chile yield was not significantly affected by legume interseeding. In 1993, legumes accumulated 57% more dry matter and 55% more N when interseeded 3 Aug. vs. 16 Aug. In 1994, legumes accumulated 91% more dry matter and 86% more N when interseeded 3 Aug. vs. 17 Aug. Aboveground dry-matter yields in 1993 ranged from 1350 kg·ha–1 for black lentil interseeded late to 3370 kg·ha–1 for hairy vetch interseeded early. Nitrogen yields ranged from 52 kg·ha–1 for black lentil interseeded late to 136 kg·ha–1 for hairy vetch interseeded early. In 1994, hairy vetch was the highest yielding legume with dry matter at 1810 kg·ha–1 and N at 56 kg·ha–1 interseeded early, while black lentil yielded the lowest with dry matter at 504 kg·ha–1 and N at 17 kg·ha–1 interseeded late. In the spring following each interseeding year, we observed that hairy vetch had overwintered well, whereas barrel medic and black lentil had not, except when a few plants of barrel medic survived the winter of 1994–95. Results from this study indicate that legumes can be successfully interseeded into chile in the high-desert region of the southwestern United States without a significant decrease in chile yield.
G.D. Hoyt and J.F. Walgenbach
Conservation tillage systems provide optimum conditions to reduce soil erosion and increase surface soil organic matter. This experiment was established with the long-term goal of developing conservation tillage systems that use either chemical inputs to produce vegetables and control pests, or legume cover crops, biological pesticides, and tillage to provide plant nutrition and control pests. The experiment consisted of cabbage (Brassica oleracea var. L. Capitata Group) grown by traditional-tillage (TT) or strip-tillage (ST) culture using either chemical or organic production methods for pest control. Cabbage heads were heavier with TT than with ST for the chemical production system. Although weed biomass was significantly higher with organic methods, there was a poor relationship between weed biomass at harvest and cabbage head weight. The lack of differences in lepidopterous pest damage suggests that the conservation tillage systems examined likely would not affect lepidopterous pest management systems using biological insecticides. Within tillage treatments, the organic production system resulted in less Alternaria infection than did the chemical production system. Since no fungicides were applied on any treatment, lower disease ratings in the organic production system may have been the result of reduced soil contact of the cabbage leaves from the increased soil coverage by the weed and intercropped legume canopy.
Steven J. Guldan, Charles A. Martin, Jose Cueto-Wong, and Robert L. Steiner
Five legumes [hairy vetch (Vicia villosa Roth.), barrel medic (Medicago truncatula Gaerth.), alfalfa (Medicago sativa L.), black lentil (Lens culinaris Medik.), and red clover (Trifolium pratense L.)] were interseeded into sweet corn (Zea mays L.) at last cultivation when sweet corn was at about the V9 (early) or blister (late) stage. The effect of legume interseeding on sweet corn yield, and late-season dry-matter and N yields of aboveground portions of the legumes was determined. Sweet corn yield was not affected by legume interseeding. In 1993, legume dry-matter yields were 1420 kg·ha–1 interseeded early and 852 kg·ha–1 interseeded late. Nitrogen yields were 49 kg·ha–1 interseeded early and 33 kg·ha–1 interseeded late. In 1994, dry-matter yields were 2760 kg·ha–1 interseeded early and 1600 kg·ha–1 interseeded late. Nitrogen yields were 83 kg·ha–1 interseeded early and 50 kg·ha–1 interseeded late. In 1993, barrel medic was the highest-yielding legume with dry matter at 2420 kg·ha–1 and N at 72 kg·ha–1 interseeded early, while red clover yielded the lowest with dry matter at 340 kg·ha–1 and N at 12 kg·ha–1 interseeded late. In 1994, dry-matter and N yields ranged from 4500 and 131 kg·ha–1, respectively, for early interseeded barrel medic to 594 kg·ha–1 and 16 kg·ha–1, respectively, for late interseeded red clover.
R.M. Coolman and G.D. Hoyt
Plant interactions are both competitive and cooperative. Farmers use intercropping to the mutual advantage of both main and secondary crops in a multiple-crop-production system. A vegetable crop has a competitive advantage over a younger secondary cover crop interseeded before vegetable maturity. Non-legume intercropped cover crops can use soil N, while a legume intercrop can increase N in agricultural systems by biological N fixation. Intercropping also may be more efficient than monocropping in exploiting limited resources. Relay-planting main crop and intercrop components so that resource demands (nutrients, water, sunlight, etc.) occur during different periods of the growing season can be an effective means of minimizing interspecific competition. Intercropping systems often exhibit less crop damage associated with insect and plant pathogen attacks, and they provide weed control.
Steven J. Guldan, Charles A. Martin, William C. Lindemann, Jose Cueto-Wong, and Robert L. Steiner
Hairy vetch (Vicia villosa Roth.), barrel medic (Medicago truncatula Gaerth.), and black lentil (Lens culinaris Medik.) were interseeded into `New Mexico 6-4' chile pepper (Capsicum annuum L.) when plants were 8 to 12 inches tall or 12 to 16 inches tall in 1993 and 1994. Hairy vetch overwintered well both years, whereas barrel medic and black lentil did not. Spring aboveground dry mass yields of hairy vetch averaged 2.11 and 2.57 tons per acre in 1994 and 1995, respectively, while N accumulation averaged 138 and 145 pounds per acre in 1994 and 1995, respectively. Forage sorghum [Sorghum bicolor (L.) Moench] dry mass yield and N accumulation were significantly higher following hairy vetch than following the other legumes or no-legume control. There was no significant difference between forage sorghum yields following barrel medic, black lentil, or the no-legume control. Fertilizer replacement values (FRV) for the legumes were calculated from regression equations for forage sorghum dry mass yield as a function of N fertilizer rate. FRV for hairy vetch were at least 7-times higher than for either barrel medic or black lentil. Hairy vetch interseeded into chile pepper and managed as a winter annual can significantly increase the yield of a following crop compared to a nonfertilized control.
Brian A. Kahn
different times per season in New Mexico. This was an example of relay intercropping; that is, planting a second crop after an initial crop has reached maturity but before harvest is completed on the initial crop ( Coolman and Hoyt, 1993 ). Intercrops