Search Results
( Yn ) and crop residue N ( Vn ) ( Table 5 ). Thus, regardless of the quantity or timing of N fertilizer, N content in the cucumber plant, expressed as kg·ha −1 , was not different. Moreover, the partitioning of N and biomass between vegetative and
composition, especially C:N ratio of the different ley species; 2) the amount of N and the chemical composition of other crop residues such as red beet foliage that can be used in biogas production; 3) the net mineralization of N from crop residues; 4) the
have a negative impact on chemical, physical, and biological measures of soil quality ( Haynes and Tregurtha, 1999 ). Increasing organic matter inputs through crop residue conservation ( Lal, 1995 ), cover crops ( Snapp et al., 2005 ), and manures or
Processing tomatoes were planted on a sandy loam soil on raised beds which were prepared in a conventional method with a power bedder (PB), or with conservation tillage (CT). The CT treatments were prepared by using Glyphosate herbicide to burn-off a fall-seeded rye cover crop at either 10cm, 15cm or 30cm height. The center of the bed was tilled with a modified conservation tillage coulter caddy, prior to planting the tomatoes, to loosen the soil but leave the rye residue on the surface. Crop residue cover on the soil surface after planting the tomatoes increased from 9% in the PB treatment, to 63% with CT at 30cm. Increasing crop residue cover resulted in cooler soil temperatures during the day and warmer soil temperatures at night. Transplant survival and early growth was comparable between the tillage systems. Tomato yield was approximately 10% higher in the PB treatment than in the CT treatments. In the conservation tillage treatments, the tomato plants had lower total nitrogen concentrations in the petioles. Nitrogen immobilization by microbes in the decaying cover crop residue may have contributed to the lower petiole N concentrations, and the yield reduction.
points throughout the cash crop season; PMN was measured once at 2 weeks after cover crops were incorporated via tillage to capture short-term impacts of cover crop residue incorporation, and pH and EC once at final pepper harvest. Measures of soil N (ExN
The usefulness of cover crops for weed management in strawberries were evaluated. Wheat (Triticum aestevum L.), rye (Secale cereale L.), and crimson clover (Trifolium incarnatum L.) were grown in individual pots then killed by tillage or herbicide and followed in the same pots by plantings of bermuda grass [Cynodon dactylon (L.) Pers.], yellow nutsedge (Cyperus esculentus L.), crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.], or strawberries (Fragaria ×ananassa `Cardinal'). Rye and wheat tilled into the medium generally increased the growth of strawberries and decreased the growth of bermuda grass. Rye and wheat residues appeared to suppress growth of weeds and strawberries when the residues remained on the medium surface. Crimson clover had little affect on the growth of weeds or strawberries. Yellow nutsedge and crabgrass were not significantly affected by cover crop residues.
`Jewel' sweetpotato was no-till planted into crimson clover, wheat, or winter fallow. Then N was applied at 0, 60, or 120 kg·ha–1 in three equal applications to a sandy loam soil. Each fall the cover crop and production crop residue were plowed into the soil, beds were formed, and cover crops were planted. Plant growth of sweetpotato and cover crops increased with N rate. For the first 2 years crimson clover did not provide enough N (90 kg·ha–1) to compensate for the need for inorganic N. By year 3, crimson clover did provide sufficient N to produce yields sufficient to compensate for crop production and organic matter decomposition. Soil samples were taken to a depth of 1 m at the time of planting of the cover crop and production crop. Cover crops retained the N and reduced N movement into the subsoil.
The purpose of this study was to determine the effect of rotation and cover crop management on vegetable production. Winter rye (Secale cereale L. cv. Wheeler) and hairy vetch (Vicia villosa Roth.) were interseeded in the fall. The following spring, tomato, snapbean and cabbage were planted using reduced tillage methods (RT). The RT were to plant into a cover crop desiccated either with glyphosate or by mowing and disking, leaving cover crop residue on the soil surface. A preplant incorporated application of trifluralin was included as the control. The experiment was a split plot with four replications. In 1991, snapbean yields were affected by cover crop management; total yields of cabbage and tomato were not affected. Tomatoes ripened significantly earlier in no-till systems. However, in 1992, the greatest yields were in the conventional production system. Insect infestation of cabbage was greater on bare ground and cover crop disked plots.
Partial steam and chemical sterilization of soil rich in organic matter increased the soil nutrients, little information exists with regard to the effect of soil solarization (SS) in this regard. A study was established to determine the effects of SS in combination with wheat residue and subsequent crop residue on increased growth response (IGR) of cole crops and soil fertility for two years. SS for 90 days increased K+, P, Ca++ and Mg++ 3 times more within five months after SS. The SS effect released higher levels of total N in the soil. However, increase levels of N was lower than that required for maximum IGR of collard. The IGR of cole crops without fertilizers was higher in SS plots as compared to bare soil. The IGR of collard was evident almost two years after SS.
Our farm operations will face an array of challenges over the next decade that are increasing both in scope and intensity. Global markets, global supply, competition for water, land costs driven by the value of non-agricultural use, complexity of regulation, and consumer concern over what they perceive to be safe food are among the many challenges to farm enterprise sustainability. We will have to “contain” our soil, nutrients, crop and animal residues and production inputs within our field boundaries and in the upper layers of soil. We must do all of this while increasing productivity (achieving ever-higher nutrient and crop residue flow) and being cost-competitive. Many exciting advances are being made in engineering as well as in crop genetics. The most far-reaching, however, will be the contributions that will come from other parts of the biological revolution. The science of production ecology is helping us to better understand the myriad of biological and biogeochemical processes that we deal with daily. We are moving toward management of the genetics of pest populations. We will purposefully manage the diversity and amounts of crop residues in our fields which, in turn will control the populations of plants and animals in our soil. We will manipulate the incorporation and release of nutrients from organic fractions in our soil for containment and nutrient recycling. Our nutrient and chemical inputs will be targeted and largely supplemental rather than the direct mainstay of our production. If our production is to be a sustainable part of the landscape we must be seen to provide a high level and quality of hydrological and biodiversity services as part of our management of green space. The more advanced farms have pieces of this future in place now. Numerous examples will be presented from current research, focusing heavily on crop/soil interactions.